ICx Radiation Inc.

Oak Ridge, TN, United States

ICx Radiation Inc.

Oak Ridge, TN, United States
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Roy U.N.,ICx Radiation Inc. | Weiler S.,ICx Radiation Inc. | Stein J.,ICx Radiation Inc.
Journal of Crystal Growth | Year: 2010

Growth interface of large diameter CdZnTe ingots grown from Te solution by travelling heater method have been studied. Both macroscopic and microscopic investigations were carried out. The results indicated that the shape of the interface strongly governs the grain growth on the ingot, while the microscopic morphology of the growth interface is responsible for Te inclusions in the grown crystal. © 2010 Elsevier B.V. All rights reserved.


Gueorguiev A.,ICx Radiation Inc. | Preston J.,ICx Radiation Inc. | Hoy L.,ICx Radiation Inc. | Pausch G.,ICx Technologies | And 2 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2010

ICx Radiation has developed a novel method to determine the direction of radiation with a device containing only two detectors by comparing and analyzing the paired-energy distributions of coincident events. The method does not require complex image reconstruction but rather extracts the directionality from the means and skewness of the two coincidence spectra. All energy data contribute to the energy spectrum, while events that occur within the coincidence time window are also added to a separate time-dependent buffer that represents the reduced spectra from each detector. These spectra contain counts only from true Compton events. The mean and skewness of each detector's reduced spectra subset is then calculated. Equal skewness and means correspond to the source being in front of the device. Opposite polarity skewness correspond to the source being located to the left or right of the device. For low count rates due to weak sources or sources located far away from the detectors, the skewness comparison gives fast indication for the hemisphere in which the source is located, while increased count rates or increased acquisition times reduce the uncertainties and allow a detailed angular detection of the source position. The simulations, experimental results and the angular resolution as a function of the strength, source energies and distance of the radiation source are discussed. © 2010 IEEE.


Kong Y.,ICx Technologies | Pausch G.,ICx Technologies | Roemer K.,ICx Technologies | Neuer M.,ICx Technologies | And 4 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2010

A complete simulation framework that combines Monte Carlo simulation with the digital-signal-processing algorithms developed in-house is presented for designing and optimizing scintillation detector systems. The framework covers basic components of a practical scintillation detector system and includes all relevant physical processes. With the complete simulation individual physical factors that can affect the performance of a detector system, such as detector geometry, surface finishing, decay time and scintillation yield of scintillator as well as responses of photodetector and front-end electronics, can be taken into account. As a demonstration of the simulation framework, the light collections of plastic (EJ200), NaI(Tl) and BGO scintillators with different surface types have been simulated as a function of the reflectivity of a diffuse reflector. Optical simulations were further performed to investigate the homogeneity of light transportation and detection in plastic scintillators with different surface finishing properties and coupled to one or two PMT(s). Finally, detector signals simulated for a NaI(Tl) detector have been compared with measured mean pulses. The simulated signal can be further digitized and used as input of digital signal processing. © 2010 IEEE.


Roy U.N.,ICx Radiation Inc. | Weiler S.,ICx Radiation Inc. | Stein J.,ICx Radiation Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The Travelling Heater Method (THM) for CdZnTe growth is a widely accepted technique for mass production of detector grade material. Compared to other characterizations of THM grown CdZnTe, study of the growth interface has been neglected in the past. In the present report, large grain/single crystalline as-grown detector grade CdZnTe crystals have been grown by THM technique with diameter up to 52 mm. The crystals were grown from Te solution and the structure of the growth interfaces were investigated for both slow cooled and rapid cooled ingots. The macroscopic shape of the interface was studied and correlated with the grain growth of the ingots. A detailed microscopic morphology of the interface was studied in order to investigate the formation of the Te inclusions at the interfaces. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Roy U.N.,ICx Radiation Inc. | Weiler S.,ICx Radiation Inc. | Stein J.,ICx Radiation Inc. | Groza M.,Fisk University | And 2 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

In this present work we have grown Cd0.9Zn0.1Te doped with indium by the traveling heater method (THM) technique. Large 2 in diameter CZT ingots of more than 1 kg each were successfully grown by the THM technique in vertical configuration. In order to evaluate our as-grown CZT samples, charge transport characteristics were studied at and below room temperature. The key parameter investigated for as-grown CZT samples was the mobilitytrapping time product and its temperature variation. Mobilitytrapping time values as high as 9×10-3 cm2/V at 30 °C were measured for samples exhibiting resistivities in the 12×1010 cm range. The as-grown samples showed moderately good resolution of 1.53.5% at 662 keV when fabricated. The variation of the internal electric field along the depth of the detector was studied for as-grown material to evaluate deformations inside the crystal due to the presence of residual stress or other defects. © 2011 Elsevier B.V.


Bell Z.W.,Oak Ridge National Laboratory | Ziock K.-P.,Oak Ridge National Laboratory | Ohmes M.F.,ICx Radiation Inc. | Ohmes M.F.,Kansas State University | And 6 more authors.
IEEE Transactions on Nuclear Science | Year: 2010

We have performed measurements of neutron production from UF4 samples using liquid scintillator as the detector material. Neutrons and gamma rays were separated by a multichannel digital pulse shape discriminator, and the neutron pulse-height spectra were unfolded using sequential least-squares optimization with an active set strategy. The unfolded spectra were compared to estimates calculated with the SOURCES 4C code. © 2010 IEEE.


Preston J.,ICx Radiation Inc. | Blankenship D.,ICx Radiation Inc. | Hoy L.,ICx Radiation Inc. | Ohmes M.F.,ICx Radiation Inc. | And 2 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2010

ICx Radiation, Inc. has implemented a novel timing method for use in a Compton telescope that is capable of nanosecond timing resolution. A critical task in Compton telescope design is to minimize the timing variance between detectors in a large array in order to reduce the background. The voxelSPEC has been developed to combine precise timing with pulse processing electronics in a single device, where all timing, communication, and power is transmitted over non-proprietary Ethernet hardware. The IEEE 1588 Precision Timing Protocol (PTP) combined with Synchronous Ethernet (SyncE) performs both phase and frequency locking of the individual detectors clock to a master clock. PTP phase locks each node to the absolute time recorded by the master clock. Hardware assist PTP uses the Ethernet PHY to time stamp the actual receiving and sending times of each PTP packet with sub-nanosecond accuracy, removing the time variance contribution of the CPU and other hardware, which can be on the order of microseconds to milliseconds. PTP-compatible network switches remove the unequal buffering delays in the switch hardware by performing a hardware assisted time correction to the PTP packet arrival and departure times directly (transparent clock mode) or by synchronizing the node to the network switch with hardware assistance (boundary clock mode). In 100MBps SyncE, the transmitters frequency is provided by the master clocks oscillator and propagated through the network switches to each individual node. Each Ethernet PHY connected to this frequency recovers the clock signal for the internal PTP clock. Using the master clock frequency minimizes the frequency drift. Results using both PTP (version 1 without PTP hardware assisted network switch) and SyncE show a node to master drift of about 8ns and a timing resolution of about 25ns between nodes. The implementation of hardware assisted PTP version 2 network switches will further reduce the timing resolution between nodes. © 2010 IEEE.


Roy U.N.,ICx Radiation Inc. | Weiler S.,ICx Radiation Inc. | Stein J.,ICx Radiation Inc. | Groza M.,Fisk University | And 2 more authors.
IEEE Transactions on Nuclear Science | Year: 2011

In this article we report the evaluation of thick (up to 10 mm) as-grown Cd 0.9Zn 0.1 Te(CZT): In detectors fabricated from ingots grown by traveling heater method (THM). The crystals were investigated by mapping the electron mobility (μ e), (μτ) e and the internal electric field of as-grown CZT samples. The detector performance was also evaluated in co-planar grid geometry. The excellent (μτ) e value and the detector performance of 10 mm thick as-grown detectors is the indication that the THM technique can be employed successfully to fabricate the detectors directly from the as-grown boule at substantially lower cost. © 2006 IEEE.


Patent
ICx Radiation Inc. | Date: 2010-08-05

A directional gamma radiation detector system for determining an angle under which a measured gamma radiation hits a gamma radiation detector system, includes gamma radiation detectors arranged in close distance; detector electronics for operating the at least two gamma radiation detectors as spectrometers in a way that the detector electronics are collecting energy spectra of the detected gamma rays for each gamma radiation detector; and system electronics allowing the directional gamma radiation detector system to identify coincident events in the at least two gamma radiation detectors.

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