Radiation Damage Studies of USn 3
- PDF / 619,811 Bytes
- 8 Pages / 415.8 x 635.4 pts Page_size
- 29 Downloads / 202 Views
427 RADIATION DAMAGE STUDIES OF USn 3 * T. K. MCGUIRE and R. H. HERBER Department of Chemistry, Rutgers University, New Brunswick, N. J. 08903 USA
ABSTRACT Uranium stannide, the most stable intermetallic compound in the Uranium/Sn system, has the Cu 3 Au(LI 2 ) structure, and The magnetic susis paramagnetic to liquid He temperature. ceptibility data are consistent with 5f band states rather Samples of this comthan a localized electronic structure. 235 U enriched, pound have been prepared both with depleted and 9 119 Detailed 11 mSn as well as Sn enriched starting material. M6ssbauer effect studies have been carried out over the tem" Co gamma ray irradiated, therperature range 78TSF. These data are summarized graphically in Fig. 2. The spin fluctuation temperature for the 1000 M rid irradiated sample, however, was observed to be -10 K, a value somewhat reduced from that of 11.9 K reported for an unirradiated specimen [4]. This observation can be understood as arising from the onset of local moment formation due to the breakup of the long range correlation implied by the narrow 5-f band model. This local disorder is not readily detected in the isomer shift parameter extracted from the M6ssbauer experiments since no major change in the 5-S electron density around the tin atom is expected to result from the presence of the radiation damage-caused lattice defects. 119
38
A sample of U Sn 3 containing only depleted 2 U was irradiated (-5 min) 16 to a total nvt of -5xlO at a reactor position where the slow to fast neutron 2 flux ratio was at least 3.6x10 . As noted from Table I the Mbssbauer spectra for this sample showed the same values of the hyperfine interaction parameters, but the temperature dependence of the recoil-free fraction (as reflected in the area measurements) increased by -10% with a concomittant decrease in the lattice temperature to 240 K. On annealing at 8000C for 2 hours the original lattice temperature was re-established in this sample. In view of the results obtained
431
TABLE I Summary of
119
Sn M6ssbauer Effect Data
Radiation Treatment
mm sec 1 19
USn 3 and U
d In Ab
Q.S.(78K)a
I.S.(78K)a
dT
mm sec,
OMc
K"1 3
K
x,0
Sn 3
(a)
none
2.45
1.38
-2.84
250
(b)
60
2.45 2.45 2.45
1.38 1.38 1.38
-2.77 -2.64 -2.84
254 260 251
(c)
~5xlO16 ncm0 anneal 800 C 2 hrs
2.45 2.45
1.38 1.38
-3.12 -2.75
240 255
2.44 none 16 2.40 ncm- 2 ~3.6xi0 0 2.40 anneal 800 C I hr 0 2.43 anneal 800 C 2 hrs aEstimated errors ±0.01 mm sec-I 1 bEstimated errors ±0.09 KCEstimated errors ±8 K
1.37 1.45 1.38 1.35
-2.84 -2.35 -2.80 -2.73
250 276 253 256
Co gamma-200 Mrad -920 Mrad -1000 Mrad 2
UI 19 Sn3
2 35
(d) (e)
1.0 4
9.9 0.8 0.7 0.6 I/* r.. oi
O.5
NroizdR
i=oc
=Temperature (deg K)
n
8.4 Iv iv
0.3 0.2 0.1
F,2 vo67. 2.
T;o prh~
56
22.
7
dgK
0. e
Resistance Ratio determined by the four-probe technique for virgin Fig. 2. 6 (triangles) and OCo gamma irradiated (filled circles) USn 3 .
432 with the 60Co irradiated samples, it is probable that the observed results in this experi
Data Loading...
