Stopping Power Analysis of 37K, 44Cl, and 71Br Incident on a He: CO2 (9:1) Gas Target

Min Sung Kim

2015

In 1930, Bethe formulated a theory that describes the quantum mechanical collision process for ions traveling through target matter. His formula calculates the relationship between the projected range and the properties of the nuclei. Some phenomenological effects were discovered after the formation of Bethe's theory, and the original theory has been modified by adding correction terms that account for the effects. The additional terms that are considered in this thesis are Barkas, Bloch, and shell corrections, following formalisms of Ziegler et al. Although descriptions of the phenomenological effects are the main focus of these terms, approximations and assumptions are made for simplicity and practicality. The composite Bethe-Bloch formula successfully describes the stopping power nuclei incident on target matter, but the accuracy can be improved by fitting with available empirical data. For ions from 19K to 92U, tabulations from ATIMA, Hubert, and SRIM are found to be best in different ranges of specific energy.

The main reactions of this thesis are 37K, 44Cl, and 71Br incident on He:CO2 (9:1) Gas Target. These reactions are produceable by equipment in the National Superconducting Cyclotron Laboratory. The beams can be delivered by the Re-Accelerator 3, and reactions are detectable by they newly commissioned Active Target-Time Projection Chamber. Ziegler's formalisms are most applicable to light stopping media and heavy projectiles. Since ions delivered by ReA3 are in this range and the AT-TPC uses gaseous targets, SRIM and LISE++, which include tabulations by Ziegler, Humbert, and ATIMA, are used to compare the calculated projected ranges. Beginning with simple incident particles such as neutrons, protons, and 12C nuclei, projected ranges through 27Al, 56Fe solids, and liquid H2O are plotted and calculated. As a result, the slope of the relationship between incident energy and projected range is determined by the property of the incident particle, not that of the target medium. Tabulations in SRIM and LISE++ are compared for reactions feasible by ReA3 and the AT-TPC: 37K, 44Cl, and 71Br incident on He:CO2 gas mixture. Projected ranges for 37K and 71Br beams are calculated in detail and plotted for 41Sc and 75Rb resonances. 41Sc and 75Rb resonances with specific excitation energy are predicted using ATIMA 1.2 Neither 41Sc nor 75Rb have been studied with 37K and 71Br. If these reactions are measured, missing properties such as spin parities may be detected.