Charge resolution of a Hungarian brand CR-39(MA-ND) detector exposed to A 84Kr beam of energy 0.45A GeV

Abstract: Hungarian brand CR-39(MA-ND) stack was irradiated at a zenith angle 30° by 36 84 Kr ions of energy 0.45 GeV/ n using Lawrence Berkeley Laboratory BEVALAC beam. The exposed plate was etched in 6N NaOH aqueous solution at 70°C for 20 h. About 636 etch pit diameters were optically measured. The response to Kr ions and the projectile fragment tracks produced in CR-39(MA-ND) target were determined for gb = 0.737. The charge resolution of the CR-39 plastic at the Kr peak was found to be 0.26 e obtained from the average of double cone etch pit data. An increase of the measured partial inelastic cross sections with nuclei charge number in the range 25 ⩽ Z ⩽ 35 has been found. Indication of ΔZ = + 1 events has been observed whose cross section is in accord with the survey presented by Ren Guoxiao et al. The experimental fragmentation cross sections have been compared with the expected results from the semi-empirical nuclear fragmentation model of Wilson et al.

Abstract: 1.88A GeV56Fe beam of Lawrence Berkeley Laboratory BEVALAC irradiated at an angle 30° to the stack, composed of Al target and CR-39 (DOP) solid-state nuclear-track detector. These polymer sheets were etched in 6.25N NaOH solution at 70°C for 48 hours. The minor axes of the elliptic etch pits were measured by a Leitz Ortholux microscope. The measured projectile fragmentation cross-section for nuclei of chargeZ ranging from 21 to 25 is in approximate agreement with the calculated result from the semi-empirical nuclear fragmentation model after Wilson, Townsend and Badavi. The existence of trans Fe nuclei was noticed. The measured double-cone charge resolution was found to be 0.20e.

Abstract: CR-39 is a commercially available, optically clear, amorphous, thermoset plastic in which nuclear particle tracks can be revealed by etching in a hot NaOH solution. Its uniformity of response (

Abstract: We review the theory of the electromagnetic interactions between rapidly moving charged particles and the matter through which they pass. The emphasis will be on very massive electric ($\ensuremath{-}100\ensuremath{\le}{Z}_{1}100$) and magnetic ($|g|=137e \mathrm{and} \frac{137e}{2}$) particles moving with relativistic velocities ($\ensuremath{\beta}g0.2$, $\ensuremath{\gamma}l100$). Consideration will be given to both the stopping power of the projectile and to the response of the absorbing medium to the excitation caused by the projectile.

Abstract: Dielectric nuclear track detectors are now being utilized in a variety of research applications involving registration of heavily ionizing charged particles. Many situations call for the identification of particle charge Z , energy E , and possibly the mass M 1,2 ). In these cases, a detailed knowledge of the etched track geometry is necessary to make possible computation of the relevant track parameters from the measured track features. Geometry of etched particle tracks can be quite complex. In this paper some of the most relevant aspects of track geometry are derived and discussed in considerable detail. Two basic assumptions are made: the detector is isotropic and homogeneous, and the particle ionization rate remains constant over the etched portion of the track. Track specification and measurement parameters are developed for a variety of different situations.

Abstract: A stack of the plastic CR-39 and nuclear emulsions was exposed at a vertical cut-off rigidity of 10.3 GV and an atmospheric depth of 7 g/cm2 for 30 h in May, 1979. Characteristics of shapes of etched cones produced by relativistic cosmic ray heavy nuclei in CR-39 are investigated and it is found that the surface ellipse of the etched track with large dip angle becomes more deformed. The detection threshold value is obtained to be Z/β ≅ 6 and the charge resolution (root mean square) to be ΔZ ≅ 0.4 charge units for relativistic iron nuclei in CR-39.

Abstract: We present measurements of charge resolution in the plastic track detectors CR39(DOP) and Tuffak polycarbonate over the region 10≤ Z β ≤105 , determined from plastic stacks exposed to projectile fragments of 1.29 GeV u 139La, 1.45 GeV u 84Kr, and 1.70 GeV u 56Fe produced by nuclear interactions within the stacks, and to 0.96 GeV u 238U and 1.0 GeV u 197Au ions. The charge resolution obtained is shown to be comparable to the irreducible limit set by fluctuations in energy loss and is consistent with that expected of a track-formation model based on the effects of both K-shell ionization and restricted energy loss.