- So what are those big yellow boxes at The Chunnel?
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?Posted 4 years agoTallpaulMember
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.Posted 4 years agoleffeboySubscriber
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?
[s]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[/s]
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)Posted 4 years agoSaccadesMember
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.Posted 4 years ago
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