Simulating the FTICR-MS Signal of a Decaying Beryllium-7 Ion Plasma in a 2D Electrostatic PIC Code

• Main Author: Nakata, Michael Takeshi
• Format: Others
• Published: BYU ScholarsArchive 2010
• Subjects: beryllium-7; electron capture; lithium-7; ion plasma; Fourier transform ion cyclotron mass spectrometry; FTICR-MS; FTMS; 2D; electrostatic; particle-in-cell; PIC; simulation; Astrophysics and Astronomy; Physics
• Online Access: https://scholarsarchive.byu.edu/etd/2003; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=3002&context=etd

Beryllium-7 (Be-7) only decays by electron capture into lithium-7 (Li-7) with a half life of 53 days. We study the effect of ionization on this decay rate. We do so by trapping a Be-7 ion plasma in a cylindrical Malmberg-Penning trap and measuring Be-7 and Li-7 concentrations as functions of time by using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). We have simulated these signals in a 2-dimensional electrostatic particle-in-cell (PIC) code. The two spectrum peaks merge at high ion densities whereas at low ion densities they can be resolved. The merged peak shifts linearly according to the relative abundances of these species. We have also simulated singly-ionized beryllium-7 hydride (BeH+) and Li-7 ion plasmas at high densities. These two separate peaks shift according to their relative abundances. We describe an analytical model that explains how these peaks shift.