SPUD - South Pole Upgrade DASI, is my new experiment. It is the follow up of my last one, again in MAPO on the DASI mount. To accommodate 3 cryostats, the existing drum had to be replaced with
a new one, also the whole drive system, computers etc. underwent a major upgrade. The cryostats are a closed system this time, i.e. we don't have to refill cryogenics every day. They are cooled
by pulse tubes to about 4 K and a "fridge" gets them down to 250mK. But now we have to cool the pulse tube compressors and we had to reactivate the DASI glycol loop, which was challenging.
The first receiver is assembled and tested in the lab at the moment and we soon gonna mount it on the telescope.
