Warm-Up and Cool-Down Procedures for the HTF

Step 1:

After inserting the sample start pumping the isolation vacuum with rotary pump and turbo pump.

Step 2:

Install water cooling circuit.

Step 3:

Wait until pressure p < 10-3 mbar at the left instrument then the right instrument for p = 10-8...10-3 mbar will start reading automatically.

Step 4:

Check if all connectors are in the correct positions (2 x 2 XRL-Plug for regulation and sample at ILL-Controller, BNC with adapter-box at the rear side of the ILL-Controller).

Step 5:

Configure the ILL-Controller PID-settings to P=5000, I=1000 and all other parameters to zero.

Step 6:

First, think about what temperature you want to work, because at temperatures lower than 800 K the regulation is slow and you have to increase the temperature very slowly. Up to 600 K is useful to work in the 500 kVA-range, at higher temperatures use the 3500 kVA-range.

Step 7:

Example: to reach 700 K, work with the "Create Temperature-profile-option" of the ILL-Controller. 1st step: ramp to 600 K in 30 min, 2nd step: stay at 600 K for 30 min, 3rd step: ramp to 700 K in 30 min. Step 1 is to prevent overshoots, step 2 gives the controller time to minimize the regulation-difference and step 3 ramps slowly to the target temperature.

Step 8:

For changing the sample, the furnance has to be cooled-down slowly. This may take many hours to temperaures T < 100°C. For a forced cool-down a bottle of Argon gas is supplied. This exchange gas procedure can be used as follows: - Shut down the pumping system and close valves. - Open the hold-position on the NW 50-top-flange, then supply p = 1 atm Argon-gas via the gas inlet at the side of the turbo pump. - Adjust smooth Ar-gas flow through the NW 50-top-flange. Take great care that no air contaminates the vacuum space, i.e. the 100 µm thin Niobiumsheets.