Wideroe型Unilac预剥离器直线加速器的拆卸于1999年初进行。必须获得SIS中最重元素的粒子数增加两个数量级以上。从那时起，新的高电流注入器（HSI）由H型整流器和DTL结构组成，用于双束操作，并成功调试。高电荷注入器（HLI）在此期间提供主直线加速器。同时完成射频发射器和射频结构的调节和运行。HSI调试策略包括在每个运输和加速段之后使用多功能诊断测试台进行束流调查。将讨论LEBT、超透镜、IH槽I和II以及剥离段之后的广泛调试测量结果（例如横向发射度、束流宽度、束流传输）。使用来自MUCIS离子源的40 Ar 1+束来填充直线加速器直到理论空间电荷极限。1999年11月开始进行例行作业。
英文摘要：
The disassembly of the Unilac prestripper linac of the Wideroe type took place at the beginning of 1999. An increase of more than two orders of magnitude in particle number for the most heavy elements in the SIS had to be gained. Since that time the new High Current Injector (HSI) consisting of H-type RFQ and DTL-structures for dual beam operation was installed and successfully commissioned. The High Charge Injector (HLI) supplied the main linac during that time. Simultaneously conditioning and running in of the rf-transmitters and rf-structures were done. The HSI commissioning strategy included beam investigation after each transport and acceleration section, using a versatile diagnostic test stand. Results of the extensive commissioning measurements (e.g. transverse emittance, bunch width, beam transmission) behind LEBT, RFQ, Super Lens, IH tank I and II and stripping section will be discussed. An 40Ar1+ beam coming from a MUCIS ion source was used to fill the linac up to the theoretical space charge limit. Routine operation started in November 1999.
The linear accelerator (LINAC) at the Los Alamos Neu-tron Science Center (LANSCE) consists of Pre-buncher, Main-Buncher, low-energy beam transport (LEBT), four 201.25-MHz Drift Tube Linacs (DTLs) and forty-four 805-MHz Coupled Cavity Linacs (CCLs). As a part of the upcoming LANSCE Modernization project, low-level RF (LLRF) systems of four 201-MHz DTLs and twenty-six 805-MHz SCLs have been digitized. Hence the net-work-based control of the cavity field and RF commis-sioning are possible. Each LLRF and high-power RF (HPRF) systems have many process variables (PVs) lo-cated on different computer …
We report results of the beam commissioning and first operation of the 1.3 GHz superconducting RF electron linear accelerator at Fermilab Accelerator Science and Technology (FAST) facility. Construction of the linac was completed and the machine was commissioned with beam in 2017. The maximum total beam energy of about 300 MeV was achieved with the record energy gain of 250 MeV in the ILC-type SRF cryomodule. The photoinjector was tuned to produce trains of 200 pC bunches with a frequency of 3 MHz at a repetition rate of 1 Hz. This report describes the aspects of machine commissioning such as …
This work describes first commissioning results from the Cornell Brookhaven Energy Recovery Test Accelerator Fractional Arc Test. These include the recommissioning of the Cornell photo-injector, the first full energy operation of the main linac with beam, as well as commissioning of the lowest energy matching beamline (splitter) and a partial section of the Fixed Field Alternating gradient (FFA) return loop featuring first production Halbach style permanent magnets. Achieving these tasks required characterization of the injection beam, calibration and phasing of the main linac cavities, demons…
The China spallation neutron source (CSNS) linac is designed with beam energy of 81MeV and a peak current of 15mA in the first phase. The RF power system for the 81 MeV Linac requires 8 units of RF power sources, each unit has one independent digital low level RF (LLRF) control system which is used to stabilize the amplitude and phase of the RF accelerating field along the linac, and to minimize beam loss. During beam commissioning, all of 8 on-line units of LLRF control system were operating stably and reliable, the control precision of accelerating fields met requirement of beam commissionin…
Design, Installation, and Initial Commissioning of the MTA Beamline
一个新的实验区，旨在开发，测试和验证使用400兆电子伏费米实验室直线加速器质子束的μ子电离冷却设备已经完全安装，目前正在调试。最初，该区域用于MUCOOL研发计划的液氢吸收剂的低温测试，现在，用于吸收剂的高功率束流测试，存在磁场的高梯度射频腔（包括充气腔）和其他原型μ子冷却装置。为μ子设施开发的实验方案涉及收集、捕获和冷却大发射率、高强度μ子束--约10**13 μ子，因此该设备的最终测试需要完整的直线加速器束，即1.6 x 10**13 p/脉冲。为了支持μ子冷却设施，这条新的初级束线直接从直线加速器提取束流并将其传输到测试设施。MuCool设施的设计概念来自早期的提案，但需要进行修改以适应高强度束流，低温和冷却实验规模的增加。此外，提供精确线的不同操作模式结合了专门的部分并利用直线加速器束参数的测量。本文报告的MuCool光束线的技术细节，这两种模式。
Notes on the design of experiments and beam diagnostics with synchrotron light detected by a gated photomultiplier for the Fermilab superconducting electron linac and for the Integrable Optics Test Accelerator (IOTA)
As an important measure of improving the efficiency and usability of X-ray free electron laser facilities, simultaneous operation of multiple undulator lines realized by a beam distribution system has become a standard configuration in the recent built XFEL facilities. In Shanghai, SXFEL-UF, the first soft X-ray free electron laser user facility in China, has finished construction and started commissioning recently. Electron beam from linac is alternately distributed between the two parallel undulator beam lines by a beam distribution system with a 6° deflection line. The beam distribution sys…
Over the last years, the generation and acceleration of ultra-short, high quality electron beams has attracted more and more interest in accelerator science. Electron bunches with these properties are necessary to operate and test novel diagnostics and advanced high gradient accelerating schemes such as plasma accelerators or dielectric laser accelerators. Furthermore, several medical and industrial applications require high-brightness electron beams. The dedicated R&D facility ARES at DESY will provide such probe beams in the upcoming years. After the setup of the normal-conducting RF photoin…
The Linac to End Station A (LESA) beamline is being constructed at SLAC and will provide a near-CW beam of multi-GeV electrons to the SLAC End Station A for experiments in particle physics. The 1st half of LESA is ready for commissioning at the end of FY22 and the full beamline will be operational Q1 FY24. The low-current multi-GeV electron beam is produced parasitically by the superconducting RF (SRF) linac for the LCLS-II/LCLS-II-HE X-ray Free Electron Laser. LESA is designed to host experiments to detect light dark matter such as the Light Dark Matter eXperiment (LDMX) as well as a wide ran…
CEA is committed to the design, construction and commissioning of a Medium Energy Beam Transfer line and a superconducting linac (SCL) for SARAF accelerator in order to accelerate 5mA beam of either protons from 1.3 MeV to 35 MeV or deuterons from 2.6 MeV to 40 MeV. The Low Level RF (LLRF) is a subsystem of the CEA control domain for the SARAF-LINAC instrumentation. The top level requirement of the LLRF system has been presented in the last LLRF conference. The paper shows a simulink model to analyse and determinate the LLRF technical specification. The public bidding for SARAF LLRF is in the …
Bridging Metal Additive Manufacturing and RF Accelerator Design: Development of a 704.4 MHz Crossbar H-Mode Linac for Efficient Beam Acceleration
GSI Helmholtzzentrum für Schwerionenforschung（GSI亥姆霍兹重离子研究中心）；Institute for Applied Physics, Goethe-University Frankfurt（法兰克福歌德大学应用物理研究所）；Helmholtz Research Academy Hesse for FAIR（黑森亥姆霍兹FAIR研究院）
To improve RHIC luminosity for heavy ion beam energies below 10 GeV/nucleon, the Low Energy RHIC electron Cooler (LEReC) is currently under commissioning at BNL. The Linac of LEReC is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with rms dp/p less than 5e-4. A 704 MHz superconducting radio frequency (SRF) booster cavity in this Linac provides up to 2.2 MeV accelerating voltage. With such a low energy and very demanding energy spread requirement, control of Higher Order Modes (HOMs) in the cavities becomes critical and needs to be carefully evaluated to ensure minimum impact on the b…
Operation of Superconducting Radio Frequency (SRF) cavities with high loaded quality factors is becoming increasingly preferred for applications which involve low beam loading including Energy Recovery Linacs (ERL). Vibration induced microphonics detuning poses a major operational bottleneck in these low bandwidth systems, adversely affecting field stability. Besides passive measures of mitigating the vibration sources, modern SRF cavities are also attached to fast tuners incorporating piezo-electric actuators. We demonstrate the narrow band active noise control algorithm for realizing active …
The KAHVE Laboratory, at Boğaziçi University, Istanbul, Turkey is home to an educational proton linac project. The proton beam will originate from a 20 keV H+ source and will be delivered to a two module Radio Frequency Quadrupole (RFQ) operating at 800 MHz via a low energy beam transport (LEBT) line. Currently, the design phase being over, commissioning and stability tests are ongoing for the proton beamline which is already produced and installed except the RFQ which is being manufactured. This work summarizes the design, production and test phases of the ion source and LEBT line components.
Characterization of relativistic electron bunch duration and travelling wave structure phase velocity based on momentum spectra measurements on the ARES linac at DESY
Experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility to elucidate the effects of long-range wakefields (LRWs) in TESLA-type superconducting rf cavities. In particular, we investigated the higher-order modes (HOMs) generated in the eight cavities of a cryomodule (CM) due to off-axis steering with correctors located ~4 m upstream of the CM. We have observed correlated submacropulse centroid slews of a few-hundred microns and centroid oscillations at ~240 kHz in the rf BPM data after the CM. The entrance energy into the CM was 25 MeV, and the exit energy w…
LCLS-II is currently in its commissioning phase at SLAC. It is an X-ray FEL driven by a CW superconducting LINAC. The beam injector plays a crucial role in the overall performance of the accelerator, and is critical to the final electron beam performance parameters. The LCLS-II injector comprises of a 185.7 MHz VHF copper gun cavity, and a 1.3 GHz two-cell L-band copper buncher cavity. The FPGA-based controller employs feedback and Self-Excited Loop logic in order to regulate the cavity fields. It also features several other functionalities, such as live detune computation, active frequency tr…
