Gas Handling System

Focal Plane

The control of the gas handling system of the S800 focal plane is realized with a LabView application running in DataU6 on a Windows machine dedicated to the gas handling. Pressure and flow of isobutane, CF4 (CRDCs) and P10 (ion chamber) are read out and displayed on the gas handling system GUI.

Alarm thresholds are set on the gas flow controllers. Deviations worrysome for the operation of the detectors will trigger a voice alarm in DataU6 and the S800 Alarm Monitor GUI running on uxpc2 will turn red and display the alarm message.

Occasionally, the communication between the gas handling system control and the terminal server in the S3 vault gets lost for a few seconds and will trigger a false alarm. For every voice alarm, please check the values displayed in the text boxes labeled M.F.C. #1, M.F.C. #2, and M.F.C.#3 on the S800 gas handling system GUI on the Windows PC.

The flows are supposed to be:

• M.F.C. # 1: above 10 sccm (P10, ion chamber)
• M.F.C. # 2: above 4 sccm (isobutane, CRDCs)
• M.F.C. # 3: above 17 sccm (CF4, CRDCs)

If the flow readings don't meet these requirements, stop the beam and immediately contact somebody from the S800 group. If the flow values on the GUI are ok, the alarm can be attributed to a temporary communication outage between the terminal server and the gas handling control.

Tracking PPACs

The gashandling system of the tracking PPACs in the intermediate image of the analysis beam line is not yet remote controlled. In case of abnormal occurrences with the tracking PPACs contact somebody from the S800 support group.