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Electron Microscopy Sciences

Technical Data Sheets

Alpha-Numeric Oven Tray

EMS Catalog #97035-01

The Alpha-numeric Oven Tray is used for calibrating and standardizing your microwave oven.


Mapping areas of maximum microwave power in your oven.


  1. Make sure the Alpha-Numeric Grid is in the left, rear corner of the microwave oven.
  2. Warm up the oven electronics by placing a beaker filled with 250 ml of water in the right, rear corner of the oven. Program the oven to irradiate for 2 minutes at 100% power. Press start. Begin the next step within 2 minutes after the oven shuts off, or you must repeat this step.
  3. Place the Neon-Bulb-Array (Cat. #97036-01) on top of the Alpha-numeric Grid. Align it so the corner with the large dot is at the left rear corner of the Alpha-Numeric Grid and oven.
  4. Replace the heated water in the beaker with your customized, room-temperature water*. Place the beaker in the right rear corner of the microwave oven.
  5. Be sure that all of the surfaces in the microwave oven are dry. It is important to blot spills with paper towel immediately.
  6. Program the oven to irradiate for 30 seconds at 100% power. Press start.
  7. Observe the neon bulbs. Look for clusters of three to four bulbs that are continuously lit. Make the Alpha-Numeric Grid coordinates corresponding to the three bulbs on the diagram of your Neon Bulb-Array.
  8. Let the bulbs cool for 2 minutes.
  9. Repeat steps 2 through 8 three times to be sure you have the right coordinates for maximum power. For each repetition, use a fresh, room-temperature customized* water load.
  10. Record the Alpha-Numeric Grid coordinates for maximum microwave power.
  11. Remove the Neon-Bulb-Array.


Clusters of three to four bulbs that light up steadily will reveal areas of maximum power approximately 5x5 cm square. These areas, which are marked on the diagram of your Neon-Bulb-Array, will receive maximum power when the microwave oven contains its customized water load.


* Customized Water Load is the maximum water load volume that absorbs most , but not all, of the microwave energy that is heating the inside of the microwave oven which controls the amount of energy to the sample.

For details on how to determine the volume of the water load needed for your microwave oven, please refer to: The Microwave Tool Book - A Practical Guide for Microscopists. Login and Dvorak. Beth Isreal Hospital Boston . ISBN 0-9642675-0-0.

Online Ordering

Alpha-Numeric Oven Tray is available online from the EMS Catalog. For ordering or product information, click here.