| Marla Cervantes wrote: |
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| Marla Cervantes wrote: |
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Tuesday, August 13, 2024, 17:20 Pressure kept increasing when turning the turbo pump on
Tuesday, August 13, 2024, 18:00 Pressure stayed constant when turning the turbo pump on
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Wednesday, August 14, 2024, 10:18
The turbo pump started up normally. System is purging. and tomorrow the target will be heated.
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Wednesday, August 14, 2024, 16:19
A vanadium wire was introduced in a tantalum pouch and snug among the graphite foils of a conditioned graphite target. The V wire was introduced in the Ta pouch to prevent the direct contact of the wire with the carbon and avoid the reaction between them.
As a first approach, the target will be heated to approximately 1377 °C, aiming at the vaporization temperature of the V wire. If the wire does not vaporize, heating with the turbo pump off would be considered to aim at the vanadium's melting point of 1910 °C.
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Vaporization (at 3e-6 Torr)
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In case of outgassing, let the pressure reduce
- Next ramping: 0.5 A/ 2min to 250 A.
Very slow rate to allow thermal equilibrium and temperature measurements. Estimated time 3h.
Thursday, August 15, 2024, 08:21
IGP1 = 5.3e-7 Torr
Good vacuum 3e-5 Torr
Bad vacuum 5e-5 Torr
Initial ramping: 2 A/min to 200 A.
Thursday, August 15, 2024, 09:01. Pressure starting to increase at 74 A
Thursday, August 15, 2024, 09:15. Pressure stabilizing 1.8e-6 Torr. Current 103 A, voltage 1.3 V
Thursday, August 15, 2024, 09:21. Pressure increasing (116 A).
Thursday, August 15, 2024, 09:29 Pressure dropping (Current approx. 120 A)
Thursday, August 15, 2024, 10:54
Started ramping to find a pressure peak corresponding to V vaporization.
IGP1 = 6.4e-7
TGHT = 200 A, 2.9 V, omega 1152 °C
Next ramping: 0.5 A/ 2min to 250 A
Thursday, August 15, 2024, 11:17
Ramp seem to slow. The temperature change was too subtle (according to the omega).
IGP1 = 6.5e-7
TGHT = 205 A, 3.03 V, omega 1157 °C
Next ramping: 1 A/ 2min to 250 A
Thursday, August 15, 2024, 11:32
Ramp changed to 0.5 A/min
Thursday, August 15, 2024, 11:54
Ramp was stopped because the pressure was increasing, suggesting the V vaporization.
IGP1 = 6.9e-7
TGHT = 222 A, 3.3 V
Omega 1210 °C, filament 1280 °C
The difference between pyrometers is negligible, suggesting that the V vaporization temperature at 6e-7 Torr of approx. 1300 °C
Thursday, August 15, 2024, 13:15
IGP1 = 7.9e-7
TGHT = 250 A, 3.8 V
Omega 1289 °C
Thursday, August 15, 2024, 13:16
Ramp set to 0.5 A/min to 300 A
Pressure mini-spike at 13:18
Omega reading 1291 °C
Thursday, August 15, 2024, 14:08
IGP1 = 8.5e-7
TGHT = 270 A, 4.18 V
Omega 1375 °C, filament 1400 °C
The system stayed at those conditions for 15min
Thursday, August 15, 2024, 14:11
Ramping to 0A at 2A/min
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