نتایج جستجو برای: آشکارساز 39 cr
تعداد نتایج: 142907 فیلتر نتایج به سال:
Particle intensity, dose equivalent and absorbed dose have been measured on board the space shuttles during their visit to the International Space Station (ISS) on STS-108 and STS-112. The dose estimates are based on very accurate measurements of recoils produced in CR-39 by cosmic ray primary and secondary protons and heavier nuclei and by secondary neutrons. The corresponding LET spectra were...
The results of the analysis of data taken in the continuation of a previously reported search1 for highly ionizing particles at PEP are presented. These data were taken in the period from October 1981 to June 1983. Assemblies consisting of Lexan and CR-39 plastic track detectors were exposed in two runs to integrated luminosities of 30 X 1O36 cm-2 and 150 X 10% crnw2% The search was sensitive t...
A time-efficient surface grinding and polishing procedure was developed to remove noise pitting associated with the etching of CR-39. CR-39 is a solid-state nuclear track detector used to measure and analyze ions produced by fusion implosions on the OMEGA and OMEGA EP laser systems. Using CR-39 thickness measurements acquired during the grinding process, surface removal rates of 68 µm/min and 5...
Energetic ions and ultrashort X-rays were generated by an intense ultrashort laser interacting with a copper target. Fast ions up to 3 MeV were observed with CR-39 nuclear track detector sheets when 7 TW laser was used. Cu ∼ Cu ions with the energy from 50 keV to 220 keV were detected with a Thomson parabola detector in the case of the laser power of 2.5 TW. Time-resolved X-ray diffraction was ...
The effects of UVC exposure on the track etch rate Vt and the detector sensitivity V of CR-39 SSNTDs were investigated through the diameters and depths of alpha-particle tracks. Both the bulk etch rate Vb and Vt increased but V decreased. The track diameters and depths were used to derive a V function for CR-39 detectors with and without UV irradiation. © 2008 Elsevier Ltd. All rights reserved.
background: a substantial part of the public’s natural radiation dose is due to the inhalation of radon gas. most of the exposure occurs indoors where the airborne concentration of radon and its decay products is usually higher than outdoors. materials and methods: radon activity concentration has been measured twice in 50 classrooms in 5 levels (10 each) during summer and winter using solid-st...
ذرات باردار پرانرژی فرودی بر سطح آشکارساز پلیمری در مسیر عبورشان ردپای نهان تولید می کنند. فرآیند خورش شیمیایی به مشاهده ردپاها کمک می کند. یکی از کارهای چالش برانگیز در استفاده از آشکارسازهای ردپای هسته ای اندازه گیری قطر ردپاهای به خصوص کم عمق ناشی از خورش های با زمان کوتاه است. در این پایان نامه ابتدا ردپاها توسط پرتودهی آشکارساز cr-39، با پرتوهای آلفا تهیه می شوند، سپس آشکارسازهای پرتودهی ش...
We discuss the properties of cosmic ray nuclearites, from the point of view of their search with large nuclear track detector arrays exposed at different altitudes, in particular with the SLIM experiment at the Chacaltaya high altitude lab (5290 m a.s.l.). We present calculations concerning their propagation in the Earth atmosphere and discuss their possible detection with CR39 and Makrofol nuc...
The nematode Caenorhabditis elegans was exposed to natural space radiation using the ESA Biorack facility aboard Spacelab on International Microgravity Laboratory 1, STS-42. For the major experimental objective dormant animals were suspended in buffer or on agar or immobilized next to CR-39 plastic nuclear track detectors to correlate fluence of HZE particles with genetic events. This configu...
Recently, Matiullah et al. described the use of NaOH/ethanol as an etchant for the CR-39 detector, and have determined the corresponding bulk and track etch properties from the track diameter method. In the present work, the bulk and track etch properties of CR39 in NaOH/ethanol were derived from direct measurements. The bulk etch rate has been found to increase with the molarity of NaOH/ ethan...
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