Beam Particle Identification and Tagging of Incompletely Stripped Heavy Beams with HEIST

TL;DR

The paper introduces HEIST, a new detector system that improves identification and tagging of incompletely stripped heavy ion beams, enabling more accurate inverse kinematics experiments with heavy nuclei.

Contribution

HEIST combines timing detectors, an ion chamber, and a Ge detector to effectively identify and calibrate heavy isotope beams, addressing charge state contamination issues.

Findings

Successfully identified $^{198}$Pb and nearby nuclei at 75 MeV/A.

Achieved 86% purity in a typical beam cut.

Charge state populations are moderately well modeled by GLOBAL.

Abstract

A challenge preventing successful inverse kinematics measurements with heavy nuclei that are not fully stripped is identifying and tagging the beam particles. For this purpose, the HEavy ISotope Tagger (HEIST) has been developed. HEIST utilizes two micro-channel plate timing detectors to measure time of flight, a multi-sampling ion chamber to measure energy loss, and a high purity Ge detector to identify isomer decays and calibrate the isotope identification system. HEIST has successfully identified $^{198}$Pb and other nearby nuclei at energies of about 75 MeV/A. In the experiment discussed, a typical cut containing 89\% of all $^{198}$Pb$^{+80}$ in the beam had a purity of 86\%. We examine the issues of charge state contamination. The observed charge state populations of these ions are presented and are moderately well described by the charge state model GLOBAL.