GS-NEUTRON-150 sensitivity

[wesley]

Hello,

I am interested in your detector, but I have to know what is the lowest neutron energy it is able to detect?
Can it detect thermal neutrons?

Thank you!

[Sesselmann]

Wesley,

The GS-Neutron-150 is a gas filled corona counter, these like gas proportional counters can only detect slow neutrons, the optimal detection is for room temperature neutrons. The gas inside the detector has a large cross section for thermal neutrons, so when a neutron passes through the gas it may get captured by a B10 or He3 nucleus and this reaction releases energy which in turn causes ionisation and results in an electronic pulse.

As most neutron sources emit very fast neutrons, these tubes only work when they are surrounded by an effective moderator to slow the neutrons down. A good moderator is any material which is rich in Hydrogen, such as water, but water isn't very practical to carry around, so we use HDPE plastic, this material is suitably high in hydrogen and does a good job of slowing down the neutrons.

You can use basic physics conservation of momentum to explain why light nuclei are more effective at slowing down neutrons than heavy nuclei are.

The GS-NEUTRON-150 is a relatively low efficiency neutron counter with an nvth of 0.15 that means it will count around 15 pulses per second in a flux of 100 n/s so it's not suitable for detecting very low neutron fluxes such as cosmic neutrons etc.. If I what I have read is correct the cosmic background neutron flux is on the order of 14 neutrons per hour, so with the GS-NEUTRON-150 you would only expect to see 1-2 counts per hour.

Steven

[wesley]

Thank you very much for your response!

Really good explanation. I am sure that we will buy the detector soon.