Low-temperature studies of recoil reactions

Abstract

LOM-IUMWTOM STUDIES Of RBOOIL R1ACTI OHS* Slobodan ke R. V el Jk o rie * * and da roan H e r b o ttle C h a n io tr y D opertnent I r o o d w m N a tio n a l L a b o ra to ry U p te e, L one la la o d , New York A b o tract Hm S a iia rd-C b a ln o ra ra a c tio n boa boon in v e r t i g d e d in o m d b t r o f c ry e ta l l i n e compounds w ith a a p o d a l e f f o r t b e in g n o d e t o no la t a i n tb o tn a a p a ra tu ra a t lo o v a lu e s d u rin g t o d a r d o n t , o t o r ago and diaeo!.ut i o n. guidance o f r a p id t h o m a l aim aalin g a t ir a te f t i r a t j r e a i n found. Ih a d a ta ow ggoot t h a t i t w ill f o r t h i a ra aaon bo e x tr o n o ly d i f f i c u l t t o o b t a i n r e l i a b l e i n f o r n e t i o a on tb o t r u e y ia ld a o f th e h o t-a t on procooaaa which o c c u r r e d b e fo re any a n n e a lin g took p la n e .

Low Temperature Thermal Annealing in Fast Neutron-Irradiated Potassium Permanganate

“…The decrease in retention above 180 ° has been noted by others [8,11] and probably results from local thermal decomposition of the crystal in the vicinity of the nuclear transformations. The retention observed by us at -196 ° (-8°/ 0 ) is in fair agreement with the 5.1 °/ 0 reported for 6e Mn by VELJKOVIC and HARBOTTLE [3,6]. According to the "MADDOCK Rule" [12], straight lines result if the changes in retention upon annealing at various temperatures are plotted against the reciprocal of the absolute temperature.…”

“…Despite the work of VELJKOVIC and HABBOTTLE [3,6] and of others [7,8] involving low temperature irradiations of KMn0 4 , there has been no systematic investigation which would detect the possible existence of other steps in the low temperature part of the annealing curve. We have undertaken such a study for 64 Mn produced in KMn0 4 by the 65 Mn(n,2n) M Mn reaction at liquid nitrogen temperature.…”

“…In crystals irradiated at room temperature, annealed at higher temperatures, and dissolved at room temperature, the retention remains at about 20°/ 0 until the annealing temperature reaches about 70 But VELJKOVIC and HABBOTTLE [3,6] have shown that the retention of 6e Mn as permanganate is very much lower β Radiochimica Acta, Band 22, Heft 1/2 if the KMn0 4 is irradiated and stored at -196 ° and dissolved (in acetone) at -95…”

“…In several systems, including K 2 Cr0 4 [2], KBrO a [la, 3,4] and C 2 Br e [5], the temperature dependence of the annealing permits the processes to be resolved into groups each having a distinct activation energy. This state-of-affairs is revealed by "steps" in the plots of retention in the parent form versus temperature for isochronal anneals.…”

Chemical Effects of Nuclear Transformations in Mixed Crystals 8. Thermal Annealing of 186Re in Neutron Irradiated K2ReBr6-K2SnCl6 Mixed Crystals. I

“…In addition the extrapolated results for vanishing K 2 ReBr 6 content from the former work are included in which only mixed crystals with 1 until 28 mol-% K 2 ReBr 6 were examined [27,41 ]. As can be seen from Table 1 It is known that the retention decreases and the yield increases if dissolution of irradiated targets is performed at lower temperature [44]. In some experiments irradiated mixed crystals were dissolved in 3.5 M H,S0 4 at -30°C.…”