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| The 4K is slower compared to the last Grenoble runs. We have checked the PT compressor pressures and they're OK: high=28.5bar; low=10bar. So we haven't lost helium. At 18h20 we reduce a bit the preref flux (from 1000mbar to 900mbar) to see if the 4K was affected (it shouldn't in principle). | The 4K is slower compared to the last Grenoble runs. We have checked the PT compressor pressures and they're OK: high=28.5bar; low=10bar. So we haven't lost helium. At 18h20 we reduce a bit the preref flux (from 1000mbar to 900mbar) to see if the 4K was affected (it shouldn't in principle). Actually YES, the 4K accelerated and the still slowed down a bit. |
Go to preparation run daily reports
Preparation visit before Run6
Daily Reports
Mon 03/06
Left Grenoble by car in the morning. Andrea, Alain, Alessandro. Reached the telescope at 20h30.
Tue 04/06
During the maintenance craned up again NIKA, installed. Warm impedance test: 20mbar/min at 3 bar
Start cooling down at 13h30.
Test with VNA at 300K:
Figures: VNA scans at 300K (0-8GHz). Left: 1mm array; right: 2mm array.
Installed the electronics with the cables.
Figures: NIKA installed again.
We have also visited the back of the antenna and in particular the receivers cabin roof for possible installation of the NIKA-2 electronics. Space available is 80cm (H) x 200cm (Width) x 100cm (Depth). In order to have enough space to work, we will use a maximum depth of 60cm. The total COAX cables length if this solution is chosen is 6-8m.
Figures: Cabin top, possible place for NIKA-2 electronics.
Cryostat temperatures at 18h (T0 + 4h30). 4K: 255K (14K/h slope); Still: 235K (25K/h slope); R_BM: 1011 Ohm.
The 4K is slower compared to the last Grenoble runs. We have checked the PT compressor pressures and they're OK: high=28.5bar; low=10bar. So we haven't lost helium. At 18h20 we reduce a bit the preref flux (from 1000mbar to 900mbar) to see if the 4K was affected (it shouldn't in principle). Actually YES, the 4K accelerated and the still slowed down a bit.