[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Status report - BCAL time difference resolution



Hi Elke

For the fit to the resolution using only T7 and T8 (weighted) the chisq is 5.1
and the d.o.f. is 7.  The resolution with T7, T8 and T9 (weighted) has
small resolution values but the the fit to the standard form (a/sqrt[E]+b)
gave a near zero floor term (there has to be the contribution from
beam width).  Anyway - I obviously agree with the criteria but there is
still the issue of fit stability.  At this stage we are still improving issues
such as understanding the TDC's, time-walks, etc...   But we're making
progress.

Cheers
Alex

At 2:43 AM -0500 2/26/08, Elke-Caroline Aschenauer wrote:
>On Mon, 25 Feb 2008, Alex Dzierba wrote:
>
>Dear Alex,
>
>absolutely true that the energy weighting improves things.
>Actually what is the chi^2 / nfd for the fits. Because that should tell us
>what is the best fit.
>
>cheers elke
>>
>>  Hi Elke
>>
>>  That's a good question.  First of all - I really have not
>>  studied the stability of the fits -- in other words, what
>>  happens to the floor term when you start the fit with
>>  different initial guesses - so the differences in the
>>  floor terms may be an artifact.  The graph does show
>>  the importance of doing weighting over the cluster.  I will
>>  continue looking at this and the mean time as well.
>>
>>  Cheers
>>  Alex
>>
>>  At 11:11 AM -0500 2/25/08, Elke-Caroline Aschenauer wrote:
>>  >On Mon, 25 Feb 2008, Alex Dzierba wrote:
>>  >
>>  >Dear Alex,
>>  >
>>  >thanks a lot for the report. I have a small question. I totally understand
>>  >your argument for cell 9, but is there and explanation why the floor terms
>>  >for cell 7 and 8 are so different. the energy dependent term so is very
>>  >similiar.
>>  >
>>  >David, do we know what changed in the reprocessing of the data.
>>  >
>>  >cheers elke
>>  >
>>  >
>>  >>Date: Mon, 25 Feb 2008 10:24:50 -0500
>>  >>From: Alex Dzierba <dzierba@indiana.edu>
>>  >>To: halld-cal@jlab.org
>>  >>Subject: Status report - BCAL time difference resolution
>>  >>
>>  >>Dear All
>>  >>
>>  >>Attached is a work-in-progress report  on understanding time
>>  >>difference resolutions for the BCAL beam test.  This follows
>>  >>discussions with Stefano and Elton
>>  >>
>>  >>Alex
>>  >>--
>>  >>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>  >>Alex R. Dzierba
>>  >>Chancellor's Professor of Physics (Emeritus)
>>  >>Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
>>  >>JLab Visiting Fellow
>>  >>Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 
>>757-269-7577
>>  >>Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
>>  >>http://www.dzre.com/alex
>>  >>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>  >
>>  >( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
>>  >  )    `\                                                  -
>>  >/    '. |                                                  +
>>  >|       `,              Elke-Caroline Aschenauer            =
>>  >  \,_  `-/                                                    -
>>  >  ,&&&&&V         Jefferson Lab                                +
>>  >,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
>>  >,&&&&&&&&&&;      Suite 8                 Hampton, VA 23664      -
>>  >|  |&&&&&&&;\     12000 Jefferson Ave                             +
>>  >|  |       :_) _  Newport News, VA 23606  Tel.:  001-757-224-1216  =
>>  >|  |       ;--' | Mail:  elke@jlab.org    Mobil: 001-757-256-5224   -
>>  >'--'   `-.--.   |                                                    +
>>  >   \_    |  |---' Tel.:  001-757-269-5352                             =
>>  >     `-._\__/     Fax.:  001-757-269-6331                              -
>>  >            +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+
>>
>>
>>  --
>>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>  Alex R. Dzierba
>>  Chancellor's Professor of Physics (Emeritus)
>>  Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
>>  JLab Visiting Fellow
>>  Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
>  > Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
>>  http://www.dzre.com/alex
>>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>
>  ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
>   )    `\                                                  -
>  /    '. |                                                  +
>  |       `,              Elke-Caroline Aschenauer            =
>   \,_  `-/                                                    -
>   ,&&&&&V         Jefferson Lab                                +
>  ,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
>,&&&&&&&&&&;      Suite 8                 Hampton, VA 23664      -
>|  |&&&&&&&;\     12000 Jefferson Ave                             +
>|  |       :_) _  Newport News, VA 23606  Tel.:  001-757-224-1216  =
>|  |       ;--' | Mail:  elke@jlab.org    Mobil: 001-757-256-5224   -
>'--'   `-.--.   |                                                    +
>    \_    |  |---' Tel.:  001-757-269-5352                             =
>      `-._\__/     Fax.:  001-757-269-6331                              -
>             +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alex R. Dzierba
Chancellor's Professor of Physics (Emeritus)
Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
JLab Visiting Fellow
Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
http://www.dzre.com/alex
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~