Speaker
Description
The development of a Nuclear Orientation (NO) thermometer system for use at the University of Cape Town is essential to address the significant challenge in the accurate measurements at ultra-low temperatures (down to 8mK). A $^{60}CoCo(hcp)$ gamma-ray thermometry source was irradiated using the NECSA SAFARI-1 research reactor for 6 minutes and a preliminary activity value of 1.3 MBq was achieved. The activity of this source has been validated using an absolute gamma-ray coincidence technique and verified using a well-type ionizing chamber. Preliminary temperature measurements were taken by placing the $^{60}Co$ source within the University of Cape Town Department of Physics dilution refrigerator using a vertical sample holder and measuring the anisotropy of the radiation at a 90 ⁰ angle using a Sodium Iodide (NaI) scintillation detector. These results were promising, but inconclusive, prompting a second set of measurements. Modifications were made to the experimental set up by re-designing the sample holder to hold the source horizontally and take measurements at 0 ⁰ angle along the c-axis. A Lanthanum Bromide $(LaBr_3)$ scintillation detector was also used to measure the radiation at temperatures ranging from 10 mK to 100 mK. These experimental improvements provided more accurate and conclusive results.
Level for award;(Hons, MSc, PhD, N/A)?
MSc
| Apply to be considered for a student ; award (Yes / No)? | Yes |
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