IAC 2-29-08
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 (A) |
| Sense | 1500 | |
| Field | -750 | |
| Guard | 750 | |
DC preamp at 5.6 Volts
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 | +1450 | |
| Field | -725 | |
| Guard | +725 | |
| Front Scint | -1127 | 30 mV threshold |
| Rear Scint | -1153 | 81 mV Threshold |
| 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 |
| 442 | -5" (+240.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76, try to get electrons missing chamber, use ADC14 to cut on electrons hitting back scintillator. ADC7 should be zero if its really an electron. |
| 443 | -3" (+140.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76 |
| 444 | -2" (+90.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76 |
| 445 | -0.5" (+15.625k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76 |
| 446 | -0.25" (+3.125k) from feedthrough , Sense wire at 1450 Volts, Gun voltage at 1.76 |
| 447 | Beam turned off, Pedestal run, Sense wire at 1450 Volts, Translator Power supply On, Preamp Power supply at 5.6 V, trigger: gun OR either scintillator |
| 448 | Beam turned off, Pedestal run, Sense wire at 1450 Volts, Translator Power supply Off |
| 449 | Beam turned off, Pedestal run, Sense wire at 1450 Volts, Translator Power supply Off, DC preamp off |
| 450 | Beam turned off, Pedestal run, Sense wire at 1450 Volts, Translator Power supply Off, DC pramp off, Now just trigger on gun pulse, DC HV off |