Download or read book Characterization of High purity Multi segmented Germanium Detectors written by Michaël Ginsz and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Segmented Large Volume High Purity Germanium Detectors written by Bart Bruyneel and published by . This book was released on 2006 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3D Characterization of Multi segmented HPGe Detectors written by Bartolomeo De Canditiis and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: New generation gamma-ray detectors arrays, such as AGATA, employ multi-segmented high purity germanium detectors in experiments of nuclear physics that require high resolution and efficiency which are obtained thanks to the application of pulse-shape analysis and gamma-ray tracking. These techniques require full volume characterization of the position sensitive detectors. The IPHC developed a scanning table that uses the Pulse Shape Comparison Scan (PSCS) technique to perform this task. Simulations are performed to quantify the accuracy of the PSCS and to validate it.They are applied on a pixelated 3x3 planar detector and a symmetrical S-type AGATA detector. The method is tested with different gamma-ray energies and input statistics. Several real scans are performed as well on both detectors, which are fully characterized. In particular a scan with agamma-ray source of 152Eu, the first ever done, prove some assumptions on which the tracking technique is based.

Download or read book Characterization and Acceptance of High Purity Germanium Detectors for the Majorana Demonstrator written by Nathan Snyder and published by . This book was released on 2015 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Mechanically Cooled High Purity Germanium HPGe Detectors at Elevated Temperatures written by Joseph Benjamin McCabe and published by . This book was released on 2015 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt: High resolution gamma spectroscopy is a tool used in nuclear security applications due to its achievable energy resolution and associated ability to identify special nuclear material. This identification ability is achieved by identifying the characteristic gamma-rays of a material. The challenges that have confronted industry concerning the use of hand-held high purity germanium (HPGe) in homeland security applications have centered on weight, geometry, and cool-down time. Typical liquid nitrogen cooled detectors ranging in size from 10% to 150% detectors will cool down sufficiently within 2-6 hours of filling. The cool-down time achieved in this research ranges from 45 min on the smallest detector to six hours on the largest 180 cm3 detector; which is consistent with typical hand held HPGe devices. The weight and package geometry for HPGe-based designs is driven by the need to cool the HPGe detector to cryogenic temperatures. This is due to small bandgap (~0.7 eV) of HPGe. Liquid nitrogen or mechanical cooling is required to achieve such temperatures. This dissertation presents work performed to characterize energy resolution performance as a function of temperature in a new mechanically cooled HPGe detector design based upon a split-Stirling cryocooler. This research also quantifies the microphonic noise contribution from this cryocooler. Measurements have been taken on detector sizes ranging from 6.75 cubic centimeters to 180 cubic centimeters. Focus has been placed on determining volume dependence on energy resolution at elevated temperatures. Microphonic noise contribution from the cooler has also been studied over the same temperature range. This energy resolution degradation was most pronounced at low temperatures (

Download or read book Comparison of Response Characteristics of High Purity Germanium Detectors Using Analog Versus Digital Processing written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this article we will discuss some of the results of the response characteristics of High Purity germanium detectors using analog versus digital processing of the signals that are outputted from the detector. The discussion will focus on whether or not there is a significant difference in the response of the detector with digital electronics that it limits the ability of the detection system to get reasonable gamma ray spectrometric results. Particularly, whether or not the performance of the analysis code Pu600 is compromised.

Download or read book Spatial Resolution Attainable in Germanium Detectors by Pulse Shape Analysis written by and published by . This book was released on 1998 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are several applications for which it is desirable to calculate the locations and energies of individual gamma-ray interactions within a high purity germanium (HPGe) detector. These include gamma-ray imaging and Compton suppression. With a segmented detector this can be accomplished by analyzing the pulse shapes of the signals from the various segments. We examine the fundamental limits to the spatial resolution attainable with this approach. The primary source of error is the series noise of the field effect transistors (FETs) at the inputs of the charge amplifiers. We show how to calculate the noise spectral density at the output of the charge amplifiers due to an optimally selected FET. This calculation is based only on the detector capacitance and a noise constant for the FET technology. We show how to use this spectral density to calculate the uncertainties in parameters, such as interaction locations and energies, that are derived from pulse shape analysis using maximum likelihood estimation (MLE) applied to filtered and digitized recordings of the charge signals. Example calculations are given to illustrate our approach. Experimental results are given that demonstrate that one can construct complete systems, from detector through data analysis, that come near the theoretical limits.

Download or read book The Characterisation of AGATA High Purity Germanium Detectors for Pulse Shape Analysis written by Samantha Colosimo and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gamma-ray spectroscopy is an essential tool in the study of nuclear phenomenon. The study of exotic nuclei and nuclear states have been used to expand the nuclear chart as well as understand the origin of the universe. Large volume high purity germanium arrays, very high beam intensities and more recently exotic beams have lead to new understanding of nuclear physics. The Advanced Gamma Tracking Array (AGATA) aims to utilise high purity germanium (HPGe) detectors in order to achieve a dramatic increase in efficiency over current spectrometers. The work detailed in this thesis shows a highly detailed characterisation of two AGATA asymmetric capsules of the same shape in order to test and compare performances. Detector A004 was acceptance tested and scanned at the University of Liverpool in February 2010. Detector A006 was scanned between April and September 2010. Resolution, efficiency and charge collection parameters have been studied, comparing these two detector. The results of the comparison show an excellent agreement between the performance of the two detectors. The depletion rate of the detectors has also been compared quantitatively indicating the dependence of depletion on impurity concentration of the capsules. An experimental pulse shape database was generated for detector A006. The sensitivity of the detector response was quantified indicating the regions of the detector of high variation in pulse shape response. The AGATA detector library, which used to simulate the detector response for pulse shape analysis, is compared with this database. The position resolution achieved between the two data sets has been calculated. The combination of the detailed comparison and characterisation of the detector with the study of the simulate database will provide the AGATA collaboration with useful information to improve detector simulations in the further for pulse shape analysis.

Download or read book Fabrication Process Development for High Purity Germanium Radiation Detectors with Amorphous Semiconductor Contacts written by Quinn Looker and published by . This book was released on 2014 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-purity germanium (HPGe) radiation detectors are well established as a valuable tool in nuclear science, astrophysics, and nuclear security applications. HPGe detectors excel in gamma-ray spectroscopy, offering excellent energy resolution with large detector sizes for high radiation detection efficiency. Although a robust fabrication process has been developed, improvement is needed, especially in developing electrical contact and surface passivation technology for position-sensitive detectors. A systematic study is needed to understand how the detector fabrication process impacts detector performance and reliability. In order to provide position sensitivity, the electrical contacts are segmented to form multiple electrodes. This segmentation creates new challenges in the fabrication process and warrants consideration of additional detector effects related to the segmentation. A key area of development is the creation of the electrical contacts in a way that enables reliable operation, provides low electronic noise, and allows fine segmentation of electrodes, giving position sensitivity for radiation interactions in the detector. Amorphous semiconductor contacts have great potential to facilitate new HPGe detector designs by providing a thin, high-resistivity surface coating that is the basis for electrical contacts that block both electrons and holes and can easily be finely segmented. Additionally, amorphous semiconductor coatings form a suitable passivation layer to protect the HPGe crystal surface from contamination. This versatility allows a simple fabrication process for fully passivated, finely segmented detectors. However, the fabrication process for detectors with amorphous semiconductors is not as highly developed as for conventional technologies. The amorphous semiconductor layer properties can vary widely based on how they are created and these can translate into varying performance of HPGe detectors with these contacts. Some key challenges include minimizing charge injection leakage current, increasing the long-term stability of the contacts, and achieving good charge collection properties in segmented detectors. A systematic study of contact characteristics is presented where amorphous germanium (a-Ge) and amorphous silicon (a-Si) contacts are sputtered with varying sputter gas hydrogen content, sputter gas pressure, and amorphous film thickness. A set of about 45 detectors fabricated from 11 different crystal samples were analyzed for electron barrier height and effective Richardson constant. Most of these detectors were subjected to as many as 10 temperature cycles over a period of up to several months in order to assess their long-term stability. Additionally, 6 double-sided strip detectors were fabricated with a-Ge and a-Si contacts in order to study their inter-electrode charge collection properties. An attempt is made to relate fabrication process parameters such as hydrogen content, sputter pressure, and film thickness to changes observed in detector performance and assess the level of reproducibility using the current methods. Several important results and conclusions were found that enable more reliable and highly performing detectors with amorphous semiconductor contacts. Utilizing the new information should enable consistent production of finely segmented detectors with excellent energy resolution that can be operated reliably for a long period of time. The passivation process could impact planar detectors as well as other designs, such as the p-type point contact detector. It is demonstrated that the long-term stability of amorphous semiconductor contacts is primarily dependent on the time the detector is at room temperature rather than the number of temperature cycles. For a-Ge contacts, higher sputter pressure yields a more stable process that changes little with time, giving a reliable hole-blocking contact. The a-Si contacts form a good electron-blocking contact with decreasing leakage current over time. Both materials, when 7% hydrogen is included in the argon sputter gas, show acceptable levels of inter-electrode charge collection to be useful for strip electrode detectors.

Download or read book Segmentation of the Outer Contact on P Type Coaxial Germanium Detectors written by Richard H. Pehl and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick ({approx}1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (

Download or read book The Fabrication and Analysis of Orthogonal Strip High Purity Germanium Detectors written by Ihor George Zubal and published by . This book was released on 1974 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characteristics of High Purity Germanium and Silicon Radiation Detectors written by William Eric Drummond and published by . This book was released on 1970 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design of a Prototype Chamber and Characterization of a High Pruity Germanium Detector written by Abu hena Muhammad Nazir Hossain and published by . This book was released on 2014 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Liquid Phase Epitaxial Growth and Characterization of Germanium Far Infrared Blocked Impurity Band Detectors written by Jordana Bandaru and published by . This book was released on 2001 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Multi Contact Low Capacitance HPGe Detector for High Rate Gamma Spectroscopy written by and published by . This book was released on 2014 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detection, identification and non-destructive assay of special nuclear materials and nuclear fission by-products are critically important activities in support of nuclear non-proliferation programs. Both national and international nuclear safeguard agencies recognize that current accounting methods for spent nuclear fuel are inadequate from a safeguards perspective. Radiation detection and analysis by gamma-ray spectroscopy is a key tool in this field, but no instrument exists that can deliver the required performance (energy resolution and detection sensitivity) in the presence of very high background count rates encountered in the nuclear safeguards arena. The work of this project addresses this critical need by developing a unique gamma-ray detector based on high purity germanium that has the previously unachievable property of operating in the 1 million counts-per-second range while achieving state-of-the-art energy resolution necessary to identify and analyze the isotopes of interest. The technical approach was to design and fabricate a germanium detector with multiple segmented electrodes coupled to multi-channel high rate spectroscopy electronics. Dividing the germanium detector's signal electrode into smaller sections offers two advantages; firstly, the energy resolution of the detector is potentially improved, and secondly, the detector is able to operate at higher count rates. The design challenges included the following; determining the optimum electrode configuration to meet the stringent energy resolution and count rate requirements; determining the electronic noise (and therefore energy resolution) of the completed system after multiple signals are recombined; designing the germanium crystal housing and vacuum cryostat; and customizing electronics to perform the signal recombination function in real time. In this phase I work, commercial off-the-shelf electrostatic modeling software was used to develop the segmented germanium crystal geometry, which underwent several iterations before an optimal electrode configuration was found. The model was tested and validated against real-world measurements with existing germanium detectors. Extensive modeling of electronic noise was conducted using established formulae, and real-world measurements were performed on candidate front-end electronic components. This initial work proved the feasibility of the design with respect to expected high count rate and energy resolution performance. Phase I also delivered the mechanical design of the detector housing and vacuum cryostat to be built in Phase II. Finally, a Monte Carlo simulation was created to show the response of the complete design to a Cs-137 source. This development presents a significant advance for nuclear safeguards instrumentation with increased speed and accuracy of detection and identification of special nuclear materials. Other significant applications are foreseen for a gamma-ray detector that delivers high energy resolution (1keV FWHM noise) at high count rate (1 Mcps), especially in the areas of physics research and materials analysis.

Download or read book High purity Germanium Crystal Growth and Characterization written by Hao Mei and published by . This book was released on 2015 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Germanium Detectors for Neutron Activation Analysis for Mercury written by Robert V. Moore and published by . This book was released on 1974 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: