PePPO 03132012

Accelerator Configuration

Accelerator Settings

beam energy	6.8 MeV
Beam type:	Electron
I_average:	0.3 nA
I_peak:	0.05[math] \mu[/math] A 0.006 duty factor
pulse width:	10 [math]\mu[/math]s (it seems on 200 [math] \mu[/math]s is possible?)
Rate:	60 Hz
PEPPO Spectrometer:	151.3 A

Set HV to Detectors

	Signal channel	HV dac	HV (V)
Detectors #1	A1	2.4	960
Detectors #2	A2	3.0	1200

How to turn HV On

Scope Pictures

CH1: Beam Sync CH2: A1 CH3: A2

Target	Pictures
No Target
Chromox Target

Annihilation Counter Runs

Signal Definitions for Trigger logic

SYNC:=60 Hz sync pulse 200 micro seconds long

Det1:= Annihilation Counter #1 (HV1)

Det2:=Annihilation Counter #2 (HV2)

Run#	run mode	Run length (sec)	Beam	Target	Trig Logic	VME discriminator Threshold (mV)	HV1 (setting/V)	HV2 (setting/V)	Deadtime
2902	sample	0	e[math]^-[/math]	Chromox	(Det1 OR Det2)	50	2.4/960	3/1200	93.1818% [math]\pm[/math] 10.3874%
2903	sample	203	e[math]^-[/math]	Empty	(Det1 OR Det2)	50	2.4/960	3/1200	84.9788% [math]\pm[/math]0.106622%
2904	sample	452	e[math]^-[/math]	Empty	Det1 AND Det2	50	2.4/960	3/1200	12.2563% [math]\pm[/math] 2.32772%
2905	sample	556	e[math]^-[/math]	Chromox	Det1 AND Det2	50	2.4/960	3/1200	3.16901% [math]\pm[/math] 4.2301%
2908	sample	150	off	out	(Det1 or Det2)	50	2.4/960	3/1200	74.0667% [math]\pm[/math] 0.157206%
2909	sample	1118	off	out	(Det1 AND Det2)	50	2.4/960	3/1200	3.57143% [math]\pm[/math]26.9725%

data analysis

Negative Energy ?

This run 2902, Int_Ch14 histogram. Why there is negative?

Pulses

run 2905

1st 100 puleses

pulse that only partially read-in:

first 10 pulses, some pulses that only partially read-in:

looks like some pulses are only partially read-in. We need to delay signal more?

One possible cut may to determine if the signal is increasing within the first 100 - 300 $Iterations.  This would be like creating a leading edge discriminator in software.

T->Draw("CH14:Iteration$","Iteration$<300 & CH14<100","L",10,1)

Why CH14 histogram is all positive, but int_14 histogram has negatives?