RESUMEN
Simulations of internal amplification processes in high purity germanium (HPGe) detectors for gamma radiation are presented. The Synopsys Sentaurus Technology Computer-Aided Design (TCAD) package was employed to study conditions favourable to charge multiplication within volume of the detector. The physics model was developed, and validated where possible against known results from existing literature. The model was then applied to a new detector and a systematic study of the measurable parameters influencing charge collection and electric field profile was performed. Evidence of the internal amplification in the developed HPGe detector model was demonstrated at 4 kV bias voltage with anode diameter below 100 µm, corresponding to 16 kV/cm electric field and when an additional dopant with concentrations >5×1010cm-3 under the anode implanted. These effects were also simulated and observed in silicon detectors, giving additional confidence in the validity of the findings for germanium, presented in this work.
RESUMEN
The results of the development and research of the characteristics of a new gamma activation analysis (GAA) facility, created for the quantitative analysis of gold-bearing ores in real conditions of a gold-mining enterprise, are presented. The values of the gold detection limit (3σ), measured from the spectra of certified reference samples with an ultralow background level, were 0.025-0.028 ppm with a single irradiation. In this case, the root-mean-square measurement error for a gold concentration of 1 ppm did not exceed 8% and 4% for a concentration of 10 ppm. The GAA facility provides the analysis of coarse-ground samples (1-3 mm) with a capacity of at least 65 samples per hour.
RESUMEN
The results of measuring the gamma background radiation in Lab 5 of the underground facility in the Pyhäsalmi Mine at a depth of 1410 m are presented. The background integral count rate per kg of germanium of the HPGe-detector was 0.028 s-1 × kg-1. After purging the measuring chamber with nitrogen gas at a rate of 0.15 L/h the count rate was reduced to 0.021 s-1 × kg-1.
RESUMEN
Herein, we measured the natural gamma-ray background in a new underground laboratory facility within Pyhäsalmi Mine in Finland at a depth of 1430â¯m (~4100â¯m.w.e). The radionuclide compositions of the rocks in the walls along with the shotcrete on the walls were investigated. The specific activities of the natural radionuclides in these materials were calculated. The measured spectra of the natural gamma-ray background and calculated minimal detected activities of several natural and artificial radionuclides are presented.