Ionising radiations: precautions for industrial users.

  • Great Britain. Department of Employment and Productivity
Date:
1969
Catalogue details

Licence: Public Domain Mark

Credit: Ionising radiations: precautions for industrial users. Source: Wellcome Collection.

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    course more important with gamma emitters such as sources used for radiography or radium activated luminous compound, than for beta or alpha emitters. Stores containing sources liable to emit a radioactive gas, e.g. radium, tritium, krypton—85 and iodine—131 should be mechanically ventilated to the open air. The discharge of the ventilation pipe should be in a position such that the gas does not enter the air of any workroom. The ventilation may have to run continuously in stores containing unsealed radioactive sources if there is a real risk of gas being evolved but where this is not necessary it should be run for not less than two minutes before the store is opened. The interior of a store, particularly for unsealed radioactive sources, should be capable of being easily de-contaminated and it should be checked regularly to determine whether or not it is contaminated. Where a number of small unsealed radioactive sources is stored, it is suggested that they be placed on a tray which can contain any leakage or spillage. Sources should be removed from stores only by or under the super- vision of an authorised person. All stores must be secured or locked so as to prevent unauthorised persons from gaining access to the sources. SPECIAL REQUIREMENTS OF THE IONISING RADIATIONS (SEALED SOURCES) REGULATIONS 1969 MONITORING The two main types of monitor available are those using ionisation chambers and those using geiger tubes. Usually they are designed to be held in the hand and have scales marked in units of dose rate. Although certain monitors can be used to measure gamma, X- and beta radiation the scale reading will not necessarily give the dose rate directly for all of these radiations, and correction factors may have to be applied. These will be determined when the instrument is calibrated. Monitors for the measurement of neutron dose rates are also available. The scale ranges should be such that dose rates of 0-75 mrem/h and 2:5 mrem/h can be clearly seen. Ionisation chamber monitors will give a direct reading only if the radiation field fills the chamber and, therefore, they may be inap- propriate for narrow beams of radiation such as those which can
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