Beam charge and current monitors
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MOCO01 Online Touschek Beam Lifetime Measurement Based on the Precise Bunch-By-Bunch Beam Charge Monitor 36
 
  • B. Gao, F.Z. Chen, Y.B. Leng
    SSRF, Shanghai, People’s Republic of China
  • Y.M. Zhou
    SINAP, Shanghai, People’s Republic of China
 
  Beam current and lifetime are the most important parameters to characterize the beam and machine quality of an electron storage ring. In order to describe the behavior of all electron bunches completely and accurately, a precisely bunch-by-bunch charge monitor has been developed at SSRF. Method called two-point equilibrium sampling is introduced to avoid the influence of longitudinal oscillation on the sampling point, thanks to this, the resolution of the BCM was below 0.2 pC. Utilizing the advantages of BCM’s high refresh rate and high resolution, the system can meet the requirement of monitor the bunch-by-bunch beam lifetime, measure touschek lifetime and vacuum lifetime. In this paper, experiments and and analysis will be described in detail.  
slides icon Slides MOCO01 [18.156 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOCO01  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOCO02 Development of a Passive Cavity Beam Intensity Monitor for Pulsed Proton Beams for Medical Applications 41
 
  • P. Nenzi, A. Ampollini, G. Bazzano, F. Cardelli, L. Picardi, L. Piersanti, C. Ronsivalle, V. Surrenti, E. Trinca
    ENEA C.R. Frascati, Frascati (Roma), Italy
 
  Funding: This work has been funded by the Innovation Department of Regione Lazio Government, Italy.
In this work the design of a passive cavity beam intensity monitor to be used in the TOP-IMPLART medical proton linac for the on-line measurement of beam current is presented. It will be used to monitor the beam between modules and at the linac exit. TOP-IMPLART produces a pulsed proton beam with 3 us duration at 200 Hz repetition rate with a current between 0.1 uA and 50 uA. The current required for medical applications is less than 1 uA and has to be known with an accuracy better than 5%. Large dynamic range and space constraints make the use of usual non-interceptive beam diagnostics unfeasible. The proposed system consists of a resonant cavity working in the TM010 mode, generating an electromagnetic field when the beam enters the cavity; a magnetic pickup senses an RF pulse whose amplitude is proportional to the current. The RF pulse is amplified and subsequently detected with zero-biased Schottky diodes. The cavity operates in vacuum when used in the inter-module space. The work reports also the results of preliminary measurements done on an copper prototype in air at the exit of the TOP-IMPLART linac to test the sensitivity of the system on the actual 35 MeV proton beam.
 
slides icon Slides MOCO02 [3.269 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOCO02  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP001 Safety Classified System Using Beam Intensity Monitoring for the Respect of Nuclear Requirements of SPIRAL2 Facility 55
 
  • P. Anger, C. Berthe, F. Bucaille, V. Desmezières, C.H. Haquin, C. Jamet, S. Leloir, G. Normand, JC-P. Pacary, S.P.G. Perret-Gatel, A. Savalle
    GANIL, Caen, France
 
  The SPIRAL2 Facility at GANIL is based on the construction of a superconducting ion CW LINAC (up to 5 mA - 40 MeV deuteron beams and up to 1 mA - 14.5 MeV/u heavy ion beams) with 2 experimental areas called S3 and NFS. The building, the accelerator and experimental equipment studies started in 2009. For safety classified system using beam intensity monitoring, SPIRAL2 project system engineering sets up a specific reinforced process, based on V-Model, to validate, at each step, all the requirements (technical, nuclear safety, quality, reliability, interfaces…) from the functional specifications to the final validation. Since 2016, the main part of the safety devices is installed and is currently under testing. These tests which are pre-requisites to deliver the first beam will demonstrate that both functional and safety requirements are fulfilled. This contribution will describe the requirements (operation field, limitation of equipment activation¿), the technical studies, the failure mode and effects analysis, the tests, the status and results of the SPIRAL2 Machine Protection System using AC and DC current transformers to measure and control the beam intensity.  
poster icon Poster MOPP001 [1.786 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP001  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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MOPP002 Current Per Bunch Distribution Measurement at ESRF 59
 
  • L. Torino, B. Roche, B. Vedder
    ESRF, Grenoble, France
 
  During the last run of the ESRF machine, several instrumentation improvements have been carried out in order to be exported on the new EBS storage ring. In particular, the top-up operation mode has been implemented and it demanded for an accurate, fast, and reliable measurement of the current per bunch distribution. In this proceeding, we describe the characteristics and the performance of the setup chosen to perform this measurement, which consists in a stripline, connected with a high dynamic range oscilloscope and a dedicated data analysis. We also comment on the integration of the measurement in the top-up routine to selectively refill less populated bunches.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP002  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP003 Beam Current Measurements with Sub-Microampere Resolution using CWCT and BCM-CW-E 63
 
  • F. Stulle, L. Dupuy, E.T. Touzain
    BERGOZ Instrumentation, Saint Genis Pouilly, France
  • W.A. Barth, P. Forck, M. Miski-Oglu, T. Sieber
    GSI, Darmstadt, Germany
 
  The CWCT current transformer and its accompanying BCM-CW-E electronics allow accurate, high-resolution beam current measurements. This is achieved by combining a high-droop current transformer with low-noise sample-and-hold electronics. Thanks to a fast response time on the microseconds level the system can be applied not only to CW beams but also macropulses. Pulse repetition rates may range from 10MHz to 500MHz, rendering CWCT and BCM-CW-E suitable for a wide variety of accelerators. We report on test bench measurements achieving sub-microampere resolution. And we discuss results of beam measurements performed at the cwLINAC (GSI), which confirm the expected performance.  
poster icon Poster MOPP003 [6.507 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP003  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP004 Development and Calibration of a Multi-Leaf Faraday Cup for the Determination of the Beam Energy of a 50 MeV Electron LINAC in Real-Time 67
 
  • C. Makowski, A. Schüller
    PTB, Braunschweig, Germany
 
  The Physikalisch-Technische Bundesanstalt (PTB), Germany’s national primary standard laboratory, operates an electron LINAC with variable energy (0.5 - 50 MeV). All parameters of the LINAC which influence the RF power (as e.g. the high voltage at modulator) as well as the number of charged particles in a bunch to be accelerated (as e.g. via gun emission) also change the beam energy. To measure the energy during the preparation or optimization of a beam, a Multi-Leaf Faraday Cup (MLFC) was developed. This MLFC allows the measurement of energy and pulse charge in real time, so the influence of the manipulated variables on energy and beam power can be immediately assessed. The MLFC consists of 128 electrically isolated Al plates where the thickness of the entire stack is sufficient to stop a 50 MeV electron beam. After each beam pulse, the charge collected by the Al plates is recorded sequentially. The MLFC was calibrated with monoenergetic electron beams at output of a magnetic spectrometer. Then the MLFC was installed at the end of the accelerator structure. From the recorded charge distributions, the corresponding energy is determined in real time and displayed for each beam pulse.  
poster icon Poster MOPP004 [3.739 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP004  
About • paper received ※ 30 August 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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MOPP005 Radiation hardness investigation of Zinc oxide fast scintillators with relativistic heavy ion beams. 71
 
  • P. Boutachkov, A. Reiter, M. Saifulin, B. Walasek-Höhne
    GSI, Darmstadt, Germany
  • E.I. Gorokhova
    GOI, St Petersburg, Russia
  • P. Rodnyi, I.D. Venevtsev
    SPbPU, St. Petersburg, Russia
 
  At GSI ion beams of many elements, from H up to U, are produced with energy as high as 4.5 GeV/u with the SIS-18 synchrotron. For absolute beam intensity and micro-spill structure measurements a BC400 organic scintillator is used. Due to the low radiation hardness of this material, alternative inorganic scintillators like ZnO:Ga and ZnO:In were investigated. The properties and possible application of these novel radiation hard fast scintillators will be discussed. Their response to Sn, Xe and U ion beams will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP005  
About • paper received ※ 04 September 2019       paper accepted ※ 09 September 2019       issue date ※ 10 November 2019  
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MOPP007 Versatile Beamline Cryostat for the Cryogenic Current Comparator (CCC) for FAIR 78
 
  • D.M. Haider, F. Kurian, M. Schwickert, T. Sieber, T. Stöhlker, F. Ucar
    GSI, Darmstadt, Germany
  • H. De Gersem, N. Marsic, W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
  • J. Golm
    FSU Jena, Jena, Germany
  • J. Golm, T. Koettig
    CERN, Meyrin, Switzerland
  • M. Schmelz, R. Stolz, V. Zakosarenko
    IPHT, Jena, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • T. Stöhlker, V. Tympel
    HIJ, Jena, Germany
  • V. Zakosarenko
    Supracon AG, Jena, Germany
 
  Funding: Work supported by AVA - Accelerators Validating Antimatter the EU H2020 Marie-Curie Action No. 721559 and by the BMBF under contract No. 05P15SJRBA and 5P18SJRB1.
The Cryogenic Current Comparator (CCC) extends the measurement range of traditional non-destructive current monitors used in accelerator beamlines down to a few nano-amperes of direct beam current. This is achieved by a cryogenic environment of liquid helium around the beamline, in which the beam’s magnetic field is measured with a Superconducting Quantum Interference Device (SQUID), which is itself enclosed in a superconducting shielding structure. For this purpose, a versatile UHV-beamline cryostat was designed for the CCCs at FAIR and is currently in production. It is built for long-term autonomous operation with a closed helium re-liquefaction cycle and with good access to all inner components. The design is supported by simulations of the cryostat’s mechanical eigenmodes to minimize the excitation by vibrations in an accelerator environment. A prototype at GSI has demonstrated the self-contained cryogenic operation in combination with a 15 l/day re-liquefier. The cryostat will be used in CRYRING to compare the FAIR-CCC-X with newly developed CCC-types for 150 mm beamlines. Both which will supply a nA current reading during commissioning and for the experiments.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP007  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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MOPP008 First Measurements of a New Type of Coreless Cryogenic Current Comparators (4C) for Non-Destructive Intensity Diagnostics of Charged Particles 82
 
  • V. Tympel, T. Stöhlker
    HIJ, Jena, Germany
  • S. Anders, J. Kunert, M. Schmelz, R. Stolz, V. Zakosarenko
    IPHT, Jena, Germany
  • H. De Gersem, N. Marsic, W.F.O. Müller
    TEMF, TU Darmstadt, Darmstadt, Germany
  • J. Golm, F. Schmidl, T. Schönau, P. Seidel, M. Stapelfeld
    FSU Jena, Jena, Germany
  • D.M. Haider, M. Schwickert, T. Sieber, T. Stöhlker
    GSI, Darmstadt, Germany
  • T. Stöhlker
    IOQ, Jena, Germany
  • J. Tan
    CERN, Geneva, Switzerland
  • V. Zakosarenko
    Supracon AG, Jena, Germany
 
  Funding: Supported by the BMBF, project numbers 05P15SJRBA, 05P18RDRB1 and 05P18SJRB1.
The non-destructive and highly sensitive measurement of a charged particle beam is of utmost importance for modern particle accelerator facilities. A Cryogenic Current Comparator (CCC) can be used to measure beam currents in the nA-range. Therein, charged particles passing through a superconducting toroid induce screening currents at the surface of the toroid, which are measured via SQUIDs. Classical CCC beam monitors make use of a high magnetic permeability core as a flux-concentrator for the pickup coil. The core increases the pickup inductance and thus coupling to the beam, but unfortunately also raises low-frequency noise and thermal drift. In the new concept from the Leibniz Institute of Photonic Technology the Coreless Cryogenic Current Comparator (4C) completely omits this core and instead uses highly sensitive SQUIDs featuring sub-micron cross-type Josephson tunnel junctions. Combined with a new shielding geometry a compact and comparably lightweight design has been developed, which exhibits a current sensitivity of about 6 pA/sqrt(Hz) in the white noise region and a measured shielding factor of about 134 dB*.
* V. Zakosarenko et al., Coreless SQUID-based cryogenic current comparator for non-destructive intensity diagnostics of charged particle beams, Supercond. Sci. Technol. 32 (2019) 014002.
 
poster icon Poster MOPP008 [13.550 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP008  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP009 Retrieving Beam Current Waveforms from ACCT Output Using Experimental Response Function for Use in Long Pulse Accelerators 85
 
  • Y. Hirata, J. Franco Campos, A. Kasugai
    QST, Aomori, Japan
 
  Current transformers (ACCT/DCCT) are used as non-interceptive means of beam current measurement in many accelerators. In the case of long pulse to CW accelerators for fusion neutron sources such as IFMIF, A-FNS, etc., current measurement using current transformers for pulses with around 10-100 ms or longer suffer such problems as drooping and the measurement accuracy is deteriorated. So, improving the accuracy for long pulse beams is highly required. We have proposed a method for retrieving the beam currents from the ACCT output using the transfer function obtainable from simple experiments. It was confirmed from numerical calculation that beam currents longer than a second could be theoretically retrieved*. The effects of associated circuits and cables such as stray capacitance, inductance and magnetic materials nearby are inherently included in the transfer function. We are working for implementing this method into FPGA. For calculation convenience, the transfer function is converted into a form of impulse function and the convolution with the digitized ACCT output is to be carried out to retrieve the beam current. The theory, algorithm and design will be discussed.
Y. Hirata, et al., IEEE Trans. Plasma Sci., Vol. 46 (2018), pp. 2272.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP009  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP010 Design and Properties of a New DCCT Chamber for the PF-Ring at KEK 91
 
  • R. Takai, T. Honda, T. Nogami, T. Obina, Y. Tanimoto
    KEK, Ibaraki, Japan
 
  A DC current transformer (DCCT) for the PF-ring was renewed during the 2018 summer shutdown. A vacuum chamber for the new DCCT was designed based on a circular duct with an inner diameter of 100 mm and has a structure housing a toroidal core inside of electromagnetic shields. The geometry of the ceramic break for interrupting the wall current flow was optimized using a three-dimensional electromagnetic field simulator, and the break was fabricated considering some technical limitations. Both ends of the ceramic break were short-circuited in a high-frequency manner by a sheet-like capacitive structure to suppress the radiation of unneeded higher-order modes (HOMs) into the core housing. The ceramic break is also equipped with water-cooling pipes on metal sleeves brazed to the both ends to efficiently remove the heat generated by HOMs. The new DCCT chamber has been used already in user operation without any problems. A temperature rise near the ceramic break is still approximately six degrees Celsius, even when a 50-mA isolated bunch is stored.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP010  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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MOPP011 A Dual Functional Current Monitor for Stripping Efficiency Measurement in CSNS 96
 
  • W.L. Huang, F. Li, R.Y. Qiu, A.X. Wang
    IHEP CSNS, Guangdong Province, People’s Republic of China
  • M.Y. Huang, M.Y. Liu, T.G. Xu
    IHEP, Beijing, People’s Republic of China
 
  Funding: This work is supported by National Natural Science Fund(No.11605214).
China Spallation Neutron Source (CSNS), the biggest platform for neutron scattering research in China, has been finished construction and already in user operation stage by the end of 2017. During the multi-turn charge-exchange injection, H stripping by a carbon primary stripper foil (100 ¿g/cm2) and a secondary stripper foil (200 ¿g/cm2) is adopted for this high intensity proton synchrotron. In order to evaluate the stripping efficiency and the foil aging, a dual-function low noise current transformer and corresponding electronics are designed to measure the ultra-low intensity of H and H0, which are not stripped completely by the 1st foil but totally stripped charge changing to H+ and delivered to the IN-DUMP. The self-designed CT sensors made of domestic nanocrystalline toroids, the noise analysis and elimination, measurement results and further improvement proposals are presented in this paper.
 
poster icon Poster MOPP011 [3.186 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP011  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP012 Development of Compact Ionization Chambers for Particle Therapy Facilities 100
 
  • M. Liu, C.X. Yin
    SSRF, Shanghai, People’s Republic of China
 
  Dose monitors and position monitors are critical equipment for particle therapy facilities. Performance of the monitors affects precision of irradiation dose and dose distribution. Parallel plate ionization chambers with free air are adopted for dose monitors and position monitors. Radiation-hardened front-end electronics are integrated in the chambers, and the output of the chambers are digital signals. The structure of the monitors is compact, modularized and easy-to-use. The ionization chambers are implemented successfully in Shanghai Advanced Proton Therapy Facility. The development details and implementation status are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP012  
About • paper received ※ 02 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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MOPP013 Faraday Cup Selector for DC-280 Cyclotron 103
 
  • V.V. Aleinikov, S. Pachtchenko
    JINR, Dubna, Moscow Region, Russia
  • K.P. Sychev, V. Zabanova
    JINR/FLNR, Moscow region, Russia
 
  New isochronous cyclotron DC-280, the basic facility of Super Heavy Element (SHE) factory was put into operation in the FLNR JINR on March 25, 2019. Key role in beam diagnostics for lossless transportation is played by Faraday cups. Five elements were installed along the two injection lines, and 12 elements on the five transport channels to the experimental facilities. The software was developed to automatically select the active Faraday cup depending on its location and track the current on a single indicator. This paper describes basic principles and algorithm of the Faraday cup Selector module which is a part of the DC-280 cyclotron control system.  
poster icon Poster MOPP013 [2.214 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP013  
About • paper received ※ 27 August 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP014 Design of the ESS MEBT Faraday Cup 106
 
  • A. Rodríguez Páramo, I. Bustinduy, I. Mazkiaran, R. Miracoli, V. Toyos, S. Varnasseri, D. de Cos, C. de la Cruz
    ESS Bilbao, Zamudio, Spain
  • E.M. Donegani, J.P.S. Martins
    ESS, Lund, Sweden
 
  The European Spallation Source (ESS) is currently under construction and the Medium Energy Beam Transfer (MEBT) is developed by ESS-Bilbao as an in-kind contribution. In the MEBT a set of diagnostics is included for beam characterization, among them the MEBT Faraday Cup is used to measure beam current and as a beam stopper for the commissioning modes. The main challenges for the design and manufacturing of the Faraday Cup are the high irradiation loads and the necessity of a compact design due to the space constraints in the MEBT. We describe the design of the FC, characterized by a graphite collector, required to withstand irradiation, and a repeller for suppression of secondary electrons. For the operation of the Faraday Cup acquisition electronics and control system are developed, all systems have been integrated in the ESS-Bilbao ECR ion source to test operation under beam conditions. In this work, we discuss the design of the Faraday Cup, the results of the tests and how they agree with the expected performance of the Faraday Cup.  
poster icon Poster MOPP014 [1.786 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP014  
About • paper received ※ 02 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP015 Charge Detection System for the CLARA/VELA Facility 111
 
  • S.L. Mathisen, Y.M. Saveliev, R.J. Smith
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
 
  The CLARA/VELA facility at Daresbury Laboratory combines an FEL test facility and an electron accelerator for scientific and industrial applications, capable of providing up to 40 MeV electrons, with an eventual goal of 250 MeV. Accurate measurement of the bunch charges in a wide range (1 - 250 pC) at a repetition rate up to 400 Hz is required. We present a new system of analogue electronics developed to interface with existing and future bunch charge measurement devices (wall current monitors, faraday cups, etc.) to measure the bunch charges accurately and precisely. The system is based on a charge amplifier with switchable sensitivity, dark current gating and on-board self-calibration. Results of circuit simulations, offline calibration tests and online beam tests of a prototype system are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP015  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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