A Micro Pixel Chamber Based Neutron Imaging Detector (µNID) with Boron Converter for Energy-Resolved Neutron Imaging at J-PARC (#4060)
J. D. Parker1, M. Harada2, H. Hayashida1, K. Hiroi2, T. Kai2, Y. Matsumoto1, K. Oikawa2, M. Segawa2, T. Shinohara2, Y. Su2, A. Takada3, T. Taniguchi3, T. Tanimori3, Y. Kiyanagi4
1 CROSS-Tokai, R&D Division, Tokai, Ibaraki, Japan
At the Energy-Resolved Neutron Imaging System RADEN, located at beam port 22 of the high-intensity, pulsed spallation neutron source at the J-PARC Materials and Life Science Experimental Facility in Japan, we take advantage of the accurate measurement of neutron energy by time-of-flight to perform energy-resolved neutron imaging. These techniques are used to directly image the macroscopic distribution of microscopic properties of bulk materials in situ, including crystallographic properties (Bragg-edge transmission), nuclide-specific density and temperature distributions (resonance absorption), and internal/external magnetic fields (polarized neutron imaging). To carry out such measurements in the high-rate, high-background environment at RADEN, we have been developing and testing cutting-edge detector systems employing micro-pattern detectors and high-speed, all-digital data acquisition systems to provide the necessary sub-µs time resolution, high count rates, and event-by-event background rejection. One such detector, the Micro Pixel Chamber based Neutron Imaging Detector (µNID), provides a spatial resolution of less than 250 µm FWHM, time resolution of 0.25 µs, 26% detection efficiency for thermal neutrons with 3He for conversion, effective gamma sensitivity < 10-12, and count rate capacity of 8 Mcps. By replacing the 3He gas with a boron-based converter, we aim to increase the count rate capacity three-fold while maintaining good spatial resolution. This is made possible by the significantly reduced event size for the alpha from the 10B-neutron interaction as compared to the lighter proton and triton in the 3He case. We are also developing a new readout element with a third strip plane oriented at 45° to the usual x and y planes to facilitate clean separation of simultaneous events at high rates. In this presentation, we discuss the preliminary testing of such a µNID with boron converter carried out recently at RADEN and consider its continued development.
Keywords: Neutron imaging, Micro-pattern detectors, Boron neutron converter
The MPGD-based photon detectors for the COMPASS RICH-1 upgrade. (#1751)
S. Levorato1, S. Levorato1
1 INFN sez Trieste, INFN sez Trieste, c/o Area di Ricerca PaL L3, Trieste, Italy
The RICH-1 Detector of the COMPASS experiment at CERN SPS has undergone an important upgrade for the 2016 physics run. Four new photon detectors, based on Micro Pattern Gaseous Detector technology and covering a total active area larger than 1.2~$m^2$ have replaced the previously used MWPC-based photon detectors. The upgrade answers the challenging efficiency and stability quest for the new phase of the COMPASS spectrometer physics programme. The new detector architecture consists in a hybrid MPGD combination of two Thick Gas Electron Multipliers and a MicroMegas stage. Signals, extracted from the anode pad by capacitive coupling, are read-out by analog F-E based on the APV25 chip. The main aspects of the COMPASS RICH-1 photon detectors upgrade are presented focussing on detector design, engineering aspects, mass production, the quality assessment and assembly challenges of the MPGD components. The status of the detector commissioning is also presented.
Keywords: MPGD, Photon detector, CsI, THGEM, Micromegas, RICH, Single Photon detection
Design and Performance of GEM-based Full-Field XRF Imaging System (#3219)
T. Fiutowski1, P. Frączek2, S. Koperny1, M. Lankosz1, B. Łach1, A. Mendys2, B. Mindur1, K. Świentek1, P. Wiącek1, P. Wróbel1, W. Dąbrowski1
1 AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow, Poland
In the paper we report on development of a full-filed X-ray fluorescence spectroscopy (XRF) imaging system equipped with a standard 3-stage Gas Electron Multiplier (GEM) detector of 10×10cm2 area and readout electronics based on dedicated full custom ASIC and DAQ system.
XRF is a commonly used technique for non-destructive elemental analysis of cultural heritage objects. By identification of inorganic pigments, it can be applied for investigation of provenance of historical object as well as for studies of artist techniques. While the XRF analysis can be relatively easy performed locally, nowadays, there is a growing interest in imaging of spatial distribution of specific elements in large area objects.
The full-field XRF is based on simultaneous irradiation and imaging of large area of an object. The image of the investigated area is projected by an optic element (usually a pinhole camera) on a position-sensitive and energy dispersive detector. One of possible detectors to be employed in full-field XRF imaging is a GEM detector with 2-dimensional readout.
The moderate energy resolution of GEM detectors limits elemental selectivity of the system being developed. However, in many applications, especially for initial fast screening of large area objects, the GEM based systems can be very useful and for this reason optimization of their energy resolution is of great interest. One of possible ways to improve the energy resolution is to reduce the noise of the readout electronics. Therefore, we have designed a new ASIC called ARTROC with carefully optimized noise performance to achieve the energy resolution at a level of 15% FWHM for 5.9 keV line in the current system.
In the paper critical design aspects of the system will be discussed and detail test results will be presented.
This work was supported by the Polish National Centre for Research and Development grant No. PBS3/A9/29/2015.
Keywords: Micropattern Gas Detectors, Front-end electronics, XRF imaging
Resistive Micromegas with small-pad readout: towards a higher rate capability (#1937)
M. Iodice1, F. Petrucci2, 1, M. Alviggi4, 3, M. Biglietti1, M. Della Pietra4, 3, C. Di Donato5, E. Farina6, S. Franchino7, P. Iengo6, E. Rossi2, 1, G. Sekhniaidze3, O. Sidiropoulou8, 6, V. Vecchio2, 1
1 INFN Roma Tre, Roma, Italy
We present here the development of resistive Micromegas with O(mm2) pad readout aiming at improving the high rate capability of the detector. The goal application is precision tracking in high rate environment without efficiency loss up to few MHz/cm2. In the proposed layout, small anode pads are overlayed by an insulating layer with a pattern of resistive pads on top. The readout and resistive pads are connected by intermediate resistors embedded in the insulating layer. A first prototype has been constructed at CERN and thoroughly tested. It consists of a 48x16 matrix of 0.8x2.8 mm2 rectangular pads with a pitch of 1 and 3 mm in the two coordinates . The active surface is 4.8x4.8 cm2 with a total number of 768 channels read-out by 6 APV-25 chips. The drift and amplification gaps of this Micromegas prototype are 5 mm and 128 microns, respectively. The detector is operated with an Ar/CO2 (93:7) gas mixture. Characterization and performance studies of the detector have been carried out by means of radioactive sources, X-Rays, cosmic rays and test beam. The results will be shown and compared to expectations from simulations. Moreover, a new development aiming at the construction of fully scalable, thousands-channels small-pad detectors, with embedded front-end electronics will be presented.
Keywords: resistive Micromegas, small pads, high rate capability, embedded front-end electronics
A low-mass GEM detector with radial zigzag readout strips for forward tracking at the EIC (#3612)
M. Hohlmann1, A. Zhang2, M. Bomberger1, S. Colafranceschi1, F. I. Jimenez1, M. Rahmani1
1 Florida Institute of Technology, Department of Physics & Space Sciences, Melbourne, Florida, United States of America
We present design, construction, and quality control for a large low-mass Triple-GEM detector prototype for forward tracking at a future Electron-Ion Collider (EIC). In this environment, multiple scattering of tracks must be minimized so that electron tracks can be cleanly matched to calorimeter clusters and hadron tracks can efficiently seed RICH ring reconstruction for particle identification. Consequently, the material budget of the forward tracking detectors is critical. The construction of the detector builds on the mechanical foil stretching and assembly technique pioneered by CMS for the muon endcap GEM upgrade. As an innovation, this detector implements drift and readout electrodes on thin large foils that get stretched mechanically together with three GEM foils in a single stack instead of on PCBs. This reduces the radiation length of the total detector material in the active area from 4% to below 0.5%. The joint assembly also aims at improving the uniformity of drift and induction gap sizes across the detector and consequently signal response uniformity. Thin outer frames custom-made from carbon-fiber composite material take up the tension from the stretched foil stack and provide rigidity while keeping the detector mass low. The gas volume is closed with aluminized mylar foils. The trapezoidal detector covers an azimuthal angle of 30.1 degrees and a radius from 8 cm to 103 cm. It is read out with radial zigzag strips with pitches of 1.37 mrad (near outer radius) and 4.14 mrad (near inner radius) that reduce the number of required electronics channels and associated cost while maintaining good spatial resolution. Scans of small readout boards with the same type of zigzag strip structure using highly collimated X-rays show resolutions of 60-90 microns. All front-end readout electronics is located away from the active area at the outer radius of the trapezoid.
Keywords: GEM, Gaseous Detector, EIC, Forward tracking
Calibration and Alignment for Belle II Central Drift Chamber (#2932)
V. T. Dong1, S. Uno1, 2, M. Uchida3, H. Ozaki1, 2, N. Taniguchi2
1 SOKENDAI (The Graduate University for Advanced Studies), Hayama, Japan
Belle II Central Drift Chamber (CDC), a multi-cell drift chamber, plays an important role in measuring momentum of charged particles, in addition to the particle identification with dE/dx. We present the calibration and alignment procedures established using cosmic data taken in March 2017. Position resolution is obtained to be about 80-120 µm depending on layer. The precise alignment studies improved the resolution and reduced the systematic shift of track parameters. Momentum resolution will be provided using global cosmic data which will be taken with magnetic field in summer 2017.
Keywords: Belle II, Drift Chamber, calibrate, alignment