New Bedford, MA, United States
New Bedford, MA, United States

Time filter

Source Type

Hennig W.,Xia Llc Inc. | Cox C.E.,Xia Llc Inc. | Asztalos S.J.,Xia Llc Inc. | Tan H.,Xia Llc Inc. | And 4 more authors.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013

Measurement of radioactive xenon in the atmosphere is one of several techniques to detect nuclear weapons testing, typically using either scintillator based coincidence beta/gamma detectors or germanium based gamma only detectors. Silicon detectors have a number of potential advantages over these detectors (high resolution, low background, sensitive to photons and electrons) and are explored in this work as a possible alternative. Using energy resolutions from measurements and detection efficiencies from simulations of characteristic electron and photon energies, the minimum detectable concentration for Xe isotopes was estimated for several possible detector geometries. Test coincidence spectra were acquired with a prototype detector. © Akadémiai Kiadó, Budapest, Hungary 2012.

Cox C.E.,Xia Llc Inc. | Hennig W.,Xia Llc Inc. | Huber A.C.,Amptek Inc | Warburton W.K.,Xia Llc Inc. | And 4 more authors.
IEEE Nuclear Science Symposium Conference Record | Year: 2013

The measurement of atmospheric radioxenon is an important tool for monitoring nuclear weapons testing. The development of new and improved xenon detection methods supports the monitoring program of the Comprehensive Test Ban Treaty Organization (CTBTO). In the current work we have developed a 24-element Si PIN diode detector to measure both the characteristic X-rays and the high energy mono-energetic conversion electrons emitted by the xenon radioisotopes. The low noise properties and ultra-thin entrance window of the PIN diodes are well suited for resolving the relatively low energy X-ray lines while simultaneously measuring the high energy conversion electrons with high collection efficiency and near-Gaussian peak shapes. The use of coincidence gating between the X-rays and conversion electrons can further improve the detection sensitivity, which we show to rival the current HPGe and scintillator based xenon detection systems that rely mostly on Gamma-ray and Beta/Gamma coincidence detection, respectively. The Si PIN detector arrangement offers others advantages compared to current xenon detection methods, such as compact construction, intrinsically low background, and the lack of any memory effect from previous measurements. We discuss the construction of the detector and present measurements performed with 131mXe, 133Xe, 133m Xe and 135Xe. Finally, we make an estimate of the minimum detectable concentration (MDC) for each isotope and compare with the CTBTO requirements. © 2013 IEEE.

Prigozhin G.,Massachusetts Institute of Technology | Gendreau K.,NASA | Foster R.,Massachusetts Institute of Technology | Ricker G.,Massachusetts Institute of Technology | And 6 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

We have studied timing properties of the Amptek Silcon Drift Detectors (SDD) using pulsed X-ray source designed at NASA Goddard Space Flight Center. The proposed Neutron Star Interior Composition Explorer (NICER) mission will use 56 of these detectors as X-ray sensors in an attached payload to the International Space Station to study time variability of millisecond X-ray pulsars. Using a rastered pinhole we have measured the delay times for single X-ray photons as a function of the impact position on the detector, as well as signal rise time as a function of impact position. We find that the interdependence of these parameters allows us to determine photon position on the detector by measuring the signal rise time, and, improve the accuracy of the photon arrival time measurement. © 2012 SPIE.

Pantazis T.,Amptek Inc | Pantazis J.,Amptek Inc | Huber A.,Amptek Inc | Redus R.,Amptek Inc
X-Ray Spectrometry | Year: 2010

Portable/hand-held X-ray fluorescence (XRF) instruments now achieve performance comparable to laboratory-sized, expensive, liquid nitrogen cooled systems. The availability of these systems has expanded XRF applications out of the laboratory to in situ analysis including that for lead in paint, alloy identification, process control, restriction of hazardous substances/waste from electrical and electronic equipment (RoHS/WEEE) compliance, and art and archaeology. The development of small, low-power, high-performance, and cost-effective X-ray detectors was a critical part of this transformation. This paper will look back at the development and technical achievements of the Amptek X-ray detector as well the future direction of portable XRF. Copyright © 2009 John Wiley & Sons, Ltd.

Redus R.,Amptek Inc. | Huber A.,Amptek Inc.
X-Ray Spectrometry | Year: 2012

How should one select the best detector for a particular measurement in energy dispersive X-ray fluorescence (EDXRF)? How should one select the optimum system configuration, i.e. the best shaping time and beam current? Manufacturers provide a variety of specifications, such as energy resolution and maximum count rate, but these are indirectly related to the end use of an EDXRF instrument, the measurement and detection limit of the measured elemental concentrations. We suggest in this paper using the time required to achieve a given statistical uncertainty as a figure of merit. We derive scaling rules for this figure of merit based on conventional specifications, including energy resolution, peaking time, maximum count rate, detector area, and intrinsic efficiency. These scaling rules also include the peak to background ratio of a photopeak and the number of overlapping peaks. We then show how this figure of merit can be used to select the optimum detector and spectrometer configuration for specific applications and compare the results to data obtained with typical systems. © 2012 John Wiley & Sons, Ltd.

Redus R.,Amptek Inc. | Huber A.,Amptek Inc. | Pantazis T.,Amptek Inc. | Pantazis J.,Amptek Inc. | Cross B.,CrossRoads Scientific
X-Ray Spectrometry | Year: 2012

Most energy-dispersive X-ray fluorescence (EDXRF) instruments use Si diodes as X-ray detectors. These provide very high energy resolution, but their sensitivity falls off at energies of 10-20keV. They are well suited for measuring the K lines of elements with Z<40, but for heavier elements, one must use K lines at low efficiency or use L or M lines that often overlap other lines. Either is a challenge for accurate quantitative analysis. CdTe detectors offer much higher efficiency at high energy but poorer energy resolution compared with Si diodes. In many important EDXRF measurements, both high and low Z elements are present. In this paper, we will compare the precision and accuracy of systems using the following: (1) a high resolution Si detector, (2) a high efficiency CdTe detector, and (3) a composite system using both detectors. We will show that CdTe detectors generally offer better analytical results than even a high resolution silicon drift detectors for K lines greater than 20 or 25keV, whereas the high resolution Si detectors are much better at lower energies. We will also show the advantages of a combined system, using both detectors. Although a combined system would be more expensive, the increased accuracy, precision, and throughput will often outweigh the small increase in cost and complexity. The systems will be compared for representative applications that include both high and low Z elements. © 2012 John Wiley & Sons, Ltd.

Redus R.,Amptek Inc. | Huber A.,Amptek Inc. | Pantazis J.,Amptek Inc. | Pantazis T.,Amptek Inc.
IEEE Nuclear Science Symposium Conference Record | Year: 2012

Thermoelectrically cooled X-ray detectors are widely used in both portable and laboratory X-ray spectrometers. The most common detectors are fully depleted 500 μm devices behind a Be window to provide a vacuum tight enclosure. These provide good resolution and efficiency for characteristic X-rays from 2 keV to about 20 keV but a larger energy range is desirable. In many applications, one needs to measure elements with K lines below 2 keV and above 20 keV with good efficiency. Recent research at Amptek, Inc. has focused on enhancing both the upper and lower ends of this energy range. First, to improve efficiency at high energies, SDDs have been fabricated on 1 mm wafers. Second, to improve efficiency at low energies, windows made of 50 nm Si 3N 4 on a Si grid have been developed. Third, to improve resolution at low energies, electronic noise has been reduced by using a modified trapezoidal pulse shape with lower 1/f noise index. The performance of systems utilizing these enhancements will be presented. © 2011 IEEE.

Amptek Inc. | Date: 2013-04-11

radiation detectors.

Amptek Inc. | Date: 2015-01-14

Preamplifiers, low power charge sensitive preamplifiers, X-ray and gamma-ray detectors for use in aerospace, nuclear, and electronic industries.

Loading Amptek Inc. collaborators
Loading Amptek Inc. collaborators