IEEE 2021 NSS MIC

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Technical Session

Session chair: Keyser , Ronald (Software & Information Services, Inc., Fairview, USA)
 
Shortcut: TC-02
Date: Wednesday, 20 October, 2021, 9:15 AM - 11:15 AM
Room: Technical Session
Session type: Exhibition

Contents

Click on an contribution to preview the abstract content.

9:15 AM TC-02-01

Large-Format Two Dimensional Scintillation Imaging Arrays (#1540)

C. Hufstetler1, S. Robare1

1 Saint-Gobain Crystals, Engineering, Hiram, Ohio, United States of America

Abstract

High-resolution x-ray imagers in the medical, security, and industrial fields often use linear arrays of scintillation detectors that move relative to the subject to build an image over a period of time. However, in systems or applications that require imaging a large area within one millisecond or less, one of the most exceptional options available is found in large-format, two-dimensional scintillation arrays. These arrays can be built with sub-millimeter pixel sizes and active areas upwards of 40cm square, allowing for high resolution imaging. These arrays have distinct advantages over other imaging methods, including the ability to take multiple images during one experiment, and the capability to accurately characterize the array for image correction, improving image quality. In this session, we will review the many considerations to make when designing these arrays. The scintillator material is the most obvious concern; however, the method of construction, reflector selection, collimation, focusing, pixel depth, and other factors all contribute to the final image quality, cost, and performance of these arrays.

Keywords: Imaging, Scintillation, Crystal, Array
9:30 AM TC-02-02

Very low afterglow CsI(Tl) scintillator using antimony and other metal cations (#1543)

P. Menge1

1 Saint-Gobain Crystals, R&D, Hiram, Ohio, United States of America

Abstract

The use of CsI(Tl) scintillator in CT and other fast imaging modalities is hindered by afterglow in which the scintillator continues to emit light after the radiation source has been removed.  Blurring, contrast loss and image artifacts result from too much afterglow.  The introduction of small amounts of metal halide compounds into CsI(Tl) have been investigated for their effect on afterglow and light output. Thirty-one candidate compounds were tested in grown CsI(Tl) crystals.  Eu, Sm, Bi and Yb have been previously identified as afterglow suppressors (and unfortunately light output suppressors as well).  In this work, nine new candidates have been discovered to also suppress afterglow albeit with varying effectiveness. The best new candidate is antimony (Sb). Ingots co-doped with Sb have achieved afterglow signals of 0.23% and 0.13% at 100 and 500 ms after x-ray beam shut-off, which is over 60% reduction in afterglow.  Typical standard CsI(Tl) values are 0.6% and 0.4%. Most significantly, there is no sacrifice of light output when doped optimally with Sb. The optimal concentration of Sb is 0.02 at% in the melt, which produces a mere 3.2 ppm Sb in the crystal, indicating that only a few ppm of Sb is enough to significantly suppress the afterglow.  Further experiments have shown that combining Sb and Bi co-dopants suppresses afterglow to a greater degree than either by themselves.  Typical afterglow results are 0.045% and 0.03% at 100 and 500 ms, respectively, with less than 1 ppm of each specie in the crystal and again, no loss in light output.  Ingots with Sb and Sb+Bi afterglow suppressants have been scaled up to 8-inch diameter (>1000 cc), which indicates this process is ready for industrialization.

Keywords: Afterglow, CsI, Co-doping
9:45 AM TC-02-03

FERS-5200: a distributed Front-End Readout System for multidetector arrays (#1548)

Y. Venturini1, N. Paoli1, M. Venaruzzo1

1 CAEN SpA, Viareggio, Italy

Abstract

Modern physics experiments usually rely on very big experimental setup where it is possible to find a wide variety of detectors: silicon microstrip trackers, plastic scintillator calorimeters, LAr cryostats readout by a Time Projection Chamber, spectrometers composed of several drift tubes and resistive plate chambers. Moreover, other large and medium scale setups for the search of neutrinos and astroparticles use thousands of scintillation detectors read out by photomultipliers or SiPMs. Nowadays, waveform digitizers and/or ASIC-based front-end cards are well-established readout electronics to build a reliable system hosting many readout channels.

The FERS-5200 is the new CAEN Front-End Readout System, answering the challenging requirement to provide flexibility and cost-effectiveness in the readout of huge detector arrays. FERS-5200 is a distributed and easy-scalable platform integrating the whole readout chain of the experiment, from detector front-end to DAQ. It is based on compact ASIC-based front-end cards integrating A/D conversion and data processing, which can be ideally spread over a large detector volume without drawbacks on the readout performance. Synchronization, event building and DAQ is managed by a single Concentrator board, capable of sustaining thousands of readout channels.

Using the appropriate Front-End, the solution perfectly fits a wide range of detectors such as SiPMs, multianode PMTs, GEMs, Silicon Strip detectors, Wire Chambers, Gas Tubes, etc, thus matching the requirements of different applications.
Keywords: SiPM, electronics, DAQ, detector arrays
10:00 AM TC-02-04

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10:15 AM TC-02-05

Recent Product Developments at RMD (#1625)

U. Shirwadkar1, K. Shah1, J. Tower1, V. Nagarkar1, S. Miller1, B. Singh1, P. Bhattacharya1, Y. Wang1

1 Radiation Monitoring Devices, Inc, Watertown, Massachusetts, United States of America

Abstract

RMD is among the world leaders offering state-of-the-art radiation detection instruments for various applications from homeland security, medical physics to basic science. In this presentation, capabilities and applications of RMD’s established, as well as emerging products will be discussed. We will showcase prototype products including Tl-based inorganic single crystals, high-performance scintillator screens, high-speed x-ray camera, and Gd-based garnet ceramic scintillators for radiography and medical imaging.

Keywords: CLYC, CLLBC, x-ray camera, scintillation films
10:30 AM TC-02-06

The next level of photon counting, spectral X-ray imaging: Pyxis, a 4-side buttable hybrid detector with 6 energy bins operating at up to 10,000 fps (#1547)

Y. Haemisch1, S. Gunn2, C. Ullberg3, M. Urech3

1 Direct Conversion AB, a Varex Imaging Company, Direct Converison GmbH, Munich, Gräfelfing, Bavaria, Germany
2 Direct Conversion Ltd., London, United Kingdom
3 Direct Conversion AB, Stockholm, Sweden

Abstract

Direct Conversion, now a Varex Imaging company, has been pioneering the application of CdTe hybrid detectors in dental imaging through its Ajat brand and currently plays the leading role in the proliferation of photon counting detectors based on CdTe/ASIC hybrids through its XCounter brand of detectors. Several thousands of them are in use all around the globe in industries such as oil & gas (pipe inspection), food inspection, non-destructive testing and quality and process control e.g. in electronics industry. In medical applications such as e.g. Breast Computed Tomography (breast CT) or whole body orthopedic imaging photon counting detectors are already demonstrating their clinical benefits.

In order to further enhance the capabilities of this technology and ease its integration especially into CT applications, a next generation detector called Pyxis has been developed. It is based on the use of Through Silicon Vias (TSV) technology enabling to read out the hybrids through the back of the chip, thus removing geometrical limitations imposed by bonding wires. This will enable the design of detectors in various sizes and shapes adapting to all potential applications. In addition, by providing up to 6 energy bins per pixel, spectral and material/tissue separating capabilities are further enhanced. On chip 2x2 binning of the 150 µm pixels reduces the amount of data to be transferred and improves performance in some imaging applications. Probably the most important feature especially for its application in CT is the extremely high speed of the new chip, both in terms of count rate (above 108 counts/mm²s) and frame rates (up to 10,000 fps). Initial imaging examples from the new chip demonstrating those features will be shown.

Charge sharing correction (CSC) as well as trapped charge release (TCR) algorithms complete the design of Direct Conversion detectors, maintaining consistency in imaging over a wide range of count rates and applications.
Acknowledgmentnone
Keywords: Photon Counting, Spectral X-ray, CdTe, Charge Sharing Correction, High count rate
10:45 AM TC-02-07

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11:00 AM TC-02-08

Application of the FalconX8 as a high-rate gamma spectrometer (#1463)

P. M. Grudberg1, C. E. Cox1, S. Myers2, P. Scoullar3

1 XIA LLC, Oakland, California, United States of America
2 Spectral Ops LLC, Los Alamos, New Mexico, United States of America
3 Southern Innovation, Melbourne, Australia

Abstract

The FalconX8 digital pulse processor powered by SITORO® Accelerated Analysis algorithms is a well-established tool for ultra-high rate x-ray spectroscopy and mapping. In a new application space, combining the FalconX8 with recently developed spectroscopic grade fast scintillators has the potential for a very high rate and high resolution gamma spectrometer.  Such high-rate instruments are required for applications like spent nuclear fuel assay, which is a critical component of nuclear safeguards.  Results are presented using an extreme high rate (few Mcps) random pulse generator representing an ideal scintillator, as well gamma-ray data with LaBr3 and a Cs-137 source approaching 1 Mcps

Keywords: Gamma spectroscopy, high-rate, high-resolution, nuclear safeguards

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