E.Guschin (INR,Moscow)

Status of PRS/SPD detector

• Cosmic test results

• Installation/tuning of monitoring system

• Status of PMT calibration

• Radiation Source with magnet separator

• Planning

E.Guschin (INR,Moscow)

Cosmic test results

• Load2 SPD#7(O “A”), SPD#8(O “A”), SPD#4(I “A”), PS#4(I “C”) – OK (+check data)

• Load 3 – PS#1,#2,#3; SPD#3 OK ; data checked

• Load 4 – PS#7,#8; SPD#1,#2 OK ; data checked

• Load 5 – PS#5,#6; SPD#5,#6 – PMT calibration done, problem with one(?) pixel on PMT#2 (over illuminated with LED). Analysis in progress.

E.Guschin (INR,Moscow)

Cosmic test results

• Load2 OK: – SPD#8 (outer “A”) – check

data for errors

– SPD#7 (outer “A”) - check

– SPD#4 (inner “C”) - check

– PS#4 (inner “C”) - OK

E.Guschin (INR,Moscow)

Cosmic results

E.Guschin (INR,Moscow)

Cosmic results

E.Guschin (INR,Moscow)

Status of monitoring system

• Monitoring system is installed on all 16 SMs. LED drivers are tuned with oscilloscope on 15 SMs.

• Scope of work done: – installation done for 750 drivers +120 splitters, – Constructed and installed ~1000 fixations, 900 cables – 40,000 tunings (3 iterations for channel) is done – Found ~ 1000 badly soldered elements, mostly trimmers– + bad contacts, shorts in connectors

• Measurements using cosmic test DAQ show that – Slope of light vs bias voltage of LEDs is rather different. – Tuning with oscilloscope is done at high signal ~ 100 MIPs and often works

badly for low signals ~ 5 MIP.– retuning at low signal improves situation. – Checking with DAQ also help to detect electrical cross-talk between drivers

(bad contacts in connectors, soldering and grounding)• 4 PS ‘C’ site are checked and fine tuned using CT DAQ and ready for transportation• Check and tuning with CT DAQ is relatively fast and very useful.

E.Guschin (INR,Moscow)

LED stability scan (violet LEDs)

• Start 27/04 21:00

• End 28/04 9:00

No temperature monitor

E.Guschin (INR,Moscow)

Stability scan - 1 , 12 hours, night

Blue LEDs (WUSTLICH)

Start at 21:00 21/04, end 9:00 22/04

Channel #10: bad soldering at the driver output, LED got disconnected -> gives an idea of effect on other channels.

E.Guschin (INR,Moscow)

Stability scan -2, 12 hours, night

The same time, another driver.Ambient temperature was not monitored.

E.Guschin (INR,Moscow)

LED amplitude scan -1

Violet LEDs:

Signal from 64 LEDs was measured by Lecroy QDC (Y-axis channels) as function of bias voltage 2.6-2.85V.

1000ADC c ~ 550 ph.el. ~ 20-30 MIPs

E.Guschin (INR,Moscow)

LED amplitude scan -2

• Example of 64 Blue LEDs scan over 2.8-3.4V is shown on the plot

• Some of LEDs have different slope of the characteristics

E.Guschin (INR,Moscow)

PMT calibration. Comparison with Clermont data.

Finally, after correction the data for the difference in pixel mapping and gain coefficient definition, the comparison of PMT calibration without mask vs calibration of Clermont (Stephane) shows quite reasonable coincidence for three from four tubes.

E.Guschin (INR,Moscow)

PMT calibration. Comparison with CF data.

• Three of four tubes are correctly identified.

• For these 3 tubes the ratio of calibration coefficients does not walk out of +-20% corridor.

• RMS of the ratio for 3 identified tubes is 9, 9.5 and 7.5%.

• RMS for the ratio of very different tubes (plot left-up) is 18% (corridor is +-33%).

E.Guschin (INR,Moscow)

PMT calibration

• PMT calibration with mask is needed for beter understanding of data

• First calibration with mask with 1 mm holes was done yesterday

• Analysis is in progress

E.Guschin (INR,Moscow)

Radiation source with magnetic separator and trigger

Sr90 370MBq

El. magnet

Trigger counterSeparator exit through collimating slit

E.Guschin (INR,Moscow)

Rad. Source with scintillator pad

Signal from rad.source was measured as a function of magnet current.

On the plots the spectrum of signal is shown. Optimal values of current are found 0.8-1.05A. The relative width ~15% of spectrum is dominated with photostatistical fluctuations

Trigger rate obtained was 200-400 Hz with fake trigger contamination ~1%.

Source efficiency with large scintillator pad was achieved as 50-60%.

E.Guschin (INR,Moscow)

Rad.source studies (scintillator vs LSO crystal)

Photo-statistics:Signal from scintillator pad was measured from both ends

of fibre ~20-25 ph.el./end

• To measure the signal with larger light output we used 1 cm^3 LSO crystal with PMT read-out.

• Resolution “in peak” obtained was ~8-9% (r.m.s).• “Peak” is ~1/3 of triggers on large low energy

substrate (due to crystal geometry?)

E.Guschin (INR,Moscow)

Rad.source studies (“dead” material)

• Dead material in front of pad: 2 mm of fiberglass ~ module box’s bottom.

• Signal losses are: 1. Energy losses are ~50%; 2. Trigger rate ‘in peak’ drops

~3-4 times.

Conclusion: rad.source with magnetic separator + trigger provide reasonable signal and rate conditions.

Final check should be done with real module.

E.Guschin (INR,Moscow)

Planning

1. To prepare SPD SMs of site “C” for transportation –next week• add. (re)measurement/replacement of 1 module• Monitoring system check/retuning with DAQ

2. Analysis of PMT calibration for the last setup – this week

3. Preparation of the rest of super-modules site ”A” for transportation – end of May