A new metal roof has been installed. It has been place as a single, slightly tilted roof made of corrugated plates a bit above the white roof as this was a cheaper option. The building temperature has been more stable then ever over the last summer. However, as this summer has not been as hot as the previous one, it is difficult to say how large a difference the new roof made. Still, when comparing to 2009 the situation has improved drastically. Only in August 16-20 we had a slight increase of 0.3 degree in the FIES room and in the spectrograph.
Some time ago it was found that the ventilator in the front room of the FIES building had stopped working, leading to a strong increase of the temperature of the front room but this was not detected directly. The ventilator has been replaced and temperature alarms have now been added to both the FIES room and the front room, so temperature excursions (in both rooms) can be detected in time and minimised, e.g., through some circulation of the air between the FIES room and the front room, or even with the outside.
One of the side effects of the recurring problems with the vacuum of the FIES detector (see above) and the need to pump it is that the FIES room heats up a lot and takes many hours to return to a stable temperature, affecting the observations in the subsequent night. It was noted that the front room of the FIES building is kept at a temperature which is higher that that of the FIES room. This means that it is difficult for any excess heat in the FIES room to be lost and the set temperature for the front room will be set at, or slightly below the value in the FIES room. As the front room has an active cooling system this would also make it an option to open the doors between the FIES room and the front room to limit the heating of the FIES room when pumping.
Thomas Augusteijn 2012-02-21