So what are those big yellow boxes at The Chunnel?

Evening all!

While you are quietly digesting your Boxing Day pork pie and bubble & squeak, can I ask a question?

For the last few years, driving back through passport control at the Chunnel in Calsis I have noticed the big yellow boxes that you have to drive between.

I’ve googled it and can’t find out what they are but the notices warning you not to park between them suggest they emit some form of ionising radiation. As does the enormous power feeds into the back of them.

So what are they? Image intensifiers using x-rays? Infrared detectors for body heat? Or chemical sniffers looking for cheese smugglers?

Great question. I always thought they were emergency hydraulic barriers, hence why you shouldn’t park between them.

They’re enormous Nigel Forage jack in the boxes.

You really don’t want to trigger one of them by having an undesirable in your car.

I always assumed my unmentionables were being quietly fried as I passed between them.

X rays maybe? I know that customs x ray containers sometimes.

I don’t think (hope) they’re x-Ray for passenger vehicles. They’d need to be v high power to penetrate steel vehicles so of questionable safety.

Possible radiation detectors? They definitely check all vehicles for radioactive material. My parents were on a coach that set one off. One of the passengers had been treated with radioactive iodine for thyroid cancer.

The thing that surprised me was the dearth of information about them on the internet. Unless my google search terms were poorly chosen I suppose but it’s not like they aren’t clearly visible to anyone passing through.

Googling ‘channel tunnel security measures’ may not be the best idea 😉

Hmm, now you mention it there has been a white transit can parked outside my house for the last week…

If they’re like the ones we have at work, they’re detectors that pick up “dirty bomb” materials. Luckily I work at the other end of the dock, I wouldn’t want to be near them for too long..

So if they detect radiation they’re giant but passive Geiger counters? If so they would be completely safe, why would there be an injunction against parking in the hashed zone in between them?

They aren’t necessarily just passive devices. There are a few bits and pieces of information out there in the public domain. Installing radiological and nuclear detection capability was called Project Cyclamen.

I’ve wondered about those for a while as well

If so they would be completely safe, why would there be an injunction against parking in the hashed zone in between them?

I wonder if it throws off the calibration ie. They have to have air there for a while to work out what the background level is if they are very sensitive

Edit: Nope, they actually do already to be active: “It works by passing tiny Muins – a type of subatomic particle – through containers and bags and monitoring how they bend as they pass through solid objects. As all nuclear materials have a unique density the machine can identify them even if they have been prevented from emitting radiation.” (I think the article meant to say muon rather than muin)

article in the independant

Banana detectors…..they trigger an alarm when people try and smuggle bananas or almonds through customs.

Potassium-40 see.

Well as someone who uses to Tunnel every 4-6 weeks I’d say they can’t be that big or that yellow or I would have noticed them 😳

Going through on Tuesday, I’ll ask and report back 😉

Are they not IMS (Ion mobility spectrometers?) units?

Similar to the stuff at airports.

You don’t need a large ionisation source (we use americanium), don’t really need much in the way of calibration (for qualitative analysis) or much sample.

So perfect for detecting low concentrations of drugs/explosives from loads and loads of cars/trucks driving by with loads of the stuff day after day.

Quite awful for quantitative work though.

@Jambalaya They are on the French side of the tunnel only as far as I can see. After you pass through French customs and immediately before you reach the UK Border Agency station. They are 7ft tall or so and, Erm, yellow.

Don’t park in the hashed zone!

Radiation scanners, we’ve got ’em at work too (major UK port for cargo)

Pretty much the only thing that sets them off if bananas and clay. No real alarms that I’m aware of thankfully, customs run and monitor them though.