The computer program LIAR for the simulation and modeling of high performance linacs

Abstract

High performance linear accelerators are the central components of the proposed next generation of linear colliders. They must provide acceleration of up to 750 GeV per beam while maintaining small normalized emittances. Standard simulation programs: mainly developed for storage rings, do not meet the specific requirements for high performance linacs with high bunch charges and strong wakefields. We present the program LIAR (" LInear Accelerator Research code") that includes single and multi-bunch wakefield effects, a 6D coupled beam description, specific optimization algorithms and other advanced features. LIAR has been applied to and checked against the existing Stanford Linear Collider (SLC), the linacs of the proposed Next Linear Collider (NLC) and the proposed Linac Coherent Light Source (LCLS) at SLAC. Its modular structure allows easy extension for different purposes. The program is available for UNIX workstations and Windows PC's. They must provide acceleration of up to 750 GeV per beam while maintaining small normalized emittances. Standard simulation programs, mainly developed for storage rings, do not meet the specific requirements for high performance linacs with high bunch charges and strong wakefields. We present the program LIAR ("LInear Accelerator Research code") that includes single and multi-bunch wakefield effects, a 6D coupled beam description, specific optimization algorithms and other advanced features. LIAR has been applied to and checked against the existing Stanford Linear Collider (SLC), the linacs of the proposed Next Linear Collider (NLC) and the proposed Linac Coherent Light Source (LCLS) at SLAC. Its modular structure allows easy extension for different purposes. The program is available for UNIX workstations and Windows PC's.A major objective of the LIAR project is to provide an open programming platform for the accelerator physics community. We invite interested scientists to join this project. The LIAR home page and the ONLINE version of the user's manual can be accessed under:

Improved Overhead Accounting in the NLC Main Linac

“…The mean phase is determined by the desired end-linac energy spread of 0.25% RMS. The RF system calculator in the program LIAR [3] indicates that the NLC2003 main linac design requires a mean phase of −12 • to achieve this end-linac energy spread.…”

Beam-Based Alignment of the NLC Main Linac, Part Two: Dispersion-Free Steering and Dispersion Bumps(LCC-0071)

“…The algorithm described above was added to LIAR (LInear Accelerator Research code) [5]. Simulation was performed using the NLC 2000 main linac optics.…”

Tests of 3 Linear Collider Beam Dynamics Simulation Programs

“…Three simulation programs are available to the TRC which are deemed adequate in principle for use in this context: PLACET [1]; MERLIN [2]; and LIAR with DIMAD tracking options [3,4]. One pre-requisite for establishing confidence in the results of the tuning simulations is to ensure that each program is reliably simulating the basic beam dynamics of the linear colliders.…”