MiniDC PreampOutput 10 10 07

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Revision as of 04:59, 17 October 2007 by Oborn (talk | contribs) (→‎Scope pictures triggering on preamp output (pin 2))
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Preamp output

The following scope pictures were taken as the preamp board was being powered on sense wire 7. The Drift chamber High Voltage was off but all cabling (grounds) were conencted.

Preamp Board Voltage (Volts) Scope Image
3.1 SenseWire7 PreAmp Noise 3.1V 10-15-07.jpgSenseWire7 PreAmp Noise 3.1V 1 10-15-07.jpg
3.2 SenseWire7 PreAmp Noise 3.2V 10-15-07.jpgSenseWire7 PreAmp Noise 3.2V 1 10-15-07.jpgSenseWire7 PreAmp Noise 3.2V 2 10-15-07.jpg
3.5 SenseWire7 PreAmp Noise 3.5V 10-15-07.jpgSenseWire7 PreAmp Noise 3.5V 1 10-15-07.jpgSenseWire7 PreAmp Noise 3.5V 2 10-15-07.jpg
5.0 SenseWire7 PreAmp Noise 5.0V 2 10-15-07.jpg
5.3 SenseWire7 PreAmp Noise 5.3V 2 10-15-07.jpg
5.5 SenseWire7 PreAmp Noise 5.5V 2 10-15-07.jpg
5.6 SenseWire7 PreAmp Noise 5.6V 2 10-15-07.jpg
5.8 SenseWire7 PreAmp Noise 5.8V 2 10-15-07.jpg


Observations
The peak-to-peak sense wire maximum noise level of 20 mV converts to a 100 mV peak-to-peak noise level coming out of the amplifier when the board is powered at 5.8 Volts.

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 -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 channel 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)

A trigger threshold of -100 mV on the preamp output 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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