I made a first attempt to investigate the probability of a beam tube tap producing a DARM glitch as a function of tap amplitude. I mounted an accelerometer on the beam tube just inside the single door at Y1-4 +1Y and tapped 2 stiffening rings away.  The only DARM glitch produced was for a tap that saturated the accelerometer (> 1.09 m/s^2). There were a total of ten taps that exceeded this threshold. No glitches were seen for the 70 taps that were under this threshold.  This data supports the contention that the glitch probability is a strong function of tap amplitude. I would like to use a shaker to inject at lower amplitudes for day-scale periods in order to better understand the probability function, but this experiment hasn’t been cleared yet because of fatigue concerns.

One could imagine sudden accelerations of the beam tube, such as thermal expansion stick-slip events, that might be high enough in amplitude and frequency to produce particulate glitches. I investigated the possibility of using microphones to detect such events. I set up a temporary microphone in the beam tube enclosure, running into the CS DAQ. I found, that for the amplitude of taps that produced glitches, I could detect the sound from 1km away (Figure 1). Thus we could monitor the entire beam tube with 8 microphones, based in the stations, but located in the beam tube enclosure just outside the stations.