Stopping power of fission fragments in thin Mylar and nickel foils

TL;DR

This study accurately measured the energy loss of heavy fission fragments in thin Mylar and nickel foils, comparing experimental data with various models to evaluate and improve stopping power calculations.

Contribution

The paper provides new experimental stopping power data for fission fragments in Mylar and nickel, and updates models and databases for better accuracy.

Findings

SRIM-2013 deviates significantly for Mylar

Knyazheva et al. model agrees well with data

Updated parameters improve model accuracy

Abstract

The energy loss of heavy ions in thin Mylar and nickel foils was measured accurately using fission fragments from $^{239}Pu(n_{th},f)$, mass and energy separated by the Lohengrin separator at ILL. The detection setup, placed at the focal plane of the Lohengrin separator enabled to measure precisely the kinetic energy difference of selected fragments after passing through the sample. From these data, the stopping powers in Mylar and nickel layers were extracted and compared to calculations. Whereas large deviations are observed with SRIM-2013 for Mylar, fairly good agreements are obtained with the semi-empirical approach of Knyazheva et al. and the calculations contained within the DPASS database. In nickel, SRIM-2013 and Knyazheva model are in agreement with our data within about 10 %, while large deviations are observed with DPASS. We used our data to provide updated parameters for the Knyazheva et al. model and rescale DPASS database for nickel and Mylar.