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.

Scope pictures representing the cosmic signals from Plastika and Metalica(Amplifier is connected)

• Plastika

• Metalica

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]
350	511 [math]\pm \sqrt{\frac{1.00028}{511}}[/math]	454 [math]\pm \sqrt{\frac{1.00028}{454}}[/math]
350	382 [math]\pm \sqrt{\frac{1.02222}{390}}[/math]	334 [math]\pm \sqrt{\frac{1.02222}{341}}[/math]
350	427 [math]\pm \sqrt{\frac{1.05222}{449}}[/math]	409 [math]\pm \sqrt{\frac{1.05222}{430}}[/math]	74

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