Showing papers on "Linear particle accelerator published in 2014"

The Spallation Neutron Source accelerator system design

Abstract: The Spallation Neutron Source (SNS) was designed and constructed by a collaboration of six U.S. Department of Energy national laboratories. The SNS accelerator system consists of a 1 GeV linear accelerator and an accumulator ring providing 1.4 MW of proton beam power in microsecond-long beam pulses to a liquid mercury target for neutron production. The accelerator complex consists of a front-end negative hydrogen-ion injector system, an 87 MeV drift tube linear accelerator, a 186 MeV side-coupled linear accelerator, a 1 GeV superconducting linear accelerator, a 248-m circumference accumulator ring and associated beam transport lines. The accelerator complex is supported by ~100 high-power RF power systems, a 2 K cryogenic plant, ~400 DC and pulsed power supply systems, ~400 beam diagnostic devices and a distributed control system handling ~100,000 I/O signals. The beam dynamics design of the SNS accelerator is presented, as is the engineering design of the major accelerator subsystems.

Design of the RAON accelerator systems

Abstract: The RAON is the name of the heavy ion accelerator facility under construction in Korea that includes the In-flight Fragment (IF) and Isotope Separation On-Line (ISOL) facilities to support cutting-edge research in various science fields. The superconducting linac is the driver for the IF facility that can accelerate beams from proton to uranium with 200 MeV/u, 400 kW (for uranium beam). A 70-MeV, 1-mA H− cyclotron is the driver for the ISOL facility and is followed by a post-accelerator consisting of s superconducting linac that can accelerate rare-isotope (RI) beams and deliver them to experimental halls. These facilities provide high-intensity stable ion and rare isotope (RI) beams for domestic and international users. In this paper, design and prototyping efforts for the RAON accelerator systems are presented.

Experimental demonstration of energy-chirp compensation by a tunable dielectric-based structure.

Abstract: A tunable energy-chirp compensator was used to remove a correlated energy chirp from the 60-MeV beam at the Brookhaven National Laboratory Accelerator Test Facility. The compensator operates through the interaction of the wakefield of the electron bunch with itself and consists of a planar structure comprised of two alumina bars with copper-plated backs separated by an adjustable beam aperture. By changing the gap size, the correlated energy chirp of the electron bunch was completely removed. Calculations show that this device, properly scaled to account for the electron bunch charge and length, can be used to remove residual correlated energy spread at the end of the linacs used for free-electron lasers. The experimental results are shown to be in good agreement with numerical simulations. Application of this technique can significantly simplify linac design and improve free-electron lasers performance.

Laser heater commissioning at an externally seeded free-electron laser

Abstract: FERMI is the first user facility based upon an externally seeded free-electron laser (FEL) and was designed to deliver high quality, transversely and longitudinally coherent radiation pulses in the extreme ultraviolet and soft x-ray spectral regimes. The FERMI linear accelerator includes a laser heater to control the longitudinal microbunching instability, which otherwise is expected to degrade the quality of the high brightness electron beam sufficiently to reduce the FEL output intensity and spectral brightness. In this paper, we present the results of the FERMI laser heater commissioning. For the first time, we show that optimizing the electron beam heating at an upstream location (beam energy, 100 MeV) leads to a reduction of the incoherent energy spread at the linac exit (beam energy, 1.2 GeV). We also discuss some of the positive effects of such heating upon the emission of coherent optical transition radiation and the FEL output intensity.

Laser acceleration in novel media

Abstract: With newly available compact laser technology [1] we are capable of producing 100 PW-class laser pulses with a single-cycle duration on the femtosecond timescale. With this fs intense laser we can produce a coherent X-ray pulse that is also compressed, well into the hard X-ray regime (∼10 keV) and with a power up to as much as 10 Exawatts. We suggest utilizing these coherent X-rays to drive the acceleration of particles. Such X-rays are focusable far beyond the diffraction limit of the original laser wavelength and when injected into a crystal it forms a metallic-density electron plasma ideally suited for laser wakefield acceleration. If the X-ray field is limited by the Schwinger field at the focal size of ∼100 nm, the achievable energy is 1 PeV over 50 m. (If the X-rays are focused further, much higher energies beyond this are possible). These processes are not limited to only electron acceleration, and if ions are pre-accelerated to beyond GeV they are capable of being further accelerated using a LWFA scheme [2] to similar energies as electrons over the same distance-scales. Such high energy proton (and ion) beams can induce copious neutrons, which can also give rise to intense compact muon beams and neutrino beams that may be portable. High-energy gamma rays can also be efficiently emitted with a bril- liance many orders of magnitude above the brightest X-ray sources by this accelerating process, from both the betatron radiation as well as the dominant radiative-damping dynamics. With the exceptional conditions enabled by this technology we envision a whole scope of new physical phenomena, including: the possibility of laser self-focus in the vacuum, neutron manipulation by the beat of such lasers, zeptosecond spectroscopy of nuclei, etc. Further, we now introduce along with the idea of vacuum as a nonlinear medium, the Schwinger Fiber Accelerator. This is a self-organized vacuum fiber acceleration concept, in which the repeated process of self-focusing and defocusing for the X-ray pulse in vacuum forms a modulated fiber that guides the intense X-rays.

The Heavy Photon Search experiment at Jefferson Laboratory

Abstract: The Heavy Photon Search experiment (HPS) at Jefferson Laboratory will search for a new U(1) massive gauge boson, or "heavy-photon", mediator of a new fundamental interaction, called "dark-force", that couples to ordinary photons through kinetic mixing. HPS has sensitivity in the mass range 20 MeV – 1 GeV and coupling 2 between 10−5 and 10−10. The HPS experiment will look for the e+e− decay of the heavy photon, by resonance search and detached vertexing, in an electron beam fixed target experiment. HPS will use a compact forward spectrometer, which employs silicon microstrip detectors for vertexing and tracking, and a PbWO4 electromagnetic calorimeter for energy measurement and fast triggering.

Experimental Demonstration of Electron Longitudinal-Phase-Space Linearization by Shaping the Photoinjector Laser Pulse

Abstract: Control of the electron-beam longitudinal-phase-space distribution is of crucial importance in a number of accelerator applications, such as linac-driven free-electron lasers, colliders and energy recovery linacs. Some longitudinal-phase-space features produced by nonlinear electron beam self- fields, such as a quadratic energy chirp introduced by geometric longitudinal wakefields in radio-frequency (rf) accelerator structures, cannot be compensated by ordinary tuning of the linac rf phases nor corrected by a single high harmonic accelerating cavity. In this Letter we report an experimental demonstration of the removal of the quadratic energy chirp by properly shaping the electron beam current at the photoinjector. Specifically, a longitudinal ramp in the current distribution at the cathode linearizes the longitudinal wakefields in the downstream linac, resulting in a flat electron current and energy distribution. We present longitudinal-phase-space measurements in this novel configuration compared to those typically obtained without longitudinal current shaping at the FERMI linac.

Emittance measurements and minimization at the SwissFEL Injector Test Facility

Abstract: A detailed analysis of measurement methods and optimization procedures for accurate measurement of the transverse slice and projected emittances of an electron beam in a linear accelerator have yielded measurement errors of 5%. After full optimization, slice emittances of about 200 nm for 200 pC and about 100 nm for 10 pC have been demonstrated at the SwissFEL Injector Test Facility.

High-gradient C-band linac for a compact x-ray free-electron laser facility

Abstract: An electron linac using a C -band rf frequency, 5.712 GHz, has enabled us to obtain an acceleration gradient of more than 35 MV / m reliably. A C -band accelerator system has been developed and constructed for the compact x-ray FEL facility, SACLA, in order to fit within the available site length at SPring-8, and to reduce construction costs. An accelerator unit consists of two 1.8 m-long accelerator structures, a cavity-type rf pulse compressor and a 50 MW pulsed klystron. In order to achieve a compact rf source and to obtain extremely stable rf fields in the accelerator structures, an oil-filled, high-voltage pulse modulator combined with an extremely stable, inverter-type, high voltage charger was developed. SACLA uses 64 sets of these accelerator units in order to achieve a final beam energy of 8.5 GeV. After rf conditioning for 1 700 hours, the maximum acceleration gradient achieved was 38 MV / m . The typical trip rate for each accelerator unit at 35 MV / m and 30 pps is about once per day. Dark current from the accelerator structures is less than 5 pC, which causes a negligible effect on the beam monitors. The phase and amplitude stability of the rf fields were measured to be 0.03 degree and 0.01% rms, respectively, which is sufficient for the XFEL operation of SACLA. Since the first beam commissioning in 2011, the C -band accelerator has demonstrated fairly stable performance under continuous operation for 20 000 hours.

Detectors and Calibration Concept for the European XFEL

Abstract: The European X-ray Free Electron Laser (XFEL.EU) is an international research facility presently under construction in the area of Hamburg, Germany, which will start its operation at the end of 2016 [1]. The superconducting linear accelerator of the facility will deliver electron bunches with an energy of up to 17.5 GeV, arranged in trains of typically 2700 bunches at a repetition rate of 4.5 MHz. Each train will be followed by a gap of 99.4 ms. Spatially coherent X-rays are generated from the electron bunches in a series of undulators based on the Self-Amplified Spontaneous Emission (SASE) process, in three photon beamlines extending over a length of up to 200 m. Each beamline serves two experiments with different scientific goals.

Large-bandwidth two-color free-electron laser driven by a comb-like electron beam

Abstract: We discuss a two-color SASE free-electron laser (FEL) amplifier where the time and energy separation of two separated radiation pulses are controlled by manipulation of the electron beam phase space. Two electron beamlets with adjustable time and energy spacing are generated in an RF photo-injector illuminating the cathode with a comb-like laser pulse followed by RF compression in the linear accelerator. We review the electron beam manipulation technique to generate bunches with time and energy properties suitable for driving two-color FEL radiation. Experimental measurements at the SPARC-LAB facility illustrate the flexibility of the scheme for the generation of two-color FEL spectra.

High-gradient test results from a clic prototype accelerating structure: td26cc

Abstract: The CLIC study has progressively tested prototype accelerating structures which incorporate an ever increasing number of features which are needed for a final version ready to be installed in a linear collider. The most recent high power test made in the CERN X-band test stand, Xbox-1, is of a CERN-built prototype which includes damping features but also compact input and output power couplers, which maximize the overall length to active gradient ratio of the structure. The structure’s high-gradient performance, 105 MV/m at 250 ns pulse length and low breakdown rate, matches previously tested structures validating both CERN fabrication and the compact coupler design.

Laser-Driven Very High Energy Electron/Photon Beam Radiation Therapy in Conjunction with a Robotic System

Abstract: We present a new external-beam radiation therapy system using very-high-energy (VHE) electron/photon beams generated by a centimeter-scale laser plasma accelerator built in a robotic system. Most types of external-beam radiation therapy are delivered using a machine called a medical linear accelerator driven by radio frequency (RF) power amplifiers, producing electron beams with an energy range of 6–20 MeV, in conjunction with modern radiation therapy technologies for effective shaping of three-dimensional dose distributions and spatially accurate dose delivery with imaging verification. However, the limited penetration depth and low quality of the transverse penumbra at such electron beams delivered from the present RF linear accelerators prevent the implementation of advanced modalities in current cancer treatments. These drawbacks can be overcome if the electron energy is increased to above 50 MeV. To overcome the disadvantages of the present RF-based medical accelerators, harnessing recent advancement of laser-driven plasma accelerators capable of producing 1-GeV electron beams in a 1-cm gas cell, we propose a new embodiment of the external-beam radiation therapy robotic system delivering very high-energy electron/photon beams with an energy of 50–250 MeV; it is more compact, less expensive, and has a simpler operation and higher performance in comparison with the current radiation therapy system.

Design and application of multimegawatt X-band deflectors for femtosecond electron beam diagnostics

Abstract: Performance of the x-ray free electron laser Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET) is determined by the properties of their extremely short electron bunches. Multi-GeV electron bunches in both LCLS and FACET are less than 100 fs long. Optimization of beam properties and understanding of free-electron laser operation require electron beam diagnostics with time resolution of about 10 fs. We designed, built and commissioned a set of high frequency $X$-band deflectors which can measure the beam longitudinal space charge distribution and slice energy spread to better than 10 fs resolution at full LCLS energy (14 GeV), and with 70 fs resolution at full FACET energy (20 GeV). Use of high frequency and high gradient in these devices allows them to reach unprecedented performance. We report on the physics motivation, design considerations, operational configuration, cold tests, and typical results of the $X$-band deflector systems currently in use at SLAC.

Compact x-ray free electron laser from a laser-plasma accelerator using a transverse gradient undulator

Abstract: Compact x-ray free electron laser from a laser-plasma accelerator using a transverse gradient undulator Zhirong Huang 1 , Yuantao Ding 1 , and Carl B. Schroeder 2 SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA (Dated: September 11, 2012) Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large energy spread hinders the poten- tial applications for coherent FEL radiation generation. In this paper, we discuss a method to compensate the e↵ects of beam energy spread by introducing a transverse field variation into the FEL undulator. Such a transverse gradient undulator together with a properly dispersed beam can greatly reduce the e↵ects of electron energy spread and jitter on FEL performance. We present theoretical analysis and numerical simulations for SASE and seeded extreme ultraviolet and soft x-ray FELs based on laser plasma accelerators. PACS numbers: 41.60.Cr, 41.75.Jv, 52.38.Kd The advent of x-ray free-electron lasers (FELs) repre- sents a revolution in light source development that en- ables the simultaneous probe of both the ultrasmall and the ultrafast worlds [1]. The first soft x-ray FEL facility, FLASH at DESY, has been in operation for users since 2005 [2]. The first hard x-ray FEL facility, the Linac Co- herent Light Source at SLAC [3], became operational in 2009. More recently, the SACLA at SPring-8 [4] started its user program beginning in 2012. These are remark- able scientific facilities in size (hundreds to thousands of meters long) and in user capacities (hundreds of users annually). A few more such facilities will come online in this decade [5]. Nevertheless, it is very desirable to develop compact x-ray FELs that are similar in charac- teristics but are much smaller in footprint. Laser plasma accelerators (LPAs) have made tremen- dous progress in generating high-energy (⇠1 GeV), high peak current (⇠10 kA) and low-emittance (⇠0.1 µm) beams [6, 7]. Such an accelerator was used to produce soft x-ray spontaneous undulator radiation [8], and active research and development e↵orts have been pursued to develop compact FELs [9, 10] based on these novel accel- erators. Nevertheless, due to the challenges in controlling the injection process, LPA beams have rather large en- ergy spread, typically on a few percent level. Such energy spread hinders the short-wavelength FEL application. The goal of this paper is to point out that a transverse gradient undulator together with a properly dispersed beam is capable of overcoming the large energy spread of LPAs for short-wavelength FEL amplification. Us- ing one-dimensional (1D) analysis and three-dimensional (3D) simulations, we show how LPAs can be used to drive extreme ultraviolet (EUV) and soft x-ray FELs in short undulators. The resulting radiation pulses can be multi- gigawatt in power, a few femtosecond in duration, and have good transverse and temporal coherence properties. The e↵ect of beam energy spread on FELs can be best understood by the undulator resonant wavelength K 0 2 u r = Here u and K 0 are the undulator period and the strength parameter, respectively. If there is a spread in the average beam energies 0 mc 2 , it will lead to a spread of the resonant condition and degrade the FEL gain. For a high-gain FEL, the typical requirement is 1 I 0 K 0 2 [JJ] 16 I A 0 3 x 2 k u 2 where ⇢ is the FEL Pierce parameter [11], [JJ] = [J 0 (⇠) J 1 (⇠)] with ⇠ = K 0 2 /(4 + 2K 0 2 ) for a planar undulator, I A ⇡ 17 kA is the Alfv´en current, k u = 2⇡/ u , I 0 is the beam peak current, and x is the average rms transverse beam size in the undulator. Todd Smith and co-workers at Stanford proposed a “transverse gradient wiggler (undulator)” (TGU) to re- duce the sensitivity to electron energy variations for FEL oscillators [12]. The idea is illustrated in Fig. 1. By canting the magnetic poles, one can generate a linear x dependence of the vertical undulator field so that K = ↵x . K 0 Consider dispersing the electron beam horizontally ac- cording to its energy such that x = ⌘ / 0 . By choosing the dispersion function 2 + K 0 2 ↵K 0 2 and keeping it constant in the TGU, the change in elec- tron’s energy is now exactly compensated by the change in the magnetic field so that every electron satisfies the

Increasing the intensity of an induction accelerator and reduction of the beam breakup instability

Abstract: A 7 cm cathode has been deployed for use on a 3.8 MV, 80 ns (FWHM) Blumlein, to increase the extracted electron current from the nominal 1.7 to 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the space-charge limitations on the beam quality, its coupling with the beam breakup (BBU) instability, and provide an independent validation of the BBU theory in a higher current regime, $\mathrm{I}g2\text{ }\mathrm{kA}$. Time resolved centroid measurements indicate a reduction in BBU $g10\ifmmode\times\else\texttimes\fi{}$ with simply a 50% increase in the average B-field used to transport the beam through the accelerator. A qualitative comparison of experimental and calculated results are presented, which include time resolved current density distributions, radial BBU amplitude relative to the calculated beam envelope, and frequency analyzed BBU amplitude with different accelerator lattice tunes.

Design of an emittance exchanger for production of special shapes of the electron beam current

Abstract: Recently, considerable attention has been focused on electron beam current profile shaping by means of a transverse beam mask followed by an emittance exchanger (EEX). This setup can transform a transverse particle distribution into a longitudinal particle distribution. We investigate the EEX technique with application to production of a double triangular drive and a trapezoidal main bunches for high transformer ratio, high brightness dielectric wakefield accelerators. We perform numerical optimization of two realistic configurations: a double dogleg and a chicane. In this paper we report sample designs and discuss the effects of the beam line nonlinearities, beam space charge, and coherent synchrotron radiation on a current profile of the output beam.

Intra pulse multi-energy method and apparatus based on RF linac and X-ray source

Abstract: The relative position of an RF waveform and electron bunches in a linear accelerator is controlled by appropriate control of the accelerator electronics. Thus the energy given to any particular electron bunch can be controlled by altering the position of amplitude peaks of the RF driving field relative to the electron bunch. This control can be applied simultaneously and independently to all electron bunches in a bunch train. An output X-ray pulse is provided by the contributions of multiple electron bunches when they hit one or more targets. When more energetic electrons hit the target, more energetic X-rays are produced. Thus this controllable electron bunch energy and intensity can provide intra-pulse control of X-ray energy.

Systems and methods for linear accelerator radiotherapy with magnetic resonance imaging

Abstract: Systems and methods for the delivery of linear accelerator radiotherapy in conjunction with magnetic resonance imaging in which components of a linear accelerator may be placed in shielding containers around a gantry, may be connected with RF waveguides, and may employ various systems and methods for magnetic and radio frequency shielding.

Top-up operation at Pohang Light Source-II

Abstract: After three years of upgrading work, PLS-II (S. Shin, Commissioning of the PLS-II, JINST, January 2013) is now successfully operating. The top-up operation of the 3 GeV linear accelerator had to be delayed because of some challenges encountered, and PLS-II was run in decay mode at the beginning in March 2012. The main difficulties encountered in the top-up operation of PLS-II are different levels between the linear accelerator and the storage ring, the 14 narrow gap in-vacuum undulators in operation, and the full energy injection by 3 GeV linear accelerator. Large vertical emittance and energy jitter of the linac were the major obstacles that called for careful control of injected beam to reduce beam loss in the storage ring during injection. The following measures were taken to resolve these problems: (1) The high resolution Libera BPM (see http://www.i-tech.si) was implemented to measure the beam trajectory and energy. (2) Three slit systems were installed to filter the beam edge. (3) De-Qing circuit was applied to the modulator system to improve the energy stability of injected beam. As a result, the radiation by beam loss during injection is reduced drastically, and the top-up mode has been successfully operating since 19th March 2013. In this paper, we describe the experimental results of the PLS-II top-up operation and the improvement plan.

Image Guided Radiotherapy with Dual Source and Dual Detector Arrays Tetrahedron Beam Computed Tomography

Abstract: A radiation treatment and imaging system for emitting a radiation treatment beam and X-ray imaging beams towards an object. The system includes an x-ray source and a collimator, first and second detectors, and a linear accelerator that delivers radiation beams to an object. The linear accelerator includes a radiation source positioned between the first and second detectors and emitting a therapy radiation beam in-line with the x-ray beams received by the first and second detectors. The system also includes a data processing device in communication with the first and second detectors. The data processing device receives imaging signals from the first and second detectors and reconstructs a three-dimensional tetrahedron beam computed tomography (TBCT) image from the received imaging signals. The system also includes a display in communication with the data processing device and for displaying the TBCT image.

Correcting the beam centroid motion in an induction accelerator and reducing the beam breakup instability

Abstract: Axial beam centroid and beam breakup (BBU) measurements were conducted on an 80 ns FWHM, intense relativistic electron bunch with an injected energy of 3.8 MV and current of 2.9 kA. The intense relativistic electron bunch is accelerated and transported through a nested solenoid and ferrite induction core lattice consisting of 64 elements, exiting the accelerator with a nominal energy of 19.8 MeV. The principal objective of these experiments is to quantify the coupling of the beam centroid motion to the BBU instability and validate the theory of this coupling for the first time. Time resolved centroid measurements indicate a reduction in the BBU amplitude, $⟨\ensuremath{\xi}⟩$, of 19% and a reduction in the BBU growth rate ($\mathrm{\ensuremath{\Gamma}}$) of 4% by reducing beam centroid misalignments $\ensuremath{\sim}50%$ throughout the accelerator. An investigation into the contribution of the misaligned elements is made. An alignment algorithm is presented in addition to a qualitative comparison of experimental and calculated results which include axial beam centroid oscillations, BBU amplitude, and growth with different dipole steering.

Thermal phenomena induced in a small tungsten sample during irradiation with a few MeV electron beam: Experiment versus simulations

Abstract: We present an experimental and theoretical semi-analytical study of thermal fields induced in a small cylindrical sample made of tungsten and irradiated by an electron beam with energy of 6 MeV and average power of 62 W, obtained from a linear accelerator (LINAC). The sample has a diameter comparable with that of the electron beam, of about 10 mm, and a length of 10 cm. Calorimetric measurements of the sample temperature were compared with simulations obtained by solving the heat equation and by taking into account the range of mono-energetic electrons in the W target. We based our assumptions on the fact that for an incident laser or electron beam on a metallic target the heat transfer formalism is the same, obeying the heat equation.

Auto-tuning systems for J-PARC LINAC RF cavities

Abstract: The 400-MeV proton linear accelerator (LINAC) at the Japan Proton Accelerator Research Complex (J-PARC) consists of 324-MHz low-β and 972-MHz high-β accelerator sections. From October 2006 to May 2013, only the 324-MHz low-β accelerator section was in operation. From the summer of 2013 the J-PARC LINAC was upgraded by installing the 972-MHz high-β accelerator section, and the proton beam was successfully accelerated to 400 MeV in January 2014. Auto-tuning systems for the J-PARC LINAC RF cavities have been successfully developed. A first generation design, an auto-tuning system using a mechanical tuner controller, was developed and operated for the first 3 years. Then the second-generation auto-tuning system was developed using a new approach to the RF cavity warm-up process, and this was applied to the accelerator operation for the subsequent 4 years. During the RF cavity warm-up process in this system, the mechanical tuner is constantly fixed and the input RF frequency is automatically tuned to the cavity resonance frequency using the FPGA (Field-Programmable Gate Array) of the digital feedback RF control system. After the input power level reaches the required value, input RF frequency tuning is stopped and it is switched to the operation frequency. Then, the mechanical tuner control begins operation. This second-generation auto-tuning system was extremely effective for the 324-MHz cavity operation. However, if we apply this approach to the 972-MHz RF cavities, an interlock due to the RF cavity reflection amplitude occasionally occurs at the end of the warm-up process. In order to solve this problem a third generation novel auto-tuning system was successfully developed in December 2013 and applied to the operation of the J-PARC LINAC, including the 972-MHz ACS RF cavities. During the warm-up process both the mechanical tuner controller and the input RF frequency tuning are in operation, and good matching between the input RF frequency and the RF cavity is obtained during the entire warm-up process. As a result of their excellent performance, 972-MHz ACS cavity operation and the J-PARC LINAC 400 MeV upgrade have been successfully implemented. In this paper, the development of the auto-tuning systems and their applications will be described in detail.

Particle production reactions in laser-boosted lepton collisions

Abstract: The need for ever higher energies in lepton colliders gives rise to the investigation of new accelerator schemes for elementary particle physics experiments. One perceivable way to increase the collision energy would be to combine conventional lepton acceleration with strong laser fields, making use of the momentum boost a charged particle experiences inside a plane electromagnetic wave. As an example for a process taking place in such a laser-boosted collision, Higgs boson creation is studied in detail. We further discuss other possible particle production processes that could be implemented in such a collider scheme and specify the required technical demands.

A 2.45 GHz intense proton source and low energy beam transport system for China Initiative Accelerator Driven Sub-Critical reactor system.

Abstract: At Institute of Modern Physics, a cw 35 keV, 20 mA intense proton source and the low energy beam transport system (LEBT) have been developed for China Initiative Accelerator Driven Sub-Critical reactor system. In order to ensure high quality transmission of the intense ion beam from the exit of ion source to Radio Frequency Quadrupole (RFQ), a low energy beam transport line is used to focus beam to the RFQ entrance and match the Twiss parameters to the RFQ requirements. The 35 keV, 20 mA ion beam extracted by a three-electrode extraction system from the ion source passes through the LEBT to the RFQ entrance and the root-mean-square emittance is measured to be less than 0.2 π mm mrad. The commissioning results of the ion source and low energy beam transport system are described in this paper. The beam quality and transmission efficiency are also studied.