View source for Back of the envelope calculation for e+/e- ratio


{| border="1"  |cellpadding="20" cellspacing="0 
|-
|  run#  || T1 || T2 || Sweep Magnet|| logic || HV-D2L || HV-D1R || Reprate  || start || stop || Int Rate || event number || pulses
|-
|  3735  || in || in || out || (DL & GunTrig) & (DR & GunTrig) || 1150V || 1150V || 300-301 || 15:54:24|| 16:11:06 (1002 s)|| 9.0200 events/s||  9045 || 301462
|-
|  3736  || in || out || out || (DL & GunTrig) & (DR & GunTrig) || 1150V || 1150V || 300-301 || 16:12:15|| 16:27:07 (892 s)|| 4.1736 events/s||   3752 || 268289
|-
|}

=Run 3735 positron charge=

positron rates is 0.26 Hz. 

Run times is 1002. 

The total positron in this run is 260. 

The current of the positron beam is: <math>260 \times 1.6 \times 10^{-19}=4.2 \times 10^{-17} </math> C.

=Run 3735 electron charge=

The electron peak current is around 100 mA.

The pulse width is: 300 ns.

Then current in a single pulse is: 300 ns * 100 mA = 30 nC.

The total pulses in this run are: 301462

Then the total charge is this run: 30 nC * 300,000 = 9 mC.

= e+ to e- ratio =

e+ / e-= <math>\frac{4.2 \times 10^{-17}~C} {9~mC}</math>

<math>= \frac {4.2 \times 10^{-17}} {9 \times 10^{-3}}</math>

<math> = 0.5 \times 10^{-14} </math>

<math>= 5 \times 10^{-15} </math>