Automatic Adjustment and Measurement of the Electron Beam Current at the Metrology Light Source (MLS)
113
Y. Petenev, J. Feikes, J. Li
HZB, Berlin, Germany
A.B. Barboutis, R. Klein, M. Müller
PTB, Berlin, Germany
The electron storage ring MLS (Metrology Light Source) is used by the Physikalisch-Technische Bundesanstalt (PTB), the German metrology institute, as a primary source standard of calculable synchrotron radiation in the ultraviolet and vacuum ultraviolet spectral range. For this, all storage ring parameters have to be appropriately set and measured with high uncertainty. E.g., the electron beam current can be varied by more than 11 orders. This adjustment of the electron beam current, and thus the spectral radiant intensity of the synchrotron radiation, for the specific calibration task is conveniently performed fully automatic by a computer program.
Analog Front End for Measuring 1 to 250 pC Bunch Charge at CLARA
117
S.L. Mathisen, T.H. Pacey, R.J. Smith
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
As part of the development of the CLARA electron accelerator at Daresbury Laboratory, a new analog front end for bunch charge measurement has been developed to provide accurate measurements across a wide range of operating charges with repetition rates of up to 400 Hz. The qualification tests of the front end are presented. These include tests of the online calibration system, compared to a bench Faraday cup test setup; online beam test data with a Faraday cup from 1 to 200 pC; online beam test data with a wall current monitor from 1 to 200 pC, and tests using signal processing such as singular value decomposition. This is demonstrated to enable the measurement of bunch charges in the order of 100 fC using both Faraday Cups and Wall Current Monitors.
Beam Current Measurements at the Nano-Ampere Level Using a Current Transformer
121
M. Xiao
UMCG, Groningen, The Netherlands
S. Brandenburg, M.J. Goethem
PARTREC, Groningen, The Netherlands
T. Delaviere, L. Dupuy, F. Stulle
BERGOZ Instrumentation, Saint Genis Pouilly, France
In conventional proton therapy (PT) typical beam currents are of the order of 1 nA. At these currents dose monitoring is reliably achieved with an ionization chamber. However, at the very high dose rates used in FLASH irradiations (employing beam currents >100 nA) ionization chambers will exhibit large intensity dependent recombination effects and cannot be used. A possible solution is a current transformer. Here we report on the performance of the LC-CWCT (Bergoz Instrumentation, France) which has been developed to push noise floor of such non-destructive current measurement systems into the nano-ampere range. We present first beam current measurements at the PARTREC cyclotron (Netherlands). Beam currents measured by the LC-CWCT and a Faraday Cup were shown to linearly correlate up to the maximum intensity of 400 nA used in the measurements. For pulsed beams, charge measured by the LC-CWCT linearly correlated with pulse length over the measurement range from 50 to 1000 µs. Measurement noise as low as 2.8 nA was achieved. The results confirm that the LC-CWCT has the potential to be applied in FLASH PT for accurate determination of beam current and macro pulse charge.
ZnO(In) Scintillation Light Spectra Investigation for Heavy Ion Detector Application
294
M. Saifulin, C. Trautmann
TU Darmstadt, Darmstadt, Germany
P. Boutachkov, M. Saifulin, C. Trautmann, B. Walasek-Höhne
GSI, Darmstadt, Germany
E.I. Gorokhova
GOI, St Petersburg, Russia
P. Rodnyi, I.D. Venevtsev
SPbPU, St. Petersburg, Russia
Funding:DLR financed this research within the framework of the ERA. Net RUS Plus Project RUSST2017-051 ZnO-based ceramics are known as promising scintillators exhibiting light emission in the ultraviolet (UV) spectral region (~390 nm) and ultrafast decay times (<1 ns). They are of great interest for applications in scintillation counters and screens at high-energy heavy ion accelerators. In this contribution, the deterioration of scintillating properties of ZnO-based ceramics subjected to heavy ion exposure at high doses is investigated. The scintillation light spectra of ZnO(In) as a function of fluence for 4.8 MeV/u 48Ca and 197Au ions were studied. We observed that the deterioration of the scintillation intensity with increasing fluence follows the Birks-Black model. * The results presented in this contribution are based on the work performed before the 24th of February, 2022. ** m.saifulin@gsi.de (corresponding author)
Beam Intensity Measurement in ELENA Using Orbit Pick-Ups
296
O. Marqversen, D. Alves
CERN, Meyrin, Switzerland
A bunched beam intensity measurement system for the CERN Extra Low ENergy Antiproton (ELENA) ring, using a cylindrical shoe-box electrostatic pick-up from the existing orbit system [1], is presented. The system has been developed to measure very challenging beam cur-rents, as low as 200nA corresponding to intensities of the order of 107 antiprotons circulating with a relativistic beta of the order of 10-2. In this work we derive and show that the turn-by-turn beam intensity is proportional to the baseline of the sum signal and that, despite the AC-coupling of the system, the installed front-end electronics, based on a charge amplifier, not only guarantees the preservation of the bunch shape (up to a few tens of MHz), but also allows for an absolute calibration of the system. In addition, the linearity of the intensity measurements and their inde-pendence with respect to average beam position is evalu-ated using a standard electromagnetic simulation tool. Finally, experimental measurements throughout typical antiproton deceleration cycles are presented and their accuracy and precision are discussed.
L. Crescimbeni, D.M. Haider, A. Reiter, M. Schwickert, T. Sieber, T. Stöhlker
GSI, Darmstadt, Germany
H. De Gersem, N. Marsic, W.F.O. Müller
TEMF, TU Darmstadt, Darmstadt, Germany
M. Schmelz, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
F. Schmidl
FSU Jena, Jena, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker, V. Tympel
HIJ, Jena, Germany
V. Zakosarenko
Supracon AG, Jena, Germany
Funding:Work supported by the BMBF under contract No. 05P21SJRB1. The Cryogenic Current Comparator (CCC) at the heavy-ion storage ring CRYRING@ESR at GSI provides a calibrated non-destructive measurement of beam current with a resolution of 10 nA or better. With traditional diagnostics in storage rings or transfer lines a non-interceptive absolute intensity measurement of weak ion beams (< 1 µA) is already challenging for bunched beams and virtually impossible for coasting beams. Therefore, at these currents the CCC is the only diagnostics instrumentation that gives reliable values for the beam intensity independently of the measured ion species and without the need for tedious calibration procedures. Herein, after a brief review of the diagnostic setup, an overview of the operation of the CCC with different stored ion beams at CRYRING is presented. The current reading of the CCC is compared to the intensity signal of various standard instrumentations including a Parametric Current Transformer (PCT), an Ionization Profile Monitor (IPM) and the Beam Position Monitors (BPMs). It was shown that the CCC is a reliable instrument to monitor changes of the beam current in the range of nA.
Differential Current Transformer for Beam Charge Monitoring in Noisy Environments
304
H. Maesaka, T. Inagaki
RIKEN SPring-8 Center, Hyogo, Japan
H. Dewa, T. Inagaki, H. Maesaka, K. Yanagida
JASRI, Hyogo, Japan
K. Ueshima
QST, Sendai, Miyagi, Japan
We developed a differential current transformer (CT) for electron beam charge measurement in noisy environments, such as near high-power pulse sources. This CT has four pickup wires coiled at equal intervals (90 deg.) on a toroidal core and each coil is wound for two turns. The midpoint of the coil is connected to the body ground so that a balanced differential signal is generated at both ends. A beam pipe with a ceramics insulation gap is inserted into the toroidal core to obtain a signal from a charged-particle beam. The four pairs of signals are transmitted through a CAT6 differential cable and fed into differential amplifiers. The common-mode noise from the noisy ground at the CT is canceled out by the amplifier. The four signals are then summed and digitized by an AD converter. We produced differential CTs and installed them into the new injector linac of NewSUBARU (*). Before the installation, the frequency response was measured in a laboratory and a flat response of up to 100 MHz was obtained as expected. Common-mode noise cancellation was also confirmed at NewSUBARU and the CTs have been utilized for beam charge monitoring stably. *: T. Inagaki et al., ’Construction of a Compact Electron Injector Using a Gridded RF Thermionic Gun and a C-Band Accelerator’, in Proc. IPAC’21, pp. 2687-2689. doi:10.18429/JACoW-IPAC2021-WEPAB039
Creation of the First High-Inductance Sensor of the New CCC-Sm Series
469
V. Tympel, T. Stöhlker
HIJ, Jena, Germany
L. Crescimbeni, D.M. Haider, M. Schwickert, T. Sieber, T. Stöhlker
GSI, Darmstadt, Germany
F. Machalett, T. Stöhlker
IOQ, Jena, Germany
M. Schmelz, T. Schönau, R. Stolz, V. Zakosarenko
IPHT, Jena, Germany
F. Schmidl, T. Schönau, P. Seidel
FSU Jena, Jena, Germany
V. Zakosarenko
Supracon AG, Jena, Germany
Funding:Supported by the BMBF, project number 05P21SJRB1. Cryogenic Current Comparators (CCC) are presently used at CERN-AD (100 mm beamline diameter) and in the FAIR project at CRYRING (150 mm beamline diameter) for non-destructive absolute measurement of beam currents below 20 ’A (current resolution 10 nA). Both sensor versions (CERN-Nb-CCC and FAIR-Nb-CCC-XD) use niobium as superconductor for the DC-transformer and magnetic shielding. The integrated flux concentrators have an inductance of below 100 ’H at 4.2 Kelvin. The new Sm-series (smart & small) is designed for a beamline diameter of 63 mm and uses lead for the superconducting shield. The first sensor (IFK-Pb-DCCC-Sm-200) has two core-based pickup coils (2x 100 µH at 4.2 K) and two SQUID units, to eliminate Barkhausen current jumps as part of the low frequency 1/f-noise. During the construction some basic experiments on noise behavior (fluctuation’dissipation theorem, white noise below 2 pA/sqrt(Hz)) and magnetic shielding (flux concentrator and shielding as LC circuit resonance , additional mu-metal shielding) were undertaken, the results of which are presented here. Finally, a current resolution of 500 pA could be achieved in the laboratory.
F. Falkenstern, J. Kuszynski, G. Rehm
HZB, Berlin, Germany
The "Booster Fillpattern Monitor" is used to measure currents in each individual electron bunch in the booster of the BESSY II machine. The booster with its circumference of 96 meters has space for max.160 electron bunches. The distance between the electron bunches of 60cm (96m/160) is determined by the RF Master Clock ~ 499, 627MHz. In practice, fill patterns of a one to five equally spaced bunches are in use. The fill pattern monitor digitizes electrical pulses generated from a strip line using a broadband ADC. The sampling frequency is selected as an integer fraction of the bunching frequency, acquiring the full fill pattern over a number of turns. Experiments performed at BESSY II demonstrate the performance of the setup and will be discussed.
Secondary Emission Monitor Simulation, Measurements and Machine Learning Application Studies for CERN Fixed Target Beamlines
476
L. Parsons França, M. Duraffourg, F. Roncarolo, F.M. Velotti
CERN, Meyrin, Switzerland
E. Kukstas, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
Funding:This work was supported by CERN and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. The CERN fixed target experimental areas have recently acquired new importance thanks to newly proposed experiments, such as those linked to Physics Beyond Colliders (PBC) activities. Secondary Emission Monitors (SEMs) are the instruments currently used for measuring beam current, position and size in these areas. Guaranteeing their reliability, resistance to radiation and measurement precision is challenging. This paper presents the studies being conducted to understand ageing effects on SEM devices, to calibrate and optimise the SEM design for future use in these beamlines. These include feasibility studies for the application of machine learning techniques, with the objective of expanding the range of tools available for data analysis.
Novel Fast Radiation-Hard Scintillation Detectors for Ion Beam Diagnostics
515
P. Boutachkov, M. Saifulin, C. Trautmann, B. Walasek-Höhne
GSI, Darmstadt, Germany
E.I. Gorokhova
GOI, St Petersburg, Russia
P. Rodnyi, I.D. Venevtsev
SPbPU, St. Petersburg, Russia
Novel radiation-hard scintillators were developed in the last years based on indium-doped ZnO ceramic with an extremely short decay time below a ns. Fast counting detectors and fast screens were considered as potential beam diagnostic applications of this material. At the GSI/FAIR facility, scintillation detectors are commonly used for measuring the intensity and detailed time structure of relativistic heavy ion beams. The scintillating material is inserted directly into the beam path. Signals from individual ions are counted, providing systematic-error-free beam intensity information. Standard scintillators require frequent maintenance due to radiation damage. To address this limitation, a large area ZnO radiation-hard detector was developed. The prototype detector operates at orders of magnitude higher irradiation levels, at higher counting rates and has better time resolution compared to a plastic scintillator. In addition, the novel detector material opens the possibilities for applications in other beam diagnostic systems, for example, scintillation screens for transverse profile measurements. Therefore, ZnO scintillation ceramics are of general interest for beam diagnostics.
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Time-Resolved Proton Beam Dosimetry for Ultra-High Dose-Rate Cancer Therapy (FLASH)
519
P. Casolaro, S. Braccini, G. Dellepiane, A. Gottstein, I. Mateu, P. Scampoli
AEC, Bern, Switzerland
P. Scampoli
Naples University Federico II, Napoli, Italy
Funding:This project was partially funded by the Bern Center for Precision Medicine (BCPM) of the University of Bern, and by the Swiss National Science Foundation (SNSF) [Grant: CRSII5180352] A new radiotherapy modality, known as FLASH, is a potential breakthrough in cancer care as it features a reduced damage to healthy tissues, resulting in the enhancement of the clinical benefit. FLASH irradiations are characterized by ultra-high dose-rates (>40 Gy/s) delivered in fractions of a second. This represents a challenge in terms of beam diagnostics and dosimetry, as detectors used in conventional radiotherapy saturate or they are too slow for the FLASH regime. In view of the FLASH clinical translation, the development of new dosimeters is fundamental. Along this line, a research project is ongoing at the University of Bern aiming at setting-up new beam monitors and dosimeters for FLASH. The proposed detection system features millimeter scintillators coupled to optical fibers, transporting light pulses to a fast photodetector, readout by high bandwidth digitizers. First prototypes were exposed to the 18 MeV proton beam at the Bern medical cyclotron. The new detectors have been found to be linear in the range up to 780 Gy/s, with a maximum time resolution of 100 ns. These characteristics are promising for the development of a new class of detectors for FLASH radiotherapy.
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Fast Spill Monitor Studies for the SPS Fixed Target Beams
522
F. Roncarolo, P.A. Arrutia Sota, D. Belohrad, E. Calvo Giraldo, E. Effinger, M.A. Fraser, V. Kain, M. Martin Nieto, S. Mazzoni, I. Ortega Ruiz, J. Tan, F.M. Velotti, C. Zamantzas
CERN, Meyrin, Switzerland
M. Bergamaschi
MPI-P, München, Germany
At the CERN Super Proton Synchrotron (SPS) the proton beam is supplied to the fixed target experiments in the North Area facility (NA) via a slow extraction process, taking place at 400 GeV. The monitoring of the spill quality during the extraction, lasting 4.8 seconds with the present SPS setup, is of high interest for minimising beam losses and providing the users with uniform proton-on-target rates. The monitor development challenges include the need for detecting, sampling, processing and publishing the data at rates ranging from few hundred Hz to support the present operation to several hundreds of MHz to serve future experiments proposed within the Physics Beyond Collider (PBC) programme. This paper will give an overview of the ongoing studies for optimizing the existing monitors performances and of the R&D dedicated to future developments. Different techniques are being explored, from Secondary Emission Monitors to Optical Transition Radiation (OTR), Gas Scintillation and Cherenkov detectors. Expected ultimate limitations from the various methods will be presented, together with 2022 experimental results, for example with a recently refurbished OTR detector.
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