1. Check that the ensemble of installed equipment works, and that there are no problems with ongoing installation. Beam is the most powerful diagnostic tool in accelerators and gives us the only 100% sure diagnostic that the aperture in the cold machine is free and has the expected size. The beam witnesses all electro-magnetic fields in the vacuum pipe and will allow: polarity checks of the corrector elements and the beam position monitors ( key concerns in the installation procedure), measurements of field errors to 1 unit, determination of any large offsets between beam and magnet, and the veracity of corrector cabling. Linear optics checks are also possible. It will be the first exposure to beam of much of the hardware and will, potentially, allow verification of assumed quench limits and spatial resolution of beam losses.
2. Pre-commission essential acquisition and correction procedures. First tests of important beam diagnostic system will be possible. The beam provides the only way to verify the proper functioning of the diagnostics: timing, BPM resolution, BPM cabling, BPM offsets, BLM resolution. It will allow tests of our control and correction systems (correctors, cabling, control system, software, procedures etc.) via bumps, trajectory correction, injection stability, beam threading.
3. Integration: full-blown system wide integration tests which go one step beyond hardware commissioning. Field test for real beam related equipment and instrumentation such as: power converters, kickers, septa, dumps, pickups, synchronisation, timing, and injectors and get them all working together. Stress test controls infrastructure and all that goes with it. It will fully validate integration and highlight oversights, and force the debugging of problems. There will be problems.
Besides this it will provide an extremely high profile milestone
forcing the preparedness of all components. These would include controls,
timing, transfer from the injectors, instrumentation, interlocks, access,
radiation protection etc. These are absolutely critical for the effective
exploitation of the machine and it cannot be stressed enough how important it is
that they are ready and tested when we come to commission the whole machine. The
test would potentially highlight oversights, misconceptions and shortcomings.
Operationally the exercise would be extremely valuable and it can be argued that the time and effort spent on the test will be more than compensated by a more efficient start-up of the completed machine.
Commissioning of the first sector will have to be done. We will have to wrestle with the problems that will be encountered during this phase. Discovering the problems during a sector test will give us a year at least to resolve any problems, perform a critically analysis of the performance of the systems involved and implement improvements. Operationally, any time spent in 2006 on an injection test will be paid back during the first year’s commissioning, enabling us to deliver physics faster. Any problems high-lighted would have a full year for resolution before the commissioning of the full machine.
A successful test would also validate the project to the wider world.
Acknowledgements to Ralph Assmann - see his talk at Chamonix 2003