RESUMO
In this work, verification data for 11 HPGe detectors from two different manufacturers and three different intrinsic configurations were analyzed in respect to the stability of both the efficiency and resolution for the 122keV peak from 57Co and the 1332keV peak from 60Co. The results allow a discussion about the stability of these parameters over time (in some cases, almost 15 years), their sensitivity to imminent detector failures and their performance after a failure has been corrected; moreover, the results show a clear correlation between the manufacturer or configuration and the long-term performance of the detector.
RESUMO
The values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn and (68)Zn(n,γ)(69m)Zn reactions were determined experimentally. The irradiations were performed near the core of the IEA-R1 3.5MW nuclear research reactor of the Nuclear and Energy Research Institute - IPEN-CNEN/SP, in São Paulo, Brazil. The results for the neutron field parameters f and α were 49.7(19) and -1.1(31)×10(-3), respectively. The resulting values of k(0) and Q(0) for (64)Zn(n,γ)(65)Zn reaction were 5.63(8)×10(-3) and 1.69(6), respectively, and the corresponding values for (68)Zn(n,γ)(69m)Zn reaction were 4.00(6)×10(-4) and 2.34(4), respectively. These results were compared with the literature.
RESUMO
A neutron irradiator has been assembled at IPEN facilities to perform qualitative-quantitative analysis of many materials using thermal and fast neutrons outside the nuclear reactor premises. To establish the prototype specifications, the neutron flux distribution and the absorbed dose rates were calculated using the MCNP computer code. These theoretical predictions then allow one to discuss the optimum irradiator design and its performance.