Curie (Ci)
| Formula / Notation | 1 Ci = 3.7 × 10¹⁰ disintegrations per second (dps) |
|---|---|
| Also Known As | Ci, unit of radioactivity (non-SI), activity unit; SI equivalent: becquerel (Bq) |
What is Curie (Ci)?
The curie (Ci) is a non-SI unit of radioactivity, defined as the amount of a radioactive substance that undergoes 3.7 × 10¹⁰ disintegrations per second (the activity of 1 gram of radium-226). The SI unit is the becquerel (Bq), where 1 Ci = 3.7 × 10¹⁰ Bq. Named after Marie and Pierre Curie, the curie is still used in nuclear medicine and radiation protection.
Formula & Notation
Other Names / Synonyms: Ci, unit of radioactivity (non-SI), activity unit; SI equivalent: becquerel (Bq)
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
The curie (Ci) is a non-SI unit of radioactivity, defined as the amount of a radioactive substance that undergoes 3.7 × 10¹⁰ disintegrations per second (the activity of 1 gram of radium-226). The SI unit is the becquerel (Bq), where 1 Ci = 3.7 × 10¹⁰ Bq. Named after Marie and Pierre Curie, the curie is still used in nuclear medicine and radiation protection.
The curie is still used in medical and industrial radioisotope work (e.g., a PET scan uses millicurie quantities of ¹⁸F-FDG). Activity measurements in curies guide shielding design, handling procedures, and radioactive waste classification for medical and research radioactive sources.
High-activity sources (above about 0.1 mCi unsealed) require Radiation Use Authorisation or equivalent national licensing. Always use ALARA (As Low As Reasonably Achievable) principles. Sealed sources prevent contamination but may emit penetrating gamma radiation requiring lead shielding.
The formula or notation for Curie (Ci) is: 1 Ci = 3.7 × 10¹⁰ disintegrations per second (dps)