Visit students from Goes Lyceum
Thursday the 5th of March, students from the Lyceum school in Goes visited the University of Antwerp to learn more about studying physics and more specifically about how experiments are done in the scientific world. The main objective of the workshop was to do tests on the HACORD detector. By working with a real experiment, not designed specifically to explain a physical phenomenon but to do real measurements, the students got a good impression on what a 'real' experiment looks like.
The students had to do all sorts of tests on the detector, including pressure tests, temperature tests and comparisons to other similar devices.
The pressure test was done by placing the detector under a glass bell jar and by gradually sucking out the air to lower the pressure to around -0.7 atm. The pressure inside the glass bell jar was monitored by using an analogue manometer. Eventually, the readout values had to be plotted vs. the values measured by the pressure sensor on the experiment itself to see how they are calibrated.
The students also had to perform temperature tests, to see how the experiment behaves at very low temperatures. The experiment was cooled down to approximately -20°C by using liquid nitrogen. This way, it could be verified that the experiment is sturdy enough to stand these low temperatures (even though there was some condensation on the PCB from the surrounding air).
Another aspect of the workshop was to compare the detection of cosmic rays by the HACORD detector with the detection of cosmic rays by a commercial Geiger counter by plotting the HACORD measurements on a graph vs. the values that appeared on the screen of the commercial Geiger counter. The goal was to show the students that the sensitivity of different sensors can vary a lot and that this should be taken into account when doing experiments. To simulate more 'cosmic rays', a strontium source was being used, which is a beta emitter.
Because of the use of a dangerous radioactive source, the students also learnt about the safety precautions that have to be followed when doing such an experiment. For example, it was forbidden to get on eye level with the source or to look directy into the opening of the source. It was also not allowed to eat or drink anything in the lab. In addition, the source had to be placed on a thick piece of lead when it was not being used, to keep the radiation on the students working on the experiment to a minimum.
As a conclusion, the students learnt about the testing of components, calibration, safety and also doing measurements. After the workshop, it was expected from the students that they would further process the data and write a report that should be of a publishable quality. The aim was to let them work with professional scientific software. They got an introduction to GNUplot and were given some scripts they could use for doing the data analysis. These scripts contained a lot of information to make it easier for them to understand and to use the software for their own measurements.
We hope that, for the students of the Goes Lyceum, this was a very interesting and - more importantly - fun experience and that they learned a lot.
