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" (+100k) 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 |
| 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 |