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Optical lithography hit an interesting point in the 1990’s. Once circuit paths shrank to 180nm, we hit the physical limits of what the light wavelength and the optics in the lithography system could imprint on the silicon. You simply could not print silicon circuits any smaller. This was a huge problem for chip companies.

What some clever researchers did was come up with a way to bend these limits. Circuits are printed on silicon using a mask that creates shadows where circuit lines should be, and allows UV light to mark the areas that should be cut away. What they discovered is they would modify the circuit images by adding little ‘corrections’ to the circuit paths. These corrections would cause optical interference patterns that would actually generate the smaller features in the silicon. They started with simple ‘dog ears’ at the ends of circuits. As the features got smaller and smaller, the optical tricks they used got more and more complex.

This image below shows you an example. Each of these 5 lithography pictures generates the same circuit ‘plus sign’ on the left marked ‘no correction’. However, the ones to the right are able to do so at tremendously smaller circuit sizes. The image on the far right, ILT, can only be generated using complex mathematical models that work backwards from the desired final circuit image to the mask that must be put into the lithography machine to generate it. This, however, takes a lot of compute power.

Fast forward to today, and nVidia has released GPU optimized software to compute lithography patterns. Not only that, but they released the software called cuLitho. Using GPU’s, they claim it is 40x faster and uses 1/9 the power of traditional methods to calculate the computed lithography masks

A number of people have reported experiencing eye pain, vision problems, and sunburnt skin after attending ApeFest, a Bored Ape Yacht Club NFT collection event Nov 3-5th in Hong Kong. One person posted he woke up at 4am and could not see anymore. They rushed to the hospital where they are hoping to make a full recovery but were diagnosed with UV eye damage. It turns out, someone was almost certainly using full-spectrum UV-C (often called germicidal) lights instead of black lights.

The same thing happened at the Hypebest event in 2017 in Hong Kong. It’s not like this kind of harm is unique. Like the Jagermeister event that left a person in a coma, you better know your science.

BigClive on Youtube (who does amazing videos about extremely dangerous and counterfeit electronic devices you can buy and should be cautious of) recently uploaded a video and found the likely culprit. In the photo of the area with the toilets there were fluorescent tubes which are the characteristic teal-blue of mercury vapor discharge which emits quite a bit of UV-C and ozone as well.

I wrote a little while back about radiation from nuclear sources and how to detect them. But what about getting voluntary radiation for medical procedures: like X-rays, CT scans, and MRI’s?

Annual background radiation

Did you know you’re getting about 3.00 mSv of radiation every year if you live in the US? This breaks down to about 0.0082mSv per day.

There’s actually quite a bit of variation in the US depending on where you live. The types of rock in your area, position relative to the planet’s poles, elevation, and wide variety of other factors can affect your daily background radiation dosage.

	Approximate effective radiation dose:	Comparable to natural background radiation for:
One day’s background radiation	0.0082 mSv	1 days
A year of background radiation (US average)	3.0 mSv	1 year/365 days
Cross-country flight from New York to Los Angeles	0.04 mSv	4.87 days

X-rays

X-rays are something most people are familiar with. It turns out, however, modern x-rays actually give you a very low dosage. The lowest doses are dental X-rays. For a full panoramic dental x-ray, you’ll get about 0.007 mSv (0.7mrem). How little is that? One full day’s background radiation is about 0.0066 mSv (depending on where you live).

Still, there does appear to be a link to dental X-rays and certain types of thyroid and laryngeal, parotid gland, and salivary gland cancers.

Moving up, a full chest X-ray gives you a 0.1mSv dose. That’s about 10 days worth of radiation.

MRI’s

MRI’s use magnetic imaging, so they do not use radiation at all. They use a very powerful rotating magnet to generate their images.

Is it perfectly safe? Well, MRI’s can be done with contrast to help identify certain issues, and those chemicals can carry risk. Chuck Norris’ wife (yes, the Chuck Norris) even filed a $10 million lawsuit when his wife experienced health issues from the contrast used in an MRI.

CT scans

CT scans are particularly troublesome because they actually give you a pretty substantial dose of radiation. How much? Ex: A chest X-ray gives you the equivalent of 10 days of natural background radiation (0.1mSv). This is a very low dosage and highly unlikely to cause permanent or long-term damage.

On the other hand, a chest CT scan gives you 2.6 YEARS of radiation dosage – the equivalent of 77 chest x-rays. See some examples below or click them to see even more dosages based on different body part:

If that wasn’t bad enough, CT’s often also involve the use of contrast chemicals that may carry their own risks.