LBNL, Berkeley, California
We present electron-cloud build-up simulations for the FNAL Main Injector at the location of the RFA electron detector. By comparing our simulated results against measurements for various bunch intensities and beam fill patterns, we determine the likely value of the peak secondary emission yield. We then extrapolate our results to higher intensities, within the range contemplated by the proposed MI upgrade program. We predict a substantial increase of the electron cloud density relative to its present value. We consider two values of the RF frequency, namely 53 and 212 MHz, and compare the electron cloud density for these two frequencies at fixed total beam intensity. We contrast the MI results against those from a similar simulation for the PS2, the first storage ring in the proposed future upgrade of the LHC injector complex. Time permitting, we will briefly comment on effects from the electron cloud on the beam dynamics.
ORNL, Oak Ridge, Tennessee
We have performed 3D particle tracking in realistic magnetic field configuration to study particle losses in the SNS ring injection dump beam line and beam profile tilt in the extraction Lambertson septum. The technique is based on accurate 3D modeling of magnet assemblies or beam lines and 3D particle trajectory calculations through the simulated field. The studies have discovered a number of design and operation issues that cause particle losses in the injection region and beam profile tilt through the extraction septum. The remedies to all the problems are also devised. This paper reports our simulation techniques and major findings.
ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
GSI, Darmstadt
The double synchrotron complex SIS100 and SIS300 is the central part of the FAIR project. SIS100 is a fast ramped superconducting synchrotron optimized for high intensity, low-charge state heavy ion operation. However, similar to the existing heavy ion synchrotron SIS18, SIS100 will also be used to accelerate all other ion species down to protons, In order to enable such a flexible operation and to avoid transition energy crossing, a triplet structure with three independent power circuits has been chosen. For the low charge state operation, a new lattice design concept has been applied which provides an optimized separation of ionized beam particles. Low charge state operation is enabled by means of the cryopumping of the actively cooled, thin wall vacuum chambers. The stability of the residual gas pressure is an essential precondition for this operation. The project status and the status of the major device developments will be presented.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
ISIS is the spallation neutron source based at the Rutherford Appleton Laboratory in the UK. There are currently 227 individual diagnostic devices distributed between the 70MeV Linac, the 800MeV accelerator ring and the two target beam lines (TS1, TS2). This paper summaries the current state of the ISIS diagnostic systems and describes how the various diagnostics are used to tune the machine, to monitor beam intensity and beam losses and to provide fast machine protection. The limitations and accuracy of the various diagnostic systems (e.g. spatial and energy resolution, sensitivity, speed) are explored along with the steps that are being carried out to tackle any shortcomings. This paper will also briefly look at the new PXI based data acquisition and diagnostic control electronics used on ISIS and the problems encountered in using these systems within radiation environments.