Detectors

Detectors

• The detectors are described in the following POLOG Entry:

http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1542515

https://cebaf.jlab.org/elog/entry/1542515

Data Sheets

- The Acrylic Light Guide is 0.125 inch x 1 inch wide x 2 inch long (data sheet: media:Light_Guide.pdf).

- The Plastic Scintillator for the DE detector is an EJ-212 machine finish of the size 1 mm x 1 inch x 1 inch 
(data sheet: media:EJ-212.pdf).

- The Plastic Scintillator Rod for the E detector is an EJ-200 (data sheet: media:EJ-200.pdf) of the size 
3 inch diameter x 2.5 inch long painted with EJ-510 (data sheet: media:EJ-510.pdf) with one end clear.

- The 1-inch PMT is R6427 (media:PMT_R6427.pdf) in an H7415 Assembly.

- The 3-inch PMT is R6091 (media:PMT_R6091.pdf) in an H6559 Assembly.

Logic Setup

• ΔE Detector PMT HV:

LEFT	-1000 V
RIGHT	-1000 V
UP	-1000 V
DOWN	-1080 V

• E Detector PMT HV:

LEFT	-1125 V
RIGHT	-1120 V
UP	-1140 V
DOWN	-1160 V

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• ΔE Detector 792 Dual Delay Module (media:792ds.pdf):

LEFT	1+2+8 ns
RIGHT	4+8 ns
UP	0.5+4+8 ns
DOWN	1+4+8 ns

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• ΔE Detector 705 Octal Discriminator Veto Thresholds (media:705ds.pdf):

LEFT	-185 mV
RIGHT	-189 mV
UP	-185 mV
DOWN	-186 mV

• ΔE Detector 715 Constant Fraction Timing Discriminator Thresholds (media:715ds.pdf):

Shaping Delay = 2 ns

LEFT	-25 mV
RIGHT	-29 mV
UP	-27 mV
DOWN	-42 mV

• E Detector 715 Constant Fraction Timing Discriminator Thresholds (media:715ds.pdf):

Shaping Delay = 4 ns

LEFT	-25 mV
RIGHT	-25 mV
UP	-30 mV
DOWN	-30 mV

Mott Electronics Logic Setup Procedure

The above is what we did in December 2013. Here is my suggestions:

1- Adjust HV such that signals are 200 mV. Last time we did we where shooting for about 150-200 mV.
2- Set E thresholds = 25 mV.
3- Set ΔE thresholds = 25 mV, we can also try 35 mV and 45 mV.
4- Set the Veto thresholds to 450 mV or 600 mV or completely remove the discriminator. Why do we need high thresholds? 
Now a value of about 185 is too low and may have cut away events. Also now we can do this cut in analysis

The FADC range is 0-500 mV.

• Step 1: E and ΔE signal triggered from the E signal with a trigger threshold of -25 mV. PMT HVs are adjusted such that all signals are -200 mV.

• Step 2: E trigger gate (30 ns) and ΔE trigger gate (5 ns) triggered from E signal (with ΔE delays listed above).