Nuclear track-formation models and the response of BP-1 detectors

The mechanism of nuclear track formation in solids is poorly understood, despite decades of experience with nuclear track-etch detectors. One of the roadblocks has been the lack of precision tests of track-formation models. Here we exploit the unparalleled resolution of a glass nuclear track-etch detector, BP-1, to test track-formation models. By the use of calibration beams, we have corrected all signals for fluctuations in detector response, eliminating a possible source of systematic error. Within this dataset we compared signals due to the same particle charge over a large range of Lorentz factor. We show from a variety of lines of evidence that the response of BP-1 is not a simple function of total energy loss nor of other quantities derived from total energy loss such as restricted energy loss. A generic feature of a large class of models is a significant relativistic rise, which we do not observe. We show that an empirical hybrid model fits the response of BP-1 detectors over a wide range of charge and energy