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101.
A. V. Belushkin 《Pramana》2008,71(4):639-651
Different types of neutron scattering experiment for the study of condensed matter properties pose specific and often contradictory
requirements for detector characteristics. There is no single type of detector which satisfies all the criteria. Therefore,
compromise is inevitable and some of the characteristics are trade off in favour of others.
Present report gives an overview of detector systems presently operating at the leading neutron scattering facilities as well
as some development work around the globe.
相似文献
102.
The powder diffractometer and Hi-Q diffractometer at Dhruva reactor make use of five identical 1-D position sensitive detectors (PSDs) to scan scattering angles in the range 3° to 140°. In order to improve the overall throughput of these spectrometers, it is planned to install a bank of 15 high-efficiency and high-resolution PSDs arranged in three layers with five PSDs in each layer. With each high pressure PSD (3He 10 bar + Kr 2 bar) showing the efficiency gain of 1.8 at 1.2 Å, detector bank is expected to show overall gain of 5.5 times the present detection efficiency and reduction in data collection time by equivalent factor. The 1-D PSDs are developed in batches of five, and are characterized so that all PSDs operate at uniform parameters such as position resolution, uniformity of efficiency and linearity of response. Position spectrum indicates the differential position resolution to be ~1 mm and integral position resolution to be 3–4 mm. Broadening of position spectrum at the extreme end of sensitive length of PSD is analysed using fine shift of the beam. Dependence of position resolution and dynamic range of output pulse on the input impedance of pre-amplifier is also presented. 相似文献
104.
105.
Türkan Özbay 《International journal of environmental analytical chemistry》2016,96(8):752-762
In 2013, an extensive study was performed in a total of 117 locations in Izmir province and indoor radon levels were measured using the alpha track etch integrated method with LR-115 detectors. As the maps are more practical to interpret the results of radiological survey, the distributions of indoor 222Rn activities in four most densely populated districts of Izmir were mapped in detail. It is seen that the estimated average radon concentration level (210 Bq m?3) determined in Izmir province was almost three times higher than the mean value for Turkey (81 Bq m?3). Exposed annual effective dose equivalents for Izmir province were estimated in the range of 0.7 to 12.3 mSv year?1 with a mean of 5.3 mSv year?1. In this study, it is pointed out that indoor radon concentration was affected by the age of the building and height above the ground. 相似文献
106.
In this paper we investigate the light response to fast neutrons and estimate the pulse height resolution of a deuterated liquid organic scintillator, EJ-315, considering the detector's non-linear light response to gamma-rays. Initially, collision data and a neutron beam trigger are recorded in coincidence mode, and incident neutron energy is calculated with a time-of-flight technique. Fast neutrons are further discriminated from gamma-ray background based on the scintillation material decay patterns using a pulse shape discrimination algorithm. A light response matrix composed of multiple neutron energy and their corresponding light outputs is derived. The pulse height resolution property of the EJ-315 is characterized utilizing the derivatives of the pulse height distributions with corrections of the measurements setup uncertainties. Additionally, the EJ-315's pulse height resolution is also characterized by comparing the smoothed derivatives of quasi-monoenergetic neutron pulse height distributions, given by the Peierls-formula-based analytic model, to match the measurement data. Results show rather consistent 10–13% pulse resolution for mono-energetic neutrons with kinetic energy above 2 MeV. The resolution decreases slightly with an increase in neutron energy indicating the improved resolution performance of EJ-315 in the higher energy events. 相似文献
107.
The single crystals of triglycine sulfate doped with bivalent and tetravalent Pt‐ions and with L‐alanine (LADTGS/Pt(II) and LATGS/Pt(IV)) were grown in the ferroelectric phase from low temperature solutions. Using stick seeds the full‐shaped crystals with many growth pyramids have been prepared. The growth rate along the axis c of the doped crystals is much higher than in an undoped one. Morphology, domain structure and P‐E hysteresis loops have been investigated. The effect of the dopant on the growth velocity is explained on the basis of catalytic action of supposed platinum complexes. The first series of the pyroelectric detectors have been prepared from these materials and their fundamental parameters are presented. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The exceedingly fragile nature of thermally grown Au-black coating makes handling and patterning a critical issue. Infrared absorption characteristics of near atmospheric, N2 ambient DC sputtered Au thin films are studied for this purpose. The thin Au films are sputtered at different chamber pressures in Ar and N2/Ar gas ambient from 4.5 to 8.0 mbar and optimized for enhanced infrared absorption. The absorber film sputtered in N2/Ar ambient at 8.0 mbar chamber pressure offers significant absorption of medium to long wave infrared radiations. The micro-patterning of sputtered Au thin film is carried out by using conventional photolithography and metal lift off methods on a prefabricated µ-infrared detector array on Si (1 0 0) substrate. The steady state temperature response of sputtered film has been examined using nondestructive thermal imaging method under external heating of the detector array. 相似文献