Detector Exposure Research Articles

Search for gamma-ray-burst correlation with neutrinos

view Abstract Citations (11) References (3) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Search for Gamma-Ray--Burst Correlation with Neutrinos Losecco, J. M. Abstract The arrival times of 183 gamma bursters are compared with two large samples of naturally occurring neutrino interactions. In the absence of a complete picture of the nature of gamma bursts such a search could tie them to other high-energy astrophysics phenomena. The neutrino samples have been collected by a large underground proton decay experiment, known as IMB. In this paper the IMB-contained neutrino sample and the IMB upward muon sample are compared to the record of gamma bursts observed with the Soviet Venera spacecraft and the Japanese Ginga spacecraft. The neutrino energies for the contained sample used in this search are from 70 MeV to 2500 GeV. The upward muon sample used is composed of neutrino interactions with energies above 2.5 GeV. There is a significant amount of overlap in exposure of the neutrino detectors and these satellites. No correlation is observed. A limit of about 2.74 x 104 ergs/sq cm is placed on the neutrino flux associated with all of the gamma bursts studied. Publication: The Astrophysical Journal Pub Date: April 1994 DOI: 10.1086/173977 Bibcode: 1994ApJ...425..217L Keywords: Astrophysics; Gamma Ray Astronomy; Gamma Ray Bursts; High Energy Interactions; Muons; Neutrinos; Ginga Satellite; Satellite Observation; Venera Satellites; Astrophysics; ELEMENTARY PARTICLES; GAMMA RAYS: BURSTS full text sources ADS |

Radiological Safety Experience in the Fabrication of Alloy Plate Fuels Bearing233U/Pu

The first incidence of [sup 233]U-bearing fuel fabrication in India was the production of aluminum-clad Al-[sup 233]U alloy fuel for the Kamini research reactor. The reactor physics experiments for this fuel are now being carried out in the Purnima III critical assembly, where Al-Pu alloy plate fuels will also be used. Both types of fuels were fabricated in the radiometallurgy laboratories of Bhabha Atomic Research Centre. The hazard potential of each step, evaluated from the site-specific radiological field data, is summarized. The parameters analyzed for this purpose include external and internal radiation hazards, contamination hazards, age of fuel material (i.e., time after separation), and experimental thermoluminescent detector exposure data. Gamma spectrometric data of the finished fuel plates were also analyzed for their utility in checking the material inventory. The collective dose equivalent from the fabrication operations for 12 subassemblies (9 bearing [sup 233]U and 3 bearing plutonium) was 67 mSv, arising from external exposures only. The internal exposure was nil. Fabrication of fuel plates constituted [gt]60% of the total exposure. Fabrication of fuel subassemblies and quality control inspection at all the stages accounted for the remaining radiation exposure. Handling of [sup 233]U/Pu-bearing fuels is likely to increase in the yearsmore » ahead in India. In this context, analysis of radiological field data has yielded useful guidelines for future work.« less

Detector response and exposure control of the RadioVisioGraphy system (RVG 32000 ZHR)

The RadioVisioGraphy system (RVG 32000 ZHR) was studied with respect to some physical properties including the precision and linearity of the exposure control and the detector response to x-rays. The x-ray unit was found to yield repetitive exposures that are precisely controlled by the CCX timer. A “preheat” and an “after exposure” period were noticed, and their resulting x-ray exposures were measured. Two RVG detectors were compared for their responses with x-rays. The differences between the detectors were insignificant. However, inhomogeneous detector responses were found in both of the detectors; with the same exposure, the central parts of the detectors yielded lower pixel values than the peripheral parts. A calibration equation was developed to correct for the inhomogeneity.

Development of mercuric iodide X-ray and alpha backscattering spectrometers for space applications

An alpha particle instrument in combination with a room temperature mercuric iodide X-ray spectrometer can provide a complete and detailed in situ chemical analyses of extraterrestrial bodies. Conceptual designs of the instrument will be presented. One of the important questions about the resistance of HgI2 detectors to the radiation damage will be addressed. Our experimental results of exposure of HgI2 detectors to proton fluxes up to 1012 protons/cm2 show no degradation in the detector performance.

HPGe detector preamplifier output pulse simulator

The pulse simulator described here can be used to simulate the output pulses of a large HPGe detector preamplifier combination. A number of such simulators can be used to obtain pulses having a fixed time origin but with randomly varying risetime. These simulators can replace large HPGe detectors at the time of setting up of electronic modules in a multidetector fast coincidence experiment using an accelerator beam. Thus the unnecessary exposure of detectors to radiation during the preparatory phase can be avoided and the entire accelerator beam time can be used for acquisition of experimental data. The minimum and maximum values of risetime can be set to have a spread within a band of 60 to 600 ns and the pulse amplitude is adjustable from 0 to −2 V. The FW (0.01) M of the pulse height distribution is 1 mV for a pulse height of 2 V, which is much less than that of a photopeak obtained with large HPGe detectors.

Results of silicon strip detector readout using a CMOS low power microplex (MX1)

A system for reading out silicon strip detectors has been fabricated on a CMOS integrated circuit. The chip consists of an array of 128 amplifiers with a single multiplexed output. These chips have been bonded to a 256-channel silicon strip detector. Results are reported on the electrical parameters of the chips and on data taken during exposure of the instrumented detectors to minimum-ionizing beta particles. The radiation tolerance of the device has been investigated. The MX1 is working to specification and is presently being incorporated into equipment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Dependence of sensitivity of cellulose nitrate(R) and Makrofol-E polycarbonate plastic detectors on etching temperature

Exposure of cellulose nitrate (Russian) and Makrofol-E polycarbonate plastic detectors to different ions have been obtained from the cyclotron at JINR, Dubna (USSR). The bulk etch rate, Vb and track etch rate, Vt are measured for different etching temperatures and hence the activation energies are determined. The dependence of activation energy for track etching, Et on mass A of the bombarding ion in studied. The variation of Vt and V = Vt/Vb along the particle trajectory is shown for different temperatures. the dependence of Vt and V on the energy loss, dE/dx of different charged particles is also shown for different temperatures. The experimental results indicate that the sensitivity of CN(R) detector depends strongly on etching temperature while that for Makrofol-E detector is independent of etching temperature.

A Cosmic-Ray Experiment on Very High Energy Nuclear Collisions

The Japanese-American Cooperative Emulsion Experiment (JACEE) was conceived in 1978 to study high energy nucleus-nucleus collisions and the composition and energy spectra of primary cosmic rays up to 10/sup 15/ eV. The primary detection aparatus is a balloon with a 0.8 x 1 m emulsion chamber whose acceptance aperture exceeds ..pi.. radians. The detector operation altitude and exposure time are 4g/cm/sup 2/ and 40 hrs, respectively. The purpose of this paper is to report on searches for new channels of particle production at high nuclear energy densities and temperatures via transverse momenta studies, particle correlations in the pion condensation region, and quark-gluon plasma studies. (AIP)

K-meson production by nu micro-deuterium reactions near threshold: Implications for nucleon-decay searches.

The extent to which atmospheric neutrino interactions can mimic nucleon decay into modes with a strange particle in the final state is evaluated using nu/sub ..mu../-deuterium interactions recorded by the 12-Foot Bubble Chamber at the ANL Zero Gradient Synchrotron. Event distributions representative of atmospheric neutrinos with 1 < E/sub nu/ < 5 GeV are studied. Such neutrino interactions in massive underground detectors will yield K/sup 0/ and K/sup +/ mesons with respective rates of 1.5 +- 0.8 and 4.2 +- 2.3 per kiloton year. However, the neutrino-induced events have final-state invariant mass and net momentum which are distinctly different from the values that characterize nucleon decay. Consequently, at lifetime levels corresponding to ten kilton years of detector exposure, experimental searches capable of reconstructing these variables will not encounter substantial neutrino background for nucleon decay modes leading to K mesons in the final state. 24 refs, 4 figs.

Dose Re-Assessment TSEE Measurements with BeO Thin-Film Detectors

The exposure of BeO thin-film TSEE detectors to UV light induced a photo-transfer (PT) of electrons from deep traps to shallow dosimetry traps, emptied by a primary TSEE readout. Thus additional PT-TSEE readouts are allowed. By this technique the dose of the primary applied irradiation can be reassessed. Spectral records reveal an intrinsic TSEE photo-excitation at a short UV wavelength (250 nm), appearing as background to PT-TSEE, Thus, for photo-transfers, the nearer UV range (300∼350 nm) is best.

Two- and three-pion production byνμdreactions near threshold: The implications for nucleon-decay experiments

We use ${\ensuremath{\nu}}_{\ensuremath{\mu}}$-deuteron reactions into exclusive multipion final states to determine the extent to which atmospheric $\ensuremath{\nu}$ interactions can imitate nucleon decay. For decays $N\ensuremath{\rightarrow}{l}^{c}{\ensuremath{\pi}}^{c}{\ensuremath{\pi}}^{c} ({l}^{c}{\ensuremath{\pi}}^{c}{\ensuremath{\pi}}^{c}{\ensuremath{\pi}}^{0})$, neutrinos induce background events at the rate 0.07\ifmmode\pm\else\textpm\fi{}0.06 (0.03\ifmmode\pm\else\textpm\fi{}0.02) per kiloton year. By requiring a multipion final state to be consistent with a $\ensuremath{\rho}$, $\ensuremath{\omega}$, or $\ensuremath{\eta}$, a fivefold reduction of the background is obtained. Thus presentgeneration experiments are capable of searching for such decays at a lifetime level corresponding to many kiloton years of detector exposure.

A flash kinetic spectrophotometer employing photodiode array sensors.

We are describing a method for rapid spectroscopic measurement of phototransients obtained in a flash photolysis apparatus. A linear photodiode array is employed as a detector to sense changes in light absorption across the visible spectrum. A microcomputer handles sampling, analysis, and plotting the data, and controls a xenon flash photolysis unit. This approach provides simultaneous wavelength acquisition compatible with millisecond time scales. The implementation described here monitors 22 wavelengths over a 300 nm range with up to 50 consecutive spectral scans spaced a minimum of 0.5 ms. Wavelength and temporal resolution, set by spectrograph and detector exposure period, are 1.5 nm and 0.5 ms. The main advantages of this method are collection of multiwavelength data for determining complex transient spectral changes with little sample, and convenience of both data acquisition and analysis. Application to measurements of bacterial rhodopsin photochemistry is described.

Fast infra-red detectors for use in pulse radiolysis: A reversible slow component

Exposure of InSb detectors to visible light at 77 K adds a slow (μs) component to the response time. This effect is reversed by warming to room temperature in the dark.