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Comment by orbifold | Hacker News Reader

More likely than not the next collider will be build in China, quite a few particle physicist luminaries have already made their case there. I for one am glad that I stayed clear of the siren call to join the 3000+ grad student workforce at CERN. Sifting through the heap of data that was assigned to you is about as fun as it sounds I think. You get to look for the J/Psi, Pomeron, Dark Matter how exciting! In reality most of the detectors are barely functional, Alice for example doesn’t produce useful data for most of the runs.

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That’s just the nature of the machines. You spend so much effort to get to the nuggets, but you still get the nuggets.

Does China have experience making particle colliders? I’ve seen their magnetic confinement fusion research devices. Even in the design stage, there are lessons yet to be learned that are well documented in other machines. That doesn’t mean the people working on them are dumb, or that all fields of large-magnetic-confinement-machine-building physicists are in the same position, but I think we should be pretty sure whoever builds the next big particle collider is actually up to the task.

These don’t get built by countries. They get built in countries. The home country matters and they’ll need to put up funding, but it’s an international workforce.

> The home country matters...but it’s an international workforce.

Given the current state of the world and the trajectory of the West's relationship with the Chinese government, it may have to be built by China if it's going to be built in China.

China has a lot of STEM expertise, I'm confident they could probably figure it out.

Then it should be easy to demonstrate with smaller scale projects. Where are those demonstrations?

https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Sp...

If you mean smaller accelerators, it's unclear what the value in that would be.

Actual design and building of physics experiments is a lot more complicated than “just doing it”. There are thousands of places that one small oversight will cause the entire project to fail. You will never successfully make a city size particle accelerator if you cannot demonstrate the ability to design and build a tabletop version, let alone a room scale, let alone a building scale, let alone a city block scale. It is cheap to demonstrate at a small scale. It is expensive to fail at a large scale.

With respect, I have no idea what your link has to do with anything. Making a giant dish is absolutely trivial compared to a particle accelerator.

My point is that Chinese medium-scale magnetic confinement fusion research devices have not learned from 60 years of painful lessons that the fusion research community have learned and published. Magnetic confinement fusion research machines share a lot of similarities to particle accelerators. Is there any indication that China would succeed in making a particle accelerator other than “they are good at STEM” and have made a giant parabola? It’s not very convincing.

There's a difference between theoretical and practical expertise.

I don't know much about particle accelerators, but I do know a bit about advanced manufacturing and I think you might be surprised at the degree to which Chinese industry is still functionally dependent on foreign machinery and expertise.

This is a country that, until about two years ago, couldn't successfully produce an entire ballpoint pen using fully domestic processes.

> an entire ballpoint pen using fully domestic processes

Which countries can?

USSR was capable of doing it in 1980s.

I feel like any possible item that you claim is domestically produced only implies you're selectively ignoring the non-domestic inputs. If you pick up a stick off the ground and whittle it, where did you get the knife? How did you earn the money to buy the knife? Where did your food come from? What about the education that allowed you to get the job, was it contaminated by foreign influence...

If you believe that there is a country that could, seems to me you would be taking it on faith, and in my opinion, ignoring uncountable foreign inputs. Unless you wanted to argue North Korea?

There probably is a country that could go from rocks to finished pen entirely domestically (Germany?) but that wasn't really my point.

I was trying to illustrate the broad chasm between theoretical and practical expertise. Just because someone "knows a lot of STEM" doesn't mean they can actually produce a useful thing. China already had perhaps the most highly concentrated amount of manufacturing engineering expertise anywhere in the world, yet still they needed help with what most people would consider a basic item.

This is fine! Most countries, as you noted, are in the same position. It's a desirable outcome of globalization.

It becomes problematic, though, when your goal is to build an incredibly complex machine that requires expertise beyond your own (like a particle accelerator, perhaps) and the people and countries whose help you require are unwilling to work with you.

Is it supposed there are enterprises located in China exempt from oversight or control by the CCP? To what extent would decisions made within the enterprise be subject to President Xi's vision of complete control?

My understanding is, when it benefits them they will make a loophole to give some degree of autonomy. But they can revoke it as easily as they offer it.

But I don’t really know anything about China.

I think people severely underestimate the scale, complexity, and time it takes to build large scale accelerators. There wont be some magical new accelerator popping up. Building them takes years, sometimes decades. Additionally you need a lot of experience in building, operating and designing those. Having worked in accelerator physics for quite some time my opinion is that China does not have the skills to do this. Research labs that built such machines had decades of prior experience and the community support. China has neither of those.

Imho the next big accelerator will be either some LHC upgrade, clic (very very unlikely) or the ILC.

> There wont be some magical new accelerator popping up.

There will and it will come from photonics research.

Or even crazier stuff like wakefield accelerators and petawatt lasers. At this point the LHC is like ITER - advancements to the foundational technology have jumped leaps and bounds yet we're still stuck with a huge multi-billion dollar machine running on fairly outdated tech.

That is simply not true, the plasma wakefield accelerators are really a rather new technique but they are NOT meant to be used at such high energies, but rather for small experiments. Also (as far as I know), while they do have vastly superior energy gain per meter, you simply can't concatenate several of them (as you do with SRF cavities). So at the current state, if you want to reach TeV of colliosion energy, SRF is the only way to go.

Current plasma wakefield accelerators are in GeV range, we need TeV.

That is really vague. Even if there are interesting advancements in photonics, I seriously doubt that it will be able to accelerate particles to terra electron volts of colision energy in a controlled manner (in the next few years). Everybody I know that works in accelerator physics believes that for large machines, superconducting radio frequency cavities are the way to go.

Of course they do because their jobs depend on it. And nothing in this field has ever been done in a time-frame of a few years.

It is a simple matter of voltage gradient. The higher the frequency, the steeper the gradient.

> The higher the frequency, the steeper the gradient.

Losses also scale with frequency.

And while other acceleration principles have higher voltage gradient, they still can't reach TeV of collision energy, since you either can't concatenate them, or you can't control the beam sufficiently well.

As I wrote in another comment, stuff like plasma wakefield accelerators need to get better by a factor of 1000 before they reach the realms of SRF accelerators. This wont magically happen over night.

And most of these people have tenure, they hardly care for trends.

I have been to all major accelerator physics conferences over nearly the last decade. Despite clic there is no one seriously claiming to go beyond LHC energy without SRF. No one. Not the plasma wakefield guys, not some strange theoretical accelerator principle. No matter what you read on Wikipedia.

Your namedropping comments with very little actual content, disregarding the work of thousands of scientists show a certain arrogance that is super annoying.

> In reality most of the detectors are barely functional, Alice for example doesn’t produce useful data for most of the runs.

Do you really expect a detector/machine of the size of a building to have 100% availability ?

This is the sciences world, boy, not aerospace engineering. These detectors are ''home-made' and much closer to an experimental prototype than to anything "engineered". We do not name them "CERN experiments" for nothing.

I’m with you.

Not only the job didn’t seem to match the prospect, the “large organization politics” drove me away pretty quickly.

And when you graduate you get a not in this field job because it's so competitive you probably were already ineligible by the time you started your PhD.

Well three of my friends are still hanging in there with a non-zero chance of success because they did their PhD in the right group. But yeah if you aren’t well connected or your advisor doesn’t like you this is a dead end.

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