A5060791028- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Atmospheric Ozone and Climate
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Advanced Semiconductor Detectors and Materials
- Advanced X-ray and CT Imaging
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Atomic and Subatomic Physics Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Photocathodes and Microchannel Plates
- Radioactive Decay and Measurement Techniques
- Medical Imaging Techniques and Applications
- Particle physics theoretical and experimental studies
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- Neutrino Physics Research
- Nuclear physics research studies
- Scientific Computing and Data Management
- Astronomy and Astrophysical Research
Photek (United Kingdom)
2020-2024
Atotech (United States)
2021-2022
Washington University in St. Louis
1998-2009
Marshall Space Flight Center
2001
Louisiana State University
1999
University of Washington
1998
University of California, San Diego
1991-1993
The High Energy X-Ray Timing Experiment (HEXTE) is one of three scientific instruments aboard the Rossi Explorer (RXTE), which was launched on 1995 December 30. RXTE performs timing and spectral studies bright X-ray sources to determine physical parameters these systems. HEXTE consists two independent clusters detectors, each cluster containing four NaI(Tl)/CsI(Na) phoswich scintillation counters sharing a common 1° FWHM field view. view switched off source provide near real-time background...
We report on abundance measurements of 10Be, 26Al, 36Cl, and 54Mn in the Galactic cosmic rays (GCRs) using Cosmic-Ray Isotope Spectrometer (CRIS) instrument aboard Advanced Composition Explorer spacecraft at energies from ~70 to ~400 MeV nucleon-1. also an upper limit GCR 14C. The high statistical significance these allows energy dependence their relative abundances be studied. A steady-state, leaky-box propagation model, incorporating observations local interstellar medium (ISM) composition...
We report improved measurements of elemental abundances and spectra for galactic cosmic-ray (GCR) nuclei obtained by the Cosmic Ray Isotope Spectrometer on board NASA's Advanced Composition Explorer (ACE) spacecraft during minimum maximum phases solar cycle 23. discuss results particles with nuclear charge 5 ⩽ Z 28 typical energies between 50 500 MeV nucleon−1. demonstrate that a detailed "leaky box" Galactic propagation model combined spherically symmetric modulation gives good (but not...
Measurements of the abundances cosmic-ray 59Ni and 59Co are reported from Cosmic-Ray Isotope Spectrometer (CRIS) on Advanced Composition Explorer. These nuclides form a parent-daughter pair in radioactive decay which can occur only by electron capture. This cannot once nuclei accelerated to high energies stripped their electrons. The CRIS data indicate that has occurred, leading conclusion time longer than 7.6 × 104 yr half-life elapsed before particles were accelerated. Such long delays...
The scientific objectives, status, and future instrumental requirements of high energy X-ray astronomy (20 to 200 keV) are discussed. Two particularly compelling are: (1) an improvement in sensitivity a level about 5 microCrab (2) survey the sky at 0.1 milliCrab, which will discover characterize 10,000 new sources. first requirement can be fulfilled by imaging telescopes that use large-area focusing mirrors, effective over 5-30 arcminute fields, second met arrays large area coded mask...
The radiation dose from galactic cosmic rays during a manned mission to Mars is expected be comparable the allowable limit for space shuttle astronauts. Most of this would due with energies < 1 GeV nucleon −1 , important contributions heavy nuclei in spite their low abundance relative H and He. Using instruments on NASA's Advanced Composition Explorer (ACE) spacecraft, we have made most statistically precise measurements date solar minimum energy spectra ray charge Z = 4–28 range ∼ 40–500...
Position-sensitive CZT detectors for research in astrophysics the five - several hundred keV range are being developed by groups. These very promising large area detector arrays coded mask imagers and small-area focal plane focusing x-ray telescopes. We have with crossed-strip readout optimized strip widths gaps to improve energy resolution. A 'steering electrode' is employed between anode strips charge collection. model of drift induction on electrodes has been allow us better understand...
CdZnTe crystals useful for room temperature x-ray astronomy detectors have recently been developed. Uniform response and good energy resolution in the 3 to 300 keV range demonstrated large area monolithic arrays. Spectral of 2.9 59.5 <SUP>241</SUP>Am line, resolved 661 peak from <SUP>137</SUP>Cs were achieved at temperature. Gain deviations 1.2% measured elements over a array. Imaging results 32 X array with active 12.4 cm<SUP>2</SUP> are presented. The stability, uniformity, producibility...
Measurements by the Cosmic Ray Isotope Spectrometer (CRIS) on Advanced Composition Explorer (ACE) spacecraft provide direct evidence that galactic cosmic rays lose energy as a result of their interactions with magnetic fields expanding solar wind. The secondary isotopes 49 V and 51 Cr can decay to Ti V, respectively, only electron capture. observed abundances these are directly related probability attaching an from interstellar medium; this decreases strongly increasing around few hundred...
Our collaboration is characterizing a prototype detector module designed for high energy X-ray astrophysics research covering the 20 - 250 keV range. The consists of three dimensional position sensitive CdZnTe detector, 25 mm X 2 mm, with 1 pitch crossed strip electrodes, an interleaved steering electrode, and Application Specific Integrated Circuit (ASIC) individual electrode readout. newly developed readout system compact, lightweight, has low power consumption will lead to reduced...
Cadmium Zinc Telluride (CZT) is a room temperature semiconductor detector well suited for high energy x-ray astronomy. We have developed CZT with 500 micron crossed strip readout and an advanced electrode design that greatly improves resolution. conducted two balloon flights from Fort Sumner, NM, to study the cross standard planar both sensitive in range of 20-350 keV. The utilized total seven shielding schemes: 3 passive, 2 active hybrid passive-active. In modes, anti- coincidence shield...