IBSIMU: A three-dimensional simulation software for charged particle optics

Abstract

A general-purpose three-dimensional (3D) simulation code IBSIMU for charged particle optics with space charge is under development at JYFL. The code was originally developed for designing a slit-beam plasma extraction and nanosecond scale chopping for pulsed neutron generator, but has been developed further and has been used for many applications. The code features a nonlinear FDM Poisson's equation solver based on fast stabilized biconjugate gradient method with ILU0 preconditioner for solving electrostatic fields. A generally accepted nonlinear plasma model is used for plasma extraction. Magnetic fields can be imported to the simulations from other programs. The particle trajectories are solved using adaptive Runge-Kutta method. Steady-state and time-dependent problems can be modeled in cylindrical coordinates, two-dimensional (slit) geometry, or full 3D. The code is used via C++ programming language for versatility but it features an interactive easy-to-use postprocessing tool for diagnosing fields and particle trajectories. The open source distribution and public documentation make the code well suited for scientific use. IBSIMU has been used for modeling the 14 GHz ECR ion source extraction and for designing a four-electrode extraction for a 2.45 GHz microwave ion source at Jyväskylä. A grid extraction has also been designed for producing large uniform beam for creating conditions similar to solar wind. The code has also been used to design a H(-) extraction with electron dumping for the Cyclotron Institute of Texas A&M University.

Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

“…A compensation time, as given in Equation 1, is the average time that it takes for one beam particle to produce a secondary particle by interacting with the residual gas. ( 1) Where N is the density, vb is the speed of the beam particles and σ the cross section of the process H -+H 2 0 ->H -+H 2 + +e. In our case, with a pressure of 1x10 -6 mbar, the compensation time is approximately 450 µs.…”

CERN’s Linac4 H− sources: Status and operational results

“…Beam optics design using the IBSimu code 13,14 . Space charge compensation in the LEBT via injection of hydrogen, argon or nitrogen 15 .…”

The relationship between visible light emission and species fraction of the hydrogen ion beams extracted from 2.45 GHz microwave discharge

“…The plasma electrode, extraction system, and Wien Filter subsystems were designed using the IBSimu code. 11 Fig. 1 shows the system cross section where solenoid pancakes and mechanical support frame have been removed for simplicity.…”