Researchers get 'compact' hard X-ray machine to work | Hacker News Reader

Researchers get 'compact' hard X-ray machine to work

tue.nl

132 pointsafyzendo28 comments

This article didn't tell me much about how the machine works. Further searching showed that it is a compact x-ray source that works on the principle of inverse Compton scattering:

https://indico.jacow.org/event/44/contributions/440/

A tunable, tabletop, Inverse Compton Scattering (ICS) hard X-ray source is being designed and built at Eindhoven University of Technology as part of a European Interreg program between The Netherlands and Belgium. This compact X-ray source will bridge the gap between conventional lab sources and synchrotrons: The X-ray photon energy will be generated between 1 and 100 keV with a brilliance typically a few orders of magnitude above the best available lab sources.

In the ICS process photons from a laser pulse bounce off a relativistic electron bunch, turning them into X-ray photons through the relativistic Doppler effect.

There's a presentation slide deck here with more details:

https://indico.cern.ch/event/1088510/contributions/4577523/a...

Great find on that presentation.

> In the ICS process photons from a laser pulse bounce off a relativistic electron bunch, turning them into X-ray photons through the relativistic Doppler effect.

They make it sound so simple. Just bounce off a big thing moving towards you to absorb some of it's energy. Fond memories of the time I discovered this effect for myself using a medicine ball and a friend's hamster I was petsitting at the time.

> Fond memories of the time I discovered this effect for myself using a medicine ball and a friend's hamster I was petsitting at the time.

Uh..

This mental picture is even better given the TFA's effect so described used the word "relativistic". That hamster time travelled - briefly.

I'm sure it underwent contraction along one axis.

Time certainly seemed to slow down for me!

Gracie was uninjured, for those concerned. Caught her gently. Learning experience. Future experimentation was done with a lacrosse ball.

I was going to compare this to the existing Cool-X Pyroelectric X-ray generator (https://www.amptek.com/internal-products/obsolete-products/c...) but after seeing those slides the intensity of the output is not really comparable. Pyroelectric accelerators/hard x-ray machines can be only a thumb drive in size but they're a weak trigger-pull squirt gun to this things' relative fire hose of hard x-ray photons.

Similar machine at Arizona state university: https://news.asu.edu/20230205-discoveries-firstofitskind-ins...

Kinda similar, the Arizona one has a beam line that alone is 10 meters and requires three separate rooms, the Belgian one is maybe 3-4 m long in total.

Looks like the new tech here is a "traveling wave RF photogun" used to accelerate the electrons.

Here's a preprint from 2020 by the researchers that I'm assuming describes their tech:

https://arxiv.org/abs/2009.00270

(Edit: Removed speculation that the system architecture was that of a free-electron laser. Presentation shared by philipkglass indicates it's something different.)

Wow! I wonder if this will mean better x-ray imaging in hospitals. Having the ability to tune the x-ray to the type of material you are looking at:

“This mid-range capability also makes this source suitable for looking into paintings, silicon wafers, or biological material without damaging it. In addition, this source is special because the energy of the X-rays can be very accurately adjusted to the material you want to detect. You can 'tune' it to visualize any periodic table element. In addition, the light beam is reasonably coherent. Because of this, the measurements you can make with it are of great accuracy.”

OK, but why do they need so much X-ray power to examine paintings? Most progress in X-ray technology has been through better sensing so less power could be used. Ordinary X-ray tubes are simple and a century old.

Now if they could build a compact synchrotron to generate soft X-rays, that would be a huge deal. The semiconductor industry has tried to get that to work for a decade as a light source for "extreme UV". ("Extreme UV" and "soft X-rays" are in the same part of the spectrum.)

It's not a lot of X-ray power - it's more energy per photon. If your photons are tuned to the materials you're looking at, you can get away with less total power.

> "Extreme UV" and "soft X-rays" are in the same part of the spectrum.

This is true only in the exact same way that the statement "UV and visible light is in the same part of the spectrum", or maybe more clearly "the eyeball and the eyelid are in the same part of the body".

I guess it depends on your scale.

The X-ray/UV boundary (10nm) is closer to IR (780nm) than the top of X-ray range (10pm). IR is similarly broad (to 1mm).

In this context energy=wavelength=frequency, and hard x-rays means x-ray with energies > approx. 5 keV. I am assuming properties they are after in their particular context are <i>tunable</i> hard x-rays with with relatively narrow bandwidth, such that they can tune the energy/frequency/wavelength of their beam to be above the absorption edge of particular elements in the pigments in paintings and compare the x-ray fluorescence maps above and below the absorption so they can see where particular pigments are and thus paintings hidden below the visible painting.

One big advantage synchrotrons have is flux over a broad spectrum. When you want monochromatic x-rays you can start with broad spectrum x-rays from a synchrotron source and throw almost all of the photons away, and still have orders of magnitude more x-rays in your 1 eV bandpass beam than the flux of a laboratory source, (even if it has a peak in its spectrum at the energy you want). The plots on slides 4-6 linked in the first comment [1] demonstrate this clearly.

However, the energy range where inverse compton scattering sources seem most attractive are at energies >100 keV where it appears there is the potential for inverse compton sources to approach and even outperform synchrotron bend-magnet sources (slides 31 to 35), particularly in comparison to bend-magnets/wigglers at synchrotrons with lower storage ring energy than facilities like ESRF (6 GeV). High flux at higher energies (>100 keV) is difficult to generate at the more common 2.0-3.0 GeV storage rings.

[1] https://indico.cern.ch/event/1088510/contributions/4577523/a...

Because the energy of a photon is a function of its frequency.

Good to see that the search for a table top synchrotron has finally yielded fruit as this could pave the way for cheaper research as lots of experiments require high brightness hard x-rays.

Going back I had the opportunity to take two tours of the NSLS at Brookhaven Labs when it was still in operation. I was a bit intrigued by the idea of synchrotron radiation and was wondering if this could be scaled down to a small room sized machine or table top. Indeed - there were attempts but non that were successful at that point - likely around 2008 - 2010.

Medical tricorders in every doctors surgery?

(Or are "hard" x-rays the wrong thing?)

Dental and bone x-rays appear to require hard x-rays.

I believe the novelty here is that the produced x-rays are in a tight range of wavelengths, and that the range can be adjusted.

It's high brightness compared to x-rays generated by ramming ~60 kV electrons into a metal target, like tungsten.

What's the difference between this and Zeiss' hardware (about the size of a refrigerator) https://www.zeiss.com/microscopy/us/products/x-ray-microscop...

As far as I can see, its 5.4 keV & 8.0 keV vs up to 100 keV.

That Zeiss hardware has a fixed frequency (and wavelength) of the X rays (there are 2 variants, the one with a higher frequency and smaller wavelength has a wavelength close to 0.15 nm).

This article is about a tunable high intensity X-ray source, which can be used instead of a huge synchrotron that could do the same thing.

One nm wavelength? So this could be used as a source for photolithography?

Far as I know, X-Ray lithography is even harder than EUV. Mostly because optical manipulation of X Rays barely exist, and X Rays only interact with heavier elements.

Current EUV sources from ASML are 13.5nm IIRC. It's increasingly difficult to do any kind of optics (focusing, masks, or even mirrors) at shorter wavelength.

easiest way to azsantiatae someone untraceable it's a ray gunn leafing no forensic trace lol :) X) -gratefuil ded

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