1 - IAEA Nuclear Data Services

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XXII. Centrai Bureau for Nuclear Measurements, EURATOM,
Geel (Belgium;
i. 5 MeV Van de Graaff Accélérâtor
1'. 1. Measurement of Neutron Fluxes
H. Liskien, A. Paulsen
For une study on fast neutron flux density standards
the following detectors are now available:
a) An Associated Particle Counting Set-Up
Particle identification is carried out with, a solid
state detector, (sensitive to E), an electro-static
analyser (sensitive to Z/E) and with time-of-flight
measurements (sensitive to M/E) (E = kinetic energy;
Z = charge; M = mass).
b) A Recoil Proton Telescope
Discrepancies detected this year gave rise to a redetermination
of the hydrogen content of thin radiator
foils and to a study of their long time "behaviour.
c) A Methane Filled Proportional Counter
A cross-check between our counter and a similar one
lent from Aldermaston was carried out. The computer
programs WALL END and FITPRO A needed for the flux
evaluation are running. The aim is to achieve an accuracy
of better than _+ 3% in the application ranges
of the different counters. Possible cross-checks between
the different methods at some fixed neutron
energies may be seen from the following table. Crosschecks
already carried out are indicated by arrows.
Neutron energy
0.5 MeV
1.0 MeV
2.0" MeV
5.0 MeV
15.0 MeV
reaction ass.part,
meth.
T(p,n) 3 He
T(p,n) 5 He
D(d,n) 3 He/
T(p,n) 5 He
D(d,n) 5 He
T(d,n) 4 He
X
X X