TOF noise rate pattern

 

VPD Operations (HV Scan Instructions)

[from Isaac Upsal's instructions to star-ops, dd.May 17, 2023]

If stable collisions are available and the BBC (ZDC) is ready to use as a trigger then we can take the VPD gain scan. The procedure is as follows:
Make sure that you are using a **non-VPD-based** Trigger for all data taking.

First :
On the sc3 machine there needs to be a "small GUI" for the VPD with 4 buttons - upVPD HV A, upVPD HV B, upVPD HV C, and Default. If it is not open or you are unsure open a terminal and execute "upvpd_settings". I just opened this ~an hour ago.
"large GUI" shows all the channel values, and where one powers them on/off.
"small GUI" selects between different gain sets A, B, C, & default.

start with the VPD HV **OFF**

1) On the small GUI choose the HV Gain setting *A*
2) On the large GUI power on the VPD HV
3) Make sure that the upper-left corner (channel 13-0) of the large GUI reports a voltage of ( 1101, 1251, 1401 ) for gain setting A, B, and C respectively.
4) Wait about a minute or two for the VPD PMT channel voltages to settle
5) Start run: TRG+DAQ+TOF (it is OK to include other detectors in if you want, but those are required), 200k events. Use string "VPD HV A" (or B, C as needed) in the shiftlog entry
6) Use the "large GUI" to power off the VPD HV
7) Wait for all channels to read a voltage of 0

Repeat these steps for each of the gain settings (A, B, C) - making the appropriate entry in the shiftlog to identify which gain setting is used (upVPD HV A, upVPD HV B, upVPD HV C ).

Once this is complete, use the "small GUI" to select "default" then power the VPD HV back on. Now you can close the "small GUI".

VPD Run17 HV Map

 

VPD Run18 HV Map

 

VPD Run22 HV Map

 

Vpd Simulation Database Table

 Variables:
    short tubeRes[38];   // The resolution of a single Vpd tube in picoseconds to be simulated.

        octet tubeId[38]; // The offline ID (0-37) of the Vpd tube

    octet tubeStatusFlag[38]; // Flag for whether tube was active (True) or not (False) in a given Run

    octet tubeTriggerFlag[38]; // Flag for whether tube was triggered on (True) or not (False) in a given Run (again, simulation). Note that there will be overlap with the tubeStatusFlag, but could be additional False entries as well.

 

Frequency:

This table will be updated whenever the Calibrations_tof::vpdTotCorr table is updated, generally once per RHIC Run

 

Index:
        *table is not indexed

 

Size:

The cumulative size of the 4 arrays is 190 bytes.

 

Write Access:

jdb - Daniel Brandenburg (Rice University)

nluttrel  - Nickolas Luttrell (Rice University)