HRRLrun 3-22-26-2010

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HRRL run on March 22-26 2010

Preliminary setup


Install detector infrastructure to mount 2 Drift chambers, 2 Scintillators and 1 GEM on a translator table.

Install collimation


Install all detectors and associated electronics (power supplies, cabling, gas lines,...)

Timing concept

There are 3 modules to be readout; an ADC, a TDC, and the V1495.

The ADC requires a gate defining the integration interval of the pulse. The TDC requires a start pulse to begin the TDC clock and a stop pulse to stop the TDC clock. The V1495 requires a trigger pulse to tell it there is data coming from the VFATs.

The ADC and TDC will be run so they get pulses every time there is a RF pulse. The data are only recorded though if there is a coincidence pulse telling them to keep the data. Otherewise the ADC and TDC will throw the data away.

ADC timing pulse

The linear output of the 3 Fold coincidence module is generated whenever there is an RF pulse from the accelerator and is sent to the 2-channel dual timer. The top channel of the dual timer receives the 3-FOld coincidence linear output and its delayed output is send to the bottom channel of the Dual timer. The bottom of the Dual timer will be used to set the gate width. So use the top channel to adjust the gate such that it is in time with the FC output pulse. Then adjust the bottom channel so the with of the gate integrate over the desired part of the FC output.

TDC timing


install DAQ system and associated readout electronics.

Check channels in histograms

Coincidence: Coincidence between Accelerator's RF pulse generator, and several PMTs

TDC start: Accelerator RF pulse generator. TDC stop: 2 DC, 1 GEM trigout, 4 PMTs

ADC: all FC channels from Accelerator ribbon cable. ADC gate: Create timing gate using scope when accelerator

V1495: Trigger pulse from coincidence logic above


Final day for completing system checks


1pm - 5pm: Tune beam for low and high current

HRRL 3-22-10 DAC timing trigger.png

HRRL 3-22-10 DAC timing triggerVeto.png

Set the DAQ electronics so the ADC is cleared via the FAST CLEAR input unless there is a coincidence trigger. Set the timing for the ADC gate so it integrates over the FC pulse.



The FC was readout using CODA and the CAEN ADC 792. There were 3 hot channels represent 3 out of the 16 2" bricks stacked up at the end of the accelerator.

Detector tracking run plan

1.) Set the TDC to clear unless there is a coincidence.

The FAST CLEAR on the CAEN 775 TDC did not work like the Fast CLEAR on the CAEN 792. Instead we decided to reset the TDC unless a coincidence pulse is generated which will veto the ADC FAST clear and the TDC reset pulses so they don't happen.


Detector tracking run plan

The VFAT cables delay the GEM trigout pulse by about 229 ns:

Cable delay time is 100 ft + 6 ft + 5 ft = 111 ft (30.96 cm/ft) (1 ns/15 cm) = 229nsec

The VFATs have a latency switch which goes back in time by MCLK cycles.

The MCLK is set to 40 MHz so the latency interval is

Latency = 1/MCLK = 1/40 MHz = 25 ns

229ns/25ns = 9.2 = latency value for VFAT to time in signal from the HRRL cell to the HRRL counting room

We should be able to get the VFAT measurement in time by setting the latency to 9 clock pulses.

First though, set the latency to 0 and set the VFAT threshold so you don;t see any hits.

Then, study how the hits in the VFAT change with latency by changing the latency between values of 8-16.

end the day with everything in time


Work on collimation to optimize detector coincidence and rate. We want a coincidence in all 5 detectors with no pileup.

This means collimation and reduced current.

Once set up we should just take data all day to practice tracking.

All coincidence with RF pulse

First take a data sample with coincidence on front and rear PMTs (2 hours).

Then add the Rear Drift chamber (2 hours)

and then finally see if the GEM trigout can be added and finish running with this configuration.


8:30 am - beam on.

Beam Parameters: Energy - 8.66 MeV, Current - 6 mAmps.

No VFAT Runs With triple coincidence, were settings thresholds and other parameters on VFATs.

Experimental Setup

RearPMT+FrontPMT+RF+Rear DC + GEM

The data below have the fron and rear PMTs in coincidence with the accelerator RF as well as the rear Drift chamber and the Qweak GEm detector trigout pulse.

  • Run Numbers

run number is r1513.dat && r1514.dat

  • Beam Parameters
Beam Current (mA) Beam Energy (MeV) Rep Rate (Hz) Event Rate in Coincidence logic (Events/sec)
17 14 900 ~1.8

  • TDC Channels
Detector type TDC Channel
Front DC 4
Rear DC 5
Front PMT 7
Rear PMT 8
Qweak GEM 9

  • VFAT Settings

Latency for all cards 0x12
MSPolarity = On

These threshold values were set by turning the GEM detector voltage off and setting the threshold right above where we were getting any hits. During the run we turned the GEM detector voltage up to 3600 V.

VThreshold1 16 = 0x98
VThreshold1 48 = 0x98
VThreshold1 64 = 0x9c
VThreshold1 80 = 0x98
VThreshold1 96 = 0x9E
VThreshold1 112 = 0xA4

MSPulseLength<2:0> = 0x7

  • HV Settings on Detectors:

Detector type HV Settings (Volts)
PMTs(Front && Rear) -1104
DCs (Metalica && Plastika) S:F:G=1400:-700:980)
Qweak GEM Drift:GEM=-3600/3300
  • Scope Pictures

HRRL 26-03-2010 1QweakGEM.pngHRRL 26-03-2010 2QweakGEM.png

HRRL 26-03-2010 3QweakGEM.pngHRRL 26-03-2010 4QweakGEM.png

Below is shown the scope picture of the TDC start and stop, as a stop i have Qweak GEM discriminated trigout pulse: TDCStartAndStopQweakGEM.png

GUI representing hits in vfats: VfatHitsHistogram.png

Run 1513

This data has the front and rear PMTs in coincidence with the accelerator RF.

as well as the rear Drift chamber and the Qweak GEm detector trigout pulse.

  • TDC Channels
Detector type TDC Channel
Front DC 4
Rear DC 5
Front PMT 7
Rear PMT 8
Qweak GEM 9

RAW TDC histograms

TDC conversion

[math]\frac{1000 {\rm ns}}{2^{12}{\rm chan}}=\frac{1000 {\rm ns}}{4096{\rm chan}}[/math]

Front PMT r1413 TDC.png Front DC r1413 TDC.png GEM r1413 TDC.png Rear DC r1413 TDC.png Rear PMT r1413 TDC.png

TDC Cuts

Time Diff

The time difference between detectors upstream and downstream should be positive. Rear-Front PMT r1413 TDC.png

File:Rear-Front PMT r1413 TDC Cut1.png

Rear-Front DC r1413 TDC Cut1.png

Rear-Front DC r1413 TDC CUT1Cut2.png

GEM r1413 TDC CUT1Cut2.png

Time Diff + Non Zero TDC

It seems that

TDC7 (FrontPMT) >0 (This cut takes out 90% of the data)

The front scintillator must not have been in the trigger for Run 1513?

TDC8-TDC7 >0 TDC5-TDC4 > 0