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Daily Reports

June 8, (Thursday)

12h: Start of the observations. The turbo pump switched off several times so we decided to start the observations without it. The plan of the day is to start the observations on a planet (Mars) to characterize the instrumental polarization (i.e intensity to polarization leakage effect). The strategy for the beginning of the observations is also to characterize the noise due to the HWP modulation which is peaked at harmonics of the HWP rotation frequency. Running faster with the HWP means that we can have access to faster scanning speeds of the telescope but we could have a noise not trivial to subtract from the timelines. In order to find a compromise between this two issues we decided to make tests doing observations with different parameters as follows:

* The turbo pump has been switched on at 09h35 UT set at 30%

* We measured the noise with the window on the cryostat and a base temperature of 265mK to check if the pulse tube is visible. It does not seem to generate a noise that can bother us during the observations. However, the 1/f noise is large. We hope that after switching on the turbo molecular pump this contribution will be decreased.

Array 1

Array 3

Array 2

June 7, (Wednesday)

* We performed the optical alignment check with Santiago. The alignment is good so we did not change the position of the mirrors. We also checked the alignment of the HWP.

* The electronics of the HWP wheel is working nominally. We tested different speeds without problems.

* Juan Penalver tested the temperature control of the cabin and setting the temperature at 12°C for few hours. Tomorrow before starting the observation we will switch on the turbo pump after setting the temperature of the cabin to 10 or 12°C.

June 6, (Tuesday)

* Aina, Alessia, Nicolas and Andrea arrived at the telescope. The idea is to prepare carefully the observations starting on Thursday since the last observation in polarisation performed with NIKA2 was more than a year ago. Nicolas Aina and Alessia worked on the polarisation pipeline, Andrea set up the polarisation facilities and check their proper operation.

* The temperature of the mixing chamber is about 265 mK without using the turbo molecular pump. The pressure on P101 is slowly increasing showing that the trap is saturating. It does not seems to be a big problem because the slope is about 40mbar/day meaning that probably we can observe until next tuesday without switching the trap.