~ 4 -
UCKL- 3087
rare earths and yttrium was pecrtorm.ed in the manner described by Nervix.
The palo was purified by repeated wrec.pitation of the chloride trom: diethyl
ether-hydrochioric acid nu.xtures and oy scavenging with terric and lanthanum hydroxides.
Gamma and bremsstrahlung vadiations trom all nuclides measured,
except Mo”,
were counted by meung ofa Nal(?l) scintillation crystal,
with the lower discriminator set at 20 kev ard the upper discriminator set
at 3 Mev.
Sufiicient beryilium (2p/em*) to stop all beta particles was inter-
posed between the counting sample and crystal.
The counting of the gamma
and bren.s-trahlung radiations by-passed the problem of peta scattering, for
experiments have shown that unde: these conditions there is no Signilicant
Variation of observed specific activity with mass thickness of sample.
The
counting etficiency o1 each nuclide was determined by relating the observed
counting rate of a carrie:r-free san ple in the scintillation crystal counters
to that in a 41..-geometry beta counter.
Several detern.inations were made
for each species anc the agreement between cuplicate detern.inations was
excellent.
The nuclide Mo?! was counted with an end-window,
-methane proportions: counter,
continuous-flow
The counting elticiency was determined
indirectly by m.eans of tission counting (described in reference >) and the
accepted thern.al-neutron iigsion yield of Mo”, t. 14%. q
cross sections are summerized in Figs,
agreement with previous data
Oe EB.
¢
&
J.
O,
Nervik,
Blomeke,
J.
Phys.
ry
3
'
Cher.
i and 2 and Tables | ani li. The
1s good.
27.
600 (1922).
7
.
_
Uak Riape Natl. Lab. Report No. ORNL-1783, Nov. 2, 1953.
M, Lindner: and K. N. Osborne,
9001873
The :ormation
Phys,
Rev. 94,
1323 (1954).