Research on a novel hybrid single cavity structure for cancer therapy

Research on a novel hybrid single cavity structure for cancer therapy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Research on a novel hybrid single cavity structure for cancer therapy Canyu Wang, Zeyang Zhang, Chaochao Xing, Cong Zhang, Liang Lu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5780790/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In recent decades, significant advancements have been made in accelerator technology, particularly with the hybrid single cavity (HSC). The HSC technology combines a radio frequency quadrupole (RFQ) and a drift tubes linac (DTL) within a unified interdigital H-type (IH) structure, resulting in enhanced compactness and system simplification. However, this design presents two fundamental challenges: reduced beam transmission efficiency and the concentration of electromagnetic (EM) fields at the matching section between RFQ and DTL sections. To address these issues, a novel coupled-window structure (CWS) has been devised to mitigate the effects of the EM fields. This paper explores the design and optimization of a 100 MHz HSC for high intensity carbon beam cancer therapy. The new HSC cavity is engineered to accelerate 20 mA C 6+ beams from 20 keV/u to 4 MeV/u within a distance of 4.4 m, achieving a total transmission efficiency of 91%. These outcomes are attainable through the implementation of CWS, which effectively mitigates the challenges associated with matching dynamic fields between the RFQ and DTL sections. Physical sciences/Physics/Particle physics/Theoretical particle physics Physical sciences/Physics/Techniques and instrumentation/Design synthesis and processing Hybrid single cavity Ion therapy Accelerator Electromagnetic coupling Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Introduction The hybrid single cavity (HSC) has emerged as a novel and promising acceleration structure of injectors for cancer therapy synchrotrons and it can be operated with high duty factor in certain application scenarios. Additionally, the HSC can be applied to the research on particle beam dynamics 1 . This novel approach employs a direct plasma injection scheme (DPIS) to generate high-intensity C 6+ beams using a laser ion source, the beams are accelerated subsequently with the HSC 2-5 . This method eliminates the need for a carbon foil within the system, thereby enhancing acceleration efficiency and offering substantial cost reductions. The HSC represents a groundbreaking innovation that unites an RFQ structure and a DTL structure within a single cavity. This achievement not only reduces the overall length of the accelerator but also facilitates the integration of peripheral devices for both the RFQ and DTL sections 3 . In this study, the novel HSC employs an interdigital H-type (IH) structure, which is renowned for its exceptional power efficiency at low and medium energy levels. Additionally, the alternating phase focus (APF) beam dynamics scheme is adopted to optimize the DTL section. The previous 100 MHz prototype HSC demonstrated the capability to accelerate C 6+ ion beams from 25 keV/u to 2.0 MeV/u over a distance of 1.8 m. However, the transmission efficiency of this prototype was limited to 30%. To achieve a higher transmission efficiency and fully optimize this novel approach, adjustments to the RFQ and DTL structures and the electric field ( E -field) matching at the junction between them are needed 2 . In summary, the HSC represents a novel and promising design for use in injectors for cancer therapy synchrotrons and some beam researches. The HSC offers substantial advantages in terms of efficiency and cost savings compared to conventional accelerator structures. However, to realize its full potential and maximize transmission efficiency, further optimization is necessary. To enhance transmission efficiency and beam quality, a novel HSC design has been explored. This new design comprises a 4-rods RFQ, an IH-DTL, and a coupled-window structure (CWS) connecting these two structures. Importantly, the RFQ and DTL sections have distinct diameters, which is a noteworthy and crucial characteristic of this design. The newly developed HSC is designed to accelerate 20 mA C 6+ ion beams from 20 keV/u to 4 MeV/u, with the primary objective of achieving a high transmission efficiency of 91%. The HSC-RFQ initially accelerates the C 6+ ion beams from 20 keV/u to 0.6 MeV/u, followed by continuous acceleration in the HSC-DTL, ultimately reaching 4 MeV/u. To overcome the E -field matching challenge between the HSC-RFQ and HSC-DTL, the design incorporates a coupled structure. This structure facilitates efficient energy transfer between the two sections by alleviating the concentration of electromagnetic (EM) fields in the matching area, thereby improving the performance of the new HSC. Methods Beam dynamics Beam dynamics is the key to accelerator design. For the HSC in this study, an RFQ and a DTL need to be designed separately. The RFQ section of the new HSC is designed for the acceleration of 20 mA C 6+ ion beams with a charge-to-mass ratio ( q /A) of 1/2, elevating the kinetic energy from 20 keV/u to 0.6 MeV/u. The beam dynamics design of the HSC-RFQ is calculated by RFQGen software 6 , which is a mature RFQ design software. RFQGen segments the RFQ structure into four distinct parts: a radial matching section (RMS), a shaper (SH), a gentle buncher (GB), and an accelerator (ACC). The RFQ's transmission efficiency and beam quality are influenced by focusing parameters B, modulation m, and synchronous phase 𝜙s. The HSC-DTL is devised for the acceleration of 20 mA C 6+ ion beams from 0.6 MeV/u to 4 MeV/u, with a length not exceeding 2.6 m, and it is housed within an IH cavity that employs the APF beam dynamics scheme. This design can alternately accomplish the transverse focusing and longitudinal bunching of the beams 7 , when 0<𝜙gap⩽𝜋/2, particles are focused in the transverse direction. Conversely, when −𝜋/2⩽𝜙gap⩽0, particles experience longitudinal bunching 8 . After passing through several alternating phase cells, the beams are of high quality in both the transverse and longitudinal directions. Beam dynamics calculations for the HSC-DTL are conducted utilizing the PiMLOC code 7-10 , which relies on matrix methods. This code has the capability to construct a lattice for the DTL and generate the accelerator's structure using the transport matrix, optimize the optical analysis of the structure, and provide various parameters including gap synchronous phase 𝜙s, gap voltage V , and gap length L . The Tracing function of the PiMLOC can create the 2D and 3D structure of APF-DTL, followed by the simulation of tracing particles and tracing analysis. Dynamics matching Achieving the dynamics matching between the HSC-RFQ and HSC-DTL is a pivotal challenge in the design and optimization of the new HSC. The key to solving this issue lies in the phase synchronization between these two structures, it determining whether particles undergo acceleration or deceleration within the HSC-DTL. To achieve the necessary phase synchronization, proper adjustments must be made to align the phase advance of the HSC-RFQ with that of the HSC-DTL. The new HSC has been designed with the aim of achieving a high transmission efficiency as much as possible at a beam intensity of 20 mA. Fig. 1 offers a comprehensive schematic diagram of the dynamic structure within the connecting portions of the new HSC. This illustration outlines the arrangement of the matching section and the beamline in the transitional region that connects the HSC-RFQ and HSC-DTL. In order to ensure that the beam is correctly transmitted in the matching section, the β (velocity to speed of light ratio) of the beams in the matching section must be taken into account, as well as the exit phase 𝜙 1 of the HSC-RFQ and the entrance phase 𝜙 2 of the HSC-DTL. Mathematical equations can be employed to derive the desired length L M of the matching section 11 : Furthermore, achieving the matching of the Twiss parameters between the HSC-RFQ and HSC-DTL is imperative. Since the matching section has no accelerating structure and is short, the beam is subjected to a small force, and its beam parameters change slightly. TraceWin 12, 13 can be used to calculate the parameter changes of the beam in a short interval. This software has high precision and ensures the accuracy of the simulation. RF design and multi-physics analysis Based on the calculated parameters of structures, a 3D model of the new HSC can be modeled using CST Studio Suite 14-16 . The design of various RF structures is mainly focused on the voltage ratio between the HSC-RFQ and HSC-DTL. Due to the fact that the HSC contains two different accelerating structures and each has its own beam dynamics characteristics, RF design mainly focuses on optimizing and designing the vacuum radii of these two parts. In actual situations, the selection of cavity radii is unique, the designed cavity radii must ensure that the frequency of the new HSC is 100 MHz, while guaranteeing that the simulated voltage ratio is consistent with that calculated by the beam dynamics softwares (RFQGen and PiMLOC), the equation is as follows 17-19 : In this equation, V(RFQ) is the inter-vane voltage, and V(DTL) is the total voltage of the HSC-DTL. ANSYS is utilized for performing multi-physics analyses of the new HSC, ensuring that temperature and deformation on the cavity wall remain within acceptable limits for steady operation 20, 21 . Furthermore, it verifies the compensatory capacity of the tuners to address frequency shift arising from temperature fluctuations and wall deformation variations. Results and discussion Dynamics of the HSC The new HSC will be operated in pulse mode with a duty factor of 1%. To reduce the risk of voltage breakdown 22 , 23 in the cavity during the operation, the Kilpatrick limit by a factor of 1.8 ( Epk = 11.35 MV/m @100 MHz) is set. To reduce the total length of the cavity, an inter-vane voltage of 120 kV in the HSC-RFQ has been chosen. Figure 2 (a) illustrates the essential beam dynamic parameters of the HSC-RFQ along the z direction. Extensive multi-particle dynamics simulations, employing a significant number of macroparticles (i.e., 20,000), have been conducted to accurately capture the intricate interactions between the accelerated ions and the RFQ structure. As the results show, the total vane length of the HSC-RFQ measures 1743.19 mm, and at a beam intensity of 20 mA, the transmission efficiency reaches 97.3% with an energy spread less than ± 0.02 MeV/u, indicating the effective transport and well-controlled longitudinal bunching of the beams. Together, these results unequivocally illustrate the HSC-RFQ's capability to provide high-quality ion beams, characterized by high transmission efficiency and low energy dispersion. Figure 2 (b) illustrates the final gap voltage and phase of each cell in the HSC-DTL, the HSC-DTL comprises 27 cells, including 13 longitudinal bunching gaps and 14 transverse focusing gaps. the total voltage is 8.93 MV calculated by PiMLOC, this total voltage is the sum of the voltages of the 27 gaps and can provide a maximum energy gain of 53.58 MeV for C 6+ beams, the beams can be accelerated form 0.6 MeV/u to 4 MeV/u. The transmission efficiency reaches 95.4% simulated by PiMLOC, which to some extent ensures the transmission quality of the beams. Correct beam transfer between The HSC-RFQ and HSC-DTL requires accurate parameter matching. In this design, β has been calculated to be 3.62×10 − 2 . 𝜙 1 is -20.621° calculated by RFQGen, whereas 𝜙 2 has a value of 0.235° given by PiMLOC, so the phase change between the HSC-RFQ and HSC-DTL is 20.856° according to Eq. ( 2 ), and the length L M of the matching section is 6.272 mm calculated using Eq. ( 1 ). Table 1 listed the Twiss parameters at the exit of the HSC-RFQ simulated by RFQGen and entrance of the HSC-DTL after the beam passes through the 6.272 mm matching section calculated by TraceWin. The beam is subject to a smaller transverse force, and its beam emittances is slightly increased. Due to the fact that PiMLOC can only define the beams with the Kapchinskij-Vladimirskij distribution (uniform particle distribution), in order to simplify the design of beam acceptance, the HSC-DTL entrance beam emittances are selected to be 9 times the RFQ exit RMS beam emittances, and about 98% of the particles can be accepted by the HSC-DTL, particles in the outer layer of the bunch will be considered lost. PiMLOC uses full emittance to design DTL structure, so the emittances in Table 1 are the converted full emittances. Table 1 The Twiss parameters at the exit of the HSC-RFQ and the entrance of the HSC-DTL. Parameters HSC-RFQ’s exit HSC-DTL’s entrance α ( x ) 1.62 1.47 β ( x ) [mm/mrad] 0.19 0.17 ε ( x ) [mm.mrad] 31 32 α ( y ) -1.47 -1.64 β ( y ) [mm/mrad] 0.14 0.16 ε ( y ) [mm.mrad] 31 32 α ( z ) -0.29 -0.24 β ( W ) [deg/MeV] 185.67 184.91 ε ( PW ) [MeV.deg] 3.5 3.6 Figure 3 (a) illustrates the beam transport process ( x -plane) calculated by PiMLOC-HSC. The beam loss is mainly concentrated in the range of 2800 mm ~ 3300 mm and after 4000 mm, this loss is mainly caused by the small value of β (x) and β ( y ) (less than 0.2 mm/mrad) in the Twiss parameters of the HSC-RFQ’s exit beam. Figure 3 (b) shows the phase-space distribution of beams at the outlet of the new HSC (due to resolution limitations, there are jagged edges in the image). Except for the outer particles, the distribution of other particles is still relatively concentrated. the emittance growth in the y direction is significantly greater than that in the x direction, which is mainly caused by the HSC-DTL’s entrance beam diverging in the y direction ( α ( y ) < 0). The longitudinal emittance has a long tail due to the linear effect in the beam transport process, and for the acceptance of the subsequent accelerating structure, some particles in the tail will actually be lost. The total transmission efficiency reaches 91%. RF of the HSC Based on the structural parameters output by the dynamics, the RF calculation of the HSC cavity is completed by CST. As Fig. 4 shows, the electrodes of the RFQ and DTL are connected through the stems to the upper and lower ridges, and the stems are arranged in IH mode. The key point of RF design is to adjust the voltage ratio between the two accelerating structures to make it consistent with that in dynamics. Based on the beam dynamics design results, V(RFQ) DYN. and V(DTL) DYN. are 120 kV and 8.93 MV, respectively, so that the designed voltage ratio is 1.34×10 − 2 . In order to obtain an RF simulation cavity model with designed voltage ratio, the HSC-RFQ and HSC-DTL are connected into one cavity for simulations. The HSC-RFQ adopts a single cylindrical cavity, and the HSC-DTL uses two conical cavities to adjust the flatness of the axial E -field. Figure 5 (a) shows the curve of the voltage ratio versus the HSC-RFQ cavity radius R RFQ with the radius of the HSC-DTL cavity remains unchanged. It can be seen that when the cavity radius of the HSC-RFQ is less than 135 mm, the EM fields inside the HSC is mainly distributed in the HSC-DTL part. As the cavity radius of the HSC-RFQ increases, the EM fields gradually transfers from the HSC-DTL part to the HSC-RFQ part. After a series of simulations, the final designed cavity radius of the HSC-RFQ is 136.81 mm (the radii of the two conical cavities of the HSC-DTL are 382.0 mm, 324.7 mm and 405.3 respectively.), and the voltage ratio is consistent with that in the beam dynamics design. In addition to the cavity radius, the length between the ridge and the beam axis L r−b can also greatly affect the voltage ratio, as shown in Fig. 5 (b). In the same way, the principle is adjusting the distribution of the EM fields in the two parts of the new HSC as well. In order to achieve the designed voltage ratio and take into account the undercut space at both ends of the ridge, the length is ultimately set at 90 mm. Similar to other RF cavities, the new HSC uses several copper cylindrical tuners. The number of tuners for the HSC-RFQ and HSC-DTL is 10 and 12, respectively. And the total tuning ability is -1.26 MHz ~ + 1.68 MHz, which can ensure the compensation for frequency shift. Additionally, the coupled structure of CWS, located in the matching section, has a relatively small impact on the E -field of the accelerating structures on both sides, and its impact on frequency can also be compensated by adjusting the cavity radii. The other two indicators for evaluating RF simulation design are the flatness of the E -field and the integration gap voltage errors of the HSC-DTL, which can reflect the difference between RF design and beam dynamic design. Figure 6 (a) and Fig. 6 (b) shows the E -field distributions in the HSC-RFQ and HSC-DTL. It can be seen that the distributions are relatively even, which can ensure subsequent tuning and high beam quality. Figure 6 (c) shows the integrated voltage error (gap voltages calculated by CST vs. gap voltages calculated by PiMLOC) of each gap in the HSC-DTL, all gap errors are less than 1%, indicating a good consistency between RF simulation and beam dynamics design. The other parameters are listed in Table 2 . Table 2 The calculated parameters of the new HSC. Parameters Value Frequency [MHz] 99.958 Q value 12099 Total length [mm] 4338.47 Tuner radius (RFQ/DTL) [mm] 65/100 Total power loss (100% Q ) [kW] 140.51 Coupled-window structure In the course of the beam dynamics design, an absence of EM fields at the junction between the HSC-RFQ's end and the first DT is noted. In actual beam transmission, particles display heightened susceptibility to dipole and quadrupole fields in this region. This susceptibility primarily results from distortions in the local E -field within the junction area, which is primarily characterized by the dipole field at the HSC-DTL's beginning and the quadrupole field at the HSC-RFQ’s end. The HSC-RFQ’s 4-rods component generates a symmetric quadrupole field in both the x and y directions. Nevertheless, the junction between the HSC-RFQ's end and the first DT is prone to dipole field distortion. To tackle this challenge, mitigating the dipole field between these structures emerges as an effective remedy. Several approaches are available for field matching in a hybrid cavity. An example of a facility utilizing a 4-rods RFQ and an 8-gaps IH-DTL to create a magnetic correction element is the Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ) 24 , 25 . The magnetic correction element can be viewed as a DT structure with an enlarged diameter, modifying the path of the magnetic field in the junction region 25 . This separation of the dipole field at the DTL's beginning and the quadrupole field at the RFQ's end enhances control over the EM fields distribution in both sections. However, the utilization of a magnetic correction element also introduces increased complexity in tuning the EM fields distribution within the hybrid cavity. The Ground Base Plate (GBP) structure employs electric coupling 26 . Consisting of a DT section and two grounded rods, this structure is primarily located at the junction connecting the RFQ and DTL. Within this connecting segment, the GBP structure introduces two additional capacitor structures: one between the GBP and the end of the RFQ, and another between the GBP and the first DT. However, the transmission efficiency of the GBP structure is only 17%. To improve transmission efficiency and optimize the matching structure between the HSC-RFQ and HSC-DTL, a new structure known as the CWS has been proposed. Positioned at the beginning of the ridge in the HSC-DTL, as shown in Fig. 4 (c), this structure resembles the undercut configuration often seen in traditional linacs. The CWS utilizes magnetic coupling to correct the distortion field in the connection section between the HSC-RFQ and HSC-DTL. Figure 7 shows the distribution of the transverse EM fields at the matching area of the new HSC with and without CWS. In Fig. 7 (a), the black curve represents the main H -field path in the absence of the CWS, the H -field forms a loop in the transverse range through the gaps between the ridges. And the concentration of the transverse E -field is evident in the red area, as shown in Fig. 7 (c), which results in a slight increase in the beam emittance. However, when the new HSC adopts the CWS, as can be seen from Fig. 7 (b), the H -field in the matching section forms two main loops. The first loop is in area 1, which is the window area of CWS. The second loop is in the end ridge area of the HSC-RFQ. Due to the change in the H -field path, part of the E -field enters the CWS, which effectively reduces the EM fields density of the matching section. By optimizing the distribution of EM fields in the matching section, the EM fields distortion in the matching section is effectively reduced, and to some extent, the problem of EM fields concentration in the area is improved. Figure 7 (e) shows the E -field distribution along the axis in the matching section with and without CWS. It can be seen that after introducing CWS, the E -field distribution in the matching section becomes very gentle, and the maximum value of E -field on the axis has a decrease of 51.8% from 850 kV/m to 410 kV/m. Substantially, the simulated results all indicate that the CWS can effectively adjust the EM fields in the matching section of the new HSC, and improve the issue of EM fields concentration. Multi-physics of the HSC Figure 8 (a) presents the distribution of cooling water path for the new HSC, and the radius of them is 5 mm. Due to the operating duty factor of the HSC is 1%, cooling is simply applied to the support rods. Based on the RF simulation results obtained through CST, and considering the actual material performance, the simulated power loss is 175.64 kW (80% Q ). The heat transfer coefficient is determined using empirical formulas 27 – 29 , and its value is 9538 W/(m 2 ·K). Figure 8 (b) illustrates the temperature distribution on the cavity wall when water cooling is applied. The maximum temperature is at the inlet of the HSC-RFQ’s vane, reaches 37.1°C. The deformation in the HSC undergoes meticulous analysis through a static structure solver. This analysis considers temperature distribution and external pressure conditions. The findings indicate that the cavity wall experiences a maximum deformation of 177.9 µm, as shown in Fig. 8 (c), and its position coincides with the maximum temperature position. Figure 8 (d) shows the stress distribution, the maximum stress is 56.37 MPa, located on the support structure near the HSC-RFQ outlet, which is less than the maximum allowable deformation stress of copper (60 MPa). The frequency of the deformed cavity is calculated again using HFSS, and the frequency shift is -2 kHz. This minor shift can be easily mitigated by the tuners, ensuring the HSC's sustained peak performance. Conclusion A novel HSC design, incorporating coupled-windows structure, has been introduced to optimize transmission efficiency and ensure the beam dynamics matching between the HSC-RFQ and HSC-DTL. This advanced 100 MHz HSC is designed for accelerating C 6+ ion beams ( q /A = 1/2) from 20 keV/u to 4.0 MeV/u. The HSC-RFQ manages the initial acceleration, taking ion beams from 20 keV/u to 0.6 MeV/u, while the subsequent boost to 4 MeV/u is achieved by the HSC-DTL. After optimization of beam dynamics, the HSC-RFQ achieves an exceptional 97.3% transmission efficiency for 20 mA C 6+ beams. Simultaneously, the HSC-DTL reaches a transmission efficiency of 95.4%. These results emphasize the viability of employing the APF method at high current levels. The overall transmission efficiency of the new HSC is 91%. In RF simulations, it is crucial to determine the voltage ratio between the HSC-RFQ and HSC-DTL in a single cavity. The incorporation of 22 tuners provides an ample tuning range, while strategically positioned undercuts within the ridge ensure a consistent E -field distribution. The most important point is that the matching section of the new HSC introduces a coupling-window structure, which can effectively improve the issue of EM fields concentration in the matching section. By providing additional EM fields paths to reduce the peak E -field, it plays a crucial role in the correct matching of the beam from the HSC-RFQ to the HSC-DTL. To meet the specific requirements of the new HSC under operation of 1% duty factor, a cooling system has been developed. The designed cooling system effectively controls temperature and deformation within safe limits. Additionally, it can quickly compensate for any minor frequency shifts, ensuring the overall system's reliability. Declarations Competing interests The authors declare no competing interests. Author Contribution Conception: Liang Lu, Chaochao Xing, Design of the work: Liang Lu, Canyu Wang, Acquisition and analysis: Canyu Wang, Zeyang Zhang, Interpretation of data: Canyu Wang, Zeyang Zhang, Cong Zhang, Drafted the work: Canyu Wang. All authors reviewed and approved the manuscript. Acknowledgements This work is supported by the National Natural Science Foundation of China (Grant No. 12175319) and Guangdong Basicand Applied Basic Research Foundation (Grant No. 2022B1515120027). Data Availability The data that support the findings of this study are available from the corresponding author upon reasonable request. References L.P. Zou, P.M. Zhang, A.J. Silenko et al. Recent progress in the physics of twisted particles. The innovation 4 , 3 (2023). M. Okamura, T. Takeuchi, R.A. Jameson et al. Direct plasma injection scheme in accelerators. Rev. Sci. Instrum. 79 , 2 (2008). L. Lu, T. Hattori, N. Hayashizaki. Design and simulation of C 6+ hybrid single cavity linac for cancer therapy with direct plasma injection scheme. Nucl. Instrum. Meth. A. 688 , 11-21 (2012). M. Okamura, H. Kashiwagi, K. Sakakibara et al. High current carbon beam production with direct plasma injection scheme. Rev. Sci. Instrum. 77 , 3 (2006). M. Okamura, T. Katayama, R.A. Jameson et al. 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University","correspondingAuthor":false,"prefix":"","firstName":"Zeyang","middleName":"","lastName":"Zhang","suffix":""},{"id":399408539,"identity":"bb75fba7-8e87-4388-9c7b-e9466a9b79cc","order_by":2,"name":"Chaochao Xing","email":"","orcid":"","institution":"Shanghai Zhangjiang Laboratory","correspondingAuthor":false,"prefix":"","firstName":"Chaochao","middleName":"","lastName":"Xing","suffix":""},{"id":399408540,"identity":"32cc6a37-ad06-4e4c-a537-aa5603325088","order_by":3,"name":"Cong Zhang","email":"","orcid":"","institution":"China Spallation Neutron Source","correspondingAuthor":false,"prefix":"","firstName":"Cong","middleName":"","lastName":"Zhang","suffix":""},{"id":399408542,"identity":"53d66693-2907-43da-a4b3-dfa8f1a37c45","order_by":4,"name":"Liang Lu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABCElEQVRIiWNgGAWjYBACPgbmhgNA2o4fSBx4ABPmwaOFjYERrCVZsgGoJYFYLSCacQNII3FaJBIbD/zcUctsfO3wQ6AtdYnzZyQwPnjbxiBvjltLw8HeM8f5zG6nGQC1HE7ccCOB2XBuG4PhzgbcWg7wth1jNrudANJyIHGDRAKbNG8bA5CLx5a/bccYN89O/wBzGPtvQloO87bVMG6QzgHZwpzYcCOBjRmvFp6HDYdl2w4kS9zOKTiQYHDYeMOZh82Sc85JGG7AoYWfPfnwx7dtdXb8s9M3f/hQUSc7vz354Ic3ZTbyuGyBgsNQ2oDBsQESUxJ41QNBHZxlT0jpKBgFo2AUjDwAANzTY2NJeuH9AAAAAElFTkSuQmCC","orcid":"","institution":"Sun Yat-sen University","correspondingAuthor":true,"prefix":"","firstName":"Liang","middleName":"","lastName":"Lu","suffix":""}],"badges":[],"createdAt":"2025-01-07 11:23:21","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5780790/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5780790/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":73358453,"identity":"60f16202-f865-483a-8b82-5bb091914c9a","added_by":"auto","created_at":"2025-01-09 08:24:12","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":62704,"visible":true,"origin":"","legend":"\u003cp\u003eThe schematic diagram matching section between the HSC-RFQ and HSC-DTL.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/ed528d723f1561d60b462c67.png"},{"id":73358423,"identity":"fafa1c8b-2f0a-4780-b42e-be25062e7290","added_by":"auto","created_at":"2025-01-09 08:24:10","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":608854,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The main beam dynamics parameters of the HSC-RFQ along \u003cem\u003ez\u003c/em\u003e direction and (b) the distribution of phase and voltage in the HSC-DTL.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/399979586e109079e445aeb0.png"},{"id":73358385,"identity":"fc8d29db-1c9f-4a60-85fc-5d2e0fc18e95","added_by":"auto","created_at":"2025-01-09 08:24:08","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2992124,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Beam transport process (\u003cem\u003ex\u003c/em\u003e-plane) of the new HSC simulated by PiMLOC-HSC and (b) beam distribution at the exit of the HSC-DTL.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/176fa8c9930c1e140cf6aa0e.png"},{"id":73358451,"identity":"a75ea9f9-3148-4e78-bf8e-e69841772686","added_by":"auto","created_at":"2025-01-09 08:24:11","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1246943,"visible":true,"origin":"","legend":"\u003cp\u003e(a) 4-rods HSC-RFQ, (b) APF-IH-HSC-DTL and (c) ridge with coupled-window structure (CWS).\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/e368f426352d0e222581e2df.png"},{"id":73358452,"identity":"024fbe9f-d2d9-42c7-abc0-793ae7b96138","added_by":"auto","created_at":"2025-01-09 08:24:12","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":429575,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Voltage ratio-\u003cem\u003eR\u003c/em\u003e\u003csub\u003e\u003cem\u003eRFQ\u003c/em\u003e\u003c/sub\u003e and (b) voltage ratio-\u003cem\u003e L\u003c/em\u003e\u003csub\u003e\u003cem\u003er-b\u003c/em\u003e\u003c/sub\u003e.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/1f7b891ba6afb7daa30e45de.png"},{"id":73358429,"identity":"135330c1-f21e-40c1-b208-d70482c151f8","added_by":"auto","created_at":"2025-01-09 08:24:10","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":522223,"visible":true,"origin":"","legend":"\u003cp\u003e(a) \u003cem\u003eE\u003c/em\u003e-field distribution of the HSC-RFQ, (b) \u003cem\u003eE\u003c/em\u003e-field distribution of the HSC-DTL and (c) the error between the gap voltages calculated by beam dynamics and the gap voltages calculated by CST.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/11a2be17f483ef258f946761.png"},{"id":73359059,"identity":"6d7458d7-5ab6-4dfc-9657-079e09d41c94","added_by":"auto","created_at":"2025-01-09 08:32:10","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":2930704,"visible":true,"origin":"","legend":"\u003cp\u003e(a) and (c) are the distribution of EM fields without CWS, (b) and (d) are the distribution of EM fields with CWS, (e) \u003cem\u003eE\u003c/em\u003e-field distribution along the axis in the matching section with and without CWS.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/b2daadcfa5bbf1dfa3e98901.png"},{"id":73358388,"identity":"1a7acda1-4251-47d8-83a9-840f2e95e1dd","added_by":"auto","created_at":"2025-01-09 08:24:09","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":2418897,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The distribution of cooling water path for the new HSC, (b) Temperature distribution of HSC after cooling, (c) deformation distribution of HSC after cooling and (d) stress distribution of HSC after cooling.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/49298cd7ba37274ccbb2855e.png"},{"id":88531089,"identity":"e9be5caf-1538-49c1-bc58-2adbc854badc","added_by":"auto","created_at":"2025-08-07 11:32:03","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":14548363,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5780790/v1/2dea9391-5c25-4c54-9c3d-38c2c4e4664b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Research on a novel hybrid single cavity structure for cancer therapy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe hybrid single cavity (HSC) has emerged as a novel and promising acceleration structure of injectors for cancer therapy synchrotrons and it can be operated with high duty factor in certain application scenarios. Additionally, the HSC can be applied to the research on particle beam dynamics\u003csup\u003e1\u003c/sup\u003e. This novel approach employs a direct plasma injection scheme (DPIS) to generate high-intensity C\u003csup\u003e6+\u003c/sup\u003e beams using a laser ion source, the beams are accelerated subsequently with the HSC\u003csup\u003e2-5\u003c/sup\u003e. This method eliminates the need for a carbon foil within the system, thereby enhancing acceleration efficiency and offering substantial cost reductions.\u003c/p\u003e\n\u003cp\u003eThe HSC represents a groundbreaking innovation that unites an RFQ structure and a DTL structure within a single cavity. This achievement not only reduces the overall length of the accelerator but also facilitates the integration of peripheral devices for both the RFQ and DTL sections\u003csup\u003e3\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn this study, the novel HSC employs an interdigital H-type (IH) structure, which is renowned for its exceptional power efficiency at low and medium energy levels. Additionally, the alternating phase focus (APF) beam dynamics scheme is adopted to optimize the DTL section.\u003c/p\u003e\n\u003cp\u003eThe previous 100 MHz prototype HSC demonstrated the capability to accelerate C\u003csup\u003e6+\u003c/sup\u003e ion beams from 25 keV/u to 2.0 MeV/u over a distance of 1.8 m. However, the transmission efficiency of this prototype was limited to 30%. To achieve a higher transmission efficiency and fully optimize this novel approach, adjustments to the RFQ and DTL structures and the electric field (\u003cem\u003eE\u003c/em\u003e-field) matching at the junction between them are needed\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eIn summary, the HSC represents a novel and promising design for use in injectors for cancer therapy synchrotrons and some beam researches. The HSC offers substantial advantages in terms of efficiency and cost savings compared to conventional accelerator structures. However, to realize its full potential and maximize transmission efficiency, further optimization is necessary.\u003c/p\u003e\n\u003cp\u003eTo enhance transmission efficiency and beam quality, a novel HSC design has been explored. This new design comprises a 4-rods RFQ, an IH-DTL, and a coupled-window structure (CWS) connecting these two structures. Importantly, the RFQ and DTL sections have distinct diameters, which is a noteworthy and crucial characteristic of this design.\u003c/p\u003e\n\u003cp\u003eThe newly developed HSC is designed to accelerate 20 mA C\u003csup\u003e6+\u003c/sup\u003e ion beams from 20 keV/u to 4 MeV/u, with the primary objective of achieving a high transmission efficiency of 91%. The HSC-RFQ initially accelerates the C\u003csup\u003e6+\u003c/sup\u003e ion beams from 20 keV/u to 0.6 MeV/u, followed by continuous acceleration in the HSC-DTL, ultimately reaching 4 MeV/u. To overcome the \u003cem\u003eE\u003c/em\u003e-field matching challenge between the HSC-RFQ and HSC-DTL, the design incorporates a coupled structure. This structure facilitates efficient energy transfer between the two sections by alleviating the concentration of electromagnetic (EM) fields in the matching area, thereby improving the performance of the new HSC.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eBeam dynamics\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBeam dynamics is the key to accelerator design. For the HSC in this study, an RFQ and a DTL need to be designed separately.\u003c/p\u003e\n\u003cp\u003eThe RFQ section of the new HSC is designed for the acceleration of 20 mA C\u003csup\u003e6+\u003c/sup\u003e ion beams with a charge-to-mass ratio (\u003cem\u003eq\u003c/em\u003e/A) of 1/2, elevating the kinetic energy from 20 keV/u to 0.6 MeV/u. The beam dynamics design of the HSC-RFQ is calculated by RFQGen software\u003csup\u003e6\u003c/sup\u003e, which is a mature RFQ design software. RFQGen segments the RFQ structure into four distinct parts: a radial matching section (RMS), a shaper (SH), a gentle buncher (GB), and an accelerator (ACC). The RFQ\u0026apos;s transmission efficiency and beam quality are influenced by focusing parameters B, modulation m, and synchronous phase\u0026nbsp;𝜙s.\u003c/p\u003e\n\u003cp\u003eThe HSC-DTL is devised for the acceleration of 20 mA C\u003csup\u003e6+\u003c/sup\u003e ion beams from 0.6 MeV/u to 4 MeV/u, with a length not exceeding 2.6 m, and it is housed within an IH cavity that employs the APF beam dynamics scheme. This design can alternately accomplish the transverse focusing and longitudinal bunching of the beams\u003csup\u003e7\u003c/sup\u003e, when 0\u0026lt;𝜙gap⩽𝜋/2, particles are focused in the transverse direction. Conversely, when \u0026minus;𝜋/2⩽𝜙gap⩽0, particles experience longitudinal bunching\u003csup\u003e8\u003c/sup\u003e. After passing through several alternating phase cells, the beams are of high quality in both the transverse and longitudinal directions. Beam dynamics calculations for the HSC-DTL are conducted utilizing the PiMLOC code\u003csup\u003e7-10\u003c/sup\u003e, which relies on matrix methods. This code has the capability to construct a lattice for the DTL and generate the accelerator\u0026apos;s structure using the transport matrix, optimize the optical analysis of the structure, and provide various parameters including gap synchronous phase\u0026nbsp;𝜙s, gap voltage \u003cem\u003eV\u003c/em\u003e, and gap length \u003cem\u003eL\u003c/em\u003e. The Tracing function of the PiMLOC can create the 2D and 3D structure of APF-DTL, followed by the simulation of tracing particles and tracing analysis.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDynamics matching\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAchieving the dynamics matching between the HSC-RFQ and HSC-DTL is a pivotal challenge in the design and optimization of the new HSC. The key to solving this issue lies in the phase synchronization between these two structures, it determining whether particles undergo acceleration or deceleration within the HSC-DTL. To achieve the necessary phase synchronization, proper adjustments must be made to align the phase advance of the HSC-RFQ with that of the HSC-DTL.\u003c/p\u003e\n\u003cp\u003eThe new HSC has been designed with the aim of achieving a high transmission efficiency as much as possible at a beam intensity of 20 mA. Fig. 1 offers a comprehensive schematic diagram of the dynamic structure within the connecting portions of the new HSC. This illustration outlines the arrangement of the matching section and the beamline in the transitional region that connects the HSC-RFQ and HSC-DTL.\u003c/p\u003e\n\u003cp\u003eIn order to ensure that the beam is correctly transmitted in the matching section, the \u003cem\u003e\u0026beta;\u003c/em\u003e (velocity to speed of light ratio) of the beams in the matching section must be taken into account, as well as the exit phase 𝜙\u003csub\u003e1\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/sub\u003eof the HSC-RFQ and the entrance phase\u0026nbsp;𝜙\u003csub\u003e2\u003c/sub\u003e of the HSC-DTL. Mathematical equations can be employed to derive the desired length\u003cem\u003e\u0026nbsp;L\u003csub\u003eM\u003c/sub\u003e\u003c/em\u003e of the matching section\u003csup\u003e11\u003c/sup\u003e:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"265\" height=\"79\"\u003e\u003c/p\u003e\n\u003cp\u003eFurthermore, achieving the matching of the Twiss parameters between the HSC-RFQ and HSC-DTL is imperative. Since the matching section has no accelerating structure and is short, the beam is subjected to a small force, and its beam parameters change slightly. TraceWin\u003csup\u003e12, 13\u003c/sup\u003e can be used to calculate the parameter changes of the beam in a short interval. This software has high precision and ensures the accuracy of the simulation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRF design and multi-physics analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBased on the calculated parameters of structures, a 3D model of the new HSC can be modeled using CST Studio Suite\u003csup\u003e14-16\u003c/sup\u003e. The design of various RF structures is mainly focused on the voltage ratio between the HSC-RFQ and HSC-DTL. Due to the fact that the HSC contains two different accelerating structures and each has its own beam dynamics\u0026nbsp;characteristics, RF design mainly focuses on optimizing and designing the vacuum radii of these two parts. In actual situations, the selection of cavity radii is unique, the designed cavity radii must ensure that the frequency of the new HSC is 100 MHz, while guaranteeing that the simulated voltage ratio is consistent with that calculated by the beam dynamics softwares (RFQGen and PiMLOC), the equation is as follows\u003csup\u003e17-19\u003c/sup\u003e:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"474\" height=\"63\"\u003e\u003c/p\u003e\n\u003cp\u003eIn this equation, \u003cem\u003eV(RFQ)\u003c/em\u003e is the inter-vane voltage, and \u003cem\u003eV(DTL)\u0026nbsp;\u003c/em\u003eis the total voltage of the HSC-DTL.\u003c/p\u003e\n\u003cp\u003eANSYS is utilized for performing multi-physics analyses of the new HSC, ensuring that temperature and deformation on the cavity wall remain within acceptable limits for steady operation\u003csup\u003e20, 21\u003c/sup\u003e. Furthermore, it verifies the compensatory capacity of the tuners to address frequency shift arising from temperature fluctuations and wall deformation variations.\u003c/p\u003e"},{"header":"Results and discussion","content":"\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003ch2\u003eDynamics of the HSC\u003c/h2\u003e \u003cp\u003eThe new HSC will be operated in pulse mode with a duty factor of 1%. To reduce the risk of voltage breakdown\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e in the cavity during the operation, the Kilpatrick limit by a factor of 1.8 (\u003cem\u003eEpk\u003c/em\u003e\u0026thinsp;=\u0026thinsp;11.35 MV/m @100 MHz) is set.\u003c/p\u003e \u003cp\u003eTo reduce the total length of the cavity, an inter-vane voltage of 120 kV in the HSC-RFQ has been chosen. Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) illustrates the essential beam dynamic parameters of the HSC-RFQ along the \u003cem\u003ez\u003c/em\u003e direction. Extensive multi-particle dynamics simulations, employing a significant number of macroparticles (i.e., 20,000), have been conducted to accurately capture the intricate interactions between the accelerated ions and the RFQ structure. As the results show, the total vane length of the HSC-RFQ measures 1743.19 mm, and at a beam intensity of 20 mA, the transmission efficiency reaches 97.3% with an energy spread less than \u0026plusmn;\u0026thinsp;0.02 MeV/u, indicating the effective transport and well-controlled longitudinal bunching of the beams. Together, these results unequivocally illustrate the HSC-RFQ's capability to provide high-quality ion beams, characterized by high transmission efficiency and low energy dispersion.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b) illustrates the final gap voltage and phase of each cell in the HSC-DTL, the HSC-DTL comprises 27 cells, including 13 longitudinal bunching gaps and 14 transverse focusing gaps. the total voltage is 8.93 MV calculated by PiMLOC, this total voltage is the sum of the voltages of the 27 gaps and can provide a maximum energy gain of 53.58 MeV for C\u003csup\u003e6+\u003c/sup\u003e beams, the beams can be accelerated form 0.6 MeV/u to 4 MeV/u. The transmission efficiency reaches 95.4% simulated by PiMLOC, which to some extent ensures the transmission quality of the beams.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCorrect beam transfer between The HSC-RFQ and HSC-DTL requires accurate parameter matching. In this design, \u003cem\u003eβ\u003c/em\u003e has been calculated to be 3.62\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e. \u0026#120601;\u003csub\u003e1\u003c/sub\u003e is -20.621\u0026deg; calculated by RFQGen, whereas \u0026#120601;\u003csub\u003e2\u003c/sub\u003e has a value of 0.235\u0026deg; given by PiMLOC, so the phase change between the HSC-RFQ and HSC-DTL is 20.856\u0026deg; according to Eq.\u0026nbsp;(\u003cspan refid=\"Equ2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), and the length \u003cem\u003eL\u003c/em\u003e\u003csub\u003e\u003cem\u003eM\u003c/em\u003e\u003c/sub\u003e of the matching section is 6.272 mm calculated using Eq.\u0026nbsp;(\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e listed the Twiss parameters at the exit of the HSC-RFQ simulated by RFQGen and entrance of the HSC-DTL after the beam passes through the 6.272 mm matching section calculated by TraceWin. The beam is subject to a smaller transverse force, and its beam emittances is slightly increased. Due to the fact that PiMLOC can only define the beams with the Kapchinskij-Vladimirskij distribution (uniform particle distribution), in order to simplify the design of beam acceptance, the HSC-DTL entrance beam emittances are selected to be 9 times the RFQ exit RMS beam emittances, and about 98% of the particles can be accepted by the HSC-DTL, particles in the outer layer of the bunch will be considered lost. PiMLOC uses full emittance to design DTL structure, so the emittances in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e are the converted full emittances.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe Twiss parameters at the exit of the HSC-RFQ and the entrance of the HSC-DTL.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHSC-RFQ\u0026rsquo;s exit\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHSC-DTL\u0026rsquo;s entrance\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eα\u003c/em\u003e(\u003cem\u003ex\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eβ\u003c/em\u003e(\u003cem\u003ex\u003c/em\u003e) [mm/mrad]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eε\u003c/em\u003e(\u003cem\u003ex\u003c/em\u003e) [mm.mrad]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eα\u003c/em\u003e(\u003cem\u003ey\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-1.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-1.64\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eβ\u003c/em\u003e(\u003cem\u003ey\u003c/em\u003e) [mm/mrad]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.16\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eε\u003c/em\u003e(\u003cem\u003ey\u003c/em\u003e) [mm.mrad]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eα\u003c/em\u003e(\u003cem\u003ez\u003c/em\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-0.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eβ\u003c/em\u003e(\u003cem\u003eW\u003c/em\u003e) [deg/MeV]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e185.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e184.91\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eε\u003c/em\u003e(\u003cem\u003ePW\u003c/em\u003e) [MeV.deg]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a) illustrates the beam transport process (\u003cem\u003ex\u003c/em\u003e-plane) calculated by PiMLOC-HSC. The beam loss is mainly concentrated in the range of 2800 mm\u0026thinsp;~\u0026thinsp;3300 mm and after 4000 mm, this loss is mainly caused by the small value of \u003cem\u003eβ\u003c/em\u003e(x) and \u003cem\u003eβ\u003c/em\u003e(\u003cem\u003ey\u003c/em\u003e) (less than 0.2 mm/mrad) in the Twiss parameters of the HSC-RFQ\u0026rsquo;s exit beam. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(b) shows the phase-space distribution of beams at the outlet of the new HSC (due to resolution limitations, there are jagged edges in the image). Except for the outer particles, the distribution of other particles is still relatively concentrated. the emittance growth in the \u003cem\u003ey\u003c/em\u003e direction is significantly greater than that in the \u003cem\u003ex\u003c/em\u003e direction, which is mainly caused by the HSC-DTL\u0026rsquo;s entrance beam diverging in the \u003cem\u003ey\u003c/em\u003e direction (\u003cem\u003eα\u003c/em\u003e(\u003cem\u003ey\u003c/em\u003e)\u0026thinsp;\u0026lt;\u0026thinsp;0). The longitudinal emittance has a long tail due to the linear effect in the beam transport process, and for the acceptance of the subsequent accelerating structure, some particles in the tail will actually be lost. The total transmission efficiency reaches 91%.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eRF of the HSC\u003c/h2\u003e \u003cp\u003eBased on the structural parameters output by the dynamics, the RF calculation of the HSC cavity is completed by CST. As Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e shows, the electrodes of the RFQ and DTL are connected through the stems to the upper and lower ridges, and the stems are arranged in IH mode.\u003c/p\u003e \u003cp\u003eThe key point of RF design is to adjust the voltage ratio between the two accelerating structures to make it consistent with that in dynamics. Based on the beam dynamics design results, \u003cem\u003eV(RFQ)\u003c/em\u003e\u003csub\u003e\u003cem\u003eDYN.\u003c/em\u003e\u003c/sub\u003e and \u003cem\u003eV(DTL)\u003c/em\u003e\u003csub\u003e\u003cem\u003eDYN.\u003c/em\u003e\u003c/sub\u003e are 120 kV and 8.93 MV, respectively, so that the designed voltage ratio is 1.34\u0026times;10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn order to obtain an RF simulation cavity model with designed voltage ratio, the HSC-RFQ and HSC-DTL are connected into one cavity for simulations. The HSC-RFQ adopts a single cylindrical cavity, and the HSC-DTL uses two conical cavities to adjust the flatness of the axial \u003cem\u003eE\u003c/em\u003e-field. Figure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a) shows the curve of the voltage ratio versus the HSC-RFQ cavity radius \u003cem\u003eR\u003c/em\u003e\u003csub\u003e\u003cem\u003eRFQ\u003c/em\u003e\u003c/sub\u003e with the radius of the HSC-DTL cavity remains unchanged. It can be seen that when the cavity radius of the HSC-RFQ is less than 135 mm, the EM fields inside the HSC is mainly distributed in the HSC-DTL part. As the cavity radius of the HSC-RFQ increases, the EM fields gradually transfers from the HSC-DTL part to the HSC-RFQ part. After a series of simulations, the final designed cavity radius of the HSC-RFQ is 136.81 mm (the radii of the two conical cavities of the HSC-DTL are 382.0 mm, 324.7 mm and 405.3 respectively.), and the voltage ratio is consistent with that in the beam dynamics design. In addition to the cavity radius, the length between the ridge and the beam axis \u003cem\u003eL\u003c/em\u003e\u003csub\u003e\u003cem\u003er\u0026minus;b\u003c/em\u003e\u003c/sub\u003e can also greatly affect the voltage ratio, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b). In the same way, the principle is adjusting the distribution of the EM fields in the two parts of the new HSC as well. In order to achieve the designed voltage ratio and take into account the undercut space at both ends of the ridge, the length is ultimately set at 90 mm.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eSimilar to other RF cavities, the new HSC uses several copper cylindrical tuners. The number of tuners for the HSC-RFQ and HSC-DTL is 10 and 12, respectively. And the total tuning ability is -1.26 MHz\u0026thinsp;~\u0026thinsp;+\u0026thinsp;1.68 MHz, which can ensure the compensation for frequency shift. Additionally, the coupled structure of CWS, located in the matching section, has a relatively small impact on the \u003cem\u003eE\u003c/em\u003e-field of the accelerating structures on both sides, and its impact on frequency can also be compensated by adjusting the cavity radii.\u003c/p\u003e \u003cp\u003eThe other two indicators for evaluating RF simulation design are the flatness of the \u003cem\u003eE\u003c/em\u003e-field and the integration gap voltage errors of the HSC-DTL, which can reflect the difference between RF design and beam dynamic design. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(a) and Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(b) shows the \u003cem\u003eE\u003c/em\u003e-field distributions in the HSC-RFQ and HSC-DTL. It can be seen that the distributions are relatively even, which can ensure subsequent tuning and high beam quality. Figure\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e(c) shows the integrated voltage error (gap voltages calculated by CST vs. gap voltages calculated by PiMLOC) of each gap in the HSC-DTL, all gap errors are less than 1%, indicating a good consistency between RF simulation and beam dynamics design. The other parameters are listed in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe calculated parameters of the new HSC.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrequency [MHz]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e99.958\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eQ\u003c/em\u003e value\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12099\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal length [mm]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4338.47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTuner radius (RFQ/DTL) [mm]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e65/100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal power loss (100%\u003cem\u003eQ\u003c/em\u003e) [kW]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e140.51\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eCoupled-window structure\u003c/h3\u003e\n\u003cp\u003eIn the course of the beam dynamics design, an absence of EM fields at the junction between the HSC-RFQ's end and the first DT is noted. In actual beam transmission, particles display heightened susceptibility to dipole and quadrupole fields in this region. This susceptibility primarily results from distortions in the local \u003cem\u003eE\u003c/em\u003e-field within the junction area, which is primarily characterized by the dipole field at the HSC-DTL's beginning and the quadrupole field at the HSC-RFQ\u0026rsquo;s end. The HSC-RFQ\u0026rsquo;s 4-rods component generates a symmetric quadrupole field in both the \u003cem\u003ex\u003c/em\u003e and \u003cem\u003ey\u003c/em\u003e directions. Nevertheless, the junction between the HSC-RFQ's end and the first DT is prone to dipole field distortion. To tackle this challenge, mitigating the dipole field between these structures emerges as an effective remedy. Several approaches are available for field matching in a hybrid cavity.\u003c/p\u003e \u003cp\u003eAn example of a facility utilizing a 4-rods RFQ and an 8-gaps IH-DTL to create a magnetic correction element is the Frankfurt Neutron Source at the Stern-Gerlach-Zentrum (FRANZ)\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. The magnetic correction element can be viewed as a DT structure with an enlarged diameter, modifying the path of the magnetic field in the junction region\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. This separation of the dipole field at the DTL's beginning and the quadrupole field at the RFQ's end enhances control over the EM fields distribution in both sections. However, the utilization of a magnetic correction element also introduces increased complexity in tuning the EM fields distribution within the hybrid cavity.\u003c/p\u003e \u003cp\u003eThe Ground Base Plate (GBP) structure employs electric coupling\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Consisting of a DT section and two grounded rods, this structure is primarily located at the junction connecting the RFQ and DTL. Within this connecting segment, the GBP structure introduces two additional capacitor structures: one between the GBP and the end of the RFQ, and another between the GBP and the first DT. However, the transmission efficiency of the GBP structure is only 17%.\u003c/p\u003e \u003cp\u003eTo improve transmission efficiency and optimize the matching structure between the HSC-RFQ and HSC-DTL, a new structure known as the CWS has been proposed. Positioned at the beginning of the ridge in the HSC-DTL, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(c), this structure resembles the undercut configuration often seen in traditional linacs. The CWS utilizes magnetic coupling to correct the distortion field in the connection section between the HSC-RFQ and HSC-DTL.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows the distribution of the transverse EM fields at the matching area of the new HSC with and without CWS. In Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a), the black curve represents the main \u003cem\u003eH\u003c/em\u003e-field path in the absence of the CWS, the \u003cem\u003eH\u003c/em\u003e-field forms a loop in the transverse range through the gaps between the ridges. And the concentration of the transverse \u003cem\u003eE\u003c/em\u003e-field is evident in the red area, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(c), which results in a slight increase in the beam emittance. However, when the new HSC adopts the CWS, as can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(b), the \u003cem\u003eH\u003c/em\u003e-field in the matching section forms two main loops. The first loop is in area 1, which is the window area of CWS. The second loop is in the end ridge area of the HSC-RFQ. Due to the change in the \u003cem\u003eH\u003c/em\u003e-field path, part of the \u003cem\u003eE\u003c/em\u003e-field enters the CWS, which effectively reduces the EM fields density of the matching section.\u003c/p\u003e \u003cp\u003eBy optimizing the distribution of EM fields in the matching section, the EM fields distortion in the matching section is effectively reduced, and to some extent, the problem of EM fields concentration in the area is improved. Figure\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(e) shows the \u003cem\u003eE\u003c/em\u003e-field distribution along the axis in the matching section with and without CWS. It can be seen that after introducing CWS, the \u003cem\u003eE\u003c/em\u003e-field distribution in the matching section becomes very gentle, and the maximum value of \u003cem\u003eE\u003c/em\u003e-field on the axis has a decrease of 51.8% from 850 kV/m to 410 kV/m. Substantially, the simulated results all indicate that the CWS can effectively adjust the EM fields in the matching section of the new HSC, and improve the issue of EM fields concentration.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eMulti-physics of the HSC\u003c/h3\u003e\n\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(a) presents the distribution of cooling water path for the new HSC, and the radius of them is 5 mm. Due to the operating duty factor of the HSC is 1%, cooling is simply applied to the support rods. Based on the RF simulation results obtained through CST, and considering the actual material performance, the simulated power loss is 175.64 kW (80%\u003cem\u003eQ\u003c/em\u003e). The heat transfer coefficient is determined using empirical formulas\u003csup\u003e\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e, and its value is 9538 W/(m\u003csup\u003e2\u003c/sup\u003e\u0026middot;K).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(b) illustrates the temperature distribution on the cavity wall when water cooling is applied. The maximum temperature is at the inlet of the HSC-RFQ\u0026rsquo;s vane, reaches 37.1\u0026deg;C. The deformation in the HSC undergoes meticulous analysis through a static structure solver. This analysis considers temperature distribution and external pressure conditions. The findings indicate that the cavity wall experiences a maximum deformation of 177.9 \u0026micro;m, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(c), and its position coincides with the maximum temperature position. Figure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(d) shows the stress distribution, the maximum stress is 56.37 MPa, located on the support structure near the HSC-RFQ outlet, which is less than the maximum allowable deformation stress of copper (60 MPa). The frequency of the deformed cavity is calculated again using HFSS, and the frequency shift is -2 kHz. This minor shift can be easily mitigated by the tuners, ensuring the HSC's sustained peak performance.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eA novel HSC design, incorporating coupled-windows structure, has been introduced to optimize transmission efficiency and ensure the beam dynamics matching between the HSC-RFQ and HSC-DTL. This advanced 100 MHz HSC is designed for accelerating C\u003csup\u003e6+\u003c/sup\u003e ion beams (\u003cem\u003eq\u003c/em\u003e/A\u0026thinsp;=\u0026thinsp;1/2) from 20 keV/u to 4.0 MeV/u. The HSC-RFQ manages the initial acceleration, taking ion beams from 20 keV/u to 0.6 MeV/u, while the subsequent boost to 4 MeV/u is achieved by the HSC-DTL.\u003c/p\u003e \u003cp\u003eAfter optimization of beam dynamics, the HSC-RFQ achieves an exceptional 97.3% transmission efficiency for 20 mA C\u003csup\u003e6+\u003c/sup\u003e beams. Simultaneously, the HSC-DTL reaches a transmission efficiency of 95.4%. These results emphasize the viability of employing the APF method at high current levels. The overall transmission efficiency of the new HSC is 91%.\u003c/p\u003e \u003cp\u003eIn RF simulations, it is crucial to determine the voltage ratio between the HSC-RFQ and HSC-DTL in a single cavity. The incorporation of 22 tuners provides an ample tuning range, while strategically positioned undercuts within the ridge ensure a consistent \u003cem\u003eE\u003c/em\u003e-field distribution. The most important point is that the matching section of the new HSC introduces a coupling-window structure, which can effectively improve the issue of EM fields concentration in the matching section. By providing additional EM fields paths to reduce the peak \u003cem\u003eE\u003c/em\u003e-field, it plays a crucial role in the correct matching of the beam from the HSC-RFQ to the HSC-DTL.\u003c/p\u003e \u003cp\u003eTo meet the specific requirements of the new HSC under operation of 1% duty factor, a cooling system has been developed. The designed cooling system effectively controls temperature and deformation within safe limits. Additionally, it can quickly compensate for any minor frequency shifts, ensuring the overall system's reliability.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eConception: Liang Lu, Chaochao Xing, Design of the work: Liang Lu, Canyu Wang, Acquisition and analysis: Canyu Wang, Zeyang Zhang, Interpretation of data: Canyu Wang, Zeyang Zhang, Cong Zhang, Drafted the work: Canyu Wang. All authors reviewed and approved the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eThis work is supported by the National Natural Science Foundation of China (Grant No. 12175319) and Guangdong Basicand Applied Basic Research Foundation (Grant No. 2022B1515120027).\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eL.P. Zou, P.M. Zhang, A.J. Silenko et al. Recent progress in the physics of twisted particles. \u003cem\u003eThe innovation\u003c/em\u003e\u003cstrong\u003e4\u003c/strong\u003e, 3 (2023).\u003c/li\u003e\n\u003cli\u003eM. Okamura, T. Takeuchi, R.A. Jameson et al. Direct plasma injection scheme in accelerators. \u003cem\u003eRev. Sci. 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Convection coefficient equations for forced air flow over flat surfaces. \u003cem\u003eSolar energy\u003c/em\u003e\u003cstrong\u003e80\u003c/strong\u003e, 1063-1071 (2006).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hybrid single cavity, Ion therapy, Accelerator, Electromagnetic coupling","lastPublishedDoi":"10.21203/rs.3.rs-5780790/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5780790/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn recent decades, significant advancements have been made in accelerator technology, particularly with the hybrid single cavity (HSC). The HSC technology combines a radio frequency quadrupole (RFQ) and a drift tubes linac (DTL) within a unified interdigital H-type (IH) structure, resulting in enhanced compactness and system simplification. However, this design presents two fundamental challenges: reduced beam transmission efficiency and the concentration of electromagnetic (EM) fields at the matching section between RFQ and DTL sections. To address these issues, a novel coupled-window structure (CWS) has been devised to mitigate the effects of the EM fields. This paper explores the design and optimization of a 100 MHz HSC for high intensity carbon beam cancer therapy. The new HSC cavity is engineered to accelerate 20 mA C\u003csup\u003e6+\u003c/sup\u003e beams from 20 keV/u to 4 MeV/u within a distance of 4.4 m, achieving a total transmission efficiency of 91%. These outcomes are attainable through the implementation of CWS, which effectively mitigates the challenges associated with matching dynamic fields between the RFQ and DTL sections.\u003c/p\u003e","manuscriptTitle":"Research on a novel hybrid single cavity structure for cancer therapy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-09 08:23:19","doi":"10.21203/rs.3.rs-5780790/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ab3003a4-caca-4af3-aef2-40a99acc6ced","owner":[],"postedDate":"January 9th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":42557333,"name":"Physical sciences/Physics/Particle physics/Theoretical particle physics"},{"id":42557334,"name":"Physical sciences/Physics/Techniques and instrumentation/Design synthesis and processing"}],"tags":[],"updatedAt":"2025-08-07T11:23:42+00:00","versionOfRecord":[],"versionCreatedAt":"2025-01-09 08:23:19","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5780790","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5780790","identity":"rs-5780790","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}