[Halld-cal] Fwd: Re: BCAL hit saturation and integration window

[Elton Smith]

Dear colleagues,

Justin has been looking at BCAL pulses saturating in Fadc (max 
count=4095). Assuming the pulse shape remains roughly unchanged, one may 
estimate the value of the integral excluding the saturated samples. For 
the integration window from spring 2016 (60 samples), the saturated 
pulses can be recovered with reasonable precision. However, Mark noted 
that the precision of this estimate depends on the number of integration 
samples. It turns out that the precision deteriorates considerably when 
the number of samples is reduced to 11 samples for the 2016 fall run. 
See log entries at
https://logbooks.jlab.org/entry/3431233

We should re-evaluate our decision to reduce the integration window for 
the upcoming spring 2017 run. Comments/thoughts are welcome.

For the Fcal, my recollection was that the "optimum" resolution was 
found using a single sample (i.e. the peak). Clearly this conclusion 
would change for saturated pulses and this evaluation may also affect 
how many Fcal samples are used for the integra.

Cheers, Elton.



-------- Forwarded Message --------
Subject: 	Re: BCAL hit saturation
Date: 	Fri, 13 Jan 2017 15:53:20 -0500
From: 	Justin Stevens <jrsteven at jlab.org>
To: 	Mark Macrae Dalton <dalton at jlab.org>
CC: 	Elton Smith <elton at jlab.org>



I tried my saturation study using the 2 integration windows in your 
logbook link (attached).  I determine a correction to the truncated 
integral using the red curve fit to the data in the middle panel.  The 
plot on the right is the residual between the saturation corrected 
integral and the true integral.

The resolution for the corrected integral with the Spring 2016 integral 
setting is < 10%, but for the Fall 2016 integral settings the integral 
correction can get quite large and has a larger spread (as expected for 
a tighter window).  I’ll collect my thoughts in some slides and send 
those out later.

-Justin



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