Physical Characteristics

• Half-life: 2.70 years
• Emissions: Principal emissions are a 6 keV x-ray and 5.2 keV [average] Auger electrons.
• Electron Maximum Range: 0.15 cm in air; 0.0 cm in tissue

Dose Rate and Shielding

• Dose rate at 10 cm: negligible
• Dose rate to basal cells from skin contamination of 1 µCi/cm²: 59 mrem/hr
• Shielding: None needed, when used in millicurie quantities, under normal laboratory operations.
• Annual Limit on Intake (ALI): 2,000 microcuries via inhalation, and 9,000 microcuries via ingestion. The intake of one ALI will produce a dose of 5 rem.

Detection

Liquid scintillation counting is the preferred method for detecting Fe-55 contamination, although a low energy sodium iodide crystal scintillation detector will also detect Fe-55 with a lower efficiency. The regular use of wipe testing, using a liquid scintillation counter, is the only way to insure that the work space does not contain low-level removable contamination.

Precautions

External radiation from Fe-55 is low energy and does not normally present an external exposure hazard. Low-level Fe-55 contamination is not readily detected with a survey meter, and special precautions are needed to keep the work environment clean. The regular use of wipe testing, using a liquid scintillation counter, is the only way to insure that your work space does not contain low-level removable contamination.

Radiation Monitoring Requirements: Radiation monitoring badges are not required for Fe-55 users.

Waste Disposal

• Solid Wastes/Liquid Scintillation Wastes:  through the Off-Site Radioactive Waste Disposal Program
• Liquid Wastes: through the Sewer Disposal Program. The laboratory disposal limit for Fe-55 is 3 mCi per month.