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Particle Physics
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“A Tangentially Viewing Fast Ion D-Alpha Diagnostic for NSTX”,
A. Bortolon, W. W. Heidbrink, M. Podestà, Review of Scientific Instruments, Volume 81, 10D728, 25 October 2010
Copyright ©2010 American Institute of Physics
A second fast ion D-alpha (FIDA) installation is planned at NSTX to complement the present
perpendicular viewing FIDA diagnostics. Following the present diagnostic scheme, the new
diagnostic will consist of two instruments: a spectroscopic diagnostic that measures fast ion spectra
and profiles at 16 radial points with 5–10 ms resolution and a system that uses a band pass filter and
photomultiplier to measure changes in FIDA light with 50 kHz sampling rate. The new pair of FIDA
instruments will view the heating beams tangentially. The viewing geometry minimizes spectral
contamination by beam emission or edge sources of background emission. The improved
velocity-space resolution will provide detailed information about neutral-beam current drive and
about fast ion acceleration and transport by injected radio frequency waves and plasma
instabilities.
“First Measurements of Non-Interceptive Beam Profile Monitor Prototypes for Medium to High Current Hadron Accelerators”,
J. M. Carmona, A. Ibarra, I. Podadera, Z. Abou-Haïdar, M. A. G. Alvarez, A. Bocci, B. Fernández, J. García López, M.C. Jiménez-Ramos, Proceedings of HB2010, Morschach, Switzerland, WEO1C04
In the frame of the IFMIF-EVEDA accelerator project (a 125 mA, 9 MeV, 175 MHz (CW) deuteron accelerator) CIEMAT has designed and tested two types of non-interceptive optical monitors based on gas fluorescence. This beam diagnostic technique offers a non-invasive beam profile characterization for medium to
high current hadron beams. Both monitors have been tested at CNA cyclotron using 9 MeV deuterons up to 40 uA and 18 MeV protons up to 10 uA. Profile measurements were carried out under high radiation background because the target and profilers were close to each other in the experimental setup. A Vertilon PhotoniQ IQSP482 with an SIB032 for the Hamamatsu H7260 32 channel multianode PMT was used for one of the fluorescence profile monitors (FPMs). In this paper, a brief description of FPMs together with the first beam measurements including systematic scans on beam current and pressure are presented.
"The NSTX Fast-Ion D-alpha Diagnostic",
M. Podestà, W. W. Heidbrink, R. E. Bell, and R. Feder, Review of Scientific Instruments, Volume 79, Number 10, October 2008
A new diagnostic, aimed at energy-resolved measurements of the spatial and temporal dynamics of fast ions in NSTX plasmas, is described. It is based on active charge-exchange recombination spectroscopy. The fast-ion signal is inferred from light emitted in the wavelength range of the D-alpha line by fast ions recombining with an injected neutral beam. Two complementary systems are operational. The first system, based on a spectrometer coupled to a charge coupled device detector, has 16 channels with space, time, and energy resolution of 5 cm, 10 ms, and 10 keV, respectively. The second system monitors the energy-integrated fast-ion signal on time scales of ~20 µs at three different radii. Signals are measured by a multianode photomultiplier tube and acquired using a Vertilon PhotoniQ IQSP480. For both systems, each channel includes two paired views, intercepting and missing the neutral beam for a direct subtraction of the background signal not associated with fast ions. Examples of signals from the 2008 NSTX run are presented.
"Development of the Fast Neutron Imaging Telescope (FNIT)",
M.R. Moser, J.M. Ryan, U. Bravar, E.O. Flückiger, J.R. Macri, M.L. McConnell, 29th International Cosmic Ray Conference
Pune (2005) 00, 101–104
A report on the development of a next generation solar neutron telescope that is sensitive to neutrons in
the energy range 3.100 MeV, optimized to study solar neutrons in the innermost heliosphere. The detection
principle is based on multiple elastic neutron-proton scatterings in plastic scintillators. By reconstructing event
locations and measuring the recoil proton energies, the direction and energy spectrum of the primary neutron
flux can be determined. Presented are the results of recent laboratory efforts, and in combination with simulation
data, the performance of the telescope under space conditions is outlined.
"Characterization of a Multianode Photomultiplier Tube for use with Scintillating Fibers to Detect Gamma Rays",
Keith Rielage, McDonnell Center for the Space Sciences & Department of Physics, Washington University, St. Louis, Missouri
The performance of a multianode photomultiplier tube (MAPMT) with 64 anodes coupled to scintillating fibers is examined. Such a detector system can be used in a pair-production gamma-ray telescope as well as in other applications. The characteristics of these tubes (Hamamatsu R5900-00-M64) are presented including single photoelectron sensitivity, electrical and optical cross-talk, and dark count. Environmental test results of these devices are also presented.
"Optical Soft X-Ray Arrays for Fluctuation Diagnostics in Magnetic Fusion Energy Experiments",
L. F. Delgado-Aparicio, D. Stutman, K. Tritz, M. Finkenthal, R. Kaita, L. Roquemore, D. Johnson, R. Majeski, Review of Scientific Instruments, Volume 75, Number 10, October 2004
Copyright ©2004 American Institute of Physics
A large pixel count, fast (100 KHz) and continuously sampling soft x-ray (SXR)
array for the diagnosis of magnetohydrodynamics (MHD) and turbulent fluctuations in magnetic
fusion energy plasmas is being developed. The arrays are based on efficient scintillators, high thoughput multiclad fiber
optics, and multichannel light amplification and integration. Compared to conventional x-ray diode
arrays, such systems can provide vastly increased spatial coverage, and access to difficult locations
with small neutron noise and damage. An eight-channel array has been built using columnar CsI:Tl
as an SXR converter and a multianode photomultiplier tube as photoamplifier. The overall system
efficiency is measured using laboratory SXR sources, while the time response and signal-to-noise
performance have been evaluated by recording MHD activity from the spherical tori (ST) Current
Drive Experiment-Upgrade and National Spherical Torus Experiment, both at Princeton Plasma
Physics Laboratory.
"Small Scintillating Cells as the Active Elements in a Digital Hadron Calorimeter for the e+e- Linear Collider Detector",
A. Dyshkant, D. Beznosko, G. Blazey, D. Chakraborty, K. Francis, D. Kubik,
J. G. Lima, M. I. Martin, J. McCormick, V. Rykalin, V. Zutshi, Journal of Physics G: Nuclear and Particle Physics, 30 (2004) N1–N16
Copyright ©2004 IOP Publishing Ltd
The ability to distinguish between hadronic W and Z decays is one of the
most challenging requirements for the future linear collider detector. Such
sensitivity requires unprecedented jet energy resolution, which may be possible
with energy-flow algorithms. A calorimeter that is optimized for energy-flow
must have fine lateral and longitudinal segmentation. Small scintillating cells
with wavelength shifting fibre readout represent an attractive basis for a digital
hadron calorimeter that trades dynamic range for superior granularity, at an
affordable price. Presented is the expected jet resolution for such a device,
based on Monte Carlo simulations and then the initial prototyping
studies is described. In particular, detailed studies are presented on cell performance under
different combinations of manufacture and assembly.
"High Spatial Resolution Scintillation Detector based on the H8500 Photomultiplier",
R. Engels, U. Clemens, G Kemmerling, J. Schelten, Zentrallabor für Elektronik in the Forschungszentrum Juelich GmbH,
Juelich, Germany
The flat-panel photomultiplier (Hamamatsu H8500) can be utilized as a high resolution area detector for thermal neutrons and high energy gamma rays. This detector type is useful for special neutron scattering experiments and for the PET applied to small animals. In various test measurements this will be demonstrated by coupling suitable scintillators (NaI, BGO, LiI single crystals, Li-glass, and LiGd-Borate) to the photocathode and by feeding the 64 output signals of the photomultiplier (PM) into an active resistor network. The four output signals from the network are transferred to the pulse processing board (UniDAQ) where the event position address is calculated and where the event storage is done by memory increment.
"Multianode Photo Multipliers for Ring Imaging
Cherenkov Detectors",
Franz Muheim, Proceedings of the 30th International Conference on High Energy Physics, July 27, 2000, Osaka, Japan
A 64-channel Hamamatsu H7546 Multianode Photo Multiplier Tube (MAPMT) has been evaluated as a possible choice for the photodetectors of the LHCb Ring Imaging Cherenkov detector.
"Development of a Directional Scintillating Fiber Detector for 14MeV Neutrons",
Justin Peel, Nicholas Mascarenhas, Wondwosen Mengesha, Duane Sunnarborg, Nuclear Instruments and Methods in Physics Research A 556 (2006) 287–290
A directional detector for 14MeV neutrons is developed. The detector consists of an 8 x 8 array of plastic scintillating fibers coupled to a Hamamatsu H7546B multi-anode photomultiplier tube. Protons in the fibers are scattered by incident neutrons and are detected as they pass through multiple fibers. The direction of the flux of incident neutrons is determined using the energy and direction of the recoil proton. The advantages of the detector are its small size and ability to detect fast neutrons. GEANT4 was used to simulate the detector performance, and report the results of experimental studies with neutrons from a 14MeV pulsed D-T neutron generator.
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