FAIR Developments
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Abstract: The following beam diagnostic topics for the GSI future facility are approached:
- Beam dynamics near the space charge limit as well as relatively small vacuum chambers in SIS100 and SIS200 require a high precision beam position measurement with feedback capabilities. Furthermore the larger part of the pick-ups has to be installed in the cryogenic environment. This and the requirement of impedance matching will request a careful mechanical design of the monitors. After theoretical studies and layout a construction phase taking into account UHV suitable materials is necessary. Afterwards, investigations of such new detectors in a cryostat are foreseen to test the electrical and cryogenic parameters.
- The large geometrical dimensions, especially of SIS100 and SIS200, result in new logistic problems concerning analogue signal transport. To avoid hundreds of kilometres of cables and to supervise the large number of monitors fast signal processing by DSPs is necessary to compress the measured position data before transmission to the control room. In addition the analogue preamplifiers have to be completely revised because of the high dynamics of the pick-up signals (about 160 dB).
- Cooling of ion beams is a central topic for the projected new storage rings. Residual gas monitors are used to measure the transversal beam profile and emittance. With this method it is possible to adjust and control the cooling parameters. Nowadays the measurement system is composed of MCP-phosphor detectors and CCD sensors. Fast cooling processes in the CR and NESR need high-speed image acquisition and suitable bus architecture for data transfer. This detector system in conjunction with a high-speed image processing by DSPs must be designed for a wide range of stored ion beam currents and a large scale of cooling times.
- The above mentioned high signal dynamics will demand a further development of the AC and DC transformers used to measure the injected and stored beam current. In addition to an upgrade of the existing devices alternative measurement schemes, e.g. via hall probes, should be investigated.
- An efficient beam loss monitor system for the SIS100/200 will be necessary as an instrument to avoid losses due to radiation protection requirements. One or two detectors per super conducting magnet will lead to a large amount of measurement places. In addition, a fast interface to the quench protection system of the super conducting magnets is required including a "post-mortem analysis". The design of such a beam loss measurement system including the fast electronics has to be developed.
- An upgrade of the GSI control system is necessary for the new facility. The demands of beam diagnostic measurement systems - use of industry standard components, large data rates of measurement readings and image acquisitions, consistent measurement readings of several detectors - have to be implemented. New solutions have to be looked for, which are interoperable with the existing control system via intelligent software interfaces, so that methods like "automatic beam steering" could be easily embedded. Sample solutions in hard- and software have to be built up.