[G14_run] Misidentified protons as neutrons

[Tsuneo Kageya]

Ciao Alessandra,


 As for the neutron data, in order to exclude events in which protons are misidentified

as neutrons, are you considering dead or inefficient SC paddles ?

It is not clear if you are cosidering this from the sentences at page 119 of your note;

"a condition requiring an anti- coincidence from the scintillator array was imposed, excluding events with hits not connected to reconstructed charged tracks and facing an EC cluster".

I guess you do, but just in case.


I am attaching a pdf file which shows some SC paddle info from g13a and g14 last target period.


(1) From 4th page, the most of particles seem to be detected on the paddle 1 to 39.

At the second page, there are shown rejected SC paddles in the g13a analysis with reasons.

If we exclude the data from paddles 40 to 48, there are 39 x 6 = 234 paddles which could detect

charged particles.    As you can see the fig. at page 3, paddles 23rd show some inefficient

counts (green arrows).   From the table of g13a, the number of the inefficient or dead paddles

is 22 among 234 and the ratio is 9.4 % which may be the worst case, althogh not so small.



(2) I think protons are misidentifies as neutrons, if

 (a) proton are detected in EC  and

 (b) either protons are not reconstructed in DC or not detected at SC


 I guess that the number of events in which protons are passing through both DC and SC without

being detected is small.   But there are some as 9.4 % which are reconstructed in DC, but

not detected at SC bad paddles.


(3) I mean if a particle is reconsructed in DC, detected in EC as a baryon in the same or

neighboring sector and not detected in SC, I wonder if the particle is a proton, which can be

misidentified as a neutron.


   Ciao, Tsuneo Kageya.




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