Beta Emitter Skin Dose Rate Calculator

Release notes

Version 1:2.  [Update 23/03/2026: added Pb-210 / Bi-210].  The Ionactive Beta Emitter Skin Dose Rate calculator works with over 100 radionuclides. The calculator is based on a data set by IAEA (and other references). Whilst Ionactive stands by the results provided in this calculator, which has been verified by calculation and reference (e.g. Radionuclide and Radiation Protection Data Handbook 2002  -  D. Delacroix et al, and IAEA-TECDOC-1162), we are also aware that the software Varskin (a computer code for skin contamination & dosimetry) is popular (although not directly readily available). The Ionactive calculator generally estimates slightly higher dose rates and shielding requirements (e.g. layers of gloves) as compared to Varskin. If you are used to using Varskin (currently known a V+), then our calculator has a "Varskin" option to output data more aligned with that software (although we would recommend our own Ionactive model first). The varskin option is not a copy of their method, and our calculator outputs will not always align regardless.

Our calculator uses a standard data set by default. However, as time allows (and as suitable information becomes available),  Ionactive can add radionuclide specific overrides to better represent the radionuclide of interest. If you use our calculator and query the output for your specific needs, then please do get in touch - we may be able to add a new override (essentially to micro tune the calculation). 

Unless otherwise stated, it should be assumed that the radionuclide entry is for that radionuclide alone. Where you see a specific entry such as Sr-90/Y-90 then the two radionuclides are considered in equilibrium. 

If you need to calculate beta dose rates in air then please use this calculator: Beta Emitter Activity to Dose Rate (in air) Calculator. 

Use example

Scenario - A researcher is working with the beta emitter P-32. The process involves aliquoting 1ml samples, each containing 2 MBq of the radioisotope.  During this process they inadvertently dispense a 1ml drop onto the end of their gloved middle finger of the left hand (which they were using to hold an eppendorf tube). After an estimated 15 mins they complete the process and upon waving their gloved hands in front of a mini monitor E, discover full scale deflection when monitoring their left gloved hand. The gloves are carefully removed and placed in an acrylic waste bin. Running a set of samples on a beta counter they note that one tube is showing negligible counts - implying it is missing its activity. They infer that the radioactivity is likely that monitored whilst they were checking their gloves. 

The following data is collected (or assumed). 

• Likely activity on the glove middle finger - 2 MBq of P-32
• Monitoring shows a 'hot spot' near glove finger tip - so a standard 1 cm² is assumed.
• The whole process took 15 minutes and the blank tube was one of the first to be run through the beta counter (so assumed to be one of the first handled). Therefore a 15 minute exposure time is assumed.
• The gloves were nitrile, with a density of 0.95 g/cm³ and 0.1 mm thick on the finger (obtained from product literature).
• Given the tight fit of the glove, no air gap is claimed (initially). 

Use the calculator to determine the skin beta exposure potential in the above scenario.  We will use the Ionactive default calculation mode as this will likely yield slightly higher estimates (a few % higher at most). 

First the calculator is set up as follows and no gloves are assumed - this gives direct skin contamination dose rate (so worse case). 

As we can see the dose rate is 3,800 mSv/h (i.e. around 63 mSv/min). That is a serious dose rate and 15 minutes of exposure could lead to a skin dose of 945 mSv (equivalent dose). The legal UK limit (for employees at least 18 years of age) is 500 mSv/year equivalent dose [i.e. equivalent dose limit to the skin is 500 mSv in a calendar year as applied to the dose averaged over any area of 1 cm² regardless of the area exposed and / or the  equivalent dose for the extremities is 500 mSv in a calendar year].

However, we note that the employee was wearing gloves (specification given above), so let's add that in as shown below. 

The results show a dose rate of 3,566.991 mSv/h (59.45 mSv/min) - the gloves have hardly provided any attenuation at all. The show gap / cover selector provides some enhanced information.

Air gap: 0 mm (no reduction). Cover: Nitrile (gloves) — 0.10 mm @ 0.95 g/cm³ → reduction ≈ 6.13% (near-field). Note: Thin gloves provide minimal shielding for high-energy betas like P-32 or Y-90. β CSDA max range in air: 790.155 mg/cm² (6.30 m).

As is well known for a high energy beta emitter like P-32, gloves will avoid contaminated hands, but will do little to attenuate the betas. 

What if the employee was actually wearing two pairs of gloves - would it have made a significant difference? 

Two pairs of gloves yields the following: 3,348 mSv/h (55.8 mSv/min).

Air gap: 0 mm (no reduction). Cover: Nitrile (gloves) — 0.20 mm @ 0.95 g/cm³ → reduction ≈ 11.89% (near-field). Note: Thin gloves provide minimal shielding for high-energy betas like P-32 or Y-90. β CSDA max range in air: 790.155 mg/cm² (6.30 m).

Another modest reduction, but the exposure still remains significant.

The employee then puts on a clean pair of the same make and size of glove, and having carefully monitored the end of the contaminated glove, determines there would have been a little air pocket between the inner surface of the glove and the skin in line with the spot of contamination (this might be wishful thinking, but good enough for demonstration purposes). It is estimated this air gap would be at least 2mm - this is introduced into the calculator as show below (where we will assume they are also doubled gloved). 

As is noted below, this air gap does lead to a significant reduction in dose rate (if it can be reasonably assumed that the gap does exist).

1,662.701 mSv/h (27.712 mSv/min)

Air gap: 2 mm → reduction ≈ 50.34%. Cover: Nitrile (gloves) — 0.20 mm @ 0.95 g/cm³ → reduction ≈ 11.89% (near-field). Note: Thin gloves provide minimal shielding for high-energy betas like P-32 or Y-90. β CSDA max range in air: 790.155 mg/cm² (6.30 m). 

Our dose estimate over 15 minutes is now about 420 mSv equivalent dose. Still significant, not ALARP, not justifiable  -  but is under the legal limit. 

During the investigation into this incident, the investigator asks the employee if it is usual to hold an eppendorf tube in the hand containing 2 MBq of P-32. Whilst this calculator is for skin contamination, it can be used to give a first order approximation of the likely dose rate to the skin (via the tube). It is found that the tube is made of polypropylene (PP) and the wall thickness is 1mm. The calculator is then reconfigured to remove the glove and air gap data, and replace with 1 mm of PP. It is assumed the finger is in direct line with the very small volume of radioactive material, which we will assume to be equivalent to 1 cm² for purpose of demonstration. The calculator is therefore set up as follows.

The results are as follows. 

2,058.951 mSv/h (34.316 mSv/min)

Air gap: 0 mm (no reduction). Cover: Polypropylene (PP) — 1.00 mm @ 0.92 g/cm³ → reduction ≈ 45.82% (near-field). β CSDA max range in air: 790.155 mg/cm² (6.30 m).

This is probably an exaggeration due to less than ideal geometry - but it shows that even a few seconds exposure per tube could lead to high finger (extremity) doses over an entire experimental procedure. Message here  - don't handle eppendorf tubes containing MBq activities of high energy beta emitters.

As always when using any of the Ionactive calculators or other resource, seek formal advice from a Radiation Protection Adviser.