Monte Carlo based studies of a polarized positron source for International Linear Collider (ILC)

The full exploitation of the physics potential of an International Linear Collider (ILC) requires the development of a polarized positron beam. New concepts of polarized positron sources are based on the development of circularly polarized photon sources. The polarized photons create electron-positron pairs in a thin target and transfer their polarization state to the outgoing leptons. To achieve a high level of positron polarization the understanding of the production mechanisms in the target is crucial. Therefore a general framework for the simulation of polarized processes with GEANT4 is under development. In this contribution the current status of the project and its application to a study of the positron production process for the ILC is presented.Comment: 5 pages, to appear in the proceedings of 10th International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT 05), Zeuthen, Germany, 22-27 May 2005. Submitted to Nucl.Instrum.Met

Implementation of muon pair production in PHITS and verification by comparing with the muon shielding experiment at SLAC

We implemented a model of muon pair production through a real photon in PHITS and compared our calculations with data of the muon shielding experiment conducted at SLAC to verify the validity of the implemented model. Our predictions of the muon fluence induced by electrons are in good agreement with the experimental data. To understand the known differences between the calculations of the muon fluence, which have been determined using other Monte-Carlo codes, we quantitatively evaluate the fluctuations in the Monte-Carlo results due to systematic errors in multiple Coulomb scattering, differences in the approximation methods and energy loss models, and whether incoherent production is considered.Comment: 16 pages, 8 figure

PEBSI - A Monte Carlo simulator for bremsstrahlung arising from electrons colliding with thin solid-state targets

We present a Monte Carlo code dedicated to the simulation of bremsstrahlung arising in collisions of polarized electrons with thin target foils. The program consists of an electron transport algorithm taking into account elastic electron-nucleus scattering and inelastic collisions with target electrons as well as a treatment of polarized-electron bremsstrahlung emission. Good agreement is found between the predictions of the electron transport code and data stemming from other simulation programs and experiments. In addition, we present first results from the bremsstrahlung simulation which indicate a significant decrease in the degree of linear polarization of bremsstrahlung even for the thinnest gold targets considered