So it’s been a while since
I’ve written something, sorry for that. This is mainly due to the fact that nothing of
interest has really happened. So being desperate I’ll tell you about Thursday two weeks ago (the 13th).

We were going to have a party at the department, a combination of
welcome party for me and a few others and a going away party for a guy
starting a new job on the 1st of December.

The idea was to have some food and drinks in the office. However, when
Marco realised that the rice we were going to have for dinner was from
Fukushima he suggested we test the levels of radiation, just for fun.

He prepared a small bag of rice and placed it in the detector we are currently developing here in the department.

After having measured the levels of radiation for a short while we saw
that it was about 150 Bq/kg. What we are measuring is the decay of
Cs-134 (Caesium) which comes from the Fukushima accident. Cs-134 has a
very short half-life, about 2 years (Which is short in comparison with
Cs-135 which has a half-life of about 2.3 million years).

150 Bq/kg is not a high number, the EU limits for consumables for adults
imported from non EU countries (except Japan) is 600 Bq/kg (For Japan
it’s 100 Bq/kg). Still 150 Bq/kg is higher than expected.

However, when we removed the rice from the detector. We realised we had
failed to remove one of the radioactive sources used for testing the
detector response… So when we removed the additional source, we got
much lower measurements, well below the 100 Bq/kg limits. And we could
start the party.

The radiation source which was already in the detector when we put the
rice in is not a dangerous source, unless you eat it or decide to keep
it in you underwear for a prolonged time. In addition the detector is
relatively shielded (to protect the measurement from background
radiation) so keeping the sample in the detector is not as careless as
it might sound. Although, not checking if the detector is empty before
starting a new measurement might whoever be considered sloppy.

There is also a big difference between a material being ‘radioactive’
and it being ‘irradiated’. Like the rice in the detector lots of every
day stuff have been irradiated, i.e. band-aids, and cotton swabs you use
to clean your ear (to name two). Just because something has been
irradiated does not mean it’s now radioactive. For instance, while the
light-bulb, hanging from the sealing in a room, is switched on, the room
is irradiated with light. But as soon as you turn of the light, the
room goes dark. It will not continue to glow by itself. In the same way,
the rice in the detector did not become hazardous due to it being in
the detector next to the radioactive source.