0.20
0.30
0.50
0.70
1.00
1.50
2.00
3.00
4.00
61.5
54.0
43.3
37.5
33.4
29.5
27.1
25.3
24.4
A.2.8 Single-Channel Analyzer (Nuclear Radiation
Branch) (Reference 57)
inches thick, Nal(T1)
Photomultiplier tube type: 6364 DuMont
Pulse-height analyzer type: Model 510-SC Atomi, Instruments
Pb shield thickness: 2'4 inches
long
Sample container type and size: glass vial, think
correction: 1.0 x 10° counts/min
diameter x 2% inches long
Counting procedure: ordinarily 3- to 1-minute
intervals for each sample; trays decontaminated and
Distance from bottom of sample to collimator opey.
ing: 2 inches
_
Calibration standards: Na”, and Hg?03
counted with \4-inch aluminum cover in place
A.2.7 Dip Counter.
A.2.9 Gamma Time-Intensity Recorder.
Crystal dimensions and type: 14-inch diameter
Scaler type: Same as doghouse counter
Shield thickness and counting chamber dimensions:
Same as doghouse counter
Sample volume: 2,000 ml (constant geometry)
Counting efficiency for several nuclides: (Private
communication from J. O’Connor, NRDL)
Hes
Au)
" Cg!
Nb
Scfé
Co®
Na
The en-
ergy and directional response characteristice of the
standard TIR detector, consisting of four ion cham-~
bers (A, Am, Bm, and Cm) with a protective dome,
X 1 inch thick, Nal(T1)
Photomultiplier tube type: 6292 DuMont
Cel!
‘
Collimator dimensions: 14-inch diameter x 6 ince
Minimum count rate requiring coincidence loss
Nuclide
oo
Crystal dimensions and type: 4-inch diameter x 4
counts /dis x 107?
1.20
1.72
1.28
0.916
0.870
1.76
1.56
1.29
were determined at NRDL.
(Measurements and cal-
Culations were carried out by G. Hitchcock, T.
Shirasawa, and R. Caputi.)
A special jig permitted both horizontal and verticaj
Totation about the center of the chamber under study.
Directional response was measured and recorded continuously for 360 degrees in planes at 30~degree
increments through the longitudinal axis of the Cm
chamber. Relative response data was obtained by
effectively exposing the chamber to a constant ioniza-~
tion rate at six different energies—four X-ray energies: 35 kev, 70 key, 120 kev and 180 kev; and two
source energies: Cs’*' (0.663 Mev) and Co® (1.2 Mev).
The results for three mutually perpendicular planar
responses have been illustrated graphically to show:
(1) shadowing interference by other chambersin the
horizontal plane (Figure A.2), (2) maximum shadowing
Minimum count rate requiring coincidence loss
correction: 2 x 10° counts/min
interference by other chambers in the vertical plane
(Figure A.3), and (3) minimum shadowing interference
by other chambers in the vertical plane (Figure A.4).
Counting procedure: 2,000-ml sampies at constant
geometry; counting intervals selected to maintain a
statistical error <1.0 percent
164