ERL PARAMETERS FOR COMPTON POLARIZED POSITRON SOURCES
One of the main challenges for also future linear colliders projects (ILC and CLIC) is to provide an efficient positron source that takes into account the constraint imposed by the target heating in the pair production. At present, different schemes have been proposed to produce high energy gammas to be converted in e-e pairs into an amorphous target [1,2,3]. One of them considers the possibility to boost the energy of the backscattered photons of a laser pulse by Compton effect [4]. This method is particularly attractive since the source is independent of the main Linac and since the photon and consequently the produced pair helicities are conserved in the scattering event. This implies that physics will have at its disposal both positron and electron polarized sources. Different solutions have been proposed to provide the electron beam for the Compton collision. They have to take into account one of the main constraints of this proposal that is the relative low value of the Thomson cross section. One of the possibilities is to design an ERL with relatively low repetition frequency and high charge per pulse and then to stack the produced positrons in an accumulation ring. Different considerations on this scheme will be illustrated and the main constraints discussed.
STACKING SIMULATIONS FOR COMPTON POSITRON SOURCES OF FUTURE LINEAR COLLIDERS
The Compton positron source of a future linear collider must obtain the target bunch population by accumulating a large number of positron packets, arriving either in a number of bursts from a ‘Compton ring’, with intermediate damping of the scattering electron beam, or quasicontinually from a ‘Compton energy recovery linac’. We present simulation results for the longitudinal stacking of Compton positrons in the ILC damping ring (DR) and the CLIC pre-damping ring (PDR), discussing parameter optimization, stacking efciency, possible further improvements, and outstanding questions.
Prediction of net pressure on pressure equalized cavities
Abstract A numerical model has been developed for prediction of net pressure on pressure equalized cavities. The results based on this model show good agreement with those obtained from mock-up tests. Parametric studies verify that reductions in cladding load are possible, with proper design of curtain walls.