Re: 4 (5?) bumps but a definite improvement

[David Lawrence <davidl@jlab.org>]

Hi Richard,

    This is because of an odd situation in which Simon chose to define 
the value of tphoton as the reference time minus the channel time (in 
order to make tphoton positive). The BCAL times were defined as channel 
time minus reference time. So, in order to get the tagger/BCAL time 
difference, you must ADD tphoton and (tn8+ts8)/2.0.

Regards,
-David

Richard Jones wrote:
> Blake,
> I do not understand this expression below (ts7+tn8)/2+tphoton.  Why is 
> it not (ts7+tn7)/2-tphoton?  I assume the subscript mismatch is a typo 
> -- it says (ts8+tn8)/2+tphoton  on the wiki page -- but it puzzles me 
> why you are adding instead of subtracting the tagger time.
>
> Richard
>
> Blake Leverington wrote:
>> Hi David,
>>
>> I redid similar plots to what you did on April 4th but now using the 
>> tagger as a reference time( i.e (ts7+tn8)/2 + tphoton ) and things 
>> look much better. However... :) ...I can clearly see 4 bumps that I 
>> am not sure where they are coming from. I sort of see gaps in the 
>> tn8+tphoton:Ephoton spectra as if we're missing the t-counter there 
>> or something.
>>
>> You can see the results here:
>> http://www.jlab.org/Hall-D/software/wiki/index.php/BCal_Beam_Test_Plots%2C_April_6%2C_2007 
>>
>>
>> -Blake
>>
>>
>>
>>
>>
>

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