Difference between revisions of "X-talk between n-dets"

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1) the x-talk effect is due to the acceptance of the analysing detector, i.e. there was no shielding in between the two detectors;
 
1) the x-talk effect is due to the acceptance of the analysing detector, i.e. there was no shielding in between the two detectors;
  
2) only 2" of borated poly was placed in between;
+
2) only 2" of borated poly (5%) was placed in between;
  
 
3) borated poly was placed in between two layers of 1" lead layers;
 
3) borated poly was placed in between two layers of 1" lead layers;

Revision as of 17:04, 19 August 2014

Behaviour of lead and borated poly under the neutron radiation:

File:Borated poly sim.pdf

File:Lead shield.pdf

The simulation of the cross talk between two neutron detectors was performed using GEANT4 program. The simulated detector layout is shown below:

Detector shielding setup.png

The following stages of simulation of the x-talk were considered:

1) the x-talk effect is due to the acceptance of the analysing detector, i.e. there was no shielding in between the two detectors;

2) only 2" of borated poly (5%) was placed in between;

3) borated poly was placed in between two layers of 1" lead layers;

4) 2 cm Al layer was added to the shielding described in stages 1)-3) from the side of the analysing detector.

The number of incident particle (neutrons) was [math]10^5[/math] and their energy spectrum is shown below:

Espectrum incident neutrons.png

Neutrons were incident uniformly over the surface of one of the neutron detectors normally to the surface w/o hitting the shielding and the analysing detector such that we have pure x-talk effect due to neutron interaction with the material BC-420 of the neutron detector being irradiated. The analysing detector detected all the particles scattered/produced in the shielding/BC-420.

Stage 1 of the simulation

The energy spectrum of all possible particles entering the analysing detector is presented below:

All particles noShield.png

Out of the cumulative particle energy spectrum we have the following number of neutrons:

Neutrons noShield.png

the following number of photons:

Photons noShield.png

and the following number of protons:

Protons noShield.png

Stage 2 of the simulation

The energy spectrum of all possible particles entering the analysing detector after placing 2" of borated poly in between the detectors is presented below:

All particles 2inBorPoly.png

Out of the cumulative particle energy spectrum we have the following number of neutrons:

Neutrons 2inBorPoly.png

the following number of photons (photon peak ~2.2MeV can be seen as a result of neutron capture reaction):

Photons 2inBorPoly.png

and the following number of protons:

Protons 2inBorPoly.png

Stage 3 of the simulation

The energy spectrum of all possible particles entering the analysing detector after adding 2 layers of 1" lead placed at the sides of the 2" borated poly is presented below:

All particles 2inBorPoly2inPb.png

Out of the cumulative particle energy spectrum we have the following number of neutrons:

NO neutrons observed.

the following number of photons:

Photons 2inBorPoly2inPb.png

and the following number of protons:

Protons 2inBorPoly2inPb.png

Stage 4 of the simulation

The energy spectrum of all possible particles entering the analysing detector after adding 2 cm of Aluminium to 2 layers of 1" lead placed at the sides of the 2" borated poly is presented below:

All particles 2inBorPoly2inPb2cmAl2.png

NO neutrons observed.

the following number of photons:

Photons 2inBorPoly2inPb2cmAl.png

and the following number of protons:

Protons 2inBorPoly2inPb2cmAl.png

Future work

Now we should see the correlation of the energy lost per particle for the given event to understand how many particles will produce energy loss in both detectors high enough to be considered as a source of cross talk. Also the effect of interaction of bremsstrahlung radiation with the material of the neutron detector and the corresponding cross talk should be considered.