| Paper |
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| TUPLT124 |
DESIREE - A Double Electrostatic Storage Ring
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1425 |
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- K.-G. Rensfelt, G. Andler, L. Bagge, M. Blom, H. Danared, A. Källberg, S. Leontein, L. Liljeby, P. Löfgren, A. Paal, A. Simonsson, Ö. Skeppstedt
MSL, Stockholm
- H. Cederquist, M. Larsson, H. Schmidt, K. Schmidt
Stockholm University, Department of Physics, Stockholm
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The advantages of storage rings with only electrostatic elements were first demonstrated by ELISA in Aarhus and later in other places. At MSL and Fysikum at Stockholm University the ideas have been developed further in the Double Electrostatic Storage Ion Ring ExpEriment, DESIREE. Beams of negative and positive ions will be merged in a common straight section of the rings so that low energy collisions can be studied. Furthermore the rings will be cooled to 10 - 20 K in order to relax internal excitations in circulating molecules. A design report can be found at www.msl.se. The project is now (January 2004) almost fully financed and the final design work has recently been started. The paper will shortly review the physics programme and describe the status of the design work.
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| THPLT112 |
Methods and Instrumentation for Measurement of Low Ion Beam Currents at Cryring
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2745 |
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- A. Paal, A. Källberg, A. Simonsson
MSL, Stockholm
- J. Dietrich, I. Mohos
FZJ/IKP, Jülich
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In many CRYRING experiments an accurate measurement of the circulating ion beam current is essential for determination of e.g. absolute cross sections. However, the current produced from the ion source can be very low. Furthermore, when surface barrier detectors are used, for example in the merged electron-ion beam experiments, the current has to be kept low to avoid saturation. With new electronics, using an Integrating Current Transformer with 5 V/A sensitivity, the current resolution of the Bergoz Beam Charge Monitor (BCM) has been increased to below 1 nA for bunched beams. The sum signal of the capacitive pick-up located at the farthest point from the RF-system is integrated by a second gated integrator. The RMS resolution is about 100 pA. To measure the intensity of coasting beams neutral particle detectors and a residual-gas beam profile monitor are used, calibrated with the BCM output during 20-100 ms after acceleration. The micro-channel plate detectors can handle a few Mcps count rate with a maximum 1 cps dark count rate. Presently a 50 Mcps secondary electron multiplier is being tested as a neutral particle monitor, having a maximum dark count rate of 0.05 cps
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