MiniPrototype SinglesCosmicRuns 2008

Goal

Use singles Cosmic events to measure rate differences between Metalica and Plastica

Apparatus

• Plastica and Metalica are stacked on top of each other. High Voltage and ionization gas are connected in parallel.
• A discriminator is connector to the amplified output (an on board preamp and the VPI Post amp) of sense wire 4.
• The discriminator output is connected to a VME scaler.

Proposed Tests

1. Measure the singles rate as a function of DC high voltage
2. Measure the singles rate as a function of Discriminator Threshold

30-04-2008

The DC high voltage is on. The DC outputs of Plastika and Metalica from sense wire 3 are connected to the Model 777 Octal Variable Gain Amplifier.

HV settings
Wire	Volts
Sense	1700
Field	-800
Guard	800

Scope picture below shows the Noise level on the DC measured in infinite persist time mode.
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Scope pictures representing the cosmic signals from Plastika and Metalica(Amplifier is connected)

• Plastika

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• Metalica

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OUTPUTS FROM DISCRIMINATOR

Discriminator Threshold=450MV

Rate -vs- Discriminator Threshold

Gas is ArCo2 . 75/25 mixture

HV settings
Wire	Volts
Sense	1700
Field	-850
Guard	850

Threshold (mV)	Metalica (Events/hr)	Plastika (Events/hr)	Coincidence
300	701 [math]\pm \sqrt{\frac{1.04194}{730}}[/math]	627 [math]\pm \sqrt{\frac{1.04194}{653}}[/math]
300	560 [math]\pm \sqrt{\frac{1.01639}{569}}[/math]	570 [math]\pm \sqrt{\frac{1.01639}{579}}[/math]
310	[math]592 \pm 11[/math]	[math]500 \pm 24[/math]
325	[math]528 \pm 65[/math]	[math]465 \pm 30[/math]	32
350	[math]421 \pm 48[/math]	[math]379 \pm 40[/math]
400	[math]305[/math]	[math]235[/math]	31

Gas is ArCo2 . 90/10 mixture

HV settings
Wire	Volts
Sense	1500
Field	-750
Guard	750

Threshold (mV)	sense wire HV settings (V)	Metalica (Events/hr)	Plastika (Events/hr)	Coincidence (Event/hr)
500	1500	5127(?)	71577(?)	177 (3019)
500	1450	547	672	79 (85)
500	1450	499	632	18 (225)

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