under construction :)
Here we will collect issues that might arise during long-term detector operation and propose simple remedies to solve most problems.
Scintillation detectors used in ambient conditions are usually housed in a light-tight casing (additionally to the reflective coatings used for improving light collection). In our case, to cut costs, we are using pond liner and black tape. Small light-leaks are usually found coincidentally by the detector being exposed to a flashlight beam or by direct sunlight. The latter leaves a periodic time pattern in some of the log data. For example, your detector is exposed to direct sunlight for the first 30 minutes after sunrise. Then you'll likely find that your count rate will decrease while your bias voltage drops and the current increases. This can easily be prevented by covering the detector with a black cloth or locating it in a location without direct sunlight exposure.
For our earlier detector models (serial numbers < X), detaching tape is a known issue. We are using quite expensive 3M tape (50 EUR / 10 meters), which, in principle, can also be used in a high-humidity environment. The problem lies within the fact that, despite all taken precautions, the optical grease used for coupling the photo-detector with the scintillator tends to seep into the detector and might lead to the tape detaching close to the photodetector. It's tough to get rid of the grease from the surfaces, and even when using ethanol, one is never able to remove all residue completely. In newer detector versions (serial numbers > X), we use optical glue that permanently glues the photo-detector to the scintillator. In case some tape is detaching from your detector, especially in the vicinity of the photosensor, please try to attach it again and use some additional tape if needed. "Viel hilft viel": the more, the better.