Radiation Diary – 52.45 μSv at Castleford

** Disclaimer: Don’t panic, I’m not a professional scientist, and I bought my Geiger Counter from Amazon for £95. No need to wear a radiation suit and take iodine tablets yet! **

I’ve only had my geiger counter a few weeks – and already it’s been quite exciting.

On the 17th January 2016 I went to watch the amazing StarWars The Force Awakens in 3D at the iMax in Castleford, South Yorkshire.

I left my geiger counter on, in the car door pocket at about 12noon. I enjoyed a big slow lunch at TGI Friday’s then watched the film. On my return my geiger counter said HELLO – with this image. (Unit GMC320 Plus, firmware v4.06).


As you can see, current Counts Per Minute is 24. This is quite a normal figure where I live, but obviously something happened while I was in the cinema, but has since passed. The unit has been calibrated so you’ll get roughly 0.005 microseiverts (μSv) per hour for 1 CPM. I’ve checked with the manufacturers and this is their default conversion rate.

So a CPM of 26338 would mean at some point, the unit detected 131.69 μSv/h.

Although this is alarming, it depends on how long it lasts for. The average value was 52.45 μSv over the hour. Of course, my GMC could be faulty, it could have experienced some electromagnetic interference or firmware fault. But maybe it didn’t! I would need another unit in parallel to be absolutely sure.

If it was correct, that’s an unsafe dose for the residents of Fukushima, let alone Castleford.


Here’s the graph of the results.

Screen Shot 2016-01-20 at 20.37.01

Here’s the position roughly my car was in the carpark.


Who did I tell?

Wakefield council, the Environment Agency, the Met Office, the nearby Ferrybridge Power Station, the local WakeField/Castleford Express newspaper (via Facebook), Xscape.

I was trying to get hold of someone from RIMNET, but RIMNET doesn’t operate in this area. They only have 5 staff (found some on LinkedIn- which is why I knew to contact the Met Office).

Who responded?

Only the council replied, shocking! However they seemed to be the more capable.

Dear Giles

 Thank-you for reporting this.

We are investigating it, and will get back to you in due course.

 Best wishes

 Dr <removed>

Consultant in Public Health Medicine

Head of service: Health Protection and Intelligence

Wakefield Metropolitan District Council (3 days/wk)

Within minutes…

Hello Mr. Middleton,

 Your query regarding the radiation readings taken at the Xscape in Castleford on Sunday have been passed to me by our local Public Health Team who were in turn contacted by Wakefield Council.

 I am a Radiation Protection Scientist at Public Health England’s Centre for Radiation, Chemical and Environmental Hazards. If possible I would like to speak with you directly regarding the instrument used and the readings taken so that I can better understand what has been measured and to look at what actions need to be taken.

 Can I ask that you provide a contact telephone number in reply to this email and an indication of when it would be convenient to call. I suspect that our conversation will take approx. 10 minutes.

 In your email to Wakefield Council you mention RIMNET monitoring sites. Whilst you are correct that there are not sites in the immediate vicinity of Castleford the monitors are sited across the UK to provide a detection network for detecting large scale plumes of radioactive material passing over the UK. We would be notified by RIMNET if one of these stations when into alarm. I can confirm that we have not been notified of any RIMNET alarms. I have also checked the readings at the RIMNET stations in the surrounding area and can confirm that during the period of interest, 16:00-18:00 17th January 2016, these stations showed normal background levels of radiation.



Public Health England, CRCE.

I had a nice chat with these guys on a con-call with, I believe, at least one other present. I had a feeling there were more ears listening.

We discussed if the car was moving or stationary, and discussed the possibility of a faulty unit. The man I was mainly talking to was really kind and informative.

The conversation left with a request for me to send the satellite image of the rough area, and leaving it with them.

Things we discussed:

  • they explained that it was unusual, interesting, and that they might investigate further.
  • I think they also determined I wasn’t a crackpot, and mentioned they normally throw these reports out the window quickly because they spot what’s gone on (faulty unit/faulty person!).
  • We explored Fly-Ash from coal burning, given FerryBridge is just down the road – they confirmed that Fly-Ash is indeed radioactive, but shouldn’t be 26k CPM active.
  • They believed it could be a radiological discharge from medical equipment/hospitals as it was short lived.
  • They told me it was unlikely my unit was faulty due to consistency of correct readings afterwards and before, and subsequently to this day.

I’ve also subsequently pointed out there is a train station which freight passes by right next to the carpark. If that was transporting nuclear warheads, waste or medical equipment, it might set off the geiger counter.

Subsequently I’ve been informed that the case has been closed, with no reason or rationale behind it. But that’s ok, I’m sure I’ll be back!

I’ve had a kind offer from a friend to take a light aircraft up and go fly by some Power Stations to see if we can get readings. Amazing what opportunities arise when you’re having fun with new toys.

In the meantime, you can see my current GMC readings on the world map – look in York for Gilesey. (There was  some data incompatibility at first, so ignore older readings with no CPM).



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