Difference between revisions of "IAC 2-29-08"

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|441||  0.0625" (-9.375k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
 
|441||  0.0625" (-9.375k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
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|441||  -5" (240.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
 
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Revision as of 17:48, 29 February 2008

Leap Day run

DC setup

This time the Sense wire HV is set to 1500 to start

90/10 ArCo2

HV settings
Wire Volts current ([math]\mu[/math]A)
Sense 1500
Field -750
Guard 750

DC preamp at 5.6 Volts


Go Back

Beam Line Configuration

A 1/4 inch diameter collimater is placed in the experimental cell just after a Helium bag inserted in the wall. A 2 cm thick scintillator is place over the beam downstream side of the collimator aligned using a laser. A 1 kG magnet placed after the drift chambers deflects charged particles onto a large scintillator paddle. A coincidence is required between the two scintillators.


Increased beam energy from 10 MeV to 12 MeV due to expected energy loss in front scintillator.

Runs

A

Decided to increase beam current until up to 10% of events in front scintilaltor pass through magnet after drift chamber and hit back scintillator. Ran in OR mode so a software coincidence can be formed based on measurement in ADC15 (ADC14 in C convention).

Run # Description
431 0" from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
432 0" from feedthrough , Sense wire at 1500 Volts, Metalica (ADC6; C-convention) sees overflows and looks hot on scope compared to Plastika (ADC8: in ntuples),Gun voltage at 1.76
433 -1" from feedthrough (beam should miss chamber), Sense wire at 1500 Volts, I see peds in Plastika but not metalica (Metalica is beam upstream of Plastika), The overflows are due to DC voltage/Gain being too high ,Gun voltage at 1.76
434 1" from feedthrough , Sense wire at 1500 Volts, Gun voltage at 1.76
435 2" from feedthrough , Sense wire at 1500 Volts, Gun voltage at 1.76

B

Change voltage on DC to values used on last day of January run 90/10 ArCo2

Drift Chamber HV

HV settings
Cable # Volts Current (ma)
Sense 1456
Field 729
Guard 731


Run # Description
436 2" (-100k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76, Less overflows in Metalica ADC
437 4" (-200k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
438 1" (-50k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76, visually inspected position and confirmed it was 1" from feedthrough
439 0.5" (-25k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
440 0.25" (-12.5k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
441 0.0625" (-9.375k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76
441 -5" (240.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76