Start Counter Shift

Detector Description

The start counter is a scintillator hodoscope surrounding the target region. It consists of 30 identical scintillator counters (each counter thus subtends 36 degrees of azimuth). Each counter has a nose section, and a straight section so that the array as a whole forms a cylinder of about ??? cm with a downstream nose cone of about ??? measured along the counter. The counter thickness is 3 mm.

Each counter is read out by a set of four 3mmx3mm Hamamatsu MPPCs. These in turn are arranged on 10 circuit boards, each board responsible for three of the counters. Each set of four operates with a common bias voltage. The output of the four MPPCs for a channel is summed and amplified locally. Each channel (set of four) is instrumented with thermisters for temperature monitoring. Cooling is done by forced air at room temperature.

Shift Duties

Shift crews should be monitoring the following:

1. MPPC bias voltages
2. amplifier power (low voltage supplies)
3. statistical information from raw data ("monitoring histograms")

MPPC bias voltages and amplifier power

Both of these classes of voltages are supplied by Weiner MPOD modules. Shift crews should monitor the GUI to insure all channels are on during data taking. Most important properties of individual bias and low-voltage channels will be monitored automatically by the EPICS alarm system. Shift crews need to respond to alarms as they arise. To facilitate this, each shift a check should be made that the Start Counter MPOD F HV is up and running.

The conditions that may cause EPICS alarms are:

• tripped voltage
• read-back voltage out-of-range
• supply current out-of-range
• EPICS communication lost

In responding to alarms shift crews should check the guidance for the alarms as provided by the alarm handler.

Statistial Information

Each run produces a set of monitoring histograms that should be compared to nominal histograms and scanned for anomalies. The histograms include:

• occupancy, channel-by-channel
• timing distributions
• amplitude distributions

Detector Expert On Call

The individuals responsible for the operation of the TOF are shown in the following table.

Table: Expert personnel for the TOF system

Name	Extension	Date of qualification
TOF EXPERT ON CALL	XXX-XXX	June 12, 2014
Mark Ito	269-5295	June 12, 2014