SABRE South will run autonomously and continuously, with human presence on site only when necessary.

Thus, it is essential that the status of the various system components and of the laboratory environment are monitored, since the correct functioning of the experiment as well as interpretation of the data it produces, depend on its operating as expected and in a stable manner.

Hardware monitoring

Since we are looking for small changes in a signal over extended periods of time, we want the most sensitive parts of the hardware to operate consistently over time. Thus, many parameters associated with the hardware will be monitored, and alerts issued and recorded if and when significant changes in their values are observed.

For example, the operating characteristics of the PMTs (both in the crystal modules and in the veto vessel) vary according to the electrical voltage with which they are supplied. A large enough change in the supply voltage will cause a change in a PMT’s output signal behaviour, and as analysis of the signals depends on a knowledge of how the PMTs behave at a certain (and optimal) supply voltage, such a variation would be most undersirable.

So we will monitor the voltage being supplied to each PMT, and any variation beyond an acceptable limit will result in an alert, with appropriate action being taken automatically or, if needed, in later data analysis.

Other operational parameters, such as nitrogen gas flow, humidity measurements in the gas lines, vessel temperature, even vibrations from mine blasting operations- and more- will be measured and monitored while the experiment is running.

Safety monitoring

Even though SABRE South will run largely unattended, personnel will be on site at various times. Nitrogen, used to keep critical volumes within the detector dry and free of naturally-occurring radioactive radon, is harmful to humans in high concentrations, as are fumes from the veto liquid (LAB) that fills the vessel.

Thus, gas and volatile compound levels in the vessel’s environment will be monitored, as will ambient temperatures within electronics racks, for example, to ensure that the laboratory space is known to be safe for personnel, and that equipment is operating within safe conditions.