Re: GlueX-doc-829

[David Lawrence <davidl@jlab.org>]

Hi Zisis,

    Just to give you an update:

    Simon and I spoke about the tagger timing calibration of the BCAL 
beam test data some more. The calibration was done using the veto paddle 
as a reference detector to line up all of the T-counters. I checked this 
and the T-counter/veto timing difference looks very flat as a function 
of T-counter id. However, the veto paddle itself does not have very good 
timing resolution due to timewalk. The timewalk can be a very big effect 
here because the point of conversion can happen anywhere within the 
paddle so there is a wide range of amplitudes that are independent of 
photon energy. Unfortunately, the veto ADC data seems to be bad so we 
cannot correct for timewalk in the veto.

    We have two options to try recalibrating the T-counters:

1.) Calibrate relative to the timewalk-corrected BCAL times
2.) Calibrate relative to neighboring T-counters using overlap regions

I think option 1.) would be the best way to go. We are going to work on 
that and should have something for you early next week.

Regards,
-David

David Lawrence wrote:
>
> Hi Zisis,
>
>    Simon and i spoke briefly about this on Friday afternoon and are 
> planning to look into it a little more today. We'll let you know what 
> we come up with.
>
> Regards,
> -David
>
> Zisis Papandreou wrote:
>> Hi Matt and others:
>>
>> I quickly put together a short document (GlueX-doc-829-v1) on 
>> Rafael's simulations with his standalone code on a single BCAL 
>> module.  They show the well-known 12% sampling fraction and the 
>> energy leakage from all four non-readout sides.  Many of these will 
>> be repeated by Blake and myself in the near future, and to greater 
>> detail.  This document is simply for quick look up at present and for 
>> future comparison of Blake's and Rafael's standalone codes.
>>
>> Cheers, Zisis...
>>
>> ---
>> Dr. Zisis Papandreou |  email: zisis@uregina.ca 
>> <mailto:zisis@uregina.ca>
>> Department of Physics |  tel. : (306) 585-5379
>> University of Regina |  tel. : (306) 585-4149
>> Regina, SK  S4S 0A2 |  fax. : (306) 585-5659
>> World Wide Web:    http://www.phys.uregina.ca/sparro/zisis/
>>
>>
>

-- 

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