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

9-05-2008

The DC high voltage is on. The DC outputs of Plastika and Metalica from sense wire 4 are connected to the Model 777 Octal Variable Gain Amplifier.

HV settings
Wire	Volts
Sense	1450
Field	-725
Guard	725

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

• Metalica

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	1450
Field	-725
Guard	725

Threshold (mV)	Metalica (Events/hr)	Plastika (Events/hr)	Coincidence (Event/hr)
100	1915	1912	27(90)
100	2148	1799	13(36)
100	1885	1758	13(37)
100	2012	1912	32(91)
100	1905	1754	8(25)
150	671	588	8(14)
150	645	596	11(11)
150	634	596	19(19)
150	629	563	13(13)
150	634	550	5(5)
175	361	358	27(20)
175	380	329	14(14)
175	396	329	15(14)
175	391	344	10(10)
200	286	256	28(25)?
250	122	120	34(2)

Threshold (mV)	Metalica (Events/hr)	Plastika (Events/hr)	Coincidence (Event/hr)
100	[math]1973 \pm 98[/math]	[math]1827 \pm 71[/math]
150	[math]643 \pm 15[/math]	[math]583 \pm 17[/math]
175	[math]382 \pm 13[/math]	[math]340 \pm 12[/math]
250	122	120

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