Tuesday, February 23, 2021, 08:49
Yesterday a heat shield was washed and when dry it was installed in the EVAP2,
A 1mm thick rhenium wire was held within two copper brackets to pass through a Cu tube with the intention of coating its inside face
Tuesday, February 23, 2021, 08:58 IGP1 = 7.7e-7 Torr
Pressure 5.88e-7 Torr, current rate set to 10 A @ 0.5 A/min
Pressure 6.1e-7 Torr, current rate set to 20 A @ 0.5 A/min
Pressure 8.51e-7 Torr current rate set to 30 A @ 0.5 A/min, temperature corrected 1800 degC (measured with filament pyrometer)
After 10 min the current and voltage are stable and the pressure is going down
Tuesday, February 23, 2021, 16:25
It seems like the wire is touching the tube so the system will be cool down.
Pressure 6.8e-7 Torr current rate set to 0A at -0.1 A/min
Tuesday, February 23, 2021, 17:38
Pressure 6e-7 Torr, TGHT = 23.3 A, 4.854 V, Temp 1788 deg C Omega, 1540 degC filament
current rate set to 0A at 0.2A/min
Wednesday, February 24, 2021, 09:37
Venting EVAP2
Wednesday, February 24, 2021, 16:47
The wire and Cu tube were fix such that the wire's deformation does not lead it to touch the tube, then the assembly was attached again and the EVAP2 was pumped down.
IGP1 = 9.3e-7 Torr, current rate is set to 5 A at 0.5 A/min
Wednesday, February 24, 2021, 17:04
IGP1 = 9e-7 Torr TGHT = 5.175A, 0,749 V
current rate is set to 10 A at 0.5 A/min
Wednesday, February 24, 2021, 17:23
IGP1 = 8.8e-7 Torr, TGHT = 10A, 1.78V
current rate is set to 20 A at 0.5 A/min
Since the wire seemed to be touching the tube, the system was vented.
The tube was shifted and the heat shield installed again, the system was pumped over nigth.
Thursday, February 25, 2021, 09:15
A water leak was performed and no leak was observed
IGP1= 4.95e-7 Torr
Thursday, February 25, 2021, 09:32 The current is increased at 0.5 A/min to 5 A
Thursday, February 25, 2021, 10:00
The current was tapped manually at 0.5 A to 6 A the wire is now glowing dimmly
Current rate set to 10A at .5 A/min
Current rate set to 20 A at 0.5A/min
Current rate set to 30 A at 0.5A/min
Thursday, February 25, 2021, 11:17 IGP1= 5.7e-7 Torr, TGHT=30.5A, 6.718V, filament=1740 degC
voltage and current stable, pressure going down.
Thursday, February 25, 2021, 11:21
Current rate set to 40 A at 0.4 A/min
Thursday, February 25, 2021, 11:53 IGP1 = 5.9e-7 Torr, TGHT = 9.267V, 39.15A, filament = 2060 degC
voltage and current stable, pressure going down.
Current rate set to 50 A @ 0.2A/min
During ramping the voltage reduced a bit and I decided to stop the ramp and reduce the current, the voltage stayed constant but the current started increasing slowly without me inputting it so I decided to ramp down the current at 0.2A/min.
When the current reached 0A the power supplies and the pumps were turned off, after an ~1h when the turbo pump had already stopped, the EVAP2 was vented and open.
The wire sintered to the copper tube confirming that the wire was in contact with the tube during heating.
The Cu tube present a grey metallic coloration indicating a Re coating.
The set up together with the copper heat shield were removed from the |