Make New Entry, Make Followup Entry
User name jpchen
Log entry time 09:44:35 on April 6,2010
Entry number 316655
Followups:
keyword=beam on thick 12C target caused the vacuum badI was called in due to scattering chamber vacuum rising alarm.
Beam was on thick 12C target. Beam went off due to bad scatteirng chamber vacuum (it went to a few *10-3). Coolant temperature also went high (from about 23K to 35K). After a while vacccum came back down to normal 10-6 (up 10-7) level. I suspect that lead melted and deposited on the thick 12C, which could outgas when beam hit, leading to such a
After talking to Mark, he told me that during the night (~2-3 am) there was a mistake that 50 uA was sent to a thin lead target (which has no diamond attached to and has a limit of 5 uA). That might have melted the lead, which might dropped on to the thick 12C target.
Thin lead is just above the thick 12C.
just above the thick 12C.
FIGURE 1
