Registration Temperature Effect Research Articles

Investigation of the response of lexan polycarbonate to relativistic ultra heavy nuclear particles

Recent investigations of the track response of Lexan to relativistic ultra heavy nuclei are reported. The inherent charge resolution of Lexan for relativistic ultra heavy nuclei under normal exposure conditions at accelerators has been investigated. The registration temperature effect was measured using gold (Z=79) at energies 2, 4 and 11 GeV/u covering a wide range of temperatures from −78°C to +22°C. In addition, the sensitivity of the track etch rate and the bulk etch rate to etch product concentration was re-examined.

Registration temperature effect in polymers: Physico-chemical aspects

Registration temperature effect in two different polymers - poly(ethylene terephthalate) (PET) and polypropylene (PP) films - is investigated. Temperature effects on track formation are considered in terms of molecular mobility and relaxation transitions. The track eth rate is measured as a function of irradiation temperature in the range of 77 to 373 K. The obtained results are compared with the radical yields, radiothermoluminescence curves and thermally stimulated currents measured with the aim of detecting changes in the mobility of macromolecules and radiolysis intermediates. It is found that the change of the track etch rate with changing registration temperature correlates with γ- and glass transitions in PP and with β-and glass transitions in PET.

DC conductivity and dielectric constant of cellulose nitrate detector

The temperature dependence of DC conductivity as well as the temperature and frequency dependence of dielectric constant of cellulose nitrate (CN) track detector was undertaken for better understanding of the track response of the detector. In the temperature range −100° to + 100°C, CN is found to be an insulating semiconductor with activation energies 0.04 eV, 0.78 eV and 1.24 eV. The transition of the activation processes takes place at (−10±1)°C and (60±1)°C. The high activation energy transition temperature coincides with the glass transition temperature of CN. The dielectric constant is found to increase with temperature and decrease with frequency. These results reveal the physical basis of the Ion Explosion Spike model of Fleischer et al. (1975). A possible explanation of the registration temperature effect is also given on the basis of these results.

Apparent binary microscopic response to relativistic ions of a large class of track-etch detectors

We find that a large class of glass track-etch detectors seems to behave in an extraordinarily simple way on microscopic scales in response to relativistic ions. The behavior of these detectors is consistent with binary, on-off behavior in response to restricted energy loss on microscopic scales, with the shape of the response curve as a function of Z β on macroscopic scales determined solely by statistical fluctuations in energy loss. This model naturally reproduces the shapes of the response curves for a variety of detectors and etchants; it also correctly predicts the charge resolution of BP-1 glass and, with an additional hypothesis, the sign and magnitude of the registration temperature effect of BP-1. Several other materials, including at least two plastics, seem to exhibit binary or nearly binary behavior.

A detailed study of the registration temperature effect in CR-39 useful for cosmic ray experiments

Using an 814 MeV/u 56Fe beam and fragments (13 ≥ Z ≥ 26) we have conducted a detailed study of the registration temperature effect (RTE) in CR-39 (DOP) from T = 0°C to 30°C. With this data we are able to resolve a number of issues surrounding the RTE relevant to cosmic ray experiments. In particular, we conclude that d(Z/β) ∗/ dT = −0.06±0.02° C −1 for cosmic ray Fe.

Measurement of the registration temperature effect in BP-1 glass

In order to determine its effect on mass measurements and charge measurements for the cosmic-ray experiments ANTIPODE and TREK, I have measured the change in detector response with temperature (the so-called registration temperature effect, or RTE) for BP-1 glass responding to relativistic gold ions and to stopping argon ions. I measure a small but finite RTE for relativistic gold, and conclude that thermal regulation is necessary for the large collector of TREK, which is being exposed outside of the Russian space station Mir. I set a small upper limit for the magnitude of RTE for stopping argon, and conclude that the thermal variations experienced by ANTIPODE in its balloon flight over Antarctica were not large enough to degrade its mass resolution; I further conclude that the thermal variations that we anticipate for the small collector of TREK, which is being exposed inside the Russian space station, will not degrade its mass resolution.

Registration temperature effect in polypropylene detectors

The registration temperature effect (RTE) was investigated using two types of polypropylene (PP) detectors. It was found that the RTE depends on the content of radical scavenger in the polymer. The results are compared with published radiothermoluminescence data and discussed in terms of relaxation transitions.

Change of CR-39(DOP) track detector response as a result of space exposure

Abstract The response functions for CR-39(DOP) plastic track detectors are calculated using simplex method for nonlinear least squares fit from experimental data obtained from accelerator beams as well as space exposure. The average detector sensitivity is reduced by over 30% in the case of space exposure. The average charge shift for the oxygen group is one charge unit, and it increases with particle charge. The effect decreases with restricted energy loss (REL), which is contrary to that observed in the registration temperature effect. We have discussed various environmental parameters which may produce the observed effect. The registration temperature effect may account for the observed effect (within the errors) for the worst case (temperature) analysis. However, a more reasonable estimate suggests that both the registration temperature as well as pressure during exposure contribute to the observed effect. However to discriminate between the separate contributions, one needs further experimental data.

Influence of temperature on track registration in olivine

Track etch rate and total etchable track length have been compared for Xe ion tracks registered in olivine crystals, at two different temperatures (160K and 293K). A small registration temperature effect has been found. It appears to vary with the crystallographic orientation of the tracks, beeing nearly inexistent in some cases. Because of its small amplitude, this effect should not pose any serious problem for the study of ultraheavy cosmic ray tracks in meteorites.

The ionisation dependence of the registration temperature effect in solid state nuclear track detectors

Abstract The Registration Temperature Effect in solid state nuclear track detectors has been investigated over a wide range of ionisation, using two types of polycarbonate detector and three types of doped allyl diglycol carbonate (CR-39) detector exposed to beams of 960 MeV/N uranium ions and 300 MeV/N iron ions at different temperatures. Beam spreaders were employed to provide a range of energies for both ions in each detector stack. The fractional change in signal strength per unit temperature change is found to be a strong, increasing function of ionisation for a given solid state nuclear track detector polymer at a given registration temperature. This fractional change in signal strength also appears to be an increasing function of charge for a given value of ionisation . In the case of both uranium ions and iron ions in polycarbonate track detectors, it is found that the mean fractional change in etch rate per degree centigrade, P, may be represented by an expression of the form P = KJM, in the energy regions studied, where K is a constant specific to the ion, J is given by Z2eff/β2 and the index, M, is ⋍ 0.75. These results constitute a major hardware “design driver” for future heavy nucleus experiments involving extended duration exposures of solid state nuclear track detectors on spacecraft.

The registration temperature effect for lightly ionizing particles in CR-39

Abstract Plastic track detectors have been used for years to measure the elemental composition of ultraheavy cosmic rays. Recently, it has been discovered that the response of these detectors can be drastically affected by detector temperature at the time particles are recorded. We have investigated this effect in CR-39 for relativistic Fe and Kr ions as well as for stopping He ions. The effect for these lightly ionizing particles is smaller and opposite in sign to that reported earlier for more intensely ionizing particles. The results reported here indicate that the detector temperature should be controlled to ±10°C in cosmic ray experiments designed to measure charge composition below Z=40. Thermal modeling of NRL's Heavy Ions in Space experiment indicates that this degree of temperature control is being achieved.

New results on the investigation of the variation of nuclear track detector response with temperature

Track response of polymers is now known to depend on the temperature of the detector during passage of the ionising particle (the registration temperature effect). This has serious consequences for cosmic ray composition studies carried out in earth orbit or on high altitude balloons. Further studies are reported for Lexan, plain CR-39 and doped CR-39 exposed to 245 MeV/N Fe ions. It was found that the relative signal strengths continue to increase down to -137°C, the minimum temperature employed in this experiment. The stack temperatures were cycled between 20°C and -137°C but no evidence of a hysteresis effect. was observed.

Preliminary results on the registration temperature effect for uranium ions in various solid state nuclear track detectors

The variation of track response with registration temperature for Uranium ions in solid state nuclear track detectors has been investigated for the first time. Preliminary results are presented for Tuffak polycarbonate, Lexan polycarbonate and three types of doped CR-39 detectors exposed to 960 MeV/N Uranium beams at registration temperatures of -78°C and +18°C. The fractional change in signal strength (VT) per °C was found to be considerably greater than that for nuclei of lower ionisation. This result has very significant implications for future ultra heavy cosmic ray experiments employing solid state nuclear track detectors. In addition, it can explain apparent anomalies in the data of previous ultra heavy cosmic ray experiments.