View source for IAC 2-29-08

=Leap Day run =

= DC setup=

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

90/10 ArCo2

{| border="1"  |cellpadding="20" cellspacing="0 
|colspan= "3" | HV settings 
|-
| Wire ||  Volts || current (<math>\mu</math>A)
|-
|Sense ||  1500 || 
|-
|Field ||  -750 || 
|-
|Guard ||   750 ||
|}

DC preamp at 5.6 Volts


[http://www.iac.isu.edu/mediawiki/index.php/Mini-prototype#IAC_Runs 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).  

{| border="1"  |cellpadding="20" cellspacing="0 
|-
| 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
{| border="1"  |cellpadding="20" cellspacing="0 
|colspan= "3" | HV settings 
|-
| Cable # ||  Volts || Current (ma)
|-
|Sense ||  1456 || 
|-
|Field||  729 || 
|-
|Guard ||   731 || 
|}


{| border="1"  |cellpadding="20" cellspacing="0 
|-
| 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
|- 
|}