Development of Novel Non-Destructive 2D and 3D Beam Monitoring Detectors at the Bern Medical Cyclotron
78
C. Belver-Aguilar, S. Braccini, T.S. Carzaniga, A. Gsponer, P. Haeffner, P. Scampoli, M. Schmid
AEC, Bern, Switzerland
G. Molinari
TERA, Novara, Italy
P. Scampoli
Naples University Federico II, Napoli, Italy
The Laboratory for High Energy Physics (LHEP) at the University of Bern is developing novel beam monitoring detectors for the 18 MeV medical cyclotron in operation at the Bern University Hospital (Inselspital). A 2D non-destructive beam monitor - named Pi2 - was developed, based on a thin aluminium foil coated with P47 scintillating material and a camera. It measures the transverse position, shape, and intensity of the beams for several applications, as radiation hardness or radioisotope production studies. This detector allows the processing of data in real time and a reconstruction of the transverse phase space. Based on the Pi2, a first prototype of a 3D beam monitoring detector - named Pi3 - was conceived, constructed, and tested. It is based on the same scintillating foil mounted on a movable support with a miniaturized camera. The Pi3 detector allows for the study of the beam evolution along a beam line, even inside a magnet, and the reconstruction of the beam envelope. In this paper, we report about the design, construction and beam tests performed with these two detectors. Further developments will be also presented and discussed.
Beam Experiments with the Multi-purpose Iris Diaphragm Beam Detector
A. Liu, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
J.H. Shao
ANL, Lemont, Illinois, USA
Funding:Project funded by the DOE SBIR and STTR programs, under contract DE-SC0019538 Non-Gaussian beam distributions around the Gaussian core can be formed in an accelerator in both the transverse and longitudinal directions. Since there are no clearly defined criteria to distinguish the halo from the core, the measurement of the halo structure without affecting the core is challenging. Previously, a novel design of an iris diaphragm detector for transverse beam halo distributions and transverse profile was reported by Euclid Techlabs*. This multi-purpose design not only measures the transverse beam distribution but may also work as a tunable collimator or an adjustable BPM. In this paper, the beam experiments using the ~ 1 MeV electron beam at the AWA Cathode Teststand (ACT) of ANL and the 200 keV TEM beam at Euclid are discussed for the most up-to-date version of this new apparatus: Iris Diaphragm e-beam Apparatus Series -Halo (IDEAS-Halo). * please see NAPAC 2019 pre-press proceedings
Development of a Thermal Response Model for Wire Grid Profile Monitors and Benchmarking to CERN LINAC4 Experiments
82
A. Navarro Fernandez, F. Roncarolo
CERN, Geneva, Switzerland
M. Sapinski
GSI, Darmstadt, Germany
The operation of wire grids as beam profile monitors, both in terms of measurement accuracy and wire integrity, can be heavily affected by the thermal response of the wires to the energy deposited by the charged particles. A comprehensive model to describe such interaction has been implemented including beam induced heating, all relevant cooling processes and the various phenomena contributing to the wire signal such as secondary emission and H− electron scattering. The output from this model gives a prediction of the wire signal and temperature evolution under different beam conditions. The model has been applied to the wire grids of the CERN LINAC4 160 MeV H-beam and compared to experimental measurements. This successful benchmarking allowed the model to be used to review the beam power limits for operating wire grids in LINAC4.
Experimental Investigation of Spectral-Angular Cherenkov Radiation Characteristics From 855 MeV Electrons
A. Potylitsyn, S.Yu. Gogolev, A.V. Vukolov
TPU, Tomsk, Russia
G. Kube, A.I. Novokshonov
DESY, Hamburg, Germany
W. Lauth
IKP, Mainz, Germany
Radiation based beam diagnostics is a versatile tool, especially for transverse beam profile measurements. While the use of Optical Transition Radiation (OTR) has long history since developed, the application of Cherenkov Radiation (ChR) having comparatively higher intensity and tunable frequency spectrum just arouse interest. In order to investigate the ChR properties, an experiment has been carried out at the 855 MeV electron beam of the Mainz Microtron MAMI (University of Mainz, Germany). The beam size was 370 um in horizontal and 6.5 um in vertical direction. A 200 um thick fused silica was used as radiator. The beam images were recorded with a standard CMOS camera and an objective lens. While the detector was at a fixed observation angle (much larger than 46.77 degrees - the Cherenkov angle for a fused silica), the radiator could be rotated with respect to the beam direction such that the ChR angular distribution was measured as a function of the radiator orientation. In addition, a spectrometer was used to get the ChR emission spectrum orientation dependency. This report gives an overview of the experiment together with measurements and first theoretical comparisons.
A Beam Profile Monitor for High Energy Proton Beams Using Microfabrication Techniques
86
I.M. Mateu, W. Farabolini, A. Gilardi, B. Gkotse, A. Mapelli, V. Meskova, G. Pezzullo, F. Ravotti, O. Sidiropoulou
CERN, Geneva, Switzerland
D. Bouvet, J.M. Sallese
EPFL, Lausanne, Switzerland
Funding:This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 777222. In High Energy Physics experiments it is a common practice to expose electronic components and systems to particle beams, in order to assess their level of radiation tolerance when operating in a radiation environment. One of the facilities used for such tests is the Proton Irradiation Facility (IRRAD) at CERN. In order to properly control the 24 GeV/c proton beam, Beam Profile Monitor (BPM) devices are used. The current BPMs are fabricated as standard flexible PCBs featuring a matrix of metallic sensing pads. When exposed to the beam, secondary electrons are emitted from each pad, thus generating a charge proportional to the particle flux. The charge is measured individually for each pad using a dedicated readout system, and so the beam shape, position and intensity are obtained. The beam profile determination with this technique requires thus the usage of non-invasive and radiation tolerant sensing elements. This study proposes a new fabrication method using microfabrication techniques in order to improve the BPMs performance while greatly reducing the device thickness, thus making them also appropriate for the monitoring of lower energy and intensity particle beams.
Progress of Profile Measurement Refurbishment Activities at HIPA
179
R. Dölling, E. Johansen, M. Roggli, M. Rohrer
PSI, Villigen PSI, Switzerland
At PSI’s High Intensity Proton Accelerator (HIPA) facility some 180 profile monitors and 10 radial probes are in use to measure transverse beam profiles in beam lines and cyclotrons at energies of 0.87 to 590 MeV. Mechanical malfunctions and increased noise in some devices, a lack of spare parts and the obsolescence of most of the driver and read-out electronics as well as extended requirements to the measurement, necessitate the development of improved versions of the electronics and of several monitors. We give an update on the status of three projects in this regard: A long radial probe in the Ring Cyclotron, a profile monitor and BPM at 590 MeV in high radiation environment and new loss monitor electronics, which should also serve as a basis for the profile monitor readout.
First Beam Profile Measurements by Beam Induced Fluorescence at the J-PARC Neutrino Extraction Beamline
184
M.L. Friend, S.V. Cao, K. Nakayoshi, K. Sakashita
KEK, Ibaraki, Japan
M. Hartz
Kavli IPMU, Kashiwa, Japan
Y. Koshio
Okayama University, Faculty of Science, Okayama City, Japan
A. Nakamura
Okayama University, Okayama, Japan
A Beam Induced Fluorescence (BIF) profile monitor is under development at the J-PARC neutrino extraction beamline, where neutrinos are produced using 30 GeV protons from the J-PARC MR accelerator. Towards the goal of continuously and non-destructively measuring the 1.3MW proton beam profile spill-by-spill using fluorescence from proton interactions with injected gas, a full working prototype monitor was installed in the beamline in 2019. The prototype includes a scheme for pulsed injection of N2 gas into the ultra-high vacuum beampipe and two optical readout arms, a conventional one using an Image Intensifier coupled to a CID camera, along with an array of optical fibers coupled to a Multi-Pixel Photon Counter array. Initial beam tests of the system were carried out in early 2020, and BIF light was successfully observed in both optical systems. Details of the prototype monitor, along with first proton beam profile measurement results, will be shown. Improvement plans towards continuous operation of the new profile monitor will also be discussed.
Simulation and Experiments of Transverse Emittance Measurements with Slit scan and Quadrupole scan at ELBE SRF Gun
S. Ma, A. Arnold, P.E. Evtushenko, A.A. Ryzhov, J. Schaber, J. Teichert, R. Xiang
HZDR, Dresden, Germany
J. Schaber
TU Dresden, Dresden, Germany
Emittance is one of the most important parameters for electron injectors and accelerator facilities. Two traditional methods, the single slit-scan, and quadrupole scan are used in most emittance measurements. Although the experiment condition is the same, one may receive different emittance results. The difference between simulation and experiment in the beamline will be discussed in this paper. As a statistical sampling, the error of the slit-scan system is related to bunch transverse distribution, bunch charge, slit width and thickness, beamlet number, drift distance, and screen resolution. In suitable conditions, the space-charge dominated beam will become emittance dominated beam after slits and emittances from slit-scan are reliable. The error quadrupole scan depends on the quadrupole field’s measurement accuracy and bunch distribution. In this paper, we use a simple way to calibrate quadrupole focus strength. Space charge usually can’t be avoided and will lead to some errors for quadrupole scan.
Recent Progress on the Commissioning of a Gas Curtain Beam Profile Monitor Using Beam Induced Fluorescence for High Luminosity LHC
188
S. Mazzoni, M. Ady, O.R. Jones, I. Papazoglou, C. Pasquino, A. Rossi, S. Sadovich, G. Schneider, R. Veness
CERN, Geneva, Switzerland
P. Forck, S. Udrea
GSI, Darmstadt, Germany
N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
N. Kumar, A. Salehilashkajani, C.P. Welsch, H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom
For the high-luminosity upgrade of the Large Hadron Collider, active control of proton/ion beam halo will be essential for safe and reliable operation. Hollow Electron Lenses can provide such active control by enhancing the depletion of halo particles, and are now an integral part of the high luminosity LHC collimation system. The centring of the proton beam within the hollow electron beam will be monitored through imaging the fluorescence from a curtain of supersonic gas. In this contribution we report on the recent progress with this monitor and its subsystems, including the development of an LHC compatible gas-jet injection system, the fluorescence imaging setup and preliminary test measurement in the LHC
Transverse Phase Portrait Tomography of Proton Beams at INR RAS Linac
193
A.I. Titov, S.A. Gavrilov
RAS/INR, Moscow, Russia
S.A. Gavrilov, A.I. Titov
MIPT, Dolgoprudniy, Moscow Region, Russia
Measuring of the parameters of the transverse phase portraits is crucial for beam dynamics. A method of tomographic reconstruction is implemented at INR RAS linac as an alternative to already existing quadrupole variation method. In this work new feature of disturbing online measurements of phase portrait parameters and important experimental results are discussed. Comparison of tomographic method with quadrupole variation method is presented.
S.V. Kuzikov, S.P. Antipov, P.V. Avrakhov, E.W. Knight, Y. Zhao
Euclid TechLabs, LLC, Solon, Ohio, USA
J.G. Power
ANL, Lemont, Illinois, USA
Funding:This work is supported with DOE SBIR Phase II Grant #DE-SC0019642. Beam halo measurement is important, because novel x-ray free electron lasers like LCLS-II have very high repetition rates, and the average power in the halo can become destructive to a beamline. Diamond quad detectors were previously used for electron beam halo measurements at KEK*. Diamond is the radiation hard material which can be used to measure the flux of passing particles based on a particle-induced conductivity effect. However, the quad detectors have metallic contacts for charge collection. Their performance degrades over time due to the deterioration of the contacts under electron impact. We recently demonstrated a diamond electrodeless x-ray flux monitor based on a microwave measurement of the change in the resonator coupling and eigen frequency**. We propose similar measurements with a diamond put in a resonator that intercepts the halo. Without electrodes, such a device is more radiation resistant. By measuring the change in RF properties of the resonator, one can infer the beam halo parameters. In a similar manner to traditional beam halo monitors, the diamond plate can be scanned across the beam to map its transverse distribution. * S.Liu et al., Nuclear Instruments and Methods in Physics Research A832 (2016) 231-242. ** S.Antipov et al., Proceeding of IPAC2018, DOI:10.18429/JACoW-IPAC2018-WEPAF058.
Radiation-based techniques for measuring electron source sizes are widely used as emittance diagnostics at existing synchrotron sources. In this presentation, we review different radiation-based methods which are being considered as source diagnostics for low emittance synchrotron storage rings. Three of these systems - pinhole imaging, double-slit interferometry, and a K-edge filter-based beam position and size monitor (ps-BPM) system - are studied in detail and optimized for small source size measurements. Each method has its advantages and limitations and provides complementary information. Pinhole imaging is the most commonly used technique which has the simplest setup but with limited resolution. Double-slit interferometry gives the highest sensitivity among the three methods. The ps-BPM system has reasonable resolution in measuring source size and divergence, and at the same time, provides real-time information on source position and angle. A combination of multiple techniques is recommended for the full characterization of the source.
Right click on video for Picture-in-Picture mode or Full screen display.
Advanced Laser-driven Plasma Accelerator Electron-beam Diagnostics with COTR Techniques
206
A.H. Lumpkin
Fermilab, Batavia, Illinois, USA
M. Downer, M. LaBerge
The University of Texas at Austin, Austin, Texas, USA
A. Irman
HZDR, Dresden, Germany
D.W. Rule
Private Address, Silver Spring, USA
Funding:Work supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. A significant advance in laser-driven plasma accelerator (LPA) electron-beam diagnostics has recently been demonstrated based on coherent optical transition radiation (COTR) imaging*. We find COTR signal strengths from a microbunched subset of beam exiting the LPA to be several orders of magnitude higher than that of incoherent optical transition radiation (OTR). The transverse sizes are only a few microns as deduced from the point-spread-function-related lobe structure. In addition, the far-field COTR interferometric images obtained on the same shot provide beam-size limits plus divergence and pointing information at the sub-mrad level when compared to an analytical model** with a recent revision. The integrated image intensities can be used to estimate the microbunching fraction and relatable to the LPA process. Initial results in a collaborative experiment at the Helmholtz-Zentrum Dresden-Rossendorf LPA will be reported for electron beam energies of about 215 MeV. * A.H. Lumpkin, M. LaBerge, D.W. Rule et al., "Interferometric Optical Signature.", subm. to Phys. Rev.Lett.(2019). ** D.W. Rule, A.H. Lumpkin, Proc. of PAC2001, Vol. 2, pp. 1288-1290 (IEEE 2001).
Right click on video for Picture-in-Picture mode or Full screen display.
Features of the Metal Microstrip Detectors for Beam Profile Monitoring
211
V.M. Pugatch, O.S. Kovalchuk, D. Ramazanov
NASU/INR, Kiev, Ukraine
Funding:National academy of sciences, Ukraine Features of Metal Microstrip Detectors (MMD) are presented for application in beam profile monitoring of charged particles and synchrotron radiation beams. Through an innovative plasma-chemistry etching production process*, thin metal micro-strips only 1-2μm thick are aligned. Because of the very thin nature of the strips, the MMD is nearly transparent, and can be used in-situ for measuring, tuning and imaging the beam online. Metal structure of sensors guaranties high radiation tolerance (about 100MGy) providing their stable response to the beam particles (by the secondary electron emission) independent upon the accumulated fluence. The spatial resolution of the MMD is determined by the strips pitch constituting from 5 to 100µm in currently manufactured samples*. The data were obtained with MMDs read out by the low noise X-DAS system** providing integration time from 1 to 500ms, and the ability to process signals in real time. The scope of MMD & X-DAS is scientific and applied research using beams: in control systems of accelerators and synchrotron radiation sources. New possibilities are discussed for equipment requiring high spatial resolution and radiation hardness. * V.M. Pugatch et al. Plasma technologies for manufacturing micro-strip metal detectors for ionizing radiation. Series «Plasma Physics» (13). 2007, № 1, p. 173-175. ** sens-tech.com
Right click on video for Picture-in-Picture mode or Full screen display.
Feasibility Study of a Non-Rad Camera for the SNS* Ring Injection Dump Imaging System
W. Blokland, A. Rakhman
ORNL, Oak Ridge, Tennessee, USA
Funding:* This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The Proton Power Upgrade (PPU) increases the the Spallation Neutron Source (SNS) accelerator power from 1.4 MW to 2.8 MW and calls for a modification of the Ring Injection Dump beam line. The charge exchange injection technique to accumulate proton beam in the SNS ring results in multiple beam spots on the ring injection dump window. To properly setup the new injection beam line, the size and locations of the beam spots must be measured. We plan to use a camera to look at a fluorescent coating made of Chromium Oxide doped Aluminum Oxide. To simplify the optical path, we want to place the camera in the tunnel. While radhard cameras are available, they typically are more expensive and have worse performance. To study the feasibility of non-radhard cameras, we measured the radiation in the tunnel in unshielded and shielded locations. We compare the radiation measurements with results from a CERN HiRadMat study and tested the cameras during full power beam to show that the non-radhard camera is an option for the Ring Injection Dump Imaging System.
Simulation Methods for Transverse Beam Size Measurements Using the Heterodyne Near Field Speckles of Hard X-rays
272
A. Goetz, D. Butti, S. Mazzoni, G. Trad
CERN, Geneva, Switzerland
U. Iriso, A.A. Nosych, L. Torino
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
B. Paroli
Universita’ degli Studi di Milano, Milano, Italy
M.A.C. Potenza, M. Siano
Universita’ degli Studi di Milano & INFN, Milano, Italy
L. Teruzzi
Università degli Studi di Milano, Milano, Italy
The Heterodyne Near Field Speckles (HNFS) is a special type of interferometry technique where radiation is scattered by nanoparticles suspended in a medium. The scattered waves and the transmitted radiation form an interference pattern, which is modulated by the spatial coherence of the radiation and by the scattering properties of the nanoparticles. The superposition of many such interference patterns results in a speckle pattern, from which the spatial coherence of the radiation and thus the transverse beam profile can be determined. In this contribution we present approaches for simulating the HNFS patterns from hard X-ray radiation and compare then with data from experiments at the ALBA synchrotron.
Calibration and Image Restoration for the Beam Profile Measurement System
276
L.X. Hu, K.Z. Ding, Y. Song
ASIPP, Hefei, People’s Republic of China
Y.C. Wu
HFCIM, HeFei, People’s Republic of China
The beam profile parameters are one of the important parameters which represent the beam quality. And the transverse beam profile parameters are closely related to the beam tuning and optimization of the cyclotron. Machine Vision is a branch of computer science that has really grown over the last 20 years. In order to improve the precision and efficiency of beam profile measurement, machine vision techniques have been developed for the analysis and processing of the beam profile images. A new calibration method has been designed for the calibration of the imaging system. Moreover, a new image noise reduction algorithm has been developed to improve the image quality, and then to improve the accuracy of the beam profile parameters measurement. And image restoration algorithm has also been adopted to eliminate the effects of defocusing blur. The experiment results show that the calibration of the imaging system enables the system can provide quantitative information for beam diagnosis. The image noise reduction and restoration algorithm greatly improve the accuracy of beam profile parameters measurement.
S.D. Williams, G. Taylor
The University of Melbourne, Melbourne, Victoria, Australia
I. Chaikovska, N. Delerue, A. Gonnin, V. Kubytskyi, H. Monard, A. Moutardier
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
Funding:Work supported by the French ANR under reference ANR-10-EQPX-51. Work also supported by grants from Région Ile-de-France. Work also supported by the Nicolas Baudin program. ThomX is a novel compact X-ray light source, utilising a laser and 50 MeV electron storage ring to produce X-ray photons via Compton scattering. Screens, observed by zoom lenses and optical cameras, can be used to monitor the transverse beam profile at various points. An issue with the implementation of this system is that after adjusting the zoom one needs to recalibrate the the optical system, measuring the resolution of the optical system and deducing the transformation from pixel space observed on the camera to geometrical space in the laboratory. To calibrate and measure the resolution limit of the cameras a USAF 1951 resolution chart that can be moved into or out of the screen position is used. We will report on and demonstrate the use of open source computer vision libraries to compute this calibration, and the affine transformation between the camera image plane and the screens can be deduced. We will also comment on how consumer available Canon EF mount lenses may be used as a remote controllable optical system.
J. Wan
SINAP, Shanghai, People’s Republic of China
F.Z. Chen, J. Chen, B. Gao, Y.B. Leng, K.R. Ye, L.Y. Yu, W.M. Zhou
SSRF, Shanghai, People’s Republic of China
SHINE is a high repetition rate XFEL facility, based on an 8 GeV CW SCRF linac, under development in Shanghai. In order to meet the requirements of measuring the beam profile of SHINE in real time and without obstruction, a new diagnostic instrument, wire scanner has been designed. This paper mainly describes the design of wire scanner in SHINE, and some simulation results are also shown and discussed.
