CERN, Geneva, Switzerland
As a part of the LHC Injectors Upgrade project (LIU) the 200 MHz Travelling Wave Cavities (TWC) of the Super Proton Synchrotron (SPS) will be upgraded. The two existing five-section cavities will be rearranged into four three-section cavities (using two existing spare sections), thereby increasing the total voltage from 7 MV (IRF = 1.5 A) to 10 MV (IRF = 3.0 A). Projections of the HL-LHC (High Luminosity Large Hadron Collider) era are conceived by the macro-particle simulation code BLonD, that makes use of an impedance model of the SPS, developed from a thorough survey of machine elements. This paper analyses the impedance contribution of the 200 MHz cavities in the two configurations, using electromagnetic simulations. Measurements of the existing cavities in the SPS and a single-section prototype are also presented.
PKU, Beijing, People's Republic of China
There’s presently a growing demand for cw high current proton and deuteron linear accelerators based on superconducting technology to better support various fields of science. Up to now, high order modes (HOMs) studies induced by ion beams with current higher than 10mA and even 100 mA accelerated by low β non-elliptical Superconducting rf (SRF) cavities are very few. One of the main HOM related issues of the SRF linac is the HOM-induced power. HOM power is the important part of beam energy loss which is used to estimate the cryogenic losses. In this paper, we compare the beam energy loss induced by 100 mA beam passing through a β=0.09 HWR SRF cavity calculated from time domain solver and frequency domain cavity eigenmodes spectrum method.
