[Gate-users] NECR using GATE data

[Vincent Vandenbussche]

Hi Abdella,

At high activities, your random coincidence rate should become more 
important than your true coincidence rate, depending on your coincidence 
time window, your minimum block coincidence, and your multiple 
coincidence policy (killAll, takeAllGoods...).
But you also need to take into account deadtime if you did not, because 
at high activities it will favor random coincidences if i'm not wrong, 
and so your NECR will decrease.

Hope this helps,

Vincent


On 07/24/2013 09:02 AM, Abdella Mohammednur wrote:
> Dear all,
>
> I want to evaluate the noise equivalent count rate (NECR) from 
> singles. But when I draw the graph it is a kind of linear (for 
> activity from 5kBq/cc to 70 kBq/cc for NEMA phantom, 70 cm height and 
> 20cm diameter). I made the following:
> 1. source type is back to back
> 2. True coinsidence count: If event Id of the two singles are the 
> same, they are consider as true (if there is no scatter in the phantom)
> 3. scatter ( if there is scattering in the phantom)
> 3. random is estimated if two coincidence events have different event ID
>
> But the NECR graph is a straight line (linear) and couldn't saturate 
> at high activities. what should I do to calculate the correct NECR 
> from singles.
>
>
> Thank you very much,
>
> Abdella
>
>
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-- 
Vincent Vandenbussche
Laboratoire IMNC
0169154471

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