[Gate-users] Z position

[Chen, Yu]

When there are nothing on root file for 1000 events, it must be something wrong.

I commented out 

/gate/world/daughters/insert 3axes

then it runs without problem.

Generated 1000 bg* 100s = 10^4 events, obtained ~5x10^3 singles in 2.5 cm NaI. 
You can estimate to see if it is correct using known attenuation coefficient.

Among them are there half with energy > 600 keV but still occured Compton scattering.

Those without Compton scatter (6426) lie a perfect exponential distribution (see attached pdf).  

Yu Chen, Ph.D.
University of Massachusetts Medical School
Division of Nuclear Medicine
55 Lake Avenue North
Worcester, MA 01655-0243
Phone:  (508) 856-6123
Fax:    (508) 856-4572



-----Original Message-----
From: venialgo_e [mailto:venialgo_e at secyt.frba.utn.edu.ar]
Sent: Wed 2/20/2008 8:47 AM
To: Chen, Yu
Subject: RE: [Gate-users] Z position
 
I attached the file 1000bq.root and 1000bq.mac .For 1000 bq  and 1  
second there aren't counts in the detector.

    bye,

    Esteban Venialgo


"Chen, Yu" <Yu.Chen at umassmed.edu> ha escrito:

> I strongly suspect you were plotting "hit" not "singles".
>
> The following is my message last time to you:
>
>> Are you sure you plotted *Singles*?
>> From you macro, we can't see any digitizing module used.
>
>> You generated 20000*3 photons but have more than 60000 entries.
>> It may explain some if what you actually plotted is hit (step)   
>> point position.
>
>
> Put
> /gate/output/root/setRootSinglesFlag 1
> in your mac
> and no energy window needed
>
> Run 1000 bq and 1 sec
> send your root file to me.
>
> Yu Chen, Ph.D.
> University of Massachusetts Medical School
> Division of Nuclear Medicine
> 55 Lake Avenue North
> Worcester, MA 01655-0243
> Phone:  (508) 856-6123
> Fax:    (508) 856-4572
>
>
>
> -----Original Message-----
> From: gate-users-bounces at lists.healthgrid.org on behalf of venialgo_e
> Sent: Mon 2/18/2008 12:34 PM
> To: Chen, Yu; gate-users at lists.healthgrid.org
> Subject: RE: [Gate-users] Z position
>
> Yes, I don't have any digitalizer modules, because I have done Matlab
> scripts in the way to have more freedom to select scatter and
> photoelectric interactions or both, calculate position using weighted
> average for position, and apply energy windows, etc.
>
> Anyway I connect an adder and a energy window to system and...
>
> In case 1 there are two peaks of counts in the crystal's top face, if
> the digitalizer is only an adder. The name of the files are
> case1_wo_window.gif and case1_wo_window.mac    .But if the digitalizer
> has an adder and energy window, so there is a maximum of counts in 18
> mm approx.   .The files for that case are case1digitalizer.gif and
> case1digitalizer.mac.
>
> For case 2, is the same than before. There are counts only in second
> half of the crystal with an adder and energy window. The files are
> case2digitalizer.gif and case2digitalizer.mac.
>
> And, In case 3, There is a maximum of counts in 10 mm approx, with and
> adder and energy window. The files are case3digitalizer.gif and
> case3digitalizer.mac .
>
>
>
> I can't understand the different shapes of Z position. I expected and
> exponential decreasing shape.
>
>
>
>      	Thanks a lot for your support.
>      	Esteban Venialgo.
>
> ----------------------------------------------------------------
> This message was sent using IMP, the Internet Messaging Program.
>
>



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