The Cornell Electron Storage Ring (CESR) undergoes significant changes in running conditions as operation for CLEO-c high energy physics is interleaved with synchrotron light operation for CHESS (Cornell High Energy Synchrotron Source).... more
The Cornell Electron Storage Ring (CESR) undergoes significant changes in running conditions as operation for CLEO-c high energy physics is interleaved with synchrotron light operation for CHESS (Cornell High Energy Synchrotron Source). Two examples of CESR beam instrumentation applications that are being used to understand storage ring conditions are described: 1) measurement of coupling at the interaction point using the single bunch, multiple turn, type I CESR Beam Position Monitor (CBPM) electronics with continuous beam excitation and 2) measurement of individual bunch tunes to explore possible electron cloud effects using the multiple bunch, multiple turn, type II CBPM electronics with a shock-excited beam. Both applications use the same acquired data for a given bunch, which is turn-by-turn beam position data, and both applications extract the relevant information using the discrete Fourier transform of the time sequences.
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In fall 1994 the new heavy ion injector at CERN was brought into operation successfully and a lead beam of 2.9´107 ions per pulse was accelerated in the SPS up to an energy of 157 GeV/u. The ion source, which was supplied by GANIL... more
In fall 1994 the new heavy ion injector at CERN was brought into operation successfully and a lead beam of 2.9´107 ions per pulse was accelerated in the SPS up to an energy of 157 GeV/u. The ion source, which was supplied by GANIL (France) was in operation almost continuously over a period of about one year and proved to be very reliable. It pro-duces a current of more than 100 µA of Pb27+ (after the first spectrometer) during the afterglow of the pulsed discharge. The current stays within 5% of the maximum value for a time of about 1 ms, which is more than required by the accel-erators. Measurements of the charge state distribution, emittance and energy spread, which were made during this window, are presented together with other operating data.
Two fast vertical beam profile monitors have been implemented at the Cornell electron storage ring (CESR); one is dedicated to electrons, the other to positrons. They are being used to probe a range of single bunch and multi-bunch beam... more
Two fast vertical beam profile monitors have been implemented at the Cornell electron storage ring (CESR); one is dedicated to electrons, the other to positrons. They are being used to probe a range of single bunch and multi-bunch beam dynamics issues as well as machine stability issues. Readout is based on the Hamamatsu H7260K multi-anode photomultiplier [1]. This device has a 32 channel linear anode array with 1 mm channel pitch and sub-nanosecond rise time. A custom 72 MHz digitizer unit allows synchronous multi- bunch and turn-by-turn data acquisition of the 14 ns spaced bunches in CESR. An on-board digital signal processor provides local data processing capability. This paper describes the profile monitor hardware, data acquisition system, and data analysis software.
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The problem of electrostatics repulsion between charged particles in a bunch is a classical mixed Dirichlet-Neumann problem. In this paper, an analytical solution of this problem is described. The approach proposed here can be extended to... more
The problem of electrostatics repulsion between charged particles in a bunch is a classical mixed Dirichlet-Neumann problem. In this paper, an analytical solution of this problem is described. The approach proposed here can be extended to other problems in mathematical physics
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The original 1973 design specification of the CERN 50 MeV Proton Linac was for a 150 mA beam but this intensity was rarely used. Preliminary tests for the high brightness beam required for LHC indicated that 170 mA could be produced for... more
The original 1973 design specification of the CERN 50 MeV Proton Linac was for a 150 mA beam but this intensity was rarely used. Preliminary tests for the high brightness beam required for LHC indicated that 170 mA could be produced for short pulses (30 micro sec). Since then further optimisation has enabled the 170 mA to be delivered reliably,
The Front End (FE) of the Spallation Neutron Source (SNS) will be commissioned at ORNL during the autumn of 2002. The Drift Tube Linac (DTL) and Cavity Coupled Linac (CCL) will be commissioned next. The delivery of beam to the Super... more
The Front End (FE) of the Spallation Neutron Source (SNS) will be commissioned at ORNL during the autumn of 2002. The Drift Tube Linac (DTL) and Cavity Coupled Linac (CCL) will be commissioned next. The delivery of beam to the Super Conducting Linac (SCL), is planned for August 2004. This paper describes the commissioning plans for the DTL and CCL parts of the linac. Techniques for finding the RF set-point, matching and steering are touched upon, as well as the order in which these will be used. Typical beam parameters, as proposed for commissioning purposes, are discussed as well as how commissioning fits together with ongoing installation work in the tunnel.
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The most demanding requirement in the design of the SNS accelerator chain is to keep the accelerator complex under hands-on maintenance. This requirement implies a hard limit for residual radiation below 100 mrem/hr at one feet from the... more
The most demanding requirement in the design of the SNS accelerator chain is to keep the accelerator complex under hands-on maintenance. This requirement implies a hard limit for residual radiation below 100 mrem/hr at one feet from the vacuum pipe and four hours after shutdown for hundred days of normal operation. It has been shown by measurements as well as
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The Spallation Neutron Source (SNS) is designed to ul- timately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups an- alyze the machine performance within the hardware con- straints, optimize... more
The Spallation Neutron Source (SNS) is designed to ul- timately reach an average proton beam power of 2 MW for pulsed neutron production. The SNS physics groups an- alyze the machine performance within the hardware con- straints, optimize the accelerator design, and establish the best path towards a 2 MW and higher spallation neutron source.
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For high intensity proton accelerators, it is vital to reduce the machine activation by minimizing the beam loss from many sources. One of such sources is longitudinal mismatch. To minimize a potential mismatch, it is important to set... more
For high intensity proton accelerators, it is vital to reduce the machine activation by minimizing the beam loss from many sources. One of such sources is longitudinal mismatch. To minimize a potential mismatch, it is important to set accurately the rf set-point (rf field amplitude and phase) of a high-intensity linac such as the drift tube linac (DTL) of the
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This report gives the results of a programme of experimental investigations, which were carried out to test stacking of lead ions in a storage ring (the former Low Energy Anti-proton Ring, LEAR) at 4.2 MeV per nucleon. The motivation was... more
This report gives the results of a programme of experimental investigations, which were carried out to test stacking of lead ions in a storage ring (the former Low Energy Anti-proton Ring, LEAR) at 4.2 MeV per nucleon. The motivation was to demonstrate the feasibility of ...