Radiation Protection Glossary

A radiation protection glossary for Radiation Protection Supervisors (RPS), Radiation Protection Advisers (RPA) and anyone else interesting in radiation safety terms and definitions. The glossary is a mixture of health physics , phrases related to radiation protection legislation, transport, practical safety, technical terms and similar.

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HASS Sources

Published: Oct 12, 2018

    Tags:
  • HASS source
  • High Activity Sealed Source
  • Radiation Hazard
  • High dose rates
  • High Radiation Exposure
  • Radiation security threat
  • HASS thresholds

Radioactive HASS sources (High Activity Sealed source) require extensive control measures due to the significant radiation hazards that may exist should the source become uncontrolled (e.g. unshielded). The aim is to ensure that adequate controls are in place throughout the entire life cycle of the source from production, purchase, use, storage and eventual disposal. These controls are designed to ensure that sources cannot be lost, that the threat of theft is minimised, and that sources can not be purchased unless there is a disposal route and resources available to make the disposal when required.

A HASS source ceases to become HASS when the radioactivity is below the HASS threshold. Examples of HASS source activity are as follows.

  • Am-241 (60 GBq)
  • Cs-137 (100 GBq)
  • Cf-252 (20 GBq)
  • Co-60 (30 GBq)
  • Ir-192 (80 GBq)
  • Ra-226 (40 GBq)
  • Se-75 (200 GBq)

The units above are in becquerels (i.e. 109 Bq).

Further Ionactive resource on HASS sources can be found at the following links:

High Activity Sealed Sources (HASS) Radioactivity Thresholds

Dose Rates from HASS (High Activity Sealed Sources)

The definition of 'safe' is not strictly an engineering term; it's a societal term. Does it mean absolutely no loss of life? Does it mean absolutely no contamination with radiation? What exactly does 'safe' mean?

– Henry Petroski -