1 - IAEA Nuclear Data Services

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VI. INSTITUT FUR REINE UND ANGEWANDTE KERNPHYSIK DER UNIVERSITÂT
KIEL
lo Fast Chopper
H.H. Jung, H.G. Priesmeyer
The new Fast Chopper facility has been installed at the FRG-lJ
it is operating since Dec» 1. Technical details of the new
spectrometer are as following;
The rotor material is steel and has a uranium core. Diameter
of the rotor is 318 mmj diameter of the uranium core is 80 mm.
The rotor has seven cigar-shaped slits with 0*2 mm width at
the ends and 1.0 mm width at the center of the slit„ Maximum
speed is 12,000 rpm. Minimum burst width is 0.5 us0
The collimators are made of nickel and are 600 mm long each.
Flight paths of 21 and 95 meters are installed. Seven lithium
glass detectors (NE 912) viewed by one photo-multiplier each
are used as neutron detectors* The glass detectors have dimensions
2*5" 0 and 1" thickness.
The flight time is measured by a 4-096-cba.nnel analyser by
TELEFUNKEN. Channel width: from 0,1 to 19.2 p.s« The resolution
of the spectrometer above 50 eV is 27 ns/m at the 21 meter
station and lower at lower energies, as the rotor has to be
slowed down.
Total cross section measurements on radioactive isotops are
planned: Cs 135/137, Pm 14-7, Tc 99 and others.
2o Crystal Spectrometer
K. Brand., M- Saad
There has been no progress in 1967 since the reactor FRG-1
was shut down. Since November, measurements of total neutron
cross sections have been performed on BaH? and CaH2»
Further measurements are planned to determine the vibration
energies of heavy metal hydrides.