Temperature effect in stratospheric balloon flight exposure of CR-39 plastic detector

A CR-39 stack equipped with a passive temperature control shielding was exposed to primary cosmic radiation in a balloon flight from Trapani (Sicily) to Arenosillo (Spain) at an average altitude of 4 g cm-2 residual atmosphere for 20 h. High vertical geomagnetic cut-off ensured the relativistic nature of registered ions. Stack temperature was monitored by means of thermal probes and associated electronics and transmitted by telemetry to an earth-based station. Temperature excursions were less than 16°C, which is shown to correspond to a 0.11e shift in the charge scale for relativistic iron ions. Best etching conditions were established for the VH relativistic component as well as a discrimination method for relativistic ions. Charge uncertainty was found to be 0.44e. Relative abundances for the iron group extrapolated to the top of the atmosphere are compared to those reported by other authors. © 1987.