Few things;
Isn't it a bit odd that a hospital MRI machine room isn't being monitored for these kinds of things? I'm curious, not accusatory.
Also, this could be a potentially catastrophic tool for terrorists. As trivial as it sounds, it's even worse than a traditional frequency jammer because it renders the device unusable instead of just not being able to communicate with the outside world.
Edit: On the other hand, interesting counter-terrorism tool as well. Is there any precedent for the CIA using this sort thing intentionally?
There are almost certainly oxygen sensors in that room. The helium concentration was probably not high enough to displace enough oxygen to trigger them. Though it wouldn't entirely surprise me if they were ignored or disabled.
Liquid helium is rather expensive and would likely draw attention in areas where it's not usually handled. Really doesn't sound like a useful terrorism tool.
I assumed liquid helium because that is what you need to fill MRI/NMR machines. You could use regular helium, but the pressure bottles are also rather conspicuous. And releasing large amounts from both is not a subtle process, so I really doubt that is practical.
To be clear, not arguing, I just want to learn.
Doesn't this contradict what you said before though, about it not displacing the oxygen sensors in the room because it was so little?
"We do not know how much of the 120 liters ended up going outdoors and how much ended up inside. Helium expands about 750 times when it expands from a liquid to a gas, so that’s a lot of helium (90,000 m3 of gaseous He)."
I wonder what this would mean in practice at any given time.
I'm very certain that there are usually oxygen sensors installed for MRI machines and NMR spectrometers. I'm not sure how sensitive they are. Either they were not triggered, e.g. because the helium concentration was low, or at least low at the position of the sensors. Or if it was high, they were disabled or ignored.
120 liters of liquid helium is a lot, but it wasn't released at once but over a longer time as far as I understand the story.
I don't mean sensors directly attached to the machine. My experience is with NMR spectrometers, which work based on the same principle as MRI machines and have the same superconducting magnets that require liquid helium and nitrogen. And those essentially always have an oxygen sensor in the room somewhere, but not connected to the spectrometer itself.
Yes - that’s what I mean too. GE located theirs in the scanner control room. The other vendors didn’t have them.
I’m going to confirm this as I’m doubting myself now, but the GE one would fail every few years as the sensors have a limited life. It was ear splittingly obvious that they had one.
One of our multi-practice facilities is having a new MRI installed and apparently something went wrong when testing the new machine.
[...]
I discovered that the helium leakage occurred while the new magnet was being ramped. Approximately 120 liters of liquid He were vented over the course of 5 hours. There was a vent in place that was functioning, but there must have been a leak. The MRI room is not on an isolated HVAC loop, so it shares air with most or all of the facility. We do not know how much of the 120 liters ended up going outdoors and how much ended up inside.
Scaling a "helium attack" against electronics is one of the dumber terrorist plots I've come across. But let's play.
Say I scored a big truckload of helium, 5000 l. (The contents of my tank will expand to 3750 m3 of He gas.) Then I got access to a ventilation duct into the subway. I manage to hook up my tank and start depleting into the subway. Assuming 20 m2 cross-section for a tunnel: if I could do the emptying at once, I could fill 0.187 km of tunnel completely with He; killing all vermin in that section.
But hey my goal is not to suffocate (that would be boring, right?) but to fritz electronics. So I do it slow and steady into a station. Say I want to keep the concentration of He in the station at around 0.1%. (I assume it would take time for operators to detect this. I don't know how sophisticated gas detection is in subways.) Let's assume an airflow of 5 m3/s into that station. I'd need 0.005 m3/s He or 400 m3 per day to keep the level at 0.1%. So for only one day, I'd need to get around 500 l liquid helium into position.
If you are a terrorist, why not get a big truckload of fertilizer? Easier and actually kills people instead of just wrecking their apple devices.
Or if you are some kind of compressed gas terrorist, 5000L of compressed oxygen or acetylene will do a lot more damage than helium.
Anyone who can mount a helium attack can mount much more severe attacks.
I think the probability of some eccentric and well-supplied terrorists trying to ruin Apple devices with helium is so remote as to not be worthy of consideration.
Even if it does come to pass. Oh well, I'll buy another iphone, or an android.
The point of terrorism is to cause terror and to inspire parallel independent actors.
About 3000 people died on 9/11, but we acted like it was the next Pearl Harbor. These 3000 people died needlessly, and it sucks, and my heart goes out to the families who lost someone that day, but statistically was a tiny blip.
9/11, as an act of terrorism, was successful. We now can't get out of the Middle East, it caused a decade long economic depression that snowballed into the housing crash, it ruined our relations with other nations, and hating Muslims is the ordre du jour like it is 1099.
Lol you clearly underestimate some people, but I'm wondering what makes you think that even a frequency jammer in the wrong hands couldn't be potentially catastrophic?
Also, this could be a potentially catastrophic tool for terrorists. As trivial as it sounds, it's even worse than a traditional frequency jammer because it renders the device unusable instead of just not being able to communicate with the outside world.
Edit: On the other hand, interesting counter-terrorism tool as well. Is there any precedent for the CIA using this sort thing intentionally?