A5021439865- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Advanced Semiconductor Detectors and Materials
- Nuclear Physics and Applications
- Advanced X-ray and CT Imaging
- Neutrino Physics Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Silicon and Solar Cell Technologies
- CCD and CMOS Imaging Sensors
- Radiation Therapy and Dosimetry
- Astrophysical Phenomena and Observations
- Electronic and Structural Properties of Oxides
- Semiconductor Quantum Structures and Devices
- Silicon Nanostructures and Photoluminescence
- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Atomic and Subatomic Physics Research
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Integrated Circuits and Semiconductor Failure Analysis
- Superconducting and THz Device Technology
Lawrence Berkeley National Laboratory
2009-2022
University of California, Berkeley
1994-2014
Durham University
2003-2010
Lawrence Livermore National Laboratory
2009
University of California System
1998-2006
United States Naval Research Laboratory
2000
George Mason University
2000
University of California, San Diego
1998
Queen's University
1992
Tennessee Technological University
1991-1992
The M ajorana D emonstrator will search for the neutrinoless double-beta<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mo stretchy="false">(</mml:mo><mml:mi>β</mml:mi><mml:mi>β</mml:mi><mml:mfenced separators="|"><mml:mrow><mml:mn fontstyle="italic">0</mml:mn><mml:mi>ν</mml:mi></mml:mrow></mml:mfenced><mml:mo stretchy="false">)</mml:mo></mml:math>decay of isotope<mml:math id="M2"/>Ge with a mixed array enriched and natural germanium detectors. observation this rare...
The Majorana Collaboration is operating an array of high purity Ge detectors to search for neutrinoless double-β decay in ^{76}Ge. Demonstrator comprises 44.1 kg (29.7 enriched ^{76}Ge) split between two modules contained a low background shield at the Sanford Underground Research Facility Lead, South Dakota. Here we present results from data taken during construction, commissioning, and start full operations. We achieve unprecedented energy resolution 2.5 keV FWHM Q_{ββ} very with no...
A novel method to perform preferential sensing of single-polarity charge carriers in ionization detectors is presented. It achieves the same function as Frisch grids commonly employed gas ion chambers but uses a coplanar electrode configuration suitable for semiconductor detectors. Through use this method, good energy resolution can be obtained from room-temperature compound despite their poor hole-collection characteristics. Experiments using CdZnTe detector demonstrate effectiveness...
A new method to preferentially sense the collection of single-polarity charge carriers in ionization detectors is presented. It uses coplanar electrodes closely emulate function Frisch grids commonly employed gas and liquid detectors. The electrode structure allows for easy implementation on semiconductor This can be used obtain good energy resolution from which only one polarity type efficiently collected. Experimental results using a CdZnTe detector demonstrate effectiveness this method.
A new approach to ionizing radiation detection is proposed. The amount of ionization produced in a detector medium measured by the heat generated as charged carriers are drifted across device under an applied voltage. energy can be orders magnitude larger than that deposited itself. dramatic increase mass achieved compared simple calorimetric particle detectors for equivalent thresholds. It possible obtain sensitivity level sufficient single-carrier detection. principle operation has been...
We have studied the \ensuremath{\beta} spectrum of $^{14}\mathrm{C}$ using a germanium detector containing crystal with dissolved in it. find feature 17 keV below end point which can be explained by hypothesis that there is heavy neutrino emitted decay mass 17\ifmmode\pm\else\textpm\fi{}2 and an emission probability (1.40\ifmmode\pm\else\textpm\fi{}0.45\ifmmode\pm\else\textpm\fi{}0.14)%.
The focus of this paper is to evaluate thick, 20×20×10 and 10×10×10mm3, cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THM). phenomenal spectral performance small size low concentration Te inclusions/precipitates these indicate that THM suitable for mass production CZT radiation detectors can be used in a variety applications. Our result also proves with careful material selection IR high-quality fabrication processes, theoretical energy...
A large-volume (150 cm/sup 3/) germanium detector with a full-depletion capacitance of only approximately=1 pf has been fabricated. The effect impurity space charge was utilized to obtain an appropriate electric field distribution in the so that carriers are collected on small-area electrode. Detectors based this principle capable very-low-noise operation and have immediate applications experiments for direct detection dark matter. Detector pulse shapes carrier-trapping effects were also...
Over 25 1-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> CdZnTe crystals produced using the Traveling Heater Method at Redlen Technologies have been characterized. The charge carrier mobility and lifetime, transport uniformity of each crystal were measured alpha particles. Some made into coplanar-grid detectors their performance characterized 662 keV gamma rays. average electron mobility-lifetime product for these was found to be a...
Gamma-ray spectroscopy is a valuable tool of science and technology. Many applications for this are in need detector technology capable achieving excellent energy resolution efficient detection while operating at room temperature. Detectors based on the material cadmium zinc telluride (CdZnTe) could potentially meet if certain deficiencies addressed. The coplanar-grid as well other electron-only techniques effective overcoming some problems CdZnTe and, consequently, have led to gamma-ray...
High-purity germanium crystals used for making nuclear radiation detectors are usually grown in a hydrogen ambient from melt contained high-purity silica crucible. The benefits and problems encountered using reviewed. A concentration of about 2×1015cm-3 has been determined by growing spiked with tritium counting the ß-decays made these crystals. Annealing studies show that is strongly bound, either to defects or as H2 dissociation energy > 3eV. This lowered 1.8eV when copper present. Etching...
The high-resolution échelle spectrograph, SALT HRS, is at an advanced stage of construction and will shortly become available to the user community Southern African Large Telescope (SALT). This paper presents a commentary on progress date gives instrument's final specification with refined estimates for its performance based initial testing optics science-grade detectors. It also contributes discussion how fibre input have been tailored specific scientific aspirations give four distinct...
The spectral performance of coplanar grid detectors using currently available CdZnTe materials is examined theoretically and experimentally. Calculated response based on the typical carrier mobility-lifetime products current shows that energy resolution close to charge-statistics limit can be achieved. Charge transport nonuniformity, which may present detectors, studied alpha particle scanning.
The authors report on the performance of high-purity Ge radiation detectors with amorphous (a-Ge) contacts fabricated using RF sputtering techniques. Electrical formed sputtered a-Ge films crystals, both n- and p-type, were found to exhibit good blocking behavior low leakage currents, contact biased under either voltage polarity. have thin dead layers associated them, can be used in place lithium-diffused, ion-implanted, or Schottky barrier detectors. use such allows fabrication...
The Nuclear Compton Telescope (NCT) is a balloon-borne telescope designed for the study of astrophysical sources in soft gamma-ray regime (200 keV–20 MeV). NCT's 10 high-purity germanium crossed-strip detectors measure deposited energies and three-dimensional positions interactions sensitive volume, this information used to restrict initial photon circle on sky using scatter technique. Thus NCT able perform spectroscopy, imaging, polarization analysis sources. one next generation...
Using 14C-spiked pyrolytic graphite-coated quartz crucibles for the growth of nine ultra-pure germanium single crystals, we have determined carbon content and distribution in these crystals. autoradiography, observe a rapidly decreasing cluster concentration successively grown Nuclear radiation detectors made from crystals measure betas internally decaying 14C nuclei with close to 100% efficiency. An average value total [14C+12C] is ~2×1014cm-3, substantially larger than expected earlier...
The low energy X-ray response of Ge detectors with amorphous entrance contacts has been evaluated. spectral background due to near contact incomplete charge collection was found consist two components: a level component which is insensitive applied voltage and high step-like dependent. At operating voltages, the can be completely suppressed, resulting in levels are much lower than those previously observed using Pd surface barrier or B ion implanted contacts, also compare favorably obtained...
SALT HRS is a fiber-fed cross-dispersed echelle spectrograph designed for high resolution and efficiency seeing-limited spectroscopy on the Southern African Large Telescope. The spectrograph, which has dual channel white pupil design, uses single R4 grating, dichroic beam-splitter, volume phase holographic gratings as cross-dispersers. grating 41.6 grooves/mm illuminated with 200mm diameter beam. This allows R = 16,000 2.2" fiber complete wavelength coverage from 370 nm to 890 nm. Resolving...