MiniDC PreampOutput 10 10 07

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Preamp output

The following scope pictures were taken as the preamp board was being powered on. The Drift chamber High Voltage was off but all cabling (grounds) were conencted.

Sense Wire HV (Volts) Scope Image
3.1 SenseWire7 PreAmp Noise 3.1V 10-15-07.jpg SenseWire7 PreAmp Noise 3.1V 1 10-15-07.jpg
3.2 SenseWire7 PreAmp Noise 3.2V 10-15-07.jpg SenseWire7 PreAmp Noise 3.2V 1 10-15-07.jpg

SenseWire7 PreAmp Noise 3.2V 2 10-15-07.jpg

3.5 SenseWire7 PreAmp Noise 3.5V 10-15-07.jpg

SenseWire7 PreAmp Noise 3.5V 1 10-15-07.jpg SenseWire7 PreAmp Noise 3.5V 2 10-15-07.jpg

5.0 SenseWire7 PreAmp Noise 5.0V 2 10-15-07.jpg


Drift chamber High voltage settings

HV settings
Wire Volts
Sense 1800
Field -800
Guard 800

I should have set the Field and Guard wires to 900 volts according to Mac's e-mail reporting his Garfield simulation results. Next time.

Scope pictures triggering on sense wire C2

The scope trigger threshold was set to below -14 mV on Ch 1 based on previous measurements. Sense wire 2 is plugged into Channel 1 on the scope and the preamp output for channel 2 (Pin #2) is connected to channels 2 of the scope.


MINIDC Sense-Preamp Output 10-10-07 SenseTrig1.jpg MINIDC Sense-Preamp Output 10-10-07 SenseTrig2.jpg MINIDC Sense-Preamp Output 10-10-07 SenseTrig3.jpg MINIDC Sense-Preamp Output 10-10-07 SenseTrig4.jpg MINIDC Sense-Preamp Output 10-10-07 SenseTrig5.jpg

Scope pictures triggering on preamp output (pin 2)

I found that a trigger threshold of -100 mV on the preamp ouput shown on scope channel #2 discriminated well (but not perfectly:see pictures 2 & 3 below) between noise and pulses consistent with previous ionization events.


MINIDC Sense-Preamp Output 10-10-07 AmpTrig1.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig2.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig3.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig4.jpg

MINIDC Sense-Preamp Output 10-10-07 AmpTrig5.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig6.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig7.jpg MINIDC Sense-Preamp Output 10-10-07 AmpTrig8.jpg


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