# Presentation: 261105

## ICD Status

**High Voltage Changes**
**Invalid Alarms**
**ICD channels in caladdress**
**LED pulser & Taking Runs**
**Calibration Data from Feb 5th**
**Strange behavior of LED**
**Calibration Data from Mar 5th**
**How to proceed next?**

## ICD High Voltage Changes

**High Voltage System conversion by Fritz Bartlett**
**Global HV GUI will show green (holding) or turquoise (locked state) only when both voltage & current readbacks are within acceptable limits for data-taking**
**Minor alarm state (LO or HI) = yellow**
**Major alarm state (LOLO or HIHI) = pastel red**
**Saturated red color indicates a trip condition while pastel red indicates a major alarm in one or both readback values**
**Voltages cannot be changed while in locked state**
**HV cannot be raised above V_set value**
**ICD channels have very narrow Voltage limits**
**Voltages are very stable - PMTs very sensitive to HV change**
**Will need specific interface to deal with LO/HI & LOLO/HIHI alarms for ICD currents**
**Only I_trip exists at this time**

## High Voltage Test Point Drifting

**ICD HV - 128 pods in rack MCH116 provide voltage to 378 PMTs in detector**
**Not enough money or room for a new rack in MCH for one-to-one pod to PMT matching **
**Use 1:3 adjustable fanout boxes (1 input, 3 output  V)**
**Set pod voltage in GUI in control room **
**48 test points on front panel of fanout box **
**Safety bar – live voltages ********800 V **
**Previously, we used a 1% resistor which was susceptable to moisture which left mineral deposits.  This changed the resistance with time, so the test point voltages **_**drifted**_**!  Did not affect the voltage received by PMT, but made the modification of voltages very difficult.**
**48 set screws on each fanout box – ********100 V variance**
**Match PMTs to minimize voltage difference between PMT sets**
**Ted Elzroth measured test points – no apparent drift after initial setup in December.  Very good news!**

## Invalid Alarms

**Sent email to Bill Lee to have the following alarms deleted**
***ICD only uses three of the eight LV modules in the LVPS***
**ICD_LVCP_PW09/12VB**
**ICD_LVCP_PW09/8VC**
**ICD_LVCP_PW09/8VD**
**ICD_LVCP_PW09/8VE**
**ICD_LVCP_PW09/6VH**
***ICD LVPS does not have a magnetic field sensor (sits in rack PW09)***
**ICD_LVCP_PW09/M***

***These two HV pods are not used (no cables connected - no PMTs in detector)***
**CALS_HVC_SE11**
**CALS_HVC_SE11/STATE**
**CALS_HVC_SE11/VOLT**
**CALS_HVC_SE11/CURR**
**CALS_HVC_SE12**
**CALS_HVC_SE12/STATE**
**CALS_HVC_SE12/VOLT**
**CALS_HVC_SE12/CURR**
**These two pods show up as Offline or**
**disabled in the channel HV GUI.**

- Problem over weekend with ICD Preamp row in Supply GUI.
- What, why & how?

## Slide 5

## ICD channels in caladdress

**Backplanes of Southwest & Northeast crates have fiber order reversed “**_***accidentally***_**” **
**Affects only ieta = 12 & 14 **
**Used RU-106 source to test map**
**Instead of dismounting two  **
**	****200+ kg crates to fix problem:**
**Change trigger summers on half **
**	****of the L-type BLS cards *****(now L2)***
**Modify caladdress package for those **
**	****channels specified as: **
****** ****= -12 ******** -14 for ******** = 1-32,49-64**
****** ****= 12 ******** 14 for ******** = 17-48**
**Bob Kehoe modified caladdress last **
**	****week – need to still verify**

## Purpose of LED Runs

**Long term monitoring of PMT response**
**The photomultiplier tubes for the Run II ICD sub-detector were *****recycled***** from the Run I ICD boxes**
**Each channel was individually *****tuned***** in order to achieve a mean MIP peak on the cosmic ray test stand**
**Only lever arm is the high voltage setting**
**Over a dozen PMTs have already been replaced**
**About a dozen channels have failed or dropped significantly in gain since the end of the Oct-Nov shutdown**
**Establish a real world baseline for the full ICD – from scintillator tile to the BLS card**
**Determine correction for channel to channel variation**

## The Basics of the ICD LED Pulser

**Scintillator LED Pulser (SLP) – *****borrowed***** from the Muon calibration system**
**ICD shares VME board with FPD – sits in MCH308**
**Accepts external NIM test pulse trigger**
**VME controlled channel enable, trigger, amplitude and delay**
**Steve Doulas provided the documentation and expertise!**
**Excellent GUI created by Marc Hohlfeld!**
**DC offset resistively coupled to a TTL signal pulse**
**TTL pulse triggers a transistor which discharges a capacitor into a group of four LEDs**
**DC offset provides the bias voltage for these LEDs**

## Taking ICD LED Runs

**Detailed instructions now part of the Cal Shifters’ Guide  ****(still being fine-tuned)**
**Needs to be given priority during periods without beam**
**A baseline still needs to be determined**
**What is the optimum delay time (between 0 and 170 ns)?**
**What DC offset(s) should be used?  **
**The turn-on voltage as seen on the oscilloscope directly**
**	****from the electronics is about 6.6 Volts.**
**The LED pulser needs to be issued a command to turn off during the prepare-for-run-1.2 download**
**There is currently no alarm to check that the ICD LED pulser is off during global data-taking**
**Bill Lee & Ulla Blumenschein working on this**

## > setup d0online> cd /home/d0icd/vme> ./lmb_int.py &

**> setup d0online****> cd /home/d0icd/vme****> ./lmb_int.py &**

**More on  LED Pulser Runs**

**Voltage is adjustable up to 10.0 Volts in increments of 0.2 Volts**
**Delay is adjustable from 0 to 170 ns in increments of 2 ns**
**All Download is preferable – Read *****feature***** sets ALL to zero**
**The only way to turn off the pulser is to set ALL (voltage & delay) to zero - then click on Read - all fields should be 0.0 or 0!**

## Last time...

**Stephanie Beauceron took the full set of runs (six DC offsets at six different time delays) on Feb 6****th****!**
**Too much work – need to reduce the number of steps  **
**hbook saved files very useful to make plots/printouts offline**
**From the spreadsheet, I was able to make plots for each channel (ADC counts vs DC offset and delay time)**
**Choose a delay time so the signal is sampled at or near the peak**

- Ted Elzroth determined ADC
- count value for one good channel
- from each Cal Crate in which
- the ICD is part of the readout -
- [Crates 0,1,4,5,6,7,10,11].  Did
- this for each DC offset & time
- delay setting – 8  6  6 = 288!

## ICD-CAL Preamp/BLS Signal Shape

## ICD Beam Signal

## All ICD channels in Cal Crates 10 & 11 readout

**All ICD channels in Cal Crates 10 & 11 readout**

## ICD in Cal Crate 0

## ICD in Cal Crate 11

## LED Pulser Runs

**There is a difference in the timing between East/West**
**180 feet SLP cable on East & 210 feet on West**
**SLP maximum delay is 170 ns**
**All channels are coming in very early**
**West appears to be near maximum, but East is even earlier**
**Dean added 130 ns delay to the trigger (both preamp and LED pulser)**
**This shifts the scale adding another 140 ns of delay range**
**Dropped two of the six DC offsets from the LED pulser runs **

## Something Strange Happened...

**Florian Beaudette took ICD LED pulser runs on owl shift of February 22 **
**4 DC offsets (7.8, 8.2, 8.6, 9.0) & 6 Delays (0,10,20,30,40,50)**
**Wrote script *****renamehbk***** ****which changes cal_elec default hbook name to include DC offset & delay time**
**Next owl shift, Florian noticed that most of the ICD cells had about -1 GeV.  **
**He looked in the crate_all_bad.txt file, noticing most of the cells reported were ICD**
**Both Florian, and the next shifter, Lee Sawyer, checked:**
**Pulsers (preamp & LED) were off & LV/HV was OK**
**redownloaded cal_prepare_for_run-1.2**

## More strange behavior

**I looked at the hbook files on Feb 24th **
**only 2 of the 24 runs had signal - the rest showed only pedestal for all channels**
**The 2 with signal were at the same DC offset at 40 & 50 ns delay**
**Despite the LED pulser GUI reading all zeroes, it seemed the SLP card was still sending signals!**
**Ran cal_elec: all ICD channels were firing as one would expect if the LED pulser was on**
**I disconnected two of the four SLP cables - half of the ICD signals returned to pedestal (as seen in cal_elec)**
**The only immediate solution (we were in shot set-up)**
**I disconnected all SLP output cables from the SLP card in M308**
**Mingcheng & Bernard took new pedestals - ICD channels looked normal again (eve of Feb 24th)**

## Fixing ICD LED Pulser

**I cannot explain it!**
**Eve of Feb 27th, I reconnected the SLP output cables**
**Dean & I looked at the VME page and LED GUI **
**Nothing unusual - I described my tests in detail in the logbook**
**I took several separate cal_elec runs, using different DC offsets & delay times - the SLP did not “lock-up”**
** ****What have we learned:**
**Shifters hesitate **_**TOO LONG**_** to page expert *****(generalization)***
**During physics data taking – Always fix problem ASAP!**
**Emails and Logbook entries are not enough!**
**Need for a NEW **_**dedicated**_** person to become ICD expert**
**I will help as much as I can...**

## Calibration Data from March 5th

**Ulla took fourteen runs: fixed DC offset of 8.6 V**
**delay time from 0-130 ns in increments of 10 ns**
**L3/DAQ work prevented her from going to 170 ns**
**Took about two hours **
**Primarily interested in optimizing delay time **
**What was the effect of Dean shifting trigger by 130 ns?**
**To verify the SLP did not “lock” in one state**
**Ulla ran a new cal_elec_ICD & looked at a few channels to watch for small changes from run to run**
**I took this step out after Stephanie tried the procedure, to make it easier - if this had been left in, I think Florian would have noticed a problem, so I will keep it from now on**
**Ted looked at the hbook files & created a spreadsheet**

## Slide 22

## Slide 23

## Slide 24

## Slide 25

## What Steps should we take next?

**Less than 2% difference between min/max ADC count value for West channels between 10 & 130 ns delay**
**East is still early - increase of 6-8% in ADC count value from 10 ns to 130 ns delay**
**Add cable to East?  Or take separate runs for East & West?**
**Continue to remove the “****black-box****” treatment of ICD**
**Suggestions?  Documentation is up-to-date.**
**44 New PMTs arrived – a gift from Heidi and Dean - will ship to UTA for testing by Kaushik et al. (?)**
**Have commitment for tested PMTs at D0 by May 1st**
**Tentative plans:  2 week access in late May/early June & 4-5 week shutdown beginning in August**
**detector will open both times, so bad/marginal PMTs can be replaced**