Realistic simulation of the ion cyclotron resonance mass spectrometer using a distributed three-dimensional particle-in-cell code

This work describes an Internet accessible three-dimensional particle-in-ce ll simulation code, which is capable of near first principles modeling of c omplete experimental sequences in Fourier transform ion cyclotron resonance mass spectrometers. The graphical user interface is a Java client that com municates via a socket stream connection over the Internet to the computati onal engine, a server that executes the simulation and sends real-time part icle data back to the client for display. As a first demonstration, this co de is applied to the problem of the cyclotron motion of two very close mass to charge ratios at high ion density. The ion populations in these simulat ions range from 50,000 to 350,000 coulombically interacting particles confi ned in a cubic trap, which are followed for 100,000 time-steps. Image charg e, coherent cyclotron positions, and snapshots of the ion population are re corded at selected time-steps. At each time-step in the simulation the pote ntial (coulomb + image + trap) is found by the direct solution of Poisson's equation on a 64 x 64 x 64 computational grid. Cyclotron phase locking is demonstrated at high number density. Simulations at different magnetic fiel ds confirm a B-2 dependence for the minimum number density required to lock cyclotron modes. (J Am Soc Mass Spectrom 1999, 10, 136-152) (C) 1999 Ameri can Society for Mass Spectrometry.