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    User name C. Armstrong

    Log entry time 22:11:56 on September 22,1999

    Entry number 17286

    This entry is a followup to: 17282

    keyword=Paul B resolves Q1 problem


    Paul Brindza stopped by (he was in a class in the neighborhood when we were trying to get in touch with him) and he tried lowering the upper limit on valve 13 of Q1. As he explains, this valve is supposed to regulate the pressure of the He reservoir, and forcing it to stay more closed will force more He to the neck (and through the neck flow meter). This appears to have completely solved our earlier problem. Currently it is set to max out at 70%; he says that if our backwards-flow problem recurs, we can lower that limit some more (but not below, say, 50%).

    Paul emphasized that we haven't completely ruled out a flakey flow switch. In addition, our earlier problems could in principle have arisen from changes to the ESR load. He also mentioned that the flow of coolant to the neck is not too critical (mainly to reduce heat transfer, not necessary for magnet operation or safety), and maybe that meter could be taken out of the interlock.

    At any rate, the HMS is on the road to recovery (we also had to reboot the Q2 PC about a half an hour ago), and we should be back in two-spectrometer action shortly. Michael S finished his BCI testing for the night, and we are running exclusively in CW mode now (earlier in the evening we had been switching back and forth between CW and modulation mode for BCI testing).