The face mask reduces inhaled radioactivity

The MiniPIX detector of ADVACAM visualizes individual particles of ionizing radiation. It can be nicely used for radiation monitoring with the identification of radiation types.

We have performed simple experiments showing the temporal change of radiation intensity and composition in a normal environment.

Face mask accumulates radioactive Radon products

The face mask filters aerosols and dust particles from the inhaled air. Since the daughter products of Radon decay originate charged they attach to the dust and aerosols. We expect that the front side of the mask would accumulate such contamination when used and, therefore, it would exhibit increased radioactivity.

The measurement was performed using PiXet software with RadView extension. It is illustrated by several screenshots taken after each step:

1. The new fresh face mask was placed over the detector for half an hour recording the natural radiation background.

2. After the face mask was used for breathing for 5 minutes it was placed back to the detector.

A huge increase in alpha, beta, and gamma activity was observed immediately.

3. Two and half hours later: The activity is back to normal.

The daughter products of Radon deposited to mask surface have already decayed to the final long-living product “Radium D”.

The result of this experiment is shown in the next chart with time series of the detected intensity of alpha, beta, and gamma radiation: Intensity of alpha radiation has increased by a factor of 50 after mask placement, the beta has grown 10 times with certain delay, Gamma rays increased twice and muons didn’t change.

The delayed increase of beta activity corresponds to the decay scheme of Radon and its products.

How much radioactivity is exhaled? How much would remain in lungs?

Flipping the mask over and sensing its backside (mouth side) shows about the same alpha activity as that measured with a fresh mask.

Comparing these two measurements we can conclude that usage of the face mask reduces the amount of inhaled radioactivity by a factor of at least 10. We have performed such measurement 3 times with different mask types resulting in reduction factors of 12x, 27x, and 98x. Even the worst mask reduced the amount of inhaled radioactivity by order of magnitude!

Check the video illustrating this measurement.

Day-night fluctuations

The second measurement shows the nicely periodic fluctuation of radioactivity in our office during six days. The office is located on the top floor of a nine-story building. Every morning when the first people come and open the door the air with accumulated Radon and its decay products ventilates out to the corridor and radioactivity significantly decreases (by a factor of 10). In the evening the situation is the opposite. When the door is closed and the whole corridor is locked, the Radon concentration starts to grow.

The history chart showing 6 day periods is here:

The alpha activity follows very well the traffic in the office. The intensity of Gamma rays and Muons is more or less constant in time.

MiniPIX EDU: Detector optimized for use in schools

A special simplified detector version MiniPIX_EDU affordable for schools, teachers, and even students is available now. It provides the same functionality as our standard MiniPIX operated on board of ISS by NASA. Less robust mechanics, less strict qualification criteria (schools are less demanding than NASA) and shortened manufacturing process allowed more than 50% price reduction.

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