Operation

Before you are allowed to work at the test beam you must have had a safety instruction and follow the test beam rules!

Check first the DESYII schedule to see the plan for the machine operation and check the message board. Then annonce your plans on the message board (login: testbeam; normal password). Afterwards you should call the accelerator control room (3500) and inform them that you would like to use the test beam.

To switch on the beam, you need to search the area and set the interlock. Then you can open the beam shutter.
To select electrons of a certain momentum (from about 1 to 6 GeV), you need to set the magnet (for testbeam 24, there are two magnets). If you want to take data at 6 GeV, you need to ask the accelerator control room to provide you with 7 GeV beam (to get a reasonable rate), for lower momenta 6 GeV (which the machine prefers) is enough, so please inform the control room when you switch to lower momenta.

The choice of the converter target and the collimator opening is under control of the user. The accelerator control room handles the fibre target.

Converter Target

There are different conversion targets available (Cu wire, Al and Cu plates of different thickness from 1 mm to 10 mm). It is controlled via a homemade NIM module (List of currently installed converters).

Moveable Collimator

The four collimator jaws have their own control box. The beam shutter and the shielding wall follow the variable collimator behind the magnet.

Lead Collimator

Inside test beam area, it is possible to put a second lead collimator. It has exchangeable insertion. Several insertions with different apertures are available. This auxiliary collimator catches particles scattered off the yaws of the main collimator. Obivously its opening should be bigger than the one of the main collimator.


Status of the Synchrotron and the other Accelerators

 The is provided by the machine physics group in the web.

In addition, in the test beam hut you find a "beam signal oscilloscope".

The oscilloscope shows the beam current and the converter spill signal that is produced by a photo multiplier with scintillator close to each converter target. Therefore, it picks up a signal, if the photon beam hits the target. This allows deciding, if a "missing beam" problem is caused by the synchrotron and the fibre target, which is under control of the main control room or by the magnets, the converter, the collimators, the beam shutter or something else which should be under your control.

The TV monitor shows the standard DESY information screen. This is the beam current and the status of DORIS and HERA. Therefore, you can see when the run ends for these machines or if an injection is in progress which effects you, as described before.


Infrastructure/Equipment


Safety

Authors: Isabell Melzer-Pellmann, Norbert Meyners, Last change: 04.04.2012, Imprint