User name Templon
Log entry time 03:11:41 on June 2,2000
Entry number 42828
keyword=electron arm vdc problem
Kozlov found funny VDC arm spectra. Electron arm, V1 plane. Symptom:
resolution is bad (presumably this is the time difference (t1-t2)-(t5-t4) for
five hit events), and efficiency is slightly but noticeably less. On second
inspection, even U1 plane efficiency looks worse than U2 and V2 while
U1 resolution is not noticably worse. As U1 and V1 share high voltage,
this is an immediate suspect. Also, threshold setting is local and this
might be responsible for problem with resolution in V1 plane. Please
check this during access Friday AM.
Problem has been around for a long time. Below are relevant plots from
run 1597 (from graveyard shift June 1). A followup log entry will
show the plots from this shift (graveyard June 2).