Notes for pregnant users
21 Nov 2011



Information for pregnant and breast-feeding users at ISIS




​Letting us know that you are pregnant or breast-feeding

If you are coming to ISIS to do and experiment and you are pregnant or breast-feeding please contact the ISIS Dosimetry Office ( and let us know. Although the radiation levels in our experiment halls are very low it is important that we know so that we can plan for your visit and carry out a risk assessment with your local contact that will cover all aspects of your time here at ISIS.​

Information for pregnant and breast-feeding users at ISIS

If you are pregnant or breastfeeding you may well have questions or concerns about your visit to ISIS. We have carried out a risk assessment for new and expectant mothers, which covers the hazards we would expect to be present on a typical experiment, however if you have specific concerns relating to your experiment, we will be happy to address them.

Work with radiation

ISIS is a radiation employer, and the experimental halls and beam lines are controlled radiation areas. The Ionising Radiations Regulations 1999 (IRR99) include specific requirements for the protection of new and expectant mothers working in radiation areas.  In addition to following the working instructions for all users given in the R55 and R80 Local Rules, we specify a small number of additional precautions, which should ensure that the dose to you and your child are kept as low as reasonably practicable.

Working with radiation – additional precautions for expectant users

IRR99 specifies that once a pregnancy has been declared, the radiation dose to the foetus as a result of the expectant user’s work with radiation must not exceed 1 mSv. This is the same as the annual dose limit for people who are not classified radiation workers, including most ISIS users. Annual doses actually received by ISIS users are much lower than this. We issue personal radiation dosimeters to all users and the vast majority receive no more than 10 µSv per visit – this is the lowest dose which the dosimeters can detect.

We also put monthly dosimeters in all instrument cabins, and results from these show that the average dose rate in any cabin during a user cycle is less than 0.5 µSv h-1.

From these results, we can be confident that someone entering the experimental halls and working in the cabin for the duration of an experiment will not receive a significant dose.

However, it is more difficult to ensure that doses are kept this low for someone who is handling active samples. For this reason, we do not normally allow pregnant users to work directly with radioactive material, and we specify in the risk assessment that your work in the experimental halls should be restricted to the cabins and walkways.

Working with radiation – additional precautions for breast-feeding users

If you are breast-feeding, the only additional precaution required for your work at ISIS is that you should not work with unsealed radioactive sources (for example, active powder samples), in order to limit the risk of accidentally inhaling or ingesting radioactive material.

Additional information

If you have any questions or would like further information, please contact the ISIS Dosimetry Office (

​The HSE publish a booklet covering work with radiation for new and expectant people​​​, which is available electronically here, or as a paper copy from ​the Health Physics office.

Please take the User Safety Test which can be found here.​


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