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| THPLT047 |
Beam Position Monitor Development for the IThemba LABS Cyclotron Beamlines
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2586 |
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- J. Dietrich, I. Mohos
FZJ/IKP, Jülich
- A.H. Botha, J.L. Conradie, J.L.G. Delsink, P.F. Rohwer
IThemba Labs, Somerset West
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In cooperation of iThemba LABS (South Africa) and Forschungszentrum Juelich the specification of a sensitive tunable rf narrowband beam position monitor system for cyclotron beamlines has been elaborated. iThemba LABS developed and manufactured the four section stripline monitor chamber. The monitor electronics were developed in the Forschungszentrum Juelich-IKP. The electronics consisting of an RF signal processing module (BPM-RF) and a data acquisition and control module (BPM-DAQ) sequentially processes and measures the monitor signals and deliver via serial network calculated horizontal and vertical beam position data. First measurements with cyclotron beam has been performed in the iThemba LABS in November 2003. Changed beam position due to changing different cyclotron parameters could be studied with high accuracy. The resolution of the beam position measurement was better than 0.1 mm with beam currents down to 0.0005 mA.
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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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