Sample annealing

Annealing power supply and controller

For annealing we use one of the DC power supplies, in most of the cases Xantrex XKW20-50 {20 V, 50 A maximum). The maximum needed currents usually do not reach 15 A, depending on the sample holder and mounting used.

For temperature reading and control we have a self-made temperature controller equipped with Eurotherm 3508 unit. Its internal parameters can be easily set using the iTools software provided by the manufacturer. The scope is to measure the sample temperature (by reading the voltage of the K-type thermocouple) and regulate the annealing power supply in order to reach and keep the desired temperature.

The controlled output knob has 3 positions:
  • nothing: in this case there is no regulation loop between the controller and the power supply. The power supply is in local mode and its output depends on its volpage and current knobs setting;
  • current: the power supply is in remote mode. The controller is setting the power supply output current (up to the output limit set by the knob) in order to reach and keep the temperature set by arrow buttons. The current knob on the power supply is inactive while the voltage knob is setting the maximum voltage limit.
  • voltage: the power supply is in remote mode. The controller is setting the power supply output voltage (up to the output limit set by the knob) in order to reach and keep the temperature set by arrow buttons. The voltage knob on the power supply is inactive while the current knob is setting the maximum current limit. On our sample holders we do not use this position.
The switch on the right side lets you decide if the programmed value is the temperature (if the thermocouple is installed) or the output current/voltage (if there is no thermocouple installed on the sample holder which is extremely rare case}.
















Computer interface

The Eurotherm unito can be also remotely controlled from the MSB-STATION computer via the iTools software.

The temperature can be graphically monitored by the OPC Scope feature refreshed once per second. The data can be logged into a file.

Unit selection (K/°C)

  1. Open the Eurotherm iTools software on the MSB-STATION computer.
  2. Connect the software to the Eurotherm controller by Scan - OK and wait until the parameters are synchronized (about 1 minute).
  3. In the parameter tree look for Instrument - Options - Units, select Kelvin or DegC and confirm.



Short annealing (flash)

  1. Move the sample to a safe position (not in front of the electron analyzer).
  2. Check that the current knob on the power supply is set to zero (fully counterclockwise).
  3. Set the temperature controller controlled output knob to nothing.
  4. Slowly increase the current limit by rotating the current knob on the power supply. Observe the current and voltage increase on the power supply, temperature increase on the temperature controller and/or heater glowing through the chamber viewport. Increase also the voltage limit by the corresponding knob on the power supply if voltage starts limiting the output power
  5. When you reach the desired temperature decrease the current limit by the corresponding knob on the power supply.

Long annealing (keeping at temperature)

  1. Move the sample to a safe position (not in front of the electron analyzer).
  2. Check that the output limit knob on the temperature controller is set to zero (fully counterclockwise).
  3. Set the temperature controller controlled output knob to current.
  4. Use the up/down arrow buttons on the temperature controller to set the desired temperature.
  5. Slowly increase the current limit by rotating the output limit knob on the temperature controller. Observe the current and voltage increase on the power supply, temperature increase on the temperature controller and/or heater glowing through the chamber viewport. Increase also the voltage limit by the corresponding knob on the power supply if voltage starts limiting the output power.
  6. When the desired temperature is reached the controller starts limiting the current in order to maintain the temperature. Oscillations around the set value may appear.
  7. Start the timer.
  8. After a while, when stabilized, write down the voltage and the current used. You may use these parameteres for setting of the limits during another annealing at the same temperature in the future.
  9. When the time is over set the output limit knob on the temperature controller to zero (fully counterclockwise).

Programmed annealing

More complicated annealing procedure can be programmed using the Programmer feature of the iTools software, e.g. a temperature ramp 5 K/s up to 600 K, dwell 10 min, cooling below 400 K and repeating such cycle 3 times. Once programmed, use the Run/Hold button on the Eurotherm unit for:
  • start (double short press) - the display will show RUN
  • pause or continue (single short press) - the display will show HOLD
  • stop, reset and exit the program (long press) - the display will go back to standard view for keeping the temperature set by arrow buttons.
The output limit knob on the annealing controller must be set to a correct value in order to be able to reach the programmed temperature.
Last Updated on Tuesday, 21 November 2017 10:40