Detector you can afford to buy is usually the best one for the experiment :)

I`m just kidding but that is true for the most of the time.

In our lab,we use plastic scintillation neutron detectors....

Dear Jan, thank you for your response.

Stilbene scintillator is the most commonly used organic scintillator detector for the detection of fast neutron applications. Stilbene is widely used to measure fast neutrons disciminatiing against the background of accompanying gamma rays. This is based on the eleastic scattering of fast neutron with the organic scintillator (such as Stilbene) by (n,p) reaction. The decay part of the produced pulse (from the fast neutrons (protons) or gamma rays (electrons)) depends on the type of radiation. However, stilbene is difficult and expensive to obtain.

Are you sure that Plastic Scintillator has the same characteristics?

Any information's or suggestions are welcome. 

here are some articles:

http://publications.jrc.ec.europa.eu/repository/bitstream/JRC101510/report%20intelligentshield%20characterisation_v06.pdf

http://www.oeaw.ac.at/fileadmin/subsites/etc/Institute/SMI/PDF/Detectors_WS2014-15_A2.pdf

I am not sure how much plastic scintillators cost, but I think that they were not expensive. You can contact http://scionix.nl/ for price quotation :)

Dear Jan, thanks for the answer and the shared experience