Finally, an article..
https://www.nature.com/articles/d41586-023-03043-0
Maybe 8 years ago, the lead scientist called me to ask how much it would cost to make a new antimatter trap magnet. He wanted to know if it scaled with length, as the new one needed was a lot longer. I said, not sure, it might be less than linear, as straight lengths were a bit easier than the corners.
He also said... oh, by the way, it will be mounted vertically... to which I said, "oh, you're testing gravity". Suddenly, dead silence on the phone... It was a secret.
(note. The actual magnet had significantly more coils, with accuracies below .001 inch, it was a bear to make..)
End result.. we built the magnet and didn't know what was going on for roughly 3 to 5 years..
Published, cool results.
The techs I work with are the best in the world.. This could never happen without the skills of the two guys who did the work. They are awesome, I am in awe.. Actually, my words to them as I shook their hands were.... you are "effin" great. (nanny software prevents actual words..)
John
ps. It is unfortunate that money doesn't accompany the accolades, as the techs certainly deserve it.
https://www.nature.com/articles/d41586-023-03043-0
Maybe 8 years ago, the lead scientist called me to ask how much it would cost to make a new antimatter trap magnet. He wanted to know if it scaled with length, as the new one needed was a lot longer. I said, not sure, it might be less than linear, as straight lengths were a bit easier than the corners.
He also said... oh, by the way, it will be mounted vertically... to which I said, "oh, you're testing gravity". Suddenly, dead silence on the phone... It was a secret.
(note. The actual magnet had significantly more coils, with accuracies below .001 inch, it was a bear to make..)
End result.. we built the magnet and didn't know what was going on for roughly 3 to 5 years..
Published, cool results.
The techs I work with are the best in the world.. This could never happen without the skills of the two guys who did the work. They are awesome, I am in awe.. Actually, my words to them as I shook their hands were.... you are "effin" great. (nanny software prevents actual words..)
John
ps. It is unfortunate that money doesn't accompany the accolades, as the techs certainly deserve it.
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Just because antimatter doesn't fall up, it doesn't mean that it falls down at exactly the same rate as matter.
The next step will be to make the experiment more sensitive, to see if there is a slight difference in the rates at which matter and antimatter fall.
Revealing a difference may be key to understanding how matter came to dominate antimatter in the first moments of the Big Bang.
The next step will be to make the experiment more sensitive, to see if there is a slight difference in the rates at which matter and antimatter fall.
Revealing a difference may be key to understanding how matter came to dominate antimatter in the first moments of the Big Bang.
Does our polarity of matter really dominate the entire universe, or just in our neck of the woods? If we can go out far enough, could we find enough antimatter to power our homes for the next 3 billion years? Never mind the problem of fetching it, does it exist?
If gravity truly is just a result of the curvature of spacetime, and not the result of an actual “force” then there is no reason for antimatter to fall “up”.
I'd like a bed that presents 1/2 G to anything upon its top surface; would help my shoulders a lot, as I'm a side sleeper.
"had to control the strength of the magnetic fields to a precision of at least one part in 10,000." I wonder what they used to measure the current in those coils? Perhaps its not even possible to do it that way, some other magnetic trick is used...
Congratulations on this remarkable achievement!
Congratulations on this remarkable achievement!
They are very diligent in their work and how they publish. They've been storing antimatter in confinement traps since 2002 as the athena group. That was the first magnetic bottle I worked on. The second they used for spectroscopy. This was the third, and it was significantly more complex.
When the spokesperson for the group gave a lecture at work here, he detailed how they used the trap. What drove me nuts is that the process they use quenches the primary octupole, and they had quenched the magnet over 10,000 times as of that date. I was not happy that they neglected to mention that, as I might have pushed for a bit more insulation and support for the conductors. Luckily, the magnet worked flawlessly.
They measured the effect of gravity, I recall they got up to about 90% with two error bars of 16% I believe. These people will certainly continue and refine the number over time.
The next bottle, if any, will be done by my replacement. He is doing fantastic in picking up the technology and the process experience.
John
Two aspects of control are needed. First, the placement of the wire on the tube has to be precise on average to roughly 5 microns. The methods used are beyond my math capability, that's what we got physicists for. I just came up with the idea. (actually, I accidentally stumbled upon the technique, the physicist figured out the math.)
Second, really good DCCT units put into a 1/10th degree C stable equipment rack are capable of 20 to 50 PPM accuracies, so the supply can be controlled to that level. For machines like synchrotrons, magnet current accuracies require that kind of precision to maintain a stable orbit that the beamline scientists require (tens of nanometers).
John
It's possible that during the Big Bang large clumps of antimatter were left alone, and may be found floating around throughout the Universe.
Some of the small globular star clusters that orbit larger galaxies could well contain anti-stars which are going about their business just like normal stars.
It's unlikely that there are antimatter galaxies out there since galactic collisions are common, and we would have noticed any extreme releases of annihilation energy.
I meant to post on this when I saw it on the BBC last week, but my brain melted when I tried reading into the ALPHA experiment. And then reading how Prof Jeffrey Hangst has spent 30 years building this (or it that failing to get it to work until it finally did?) That's Stoicism for you right up with Monty Python and 'they said you couldn't build a castle on the swamp'!
I also realised that this is was a win whatever. If relativity was proven to still hold a load of theoretical guys would say 'yay', if it was shown not to hold the same lot might have gone 'yay' and run off to fill out funding requests to examine this, and the guys at CERN get to go ask for more money to rebuild ALPHA but bigger this time.
Just as my brain congealed again my eldest pointed me at a paper from her work where they are hunting Axions and I went back to being a gibbering wreck. Just got back to normal. Note to self, approach academic papers on fundamental particles only under adult supervision!
Favourite post from linked paper “Gravity is just so bloody weak, you really have to be careful,”
I also realised that this is was a win whatever. If relativity was proven to still hold a load of theoretical guys would say 'yay', if it was shown not to hold the same lot might have gone 'yay' and run off to fill out funding requests to examine this, and the guys at CERN get to go ask for more money to rebuild ALPHA but bigger this time.
Just as my brain congealed again my eldest pointed me at a paper from her work where they are hunting Axions and I went back to being a gibbering wreck. Just got back to normal. Note to self, approach academic papers on fundamental particles only under adult supervision!
Favourite post from linked paper “Gravity is just so bloody weak, you really have to be careful,”
As a High Energy Physicist, I am pleased that reliable sources are being quoted here:
https://cerncourier.com/a/exploring-how-antimatter-falls/
It was Paul Dirac who first predicted antimatter:
@jneutron, is this the magnet in question?
Enquiring minds want to know.
https://cerncourier.com/a/exploring-how-antimatter-falls/
It was Paul Dirac who first predicted antimatter:
@jneutron, is this the magnet in question?
Enquiring minds want to know.
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Yes, that is the magnet. We were worried about the magnet as we hadn't heard anything from them since Nov 2018.
Because cold testing is so expensive, and historically these direct wind magnets reach short sample without training, nobody wants us to cold test the magnets.
It's always scary.
Note: "short sample" is the ultimate limit for the superconductor within the magnet. It is dependent on the wire capability, temperature, current, and magnetic field. The base conductor is roughly an 18 AWG size wire capable of about 2500 amps at 4.5K by itself, in a magnet the field generated by the coils decreases the ultimate current the wire will take before quenching, typically 1kA to 1.5 kA.
"Training" is what all other superconducting magnets do. It sometimes takes many training quenches to "teach" the magnet how to get up to the desired current. Typically the training is a result of the wires settling into a position due to magnetic forces which can be 5 to 10 thousand lbs/inch or heating of an internal splice joint. At 4.5K, there is essentially no heat capacity in the materials (only helium has heat capacity there), so if an area of the magnet cannot get direct forced flow cooling from the helium then microwatts of dissipation can cause a quench.
John
Because cold testing is so expensive, and historically these direct wind magnets reach short sample without training, nobody wants us to cold test the magnets.
It's always scary.
Note: "short sample" is the ultimate limit for the superconductor within the magnet. It is dependent on the wire capability, temperature, current, and magnetic field. The base conductor is roughly an 18 AWG size wire capable of about 2500 amps at 4.5K by itself, in a magnet the field generated by the coils decreases the ultimate current the wire will take before quenching, typically 1kA to 1.5 kA.
"Training" is what all other superconducting magnets do. It sometimes takes many training quenches to "teach" the magnet how to get up to the desired current. Typically the training is a result of the wires settling into a position due to magnetic forces which can be 5 to 10 thousand lbs/inch or heating of an internal splice joint. At 4.5K, there is essentially no heat capacity in the materials (only helium has heat capacity there), so if an area of the magnet cannot get direct forced flow cooling from the helium then microwatts of dissipation can cause a quench.
John
About all I can gleen from that photo is the "insertion" of the vertical pipe part into the hole in the platform one fellow is standing on. I assume there's a crane and the fellow underneath is guiding the end of the pipe. Where in the photo would the 2m tall magnetic trap be? I assume within the big chunk at the top. The rest of the pipe length is what the antihydrogen atoms fall into?
The long pipe is actually the magnet produced here. Not sure what the box structure above is but suspect it's magnets to steer the antiprotons and positrons down into the trap as well as vacuum pumps of various types.
The yellow above is indeed the crane.
I believe there is also larger quadrupoles and solenoid magnets that go around the trap as well. Also, the detector apparatus to see the annihilation products.
John
The yellow above is indeed the crane.
I believe there is also larger quadrupoles and solenoid magnets that go around the trap as well. Also, the detector apparatus to see the annihilation products.
John
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I'm not sure why there was any doubt in the result but of course, you have to do the experiment to be sure.
I agree with a growing viewpoint that mass is an emergent (not fundamental) property (protons/neutrons dominate matter we are familiar with and their mass is due to the energy of the particles contained within them) and anti-particles have the same property.
I agree with a growing viewpoint that mass is an emergent (not fundamental) property (protons/neutrons dominate matter we are familiar with and their mass is due to the energy of the particles contained within them) and anti-particles have the same property.
Wouldn't matter and antimatter have to be superbly symmetrical, in all senses, or annihilation would not occur?
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