Notes for pregnant users
21 Nov 2011



Information for pregnant and breast-feeding users 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.

Letting us know that you are pregnant or breast-feeding

You do not have to let us know that you are pregnant or breast-feeding, but we can only make sure we are taking the necessary actions if you choose to tell us. You can do this by contacting Xavier Queralt in advance of your experiment. Unless you request otherwise, we will let your Local Contact know and send them a copy of the risk assessment.


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 mothers

IRR99 specifies that once a pregnancy has been declared, the radiation dose to the foetus as a result of the expectant mother’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 women 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 mothers

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 one of the following:

Dani Mills (Health Physics Administrator)

Paul Wright (Radiation Protection Adviser)


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

After completing the reading list along the right hand side, please take the User Safety Test which can be found here.​

Previous  Next