ELOG CARME

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

CARME

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Mon Aug 14 09:22:56 2023

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14/08/23

Temperature in the baking volume is ~ 42 C and the pressure is 4.6e-8 mbar. Current heaters set point is 135 C. This will now be increased to 200 C to start increasing the baking temperature more significantly.

Some issues with the interaction chamber heaters were noticed this morning. This included very large increases in temperature despite only small increases in the setpoint. When this occurred the heater channels were simply turned off. Channel 3 on the interaction chamber (main jacket on the centre of the chamber was also observed to smoke slightly). This smoking was seen when the temperature for channel 3 was ~ 70 C.&nbsp;

Changing the settings of these heaters appears to have resolved most of the issues. The heaters now ramp in a much more controlled manner and remain roughly constant at the setpoint value.&nbsp; The interaction chamber heaters were all increased to 70 C with no issues observed. Channel 3 also appears OK.

The CARME heaters settings have also been changed and now the heaters temperature and power output do not oscillate as observed previously. Power output per heater is approximately 15 % of total at heater temperatures of 220 C, and this value remains consistent over time. The temperatures inside the baking volume are now ~ 50 C with the pressure equal to 7e-8 mbar. Heating has not been the priority while investigating the issues observed with the heaters.

As a precaution CARME will now be maintained at the 50C level. The interaction chamber and e-target temperatures have been set to 50 C also. If the system remains stable overnight we will again begin increasing the temperature in the morning.

15/08/23

Temperatures across the whole of YR09 have remained very stable overnight. Temperature of CARME has increased slightly and is now ~ 55 C. Pressure is ~1e-7 mbar. A brief lincrease in pressure was observed yesterday due to the de-gassing of the GSI ion pump on CARME. Plan is to now increase the temperatures of YR09 to the 100 C level&nbsp;

Temperature is ~ 70 C. Heating is slower than expected as I am aiming to minimise thermal gradients across the chamber, which was previously done automatically by our baking code. Current heater temperature values are ~ 320 C. I have increased the temperatures across YR09 to 70 C to match carme . Pressure in CARME is 2.1e-7 mbar.

16/08/23&nbsp;

The temperatures of the CARME heaters were further increased to ~ 420 C to further increase the chamber temperature. Average chamber temperatures of ~93C achieved. Heater temperatures can be pushed to 450C which should allow us to achieve 100 C. Will allow chamber to equillibriate as temperature gradient between top and bottom is quite large.

17/08/23&nbsp;&nbsp;

Baking will be unsupervised over the weekend. To remain safe, the berylium window and the interaction chamber will be kept at a temperature&nbsp;of 50C. Carme will be reduced to ~60C during this period.

Attached are plots for the bakeout period concerning this week.&nbsp;&nbsp;

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