Calibration of Sample Heater for UHV Applications

1
Calibration of Sample Heater for UHV
Applications

• Name John Magulick
• Level Junior
• Number of Semesters Participated 3
• Date of Submission 09/09/04
• Advisor Dr. Schlaf
• Department Electrical Engineering

2
Construction of Heater

• Built on resistive heating design
• Copper stage with integrated, insulated Ta wire
  passages
• Attached thermocouple
• Connected to electrical feedthrough, remote power
  supply and parallel/integral/differential (PID)
  controller
• Schematic shown at left

3
Heater Calibration

• The heater was first run at 3A and the
  temperature of the heater (TH), under the
  substrate (TU), and over the substrate (TO) was
  recorded every minute for 100 minutes.
• The top graph shows the temperatures recorded,
  while the bottom graph shows the fits of each
  curve.
• TH stabilized at 101C, TU and TO stabilized at
  65C.
• Fluctuations in TH may be due to controls within
  remote power supply
• Ratio of TO to TH is .6534

4
Heater Calibration

• The same experiment was run at 4A
• The top graph shows the temperatures recorded,
  while the bottom graph shows the fits of each
  curve.
• Temperatures were slightly rising but the final
  TH was 194.3C, TU was 127.2C and TO was
  130.7C.
• There were less fluctuations at 4A
• Ratio of TO to TH is .6701
• The similar ratios may indicate a similar
  relationship of TO to TH at other temperatures
  with this heater
• TO and TU remained similar throughout the
  experiment which suggests uniform heat
  distribution
• Further experiments at lower temperatures are
  still needed