bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy measurement and correction for stable operation in J-PARC
Authors: Moriya K , Harada H , Liu Y , Otani M 
Published: December 2019

Abstract
In Japan Proton Accelerator Research Complex (J-PARC), the beam accelerated up to 400MeV in the Linac is injected to 3 GeV rapid cycling synchrotron (RCS), and we realize the high intensity beam by using multi-turn injection. During a user operation, we rarely detected the beam loss at the high dispersion area in the RCS or the beam collimator section in the extraction beam transport line. These incidents indicate that the beam loss is caused by the momentum shift of RCS injection beam according to the experimental and simulated data. In the beam commissioning, we check the Linac beam momentum just before a user operation of the RCS. However, we could not previously measure the Linac beam momentum during the user operation because we adopt the multi-turn injection with synchrotron oscillation for longitudinal plane. Therefore, we measured the beam momentum in the beam injection line of the RCS. Because the Linac-to-3-GeV-RCS Beam Transport line (L3BT) has the high dispersion areas, we estimated the RCS-injection momentum from the beam orbit data by the Beam Position Monitors (BPMs). We measured the beam position data by these BPMs, and estimated the momentum shift by using the data and beam simulation. As a result, we found the momentum fluctuation during the user operation, and the fluctuation ∆p/p was shifted up to 0.1% from the reference. In addition, to suppress this beam loss induced by the momentum fluctuation and shift, we developed the momentum correction system. The fluctuation was achieved less than ±0.02 % with this system. Finally, the beam loss incidents induced by the beam momentum shift does not occur, and we successfully achieved the more stable user operation in J-PARC.
Reduction of beam induced RF-heating in the horizontal stripline kicker at the TPS
Authors: Chou P J , Chan C K , Chang C C , Hsu K T , Hu K H , Kuan C K , Sheng I C 
Published: December 2019

Abstract
In preparation for 500 mA operation at the Taiwan Photon Source (TPS), we redesigned the horizontal stripline kicker for the beam feedback system to gain a smaller loss factor with higher shunt impedance. We introduced ground fenders (see figure 1) to this new design which resulted in the reduction of the loss factor and substantial increase of the kicker shunt impedance. The transverse profile of the kicker electrodes was matched to the racetrack beam pipe in the straight sections to minimize broadband impedance. The ground fenders can reduce the leakage of image currents through the gaps between the two strip line electrodes and also help to achieve a better impedance matching for the TEM modes in the transmission lines formed by the stripline electrodes and beam pipe in the kicker. The RF design and analysis of trapped resonant modes in the kicker were simulated by the 3-D electromagnetic code GdfidL [1]. Results of the RF design and analysis of trapped resonant modes will be discussed together with analytical estimates of coupled bunch instabilities at a beam current of 500 mA.
A remote-controlled robot-car in the TPS tunnel
Authors: Lee T Y , Chen B Y , Hsu T W , Huang B Y , Lin W Y , Kuo C H 
Published: December 2019

Abstract
A remote-controlled robot-car named “PhotonBot” was put into the TPS accelerator tunnel and is equipped with a 360 ° LiDAR for SLAM and navigation, two cameras for perception and first-person view, and a thermal imaging system. The robot can be remotely controlled and can send data to a remote PC through Wi-Fi. With SLAM, it can go more freely without being restricted to a designated path. In order to ensure it can work continuously, there is a wireless charging station in case of a low battery.
Archive System of Beam Injection Information at SuperKEKB
Authors: Kaji Hiroshi , Obina Takashi , Iitsuka Yuichi , Hirose Masaya 
Published: December 2019

Abstract
The injection archiver system is developed for the SuperKEKB collider. It records the information related to beam injection, pulse-by-pulse, so that the detailed studies of injection conditions become possible. The system is successfully operated during the phase-2 operation of SuperKEKB. The fluctuation and significant loss of injected current are observed with its new determination method. Besides, the recorded data can be utilized for studying the beam backgrounds related to the injection.
Beam Control and Monitors for the Spiral Injection Test Experiment
Authors: Rehman Muhammad Abdul , Iinuma Hiromi , Ohsawa Satoshi , Nakayama Hisayoshi , Furukawa Kazuro , Mibe Tsutomu , Hisamatsu Hiromi 
Published: December 2019

Abstract
A new experiment at J-PARC (E34) is under construction to measure the muon's g – 2 to unprecedented precision of 0.1 ppm and electric dipole moment up to the sensitivity of 10–21 e.cm in order to explore new physics beyond the standard model. A novel three-dimensional spiral injection scheme has been devised to inject and store the beam into a small diameter MRI-type storage magnet for E34. The new injection scheme features smooth injection with high storage efficiency for the compact magnet. However, spiral injection scheme is an unproven idea, therefore, a Spiral Injection Test Experiment (SITE) at KEK Tsukuba Campus is underway to establish this injection scheme. SITE consists of a 80keV thermionic electron gun, two-meter-long beamline, and a solenoid storage magnet. The DC electron beam spiral track has been confirmed by the de-excitation of the nitrogen gas in the vacuum chamber of the storage magnet. A new wire scanner system has been developed to extract the beam current, profile and geometrical information of three-dimensional trajectory.
Multi-Ribbon Profile Monitor for high power proton beam at J-PARC MR Abort Line
Authors: Sato K , Hashimoto Y , Sato Y , Igarashi S , Koseki T , Hamada E 
Published: December 2019

Abstract
Japan Proton Accelerator Research Complex (J-PARC) Main Ring (MR), the world-class high intensity proton synchrotron, provides proton beam to two experimental facilities with two extraction modes: Fast extraction (FX) and Slow extraction (SX). The number of protons per pulse (ppp) in MR recorded the world highest value of 2.7 × 1014 in the FX mode. Now we are planning to increase the ppp further up to 3.3 × 1014 in near future. The beam profile is one of the most important parameters to discuss the high intensity beam dynamics in MR. Monitors using multi-wires /ribbons are effective to measure the beam profile with good accuracy and wide dynamic range. However, they cause significant beam losses by interactions with high-intensity circulating beam in synchrotrons. Recently, we installed new multi-ribbon profile monitor (MRPM) in an abort line in MR. The abort line is one of the extracted beam lines of the FX system. It has a quadrupole doublet which is called Abort Q and transports extracted beam to a beam dump. The FX system can extract the circulating beam in MR with an arbitrary energy. Performing the single-pass measurement with MRPM and changing the transfer matrix by sweeping field strength of Abort Q, the emittance of the extracted beam can be measured. In this paper, we present the design, manufacturing, and results of the first beam test of newly installed MRPM system.
Study on the influence of beam transverse position on the cavity bunch length measurement
Authors: Wang Qian , Luo Qing , Sun Baogen 
Published: December 2019

Abstract
Monopole modes in the resonant cavities are wildly used to obtain the beam current and the bunch length, while dipole modes are used to measure the beam transverse position. It is generally recognized that the monopole modes are independent of the beam transverse offset. In this paper, the influence of beam transverse offset on the bunch length measurement using monopole modes is analyzed. The simulation results show that the relative error of the bunch length measurement is less than 1 % when the beam offset is within 1 mm.
A rotation method to calibrate BPM electric offsets
Authors: Wang M.W. , Wang D. , Wang Z.M. , Qiu M.T. , Zheng S.X. , Ma P.F. , Guan X.L. , Huang W.H. , Wang X.W. 
Published: December 2019

Abstract
Beam position monitor is a key instrument for machine commissioning. To measure beam position accurately, offline calibrations to acquire the sensitivity and offsets of the BPM are essential prerequisites. A new method to calibrate the BPM electric offset is proposed in this paper. By measuring the location variation of the BPM electric center after rotating the BPM 180 degrees, the BPM offset can be derived. The method is more convenient, universal and accurate than the traditional methods. The method is successfully applied to calibrate the button BPM of Xi’an Proton Application Facility. The repetitive measurement error is 20.8μm.
Design and simulation of thin eddy-current septum for injection of diffraction limited storing ring
Authors: Tong J , Gu M , Liu B , Liu Y , Wang R 
Published: December 2019

Abstract
Ultra-low emittance in Diffraction Limited Storage Ring (DLSR) usually has small Dynamic Aperture (DA), which makes the traditional off-axis injection inadequate. Fast kickers together with thin septum magnets or direct current lambertsons could support on-axis injection for closely-spaced bunches with small DA. Thin eddy-current septum prototype had been designed for injection with laminated silicon steel sheets as magnet core. Theoretical analysis and transient simulation had been carried out within OPERA software. Due to the minimum thickness of the septa is only 1 mm, several optimization approaches had been applied, such as shielding with strongly paramagnetic material and exciting with full cycle driving pulse, to satisfy the requirement that the leakage field is less than 0.1% with respect to the main one.
The preliminary long-term slow drift calibration study in low- level RF system
Authors: Lin Z.Y. , Du Y. C. , Huang W.H. , Tang J.H. , Tang C.X. , Huang G. , Xu Y.L , Zhang D. , Sun Z.C. 
Published: December 2019

Abstract
The phase drift of the RF signal in the low-level radio frequency (LLRF) system is observed in the long-term operation, which limits the performance and stability of the LLRF system. The long-term drift was reproduced in the lab. Its effect and sources of error were explored in the simple LLRF46 board and the simplest LLRF system. It is founded that the temperature will significantly lead to the phase distortion of the two signal channels, although with the same electron device. The distortion will finally cause the long-term drift with temperature floating. A fixed phase calibration signal (CAL signal) is applied to deal with the signal channels difference. The preliminary tests were conducted and the results were analysed.
HiRadMat: A Facility Beyond the Realms of Materials Testing
Authors: Harden F J , Bouvard A , Charitonidis N , Kadi Y 
Published: December 2019

Abstract
The ever-expanding requirements of high-power targets and accelerator equipment has highlighted the need for facilities capable of accommodating experiments with a diverse range of objectives. HiRadMat, a High Radiation to Materials testing facility at CERN has, throughout operation, established itself as a global user facility capable of going beyond its initial design goals. Pulsed high energy, high intensity, proton beams have been delivered to experiments ranging from materials testing, detector's prototype validation, radiation to electronics assessment and beam instrumentation. A 440 GeV/c proton beam is provided directly from the CERN SPS. Up to 288 bunches/pulse at a maximum pulse intensity of 3.5 × 1013 protons/pulse can be delivered. Through collaborative efforts, HiRadMat has developed into a state-of-the-art facility with improved in situ measurement routines, beam diagnostic systems and data acquisition techniques, offered to all users. This contribution summarises the recent experimental achievements, highlights previous facility enhancements and discusses potential future upgrades with particular focus on HiRadMat as a facility open to novel experiments.
RF Data Acquisition and Soft Alarm System for the Taiwan Photon Source
Authors: Liu Z. K. , Chang F. Y. , Chang L. H. , Chang M. H. , Chang S. W. , Chen L. J. , Chung F. T. , Li Y. T. , Lin M. C. , Lo C. H. , Wang C. , Yeh M. S. , Yu T. C. 
Published: December 2019

Abstract
The Taiwan Photon Source (TPS) is a modern, high brightness 3 GeV light source. A data acquisition program for the radio frequency (RF) system, including a transient data recorder, a long term data archiver and real time data monitoring, has been developed for the analysis of RF trips and RF system debugging. A soft alarm system is implemented as well utilizing EPICS and python packages. The hardware architecture and the functionality of the RF data acquisition and soft alarm system will be discussed in this article.
Progress and TDR plans of the Mechanical system of CEPC
Authors: Wang H , Bai S , Li M , Liu Y , Meng C , Qu H , Wang J , Zhang P , Zhou N 
Published: December 2019

Abstract
The TDR of CEPC is aimed at the key science and technology problems and makes preparations for the real project. This paper will describe the progress of mechanical system including the regular supports and transport vehicle design, the mockup plan, the installation scenario of machine detector interface (MDI) and the movable collimator, as well as the TDR plans of mechanical system.
Preparation of Titanum-Zirconium-Vanadium films by quantitative deposition
Authors: Shao J Q , Ge X Q , Wei W , Zhang B , Wang S H , Zhang Y X , Zhu B L , Chen C , Li W M , Wang Y 
Published: December 2019

Abstract
TiZrV has been used in vacuum technology and electric vacuum devices due to its high pumping speed and low activation temperature in recent years. At the same time, many preparation methods have been developed. Different from the current coating method of magnetron sputtering, this paper discusses the preparation of thin film coating from the viewpoint of vacuum sintering, which is flexible in design and more suitable for operation. Based on the analysis of the surface morphology of the sintered film, the feasibility and operability of the experimental method were explored from the surface compactness of the getter.
New small diameter rotating coil shaft for characterizing new generation of multipolar magnets
Authors: Campmany J. , Marcos J. , Massana V. , Ribó Ll. , Petrocelli R. 
Published: December 2019

Abstract
The proliferation of ultimate-light source facilities around the world has yielded the need of accurate characterization of small gap magnets. This also applies to multipolar magnets. Clearance diameters down to 10 mm for quadrupoles and sextupoles become to be used and need to be accurately measured. At these small gaps, the high order multipoles influence on electron beam dynamics is high, and it should be well characterized in order to guarantee a feasible operation of the accelerator. To face this challenge, ALBA magnetic measurement laboratory has developed a new rotating coil shaft with a diameter of 10 mm able to be introduced inside narrow-gap multipolar magnets. In this paper we present the design as well as the manufacturing of such a device.
The commission of the home-made 500MHz, 80kW solid-state amplifier in NSRRC
Authors: Yu T C , Wang Ch , Chang L H , Yeh M S , Lin M C , Lo C H , Chung F T , Chang M H , Chen L J , Liu Z K , Chang Fu-Yu , Chang S W , Li Yi-Da 
Published: December 2019

Abstract
Solid-state for high power RF application is an attracting and interesting technology which is now become popular in accelerator field. To adopt and master such technique, a 500MHz, 80kW solid-state amplifier is thus developed in NSRRC. The amplifier is consisted of 100 900W amplifier modules which are driving by identical modules. Each module contains input and output directional couplers and status monitoring circuits. To have longer life time and better performance, the RF power transistors are integrated with water cooled heat sink directly. In such a way, the transistors have higher output power and better efficiency. The RF power of each module is combined through coaxial combiner while its DC power is provided by parallel connected DC power supplies which can provide better redundancy and reliability. The home-made solid-state amplifier is demonstrated to have quite high quality RF power and reliability with acceptable power combination efficiency.
Design of the Neutron Imaging Differential Pumping Line at LLNL*
Authors: Caggiano J A , Castronovo D , Fitsos P , Gibson D J , Hall J , Johnson M S , Marsh R A , Rusnak B 
Published: December 2019

Abstract
The neutron imaging system at LLNL is a radiographic capability for imaging objects with fast, quasi-monoenergetic neutrons at ⩽1mm spatial resolution. The neutron production source is a deuteron beam (4 or 7 MeV) incident upon a rotating, high-pressure, windowless, pure-deuterium gas target. The windowless nature of the target combined with the high pressure leads to significant gas leakage upstream of the neutron production target. This leakage degrades the imaging quality by (1) increasing the depth-of-field blurring and (2) increasing the beam diameter and divergence in the transverse direction via angular straggling in the residual gas. To mitigate these effects, and guided by bench tests and simulations, we designed a differential pumping line (DPL) to ensure the highest quality imaging system. The system consists of three primary stages (chambers), each separated by carefully shaped apertures. These apertures can be long and thin with low-angle tapers due to the high quality of the beam optics (convergence at the target < 5mrad) and low emittance of the beam (~5 pi mm- mrad). The primary cascaded roots pumps are sized to remove >99% of the incoming mass flow in each stage, ensuring that by the third stage furthest from the target, turbomolecular pumps are able to operate in a nominal ~mTorr range. We anticipate full system testing with helium in mid 2019.
Data-driven Controller Design Using the CERN Power Converter Control Libraries (CCLIBS)
Authors: Nicoletti Achille , Martino Michele 
Published: December 2019

Abstract
The data-driven control approach is a control methodology in which a controller is designed without the need of a model. Parametric uncertainties and the associated unmodeled dynamics are therefore irrelevant; the only source of uncertainty comes from the measurement process. The CERN Power Converter Control Libraries (CCLIBS) have been updated to include data-driven H-infinity control methods recently proposed in literature. In particular, a two-step convex optimization algorithm is performed for obtaining the 2-degree-of-freedom controller parameters. The newly implemented tools in CCLIBS can be used both for frequency response measurement of the load and for controller synthesis. A case study is presented where these tools are used for an application in the CERN East Area Renovation Project for which a high-precision 900 A trapezoidal current pulse is required with 450 ms flat-top and 350 ms ramp-up and ramp-down times. The tracking error must remain within +/- 100 parts-per-million (ppm) during the flat-top (before the ramp-down phase starts). The magnet considered in the case study is of non-laminated iron type, hence the necessity of data-driven techniques since the dynamics of such a magnet is difficult to be modeled accurately (due to eddy currents losses). The power converter used is a SIRIUS 2P (with a current and voltage rating of 400 Arms and 450 V, respectively) whose digital control loop is regulated at a sampling rate of 5kS/s.
Stand-alone accelerator system based on SRF quarter-wave resonators
Authors: Kutsaev S V , Agustsson R , Berry R , Chao D , Conway Z A 
Published: December 2019

Abstract
Superconducting accelerators are large and complex systems requiring a central refrigerator and distributed transfer systems to supply 2-4 K liquid helium. Stand-alone, cryocooler-based systems are of interest both to scientific facilities and for industrial applications, as they do not require large cryogenic infrastructure and trained specialists for operation. Presented here is our approach to the challenge of using low-power commercially avail-able cryocoolers to operate niobium superconducting resonators at 4.4 K with high accelerating voltages and several watts of heating. Engineering and design results from RadiaBeam Systems, collaborating with Argonne National Laboratory, for a stand-alone liquid-cooled cryomodule with 10 Watts of 4.4 K cooling capacity housing a 72.75 MHz quarter-wave resonator operating at 2 MV for synchronous ions travelling at 7.7% of speed of light will be discussed.
Simulation of quench detection algorithms for Helmholtz Zentrum Berlin SRF cavities
Authors: Echevarria P , Garcia Arruabarrena B , Ushakov A , Jugo J , Neumann A 
Published: December 2019

Abstract
The Helmholtz Zentrum Berlin is carrying out two accelerator projects which make use of high gradient Continuous Wave (CW) Superconducting Radiofrequency (SRF) cavities: bERLinPro and BESSY-VSR. In both projects, a prompt detection of a quench is crucial to avoid damages in the cryomodules and cavities themselves. In this paper, the response of real time estimation of the cavity parameters using the transmitted and forward RF signals is simulated, in order to perform the quench detection. The time response of the estimated half bandwidth is compared with the dissipated energy in the cavity walls for the different type of SRF cavities used in both projects, i.e., bERLinPro’s photoinjector, booster and linac, and BESSY-VSR 1.5 GHz and 1.75 GHz cavities. As an intermediate step prior to the implementation in an mTCA.4 system together with the LLRF control and test with a real cavity, the algorithm has been implemented using a National Instruments FPGA board to check its proper behavior.
Tuning of a tapered ridge-loaded waveguide coupler for a drift tube linac of the compact pulsed hadron source
Authors: Lei Y , Zheng S , Xing Q , Tang R , Du C , Guan X , Wang X 
Published: December 2019

Abstract
This paper presents the tuning result of a tapered ridge-loaded waveguide coupler for the drift tube linac (DTL) of the compact pulsed hadron source (CPHS) at Tsinghua University. The coupler has been designed, manufactured, and mounted on the DTL cavity for the cold measurement and tuning. The iris diameter of the coupler which is related to the coupling coefficient needs to be determined in the tuning experiment, due to the difference between the designed and measured quality factors. Meanwhile, we found that the relationship between the coupling coefficient and iris diameter from the traditional analytical design method is not applicable when the iris diameter is relatively large. In this paper, the target coupling coefficient is analyzed, and the limit of the original analytical design is presented. The measurement method is introduced to improve the measurement efficiency and the tuning process of the coupling coefficient to the target value is described. After several iterations, the coupling coefficient is tuned to 1.54 which is close to the desired value of 1.56.
Multi-physics computation and deformation testing of a shell-type 1.5-GHz cavity
Authors: Lin M C , Yeh M K , Lu M R , Lo C H 
Published: December 2019

Abstract
A copper prototype of a 1.5-GHz cavity was manufactured to simulate a superconducting radio-frequency cavity for technique development. Frequency tuning with longitudinal compression of this prototype and cryogenic cooling with liquid nitrogen were performed to examine the numerical results from finite-element models, mainly the corresponding shifts of the fundamental resonant frequency. An appropriate element option improved the accuracy of the resonant frequency and the distribution of the magnetic field. Effects of geometry distortion of an uneven length on the frequency shift of this shell-type cavity as loaded on longitudinal compression are also examined and discussed.