Final answer:
The Thermoluminescent dosimeter is the type of radiation monitor that contains aluminum oxide. This device uses the radiation-stored energy in aluminum oxide, released as light during heating, to measure radiation exposure.
Step-by-step explanation:
The question asks which type of radiation monitor contains aluminum oxide. Out of the options provided (Geiger-Muller counter, Scintillation counter, Ionization chamber, and Thermoluminescent dosimeter), the correct answer is the Thermoluminescent dosimeter.
Thermoluminescent dosimeters (TLDs) use various crystalline materials, including aluminum oxide, to measure ionizing radiation exposure. When the material within the TLD is exposed to radiation, it stores energy. This energy is later released in the form of light when the material is heated, which is measured to determine the amount of radiation exposure.
Other devices mentioned, such as Geiger-Muller counters, detect ionization in gas-filled tubes. Scintillation counters use materials that emit light when hit by radiation, but generally do not contain aluminum oxide. Ionization chambers measure the charge of the ions produced by radiation passing through a gas, and also do not contain aluminum oxide.