Bore hole probe

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Project description

In this project, radioactivity measurements will be performed in several Boreholes around Bergen region. Boreholes are drilled to provide thermal energy coming from hot underground water that is used to heat buildings. The goal of this project is to perform radioactivity measurements as a function of depth in Boreholes. The radioactivity will be monitored by means of a Geiger-Muller (GM) counter (Figure 1 shows the details of the detector to be utilized in this work). This is a gas-filled, cylindrical radiation counter that has found many industrial applications such as level gauges in the oil and gas industry. This is primarily due to the GM counter's robustness, low cost, simple read-out electronics and insensitivity to pressure and temperature changes in the environment. GM counters are also relatively insensitive to mechanical vibrations. These properties of the counter make it a good alternative for the pertinent measurements, as these will be carried out at varying depths in the boreholes. The counter will need to be lowered down as deep as 300 m. In order to carry out measurements across very long cables, there will be a need for a special detector data acquisition (DAQ) system, which includes electronic micro-controller, amplifier, pulse inverter, and hardware control programming. The project will start by designing the aforementioned DAQ system. Following a successful design, the system will be fabricated/built and tested. Once this is ready one can start measuring activities in Boreholes around the Bergen area.

Students who are interested in radiation detection and detector readout electronics are very welcome.

Supervisors

Prof. Dr. Bjarne Stugu

Dr. Ilker Meric

Dr. Enver Alagoz


GM counter

Figure 1. Cross-sectional view of the ZP1200 GM counter. All dimensions are given in mm.
Figure 2. ZP1200 circuitry

The GM counter for this project is ZP1200. This is a Na-Halogen filled GM with a 446 stainless steel cathode. Its effective length is 38.1 mm. Operates in the temperature range from -40°C to +75°C. It has a max starting voltage of 325 V, an operating voltage range from 450 V to 650 V, recommended operating voltage of 500 V and a max slope of the plateau 6%/100V. The dead time of the detector is minimum 90 µs. It weighs 8 g.