Beam Control Program - How to Set Safety and Warning Limits

Beam-Current Safety and Warning Limits (NODAL)

In the current implementation of the Beam Conrol Program, the best way to detect too high beam intensity (so high that it endangers the target) is to watch the "NODAL" values, i.e. the values fetched from the accelerator network. The current values, as fetched from the accelerator network, is shown in the TRAFO windows on the upper row in the main window.

To set upper and lower safety limits on the readings for these two trafos, access the "Safety Limits..." menu selectin from the "Configuration" sub-menu. The safety values must be entered as "pulse current" values (i.e. the electrical current during a macro pulse). The unit selector on the maiin screen do not apply to the units for the Safety values.

The upper trafo-limits will automatically engage the chopper to cut of the beam if the current exceeds the limit on either trafo.

The lower limits will generate an alarm sound if the warning beep switch is set set to "Enable".

Safety and Warning Limits on the Beam Macro Pulse

Safety limits and warning tresholds on the Beam Marco Pulse structure are set from the "Tresholds..." menu selection in the "Configuration" sub-menu. You can set thresholds on the Macro Pulse frequency and width. DO NOT use the tresholds for Beam Current, it is not implemented correctly. Safety limits (maxium value) on the current within each macro pulse should be set in the Beam MONITORING program, not the Beam Control Program which is described here!

Detector Rate Safety Limit

Select the maximum detector count rate from the "Thresholds ..." menu choice. If the detector count rate exceeds this limit the chopper will be engaged to stop the beam. Due to an internal problem in the program, the values have to be about twice as high as the correct value, otherwise the safety trips without reason all the time.

-- JonPetterOmtvedt - 10 Jun 2011