[b1_ana] Fwd: Re: BCM accuracy

[J. P. Chen]

-------- Original Message --------
Subject: 	Re: BCM accuracy
Date: 	Mon, 6 May 2013 17:22:17 +0800
From: 	Pengjia <pzhu at jlab.org>
To: 	Jian-ping Chen <jpchen at jlab.org>
CC: 	Alexandre Camsonne <camsonne at jlab.org>



Hi JP,
Sorry for late, I don't know the deadline is tonight before.
I checked several production runs by using T3 count and bcm count saved 
in helicity ringbuffer(since there is more events saved in ringbuffer 
raw data(1 event recorded per 0.001s) than in normal sis3800 scaler(1 
event recorded per 2s), also I checked from normal sis3800 scaler and 
got same result), the main idea is:
1.calculate the charge(after calibration) rise,T3 count rise per 1 
second(bcm count rise in 1 sec), time use fastclock
2.get the ratio between T3 count rise and charge rise(total), fit it as 
charge=a+b*t3
3.get the relationship between 
(charge_per_sec-(a*t3_per_sec))/charge_per_sec
The result is:
by using run from 4234 to 4249,  from 4/12/2012 14:24 to 4/12/2012 18:50,
the result can be shown in attachment, t3ps is t3 count per second, upps 
is calibrated upstream bcm charge per second, clk is from 
fastclock/103920, unit is second
the stability in 5 hours can be reach as 0.75%, less than 1%,
more data need to be replayed for study for more than 20hours.


Pengjia


On Mon, May 6, 2013 at 4:51 AM, Jian-ping Chen <jpchen at jlab.org 
<mailto:jpchen at jlab.org>> wrote:

    Pengjia,

    The deadline for submitting the proposal is 8 am Monday (US East time),
    Will need the inf on long-term (~20-24 hours) stability for the BCM
    some hours
    before the deadline. We have only a few hours left.let me know if
    you have anything.

    Thanks.

    Jian-ping


    On 5/4/2013 5:16 AM, Pengjia wrote:
>     Hi JP, Alex,
>     I will figure it out as soon as possible, Thanks!
>
>     Pengjia
>
>
>     On Sat, May 4, 2013 at 5:56 AM, J. P. Chen <jpchen at jlab.org
>     <mailto:jpchen at jlab.org>> wrote:
>
>         Hi, Pengjia and Alexandre,
>
>         I need information on BCM for 100 nA. Precision and stability.
>         Also a question: do we reach 1% (statistics) in less than 1 s?
>
>         Thanks.
>
>         Jian-ping
>
>
>         On 5/3/2013 5:36 PM, Alexandre Camsonne wrote:
>>         I guess you could normalize by trigger rates too to correct
>>         for beam fluctuations.
>>
>>         Alexandre
>>
>>
>>         On Fri, May 3, 2013 at 5:19 PM, Alexandre Camsonne
>>         <camsonne at jlab.org <mailto:camsonne at jlab.org>> wrote:
>>
>>             Hi Pengjia,
>>
>>             JP would need the accury to which we measure the charged=
>>             at 50 nA.
>>
>>             I need to look back at the data
>>
>>             but I think we have several calibrations
>>             with the calorimeter.
>>
>>             Could you make a plot of the stability
>>             of the calibration constants ?
>>
>>             Also can you plot the width of the measured current ?
>>
>>             And give the resolution on the current we have :
>>
>>             sigma / mean.
>>
>>
>>             Alexandre
>>
>>
>
>




-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/b1_ana/attachments/20130506/2cdd2e15/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 4234_4249.png
Type: image/png
Size: 43542 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/b1_ana/attachments/20130506/2cdd2e15/attachment-0001.png