The “Heavy Ions in Space” Experiment

Abstract

The Heavy Ions in Space (HIIS) experiment was developed at Naval Research Laboratory and is currently in orbit onboard NASA's Long Duration Exposure Facility (LDEF). HIIS will record relativistic cosmic ray nuclei heavier than magnesium and stopping nuclei down to helium.The experiment uses plastic track detectors that have a charge resolution of 0.15 charge units at krypton (Z=36) and 0.10 charge units, or better, for nuclei lighter than cobalt (Z=27).HIIS has a collecting power of 2 square meter steradians and it has already collected more than a year's data.

The Use of Dielectric Track Recorders in Particle Identification

“…After irradiation the two parts of the crystal were again separated so that the etching could be carried out more conveniently from the boundary, thus avoiding the blocking of the etchant along a very long sparsely ionized track. He reports a total etchable range of relativistic 238 U ions which is very much longer than those predicted by 27 The fully etched track in each case encompasses both segments extending on either side of the etch channel. These are also referred to as "confined length measurements".…”

LET calibration for CR-39 detectors in different oxygen environments

“…Previous research indicates that the sensitivity of CR-39 detectors is different and dependent on the concentration of environmental oxygen around CR-39. The Adams group (Adams et al, 1991) and the Beaujean group (Beaujean et al, 1993) reported that their LDEF (long duration exposure facility) met low CR-39 sensitivity problem because their CR-39 detectors were exposed in vacuum while DIAS (Dublin Institute for Advanced Studies) group and USF (University of San Francisco) group did not have such problem because their detectors were in a good-oxygen environment. Fujii et al (1997) did some research for the effect of the track registration on oxygen and other gases.…”

Research on sensitivity fading of CR-39 detectors during long time exposure

“…Oxygen around the CR-39 detectors tends to mix with ions and radicals, thus preventing their recombination and changing the sensitivity of the CR-39 detectors, the less oxygen, the more fading (Adams et al, 1991;Beaujean et al, 1993;Fujii et al, 1999;Dö rschel et al, 2005); higher temperature will make the recombination of the ionization easier and faster; the higher temperature, the more fading. However, practically it is difficult to consider all the factors separately in the formula of fading correction.…”

“…The NASA-LDEF was designed to provide long-term data on the space environment and its effects on space system and operation and was conducted from 7 Apr. 1984-12 Jan. 1990 (Adams et al, 1991;Beaujean et al, 1993). The Matroshka phantom (Reitz et al, 2009 Sensitivity fading of CR-39 detectors was observed during space missions LDEF (5.7y), Matroshka-1 (616d), Matroshka-2 (367d), 13 (183d),14 (215d) and 15 (195d).…”