Report from BESSY for 10/15/97

We finished the response function measurements with the Si double crystal monochromator from 2.1 keV to 5.9 keV for the SSD_X. There were no surprises in the data. The interpeak events are typically less than 0.02% of the main peak. The pulser autoDeadtime counts are being recorded properly.

We switched to the Beryl Crystals at 5:00 pm to do the lower energy measurements. Since these crystals can be easily damaged with high storage ring currents, we have to wait for the ring current to decay below 400 mA until we are able to open the beam shutters. During the normal working hours, this gives us about 2 hours of data collection time out of every 4 hours. In the evenings, the storage ring is injected at 10:30 pm and allowed to run with out an injection until 4:00 am (called the Dawn Special). We took advantage of this last night and were able to complete the Beryl crystal measurements around 4:00 am.

After completing the Beryl measurements, the SSD_X was removed from the beamline and the SSD_5 was installed. This was completed about 6:00 am. It takes about 6 hours to pump down the beamline once it has been opened. We have our pump station attached to the beamline to help with the vacuum. As a result we had the beamline pumped down in about 4 hours.

Plan:

Today we plan on finishing the Beryl measurements with the SSD_5. The storage ring is being used for studies of the ring tonight starting at 5:00pm, however they do a "Dawn Special" tonight so we will have more beamtime starting at 1:00 am which should allow us to complete the Beryl measurements.

Tomorrow we will switch to the Si crystal and hopefully on Friday switch to the InSb crystals.

Problems:

I did not report yesterday that one of the pulsers could not be used because it would not accept an external voltage input meaning we could not change the amplitude of the pulser remotely. We decided to use the SSD_5 pulser for the tests with the SSD_X. When we start running both detectors at the same time, we will tee the output of the "good" pulser to both detectors as was done with the BND-H detectors.

NOTE: This page copied from the email posted and edited in format only.