Gamma-Ray Laser Moves a Step Closer To Reality (phys.org) 85
A physicist at the University of California, Riverside, has performed calculations showing hollow spherical bubbles filled with a gas of positronium atoms are stable in liquid helium. The calculations take scientists a step closer to realizing a gamma-ray laser, which may have applications in medical imaging, spacecraft propulsion, and cancer treatment. Phys.Org reports: Extremely short-lived and only briefly stable, positronium is a hydrogen-like atom and a mixture of matter and antimatter -- specifically, bound states of electrons and their antiparticles called positrons. To create a gamma-ray laser beam, positronium needs to be in a state called a Bose-Einstein condensate -- a collection of positronium atoms in the same quantum state, allowing for more interactions and gamma radiation. Such a condensate is the key ingredient of a gamma-ray laser.
"My calculations show that a bubble in liquid helium containing a million atoms of positronium would have a number density six times that of ordinary air and would exist as a matter-antimatter Bose-Einstein condensate," said Allen Mills, a professor in the Department of Physics and Astronomy and sole author of the study that appears today in Physical Review A. [...] Mills, who directs the Positron Laboratory at UC Riverside, said the lab is configuring an antimatter beam in a quest to produce the exotic bubbles in liquid helium that Mills' calculations predict. Such bubbles could serve as a source of positronium Bose-Einstein condensates.
"My calculations show that a bubble in liquid helium containing a million atoms of positronium would have a number density six times that of ordinary air and would exist as a matter-antimatter Bose-Einstein condensate," said Allen Mills, a professor in the Department of Physics and Astronomy and sole author of the study that appears today in Physical Review A. [...] Mills, who directs the Positron Laboratory at UC Riverside, said the lab is configuring an antimatter beam in a quest to produce the exotic bubbles in liquid helium that Mills' calculations predict. Such bubbles could serve as a source of positronium Bose-Einstein condensates.
ah, the graser (Score:3)
Was this not a weapon in Larry Niven's Known Space?
We just call it a Converter Of Weeds. (Score:3)
Or "COW", for short.
Re: (Score:3)
and many SF authors since Niven have had 'graser' weapons in their spaceship battles.
For short range combat anyway. Missile with graser warheads have also been popular.
I'm not sure about "a gas of positronium atoms" - is that antimatter?
Re: (Score:2)
Re: (Score:2)
Re: ah, the graser (Score:2)
Yeah, and maybe you call all sandwiches "hamburgers", but most people will stick with the existing convention.
Re: (Score:1)
Re: (Score:2)
In this context, one frying pan would be made of metals and electrical conductors, another would be made of non-conducting solids (sometimes liquids or gases) with "pumping" from optical components, and now a new frying pan composed of liquid helium and positronium is being proposed.
It may not make much difference to you, but when I'm doing gas analysis, I tend to use different names for machines that work by IR spectroscopy, chromatographic separation, and w
Re: (Score:2)
Actually Mr nitpick, they are all lasers.
As gamma rays and microwaves are photons, aka: light.
Re: (Score:2)
Wow,
not all photons are light?
And what are they?
Re: (Score:2)
Assuming you agree with the definition of "light" as EM in a certain portion of the spectrum, then those photons that are not light are photons whose wavelength is not in that visible region.
Re: (Score:2)
And using gamma rays for position and movement detection should be called Gaydar.
Re: (Score:2)
Re: (Score:2)
I thought a "graser" was a gravity-laser (e.g. coherent gravity waves).
Re: (Score:2)
I thought a "graser" was a gravity-laser (e.g. coherent gravity waves).
In which SF universe? In one that leaps to mind (David Weber's Honor Harrington universe), grasers [fandom.com] are gamma ray lasers.
Re: (Score:2)
I was working from the Honorverse. It's been a while, and I thought that Honor's command in the first novel had experimental gravity lasers.
Re: (Score:2)
I was working from the Honorverse. It's been a while, and I thought that Honor's command in the first novel had experimental gravity lasers.
Ah, you were thinking of the experimental "grav lance" carried by HMS Fearless in "On Basilisk Station".
Re: (Score:2)
The effects on a target could be ... spectacular. Of course, it would probably have bigger effects on objects held together by gravity than on things held together by 10^15 or so fold stronger electro-weak forces.
Re: (Score:2)
Wasn't it some over zealous scientist experimenting with gamma radiation that created the Hulk?
Re: (Score:2)
Was this not a weapon in Larry Niven's Known Space?
I know Niven's Known Space pretty well and I do not remember any gamma ray lasers or anything specifically related to gamma rays. You might be thinking of the Ringworld superthermal laser but I think it was ultraviolet. All of the few references to weapon lasers were visible light.
Re: (Score:2)
I think that GR lasers do get a mention or several, but it may well be in the Man-Kzin Wars section of the universe, which is not exactly canon, in the sense that Larry won't be bound by things mentioned there, and reserves the right for events and technologies from the Wars to have been forgotten in later events in Known Space.
That's some weird shit. (Score:3)
"Positronium is an onium which consists of an electron and a positron bound together as a long-lived metastable state. Positronium has been studied since the 1950s to understand."
70 years old, matter and antimatter making a thing. And the mass is two electrons and some binding energy. And PET scans use this shit. I'm gonna need to lie down.
Wanna hear some real weird shit? (Score:5, Informative)
That electron and positron might actually be the same particle. As anti-matter is just regular matter, going backwards in time.
So the photon they create wile annihilating is merey it bouncing in the time dimension.
And that photon only exists from the outside perspecive of matter. From its own perspective, it never exists, because it uses all its speed to move through space, so there is nothing left for time, so its duration of existence is zero, and due to time being distorted, from its perspective, the universe never expanded and all the particles are at the same Planck length spot and there are no causality nor Pauli exclusion. So it has no reason to exist either, as the particles it moves between are already at the same spot.
We may never know how "real" that is, or what we should even define "real" to be, but the math checks out and all our observation is fitting it.
NOW you can lie down. :)
Source: PBS SpaceTime (Score:2)
Long time viewer here.l. Fantastic show.
Just ignore their philosophy stuff (As in: The current topic / series of videos.) They are badly clueless in that area, and sadly don't seem to realize. Probabaly t
...heir current sponsor. (Score:3)
Sorry a rain drop literally pushed "Submit" on this retarded touchscreen phone
Re: (Score:3)
Re: (Score:2)
And in SEATTLE.
Re: (Score:3)
Re: (Score:3)
That electron and positron might actually be the same particle. As anti-matter is just regular matter, going backwards in time.
So the photon they create wile annihilating is merey it bouncing in the time dimension.
And that photon only exists from the outside perspecive of matter. From its own perspective, it never exists, because it uses all its speed to move through space, so there is nothing left for time, so its duration of existence is zero, and due to time being distorted, from its perspective, the universe never expanded and all the particles are at the same Planck length spot and there are no causality nor Pauli exclusion. So it has no reason to exist either, as the particles it moves between are already at the same spot.
We may never know how "real" that is, or what we should even define "real" to be, but the math checks out and all our observation is fitting it.
NOW you can lie down. :)
So our theoretical math is consistent with itself? That's nice ...
Re: (Score:1)
A lot of that mostly proves that natural language (English in this case) is insufficient to describe the mathematical constructs and concepts of modern quantum and particle physics.
It can't be that (Score:1)
Re: (Score:2)
From its own perspective, it never exists, because it uses all its speed to move through space, so there is nothing left for time, so its duration of existence is zero
Not quite correct. It’s more like it experiences all the oscillations simultaneously (all states at the same time) and thus the duration of its existence is zero
and due to time being distorted, from its perspective, the universe never expanded
All the states just exist simultaneously, including the longer wavelengths caused by space expanding, they are separated by distance which is experienced by outside observation but arguably also experienced by the photon though it is strange because it experiences all locations simultaneously from its perspective.
and all the particles are at the same Planck length spot and there are no causality nor Pauli exclusion.
First, you can’t hav
Re: (Score:1)
Re: (Score:2)
PET scan CAN use this, Maybe. (Score:3)
Positronium exists only for a few parts of a nanosecond.
This article is neat because of the "Stable" claim.
In PET scans, Positrons Combine with the Electrons, making two 511keV gamma rays, who's neat thing is they travel 180 degrees apart from each other.
They detect the two gammas, and can tell where they came from using tomography. ( A gamma Camera)
Cancer takes up the sugar they dope with the gamma emitter, FDG, so they can locate the cancer.
A Beam of Positrons would be like a flashlight to a gamma camera,
Therapy (Score:5, Informative)
This is a neat thing, but other than a weapon, I can't see how it's useful.
Shining an antimatter beam on something would be pretty destructive, because whatever it hits would be emitting a shitload of radiation.
Well, there's this thing called Radiotherapy or Radiation Therapy [wikipedia.org] (a part of nuclear medicine), that indeed uses radiation as a weapon (like you say) against tumors.
Emitting shitload of radiation is exactly what you need, specially if you can aim them precisely as in a laser.
(i.e.: having a gamma *laser* source will make it easier to focus the beam on the tumor, and avoid hitting too much around it.
Usually you do it by rotating around the target. You always keep the tumor in the center of the target - so the tumor is hit by every single "zap" - but move around so the other non-tumor aren't hit on each "zap". Having a laser source would theoretically help better pinpoint the tumor).
Depending on the depth of the tumor you also need a type of ray that can easily penetrate to where the tumor is situated while interacting less with the surrounding tissue. Gamma rays are interesting from that point of view.
(And conversly, that's why they are also used in PET scan, they are more likely to get out of the body instead of getting blocked by the surrounding tissue).
Saddly, I'm not a physicist and have only moderate knowledge of nuclear medicine, so I don't know if hitting a tumor close to the surface with positrons would make sense (but given the long distance of interaction / penetration of gamma rays, if they are evenly spread all over the place, they should leave the patient without much interaction - and thus danger to them - just like the image produced by PET scans).
But, well... {Dr. Leonard "Bones" McCoy's voice} "I'm a doctor, jim ! Not a nuclear physicist !"
Re: (Score:2)
As someone who had their brain repaired by a tool with a proton beam moving in arcs 15 years ago, I heartily concur with your description.
The only scars I have on the outside are where they bolted my head to the table. And they won't be visible unless I go bald.
All surgery should be this awesome.
Re: (Score:2)
Re: (Score:1)
Re: (Score:2)
Most skyscrapers and modern bridges are held up by steel beams (and columns).
But all seriousness aside, cathode ray beams were discovered in 1869, and shown to be beams of electrons in 1897. I'd suggest doing a web search before posting.
Anti-matter beam? (Score:2)
I thought we could only produce anti-matter very slowly, a single particle at a time... and thee maximum ever collected was under a 100.
Did something change and we're able to create entire beams of it? Or are they just calling this slow source a beam?
Because the former would be quite the news!
Re: (Score:1)
A physicist at the University of California, Riverside, has performed calculations...
It's all theoretical for now.
Re: Anti-matter beam? (Score:2)
They've probably still already patented it
Re: (Score:2)
We always could create it in significant amounts.
Problem is storage, or "keeping it stable".
And of course it is energy wise expensive, and even if it was not, it would energy wise never be profitable. Aka an antimatter "reactor" or "drive" would never be better than the energy used to make the antimatter.
Re: (Score:2)
For that, gotta have them dilithium crystals.
Re: (Score:1)
If it came into contact with regular matter then 100% of the mass is converted to energy.
Basically it's the most efficiently exploding bomb conceivable.
Re: (Score:2)
OK, time to unpack that. What does "jepordize the world" mean? to destroy the planet ... you'd need to move all the matter of the Earth sufficiently far from the rest to prevent it re-forming (which has already almost happened at least once in the history of the Earth, without necessarily re-setting all of it's radiometric clocks ; in other words, the Earth survived the Moon forming event - just). That means moving the mass of the Earth from an average positi
Re: (Score:2)
Ok you need anti hydrogen in liquid helium ? (Score:3)
This is making Edward Teller's original concept of an atomic bomb pumping heavy metal rods look good
https://en.wikipedia.org/wiki/... [wikipedia.org] (scroll down to project Excalibur)
Re:Ok you need anti hydrogen in liquid helium ? (Score:5, Funny)
https://en.wikipedia.org/wiki/Gamma_Ray_(band)
Re:Ok you need anti hydrogen in liquid helium ? (Score:4, Informative)
It's not anti-hydrogen. That would be an anti-proton and a positron, not an electron and a positron.
Uses (Score:4, Informative)
"may have applications in medical imaging, spacecraft propulsion, and cancer treatment"
Yeah, and the military naturally. Something like this could kill electronics stone dead from a great distance and its affects on soldiers I imagine wouldn't be too pleasent either though whether that would be more practical than just bullets is anyones guess. However it would be extremely stealthy.
Re: (Score:2)
Yeah, and the military naturally. Something like this could kill electronics stone dead from a great distance and its affects on soldiers I imagine wouldn't be too pleasent either though whether that would be more practical than just bullets is anyones guess. However it would be extremely stealthy.
if it's public, the military already has it
If it works... (Score:2)
Sparky's theorem (Score:5, Funny)
Any sufficiently advanced technical description is indistinguishable from a line of dialog from a Star Trek episode.
Attach it to sharks (Score:2)
Re: (Score:2)
Because we need sharks with frickin' laser beams attached to their heads.
Sharks which can swim in liquid helium. They're going to be frickin' cold. PETA is going to flip out.
Re: (Score:2)
Laser capable of emitting a beam of pure antimatte (Score:3)
Oh, dear. I still remember the Rocky Horror Picture Show. If you already have plentiful positronium, you already have plentiful antimatter, and control of its trajectory. What possible use do you have for a gamma ray laser at that point? You're already dealing with Gigawatts if not Terawatts of power simply to generate and control the anti-matter.
Re: (Score:2)
"What possible use do you have for a gamma ray laser at that point? "
It's the coolness factor.
Re: (Score:2)
Yeah, because plugging your phone into the plug in your room to charge it is the same energy like carrying 100kg of sand up into your room ....
Re: (Score:3)
What possible use do you have for a gamma ray laser at that point?
Illuminate the Moon? [xkcd.com]
My roommate in college worked in a laser lab. One day he came home and told me they'd made some ultra short laser pulse. He was annoyed because people complained there wasn't any good reason to want a picosecond flash. Fast forward and some guys got a Nobel Prize for using very short laser pulses to understand chemical reactions.
We science because we're curious. I have no idea why you need such a high frequency laser but I'm sure someone will find a way to discover something about how
Re: (Score:2)
> We science because we're curious
Yes, we do. That doesn't mean we should break the budget on producing plentiful matter without some goal in mind.
Re: (Score:1)
Re: (Score:3)
Positrons _are_ antimatter. While they may be relatively "easy to make", they cost energy to make and tend to combine with electrons and be consumed quite quickly, so you hve to contain them effectively and keep regenerating your supply. This is _expensive_, especially in energy consumption.
Oblig (Score:2)
You want Incredible Hulks? Cause this is how you get Incredible Hulks.
why? (Score:2)
So why do we need a gamma ray laser? We have a lot of other kinds of lasers to pick from. I'm not arguing against it, I'm just curious what applications are expected to benefit from or be possible with such a laser? (though I'm sure there's some Hulk jokes in there aplenty)
Re: (Score:3)
A gamma ray laser would be useful for the existing applications which currently use x-ray lasers.
What kind of ... (Score:1)
Re: (Score:2)
Do you want sharks with Hulk-like powers? Because that's how you get sharks with Hulk-like powers!
Dr. Banner: "Yeah, well be careful." (Score:2)
Is this safe? (Score:2)
One of these days one of these antimatter guys is going to miscalculate and blow up the planet. I don't think they can be trusted.
Re: (Score:2)
This sort of thing has already happened, numerous times. In parallel universes. Remember the worries about powering up the Large Hadron Collider?
Re: (Score:2)
Gamma-Ray Laser Movies? (Score:2)
Time to experiment? (Score:2)
it is time to try doing some experiments. A microgram of experiment outweighs a megagram of calculation.