The Mechanical Design Of The Bpm Inter-Tank Section For P-Linac At FAIR

At the planned Proton LINAC at the FAIR facility,four-fold button Beam Position Monitor (BPM) will beinstalled at 14 locations along the 30 m long FAIR p-LINAC. The LINAC comprises of crossbar H-mode (CH)cavity to accelerate a 70 mA proton beam up to 70 MeVat frequency of 325 MHz. At four locations, the BPMswill be an integral part of the inter-tank section betweenthe CCH and CH cavities within an evacuated housing.As the BPM centre is only 48 mm apart from the upstreamcavity boundary, the rf-background at the BPMposition, generated by the cavity must be evaluated. Inthis paper the mechanical design of the BPM for the intertanksection is presented and the rf-noise at the BPMlocation is discussed

Status Of The FAIR Synchrotron Projects SIS18 And SIS100

A large fraction of the program to upgrade the existingheavy ion synchrotron SIS18 as injector for the FAIR synchrotron SIS100 has been successfully completed. With the achieved technical status, a major increase of theaccelerated number of heavy ions could be reached. Thenow available performance especially demonstrates thefeasibility of high intensity beams of medium charge stateheavy ions with a sufficient control of the dynamicvacuum and connected charge exchange loss. Two furtherupgrade measures, the installation of additional magneticalloy (MA) acceleration cavities and the exchange of themain dipole power converter, are presently beingimplemented. For the FAIR synchrotron SIS100, theprocurement of all major components with longproduction times has been started. With the delivery andtesting of several pre-series components, the phase ofoutstanding technical reserach and developments could becompleted and the readiness for series productionachieved

Performance of the closed orbit feedback systems with spatial model mismatch

Closed orbit feedback (COFB) systems used for the global orbit correction rely on the pseudo-inversion of the orbit response matrix (ORM). A mismatch between the model ORM used in the controller and the actual machine ORM can affect the performance of the feedback system. In this paper, the typical sources of such model mismatch such as acceleration ramp ORM variation, intensity-dependent tune shift and beta beating are considered in simulation studies. Their effect on the performance and the stability margins are investigated for both the slow and fast regimes of a COFB system operation. The spectral radius stability condition is utilized instead of the small gain theorem to arrive at the theoretical limits of COFB stability and comparisons with simulations for SIS18 of GSI and experiments at the Cooler synchrotron (COSY) in the Forschungzentrum J\"ulich (FZJ) are also presented