Here are the efficiency vs. threshold calculations for the
neutron energies listed in your proposal. I used the code written
at Kent State University by Madey et al. [NIM 161 (1979) 439-447].
Efficiencies are shown for various thresholds between one and forty
MeV (electron equivalent). These calculations are done for a neutron
bar measuring 10 cm x 10 cm x 160 cm.
Energy
e(%) e(%) e(%)
e(%) e(%) e(%)
e(%)
(MeV)
@ 1 @ 5 @ 10
@ 15 @ 20 @ 25
@ 40
~~~~~~~~ ~~~~
~~~~ ~~~~ ~~~~ ~~~~
~~~~ ~~~~
267
11.3 10.2 9.4
8.6 7.8
7.1 5.0
533
11.4 10.2 9.2
8.3 7.3
6.4 3.9
799
11.3 10.0 8.9
7.7 6.6
5.6 3.4
1065
10.9 9.6 8.2
7.0 5.9
4.9 3.0