1. The high voltage is controlled using the high voltage control VI on the Plastic HV & Camac Controls computer. (The operator's manual is on the desktop with a help button on the VI front panel.)

2. High voltage to the mainframe should always be on.

3. All TOF channels need to be enabled, showing green in the status field.

4. If any channels are disabled, determine why by looking at the status field and make a note in the logbook.

5. If an alarm occurs, call Erik at 1036 or at beeper number 7604. Also, inform Edmundo, and note the alarm in the logbook.

6. Turn off the alarm by clicking the alarm button.

7. Refer to the expert's manual for any common solutions.

1. The Camac crates are controlled using the Camac controls VI on the Plastic HV & Camac Controls computer. (The operator's manual is on the desktop with a help button on the VI front panel.)

2. All TOF channels should be unmasked, illustrated as a light yellow in the mask fields.

3. If a channel is masked, determine why.

4. Don't unmask a channel for no reason. Just make a note in the logbook.

5. The TOF thresholds should be greater than 9mV (baseline value), and the widths need to be larger than 0ns (baseline value).

6. If a communication error occurs while trying to talk to the crates, click the alarm button.

7. Make a note in the logbook.

8. Press the readout all crates button.

9. If the values are reasonable (i.e. other than 9mV for the TOF thresholds and 0ns for the widths), then the error is nothing to worry about.

10. If the values turn out to be unreasonable and/or and another error alarm occurs after the read out button is pressed, then call Erik at 1036 or at beeper number 7604. Also, inform Edmundo, and note the alarm in the logbook.

11. Refer to the expert's manual for any common solutions.

1. Timing Discriminators- these discriminators are located in the TOF Camac crates #3 and #4 in slots 1-15, and slot #17 in crate #3. The Camac controls VI allows control of the discriminator thresholds and widths.

2. Trigger Discriminators- These discriminators are located in slots #20 in TOF crates #3 and #4. The Camac controls VI allows control of the discriminator thresholds and widths.

3. 4-fold Logic Unit- The unit is located in the NIM bin above the Fastbus crate. It says 4-fold logic unit on it. There are small pins on the right side of the unit. To mask a channel, stick a pin in the cooresponding channel. To set the coincidence level, stick a pin in the cooresponding level. Level 1 will generate a NIM pulse is any of the unmasked channels receives a signal. Level 2 requires at least 2 channels to receive a pulse. Level 3 requires 3, and level 4 requires all 4. One cable from the output should be routed to a counter to the left of the unit, and another cable needs to be routed to the trigger electronics expect during normal operation.

The rate in the counter should be approximately 100 counts per second for all runs except during normal running or if the threshold levels for the discriminators are set differently as what is mentioned above.

4. Time Calibrator- The unit is in the NIM bin above the Fastbus crate and is label Time Calibrator. The timing calibration unit has two controls to it. You can choose a range of time over which you want to generate pulses. The period is the time between pulses. With this in mind, the range must be greater than the period. As an example, if the range is 10 microseconds and the period is 2 microseconds, then pulses will be generated at a relative zero, two microseconds after the zero, four microseconds after the zero, six, eight, and ten microseconds after the zero. The rate at which these pulses will fire is controlled using the rate knob at the bottom left of the module.

The start signal should be routed into the 4-fold logic unit, and the stop goes into a fan out. From the fan out, there are two signals that go into the tunnel and trigger the test input of the discriminators.

5. Gate Generator Pulse Unit - This unit is located in the NIM bin above the Fastbus crate and is a dual gate/delay generator NIM module. It is used for the LED gain monitoring system. The delay output of one gate generator is sent into the start of another, and the delay output of the later is sent into the start of the former. This loop generates standard NIM pulses, which can be varied in time by changing the width (delay) of the output signal. The loop is begun by pressing the trigger button on the gate generator. One of the gate generators puts out a NIM signal that is feed into a fan out. Four channels go into the tunnel to drive an LED circuit, while another goes into a gate generator to be properly delayed.

6. LED Voltage Supply Unit- The units are two dual high voltage supplies located above the Lecroy high voltage mainframe. Each module controls the supply voltage to the LED circuit that is in a NIM bin in the tunnel. There is a dial to control the amount of voltage with a switch to enable the channel. There is a main power switch for each sub-unit in the modules. The display read out can either show current or voltage by using the appropriate switch. The LED circuits require +120V. DO NOT exceed this voltage. Damage to the LED system and/or the photo-tubes may occur.

The reasons a high count rate in the cosmic trigger mode can be due from the time calibrator is on, the high voltage to the LED’s are on, the thresholds to the discriminators are set too low, or there is a light leak in the detector.

The power to the crates can be off, or the VI is in a funny state. If reading out the crates operation doesn’t work, restart the VI.