rHXN - CERN bids farewell to the LHC and enters Long Shutdown 3

max-ch - 5 hours ago

I was visiting CERN on one of their Open Days during the previous shutdown. This is one of the rare occasion where visitors can enter the LHC. I walked for about 500m along the beam which is remarkably small despite all its protection.

Standing inside LHCb (one of the experiments where they track collisions) was one of my most awe-inspiring moments about science and technology. Photos don’t do it justice. It’s a multi-story building underground, but every inch is covered with cables, sensors etc. Seeing it on photos is one thing, standing inside the biggest machine built by humankind is a completely different experience and hard to put into words.

The amount of thinking and planning that went into it is insane. CERN staff is super-friendly and open to talk and explain. If you have the possibility to visit, do it - especially with guided tours and on their annual Open Days.

g6pdh - 3 hours ago

I'm a former LHCb physicist and I worked for years in the cavern, fixing the cables you saw :) Thanks for your enthusiasm. Obviously, things seen from the inside aren't as ideal as a non-physicist person might think. There are the usual power dynamics you find in academia: PhD students and postdocs exploited to do service and technical work instead of independent research, careerism, researchers who have to worry more about symbolic roles and political aspects than actual research, as if the PhD->Postdoc->Tenure->Professor career model serves to create real expertise and not vice versa. In general (personally) I've felt a strong sense of frustration at how modern research in particle physics is producing papers that are all identical to each other and have no true scientific impact, other than increasing the h-index, hoping to get a permanent position somewhere. Forgive the outburst, I'm in the IT industry now and I'm feeling definitely better, but eventually it was great and educational to do research at CERN.

kashyapc - 1 hour ago

> felt a strong sense of frustration at how modern research in particle physics is producing papers that are all identical to each other and have no true scientific impact

Your comment above makes me think of Sabine Hossenfelder[1]. I'm sure you must've heard of her. I know she's somewhat of a "polarizing" figure. As a former "insider", do you think her core point stands? (Which is, the particle physics field has largely nothing to show for after spending billions of public money. Some particle physicists have even predicted so-called "unparticles", which almost sounds like trolling!)

[1] https://en.wikipedia.org/wiki/Sabine_Hossenfelder

g6pdh - 53 minutes ago

Yes, I know her and I agree with what she says. I also think many physicists working in the field secretly agree with her but it's a taboo to admit it openly. As an insider I can assure you that currently most analyses in experimental particle physics are a mechanical repetition of previous analyses with a few slight modifications to adapt them to the bigger statistics. It's true that it could simply be an effect due to the experiments lifetime, that have been running for 20 years now and where younger generations are struggling to come up with ideas not yet explored. I can speak less from the perspective of theoretical physics, but it seems obvious to all those in the field that there's a proliferation of papers proposing new particles, new interactions, etc. with no real impact.

kashyapc - 43 minutes ago

I see; thanks for expanding on it so honestly.

atemerev - 2 hours ago

I am in the industry too and I wish to get back to the academia sometimes. Sadly, CERN is not hiring Russians no matter what are their political convictions (I am pro-Ukraine, of course). But yes, as a Geneva resident, I was at the tunnels too (Alice), and I am always in awe every time I see this wonder of the modern world. Sometimes I wonder how actual humans could build this, much like people did for the pyramids.

PradeetPatel - 2 hours ago

>Sadly, CERN is not hiring Russians

Is that even legal under Swiss discrimination laws?

Symbiote - 1 hour ago

I don't think CERN is bound by Swiss laws. It's an intergovernmental organization with sovereign immunities.

Cthulhu_ - 1 hour ago

Try proving they're rejected because of their nationality. That said, CERN itself does have some official statements on the matter:

- The International Cooperation Agreement has been terminated in 2023, following the invasion of Ukraine (https://international-relations.web.cern.ch/stakeholder-rela...)

- Their recruitment policy states they source among their member states except when they really really can't find someone to fill a position from there (https://careers.cern/recruitment-policy/).

I'm not sure if / how that works together with discrimination laws, however, discrimination is a different subject than nationality I think. I can't just work in the US, not because I'm Dutch but because of visum / labor / market protection / etc laws. And with CERN, added factors to consider are international funding, espionage, sabotage, etc. Some countries may decide to pull funding if CERN were to, for example, continue working with Russia or hire Russians.

tl;dr it's a lot more complicated than discrimination.

dylan604 - 5 hours ago

As a high school kid taking physics, we got to tour the Superconducting Super Collider campus. Obviously, this was nothing compared to being next to something that was actually built and did science, but they had a the various instruments and segments the beam tube with the magnets on display. Some students would intern there during the summer. The plug was pulled by Congress before I could apply. That was my introduction to politics in science where the kid like notions of how things worked were shattered.

adastra22 - 4 hours ago

You can still tour the SSC. Just requires wire cutters and a bit more spelunking.

amarant - 1 hour ago

Damn that sounds fun! How big a risk of being shot would I be running if I tried this?

adastra22 - 1 hour ago

A non-negligible risk. More likely to get lost and drown. I wouldn't do it. But you can read about it:

https://medium.com/@liboski/the-superconducting-super-collid...

https://weburbanist.com/2014/09/11/the-desertron-worlds-larg...

MikeNotThePope - 5 hours ago

I felt a similar way when I visited the Gran Telescopio Canarias, a 10.4m telescope in La Palma in the Canary Islands. It’s hard to take pictures of the entire telescope because it’s so damn big. I love experiencing the feeling of being in awe.

braggerxyz - 2 hours ago

I totally feel you. I visited CERN in 2002 when LHC was already in construction and we also visited the construction site of one of the earliest detectors ever build there. This thing was really really huge. We also visited the data center of the detector with its multi-pass data collection system which at that time was super impressive. It was designed to collect Terabytes of data within a fraction of a second. The hardware was very impressive. We also visited the central data center where one of Europe's internet backbones is hosted. The data silos were also very impressive. The amount of compute power and data storage available there were unimaginable high for that time. I think it will dwarf those numbers today while being not that impressive because data and compute density skyrocketed since then.

madaxe_again - 4 hours ago

I spent a week there between the LEP going offline and the LHC going online on a school trip - the scale of it is just unreal - as you say, photos are one thing, but as you stand there in a vast subterranean cathedral looking up at the frantically complex detectors (we hung out with ATLAS a fair bit) it’s… awesome. In the very literal sense of the word.

Don’t know if you visited the antiproton decelerator/LEAR but they’re similarly unreal - a vast cavern, half a dozen stories high and so large it fades into blackness beyond the floodlights illuminating the various buildings and experiments within there. You descend in a rickety cage loft surrounded by no more than a box of girders, to be greeted by a vision straight out of sci-fi. Vast lead megaliths tower around like the work of some very precise techno-druids, cables and ducts snake across the floor to join unknown experiments occluded by the henges, and in this place, they make the stuff the universe abhors.

Wild stuff.

Oh, I also got to tool around on Tim’s computer which was just sat in the cafeteria at the time.

someonebaggy - 1 hour ago

Sounds like it probably inspired the underground part of Aperture Science

kakacik - 2 hours ago

Same here, beautiful experience and I am not hardcore phsysics/cabling/engineering nerd. The cleanness, the precision of lay of every single little cable, the sheer size of the detector when opened (was there... 2012ish, one of maintenance times).

This is spending that makes me proud to be a human and gives me hope for mankind, in similar vein as ie JWST telescope.

agar - 12 hours ago

I wonder whether the cancellation of the superconducting supercollider was a net positive or negative for science.

If it continued to completion, it would have had almost 3x the beam energy of even the upgraded LHC in 2030 (20TeV vs. 7TeV). But the questions are fundamentally political, not scientific: Would SSC operations and funding have continued through the US economic challenges of 2001, 2008, and 2020?

I could see a timeline in which the SSC got built and discovered the Higgs boson before LHC came online, causing the LHC to be canceled, delayed, and/or starved of funding -- only for the SSC to be shuttered during the "great recession" of 2008 or during any other US Gov't belt tightening exercise. Today we would have neither the SSC nor the LHC.

Or, perhaps SSC would have accelerated other discoveries by 10 to 15 years (SSC go-live was to be in the late-1990's versus LHC's Higgs discovery in 2012).

adgjlsfhk1 - 9 hours ago

From what I've heard, the SSC would have had higher power, but much worse luminosity (i.e. much more noise) than the LHC.

pfdietz - 11 hours ago

Perhaps SSC's cancellation avoided a nightmare scenario where all that energy beyond what was needed to find the Higgs was wasted. And perhaps Science as a whole benefited from diversion of resources away from fundamental particle physics.

agar - 10 hours ago

Perhaps. I do remember the discussion about whether the SSC consumed so much basic research funding that other areas would have their funding significantly constrained.

Basic research has such a long time horizon it's interesting to think of the fundamental grants that might have been affected. Quantum computing? CRISPR? mRNA?

brokencode - 13 hours ago

I feel like the title is a little overdramatic.

They’re not saying goodbye to the LHC, they’re upgrading it to have 10x the power.

sigmoid10 - 12 hours ago

Probably because the upgrades to the collider are so significant that it will be called the HL-LHC afterwards.

jdironman - 7 hours ago

Hella Large - Large Hadron Collider?

someonebaggy - 1 hour ago

I think it stands for Huge Large Large Huge Colossal, in reference to its size.

onion2k - 6 hours ago

Ho-Ly - LHC maybe.

moi2388 - 6 hours ago

High luminosity large hadron collider

p1mrx - 11 hours ago

They're collecting 10X more data, at roughly the same energy per collision.

vikingerik - 10 hours ago

The article says "10x luminosity", and here's what seems to be the explanation.

https://en.wikipedia.org/wiki/High_Luminosity_Large_Hadron_C...

That's the wiki article for the new one. Says "Increasing LHC luminosity involves reduction of the beam size at the collision point, and either the reduction of bunch length and spacing, or significant increase in bunch length and population."

The linked article says the new one will have "between 140 and 200 proton–proton collisions in every bunch crossing, compared to around 60 during the last LHC run." So the "10x luminosity" seems to be composed of ~3x more protons at a time along with presumably a ~3x tighter focused beam.

NooneAtAll3 - 1 hour ago

luminocity is collisions per second

energy is per individual collision

can't increase energy that much without increasing radius

doodlebugging - 10 hours ago

I had to chuckle a week or so ago when I was bumbling across the internet and landed on an article that had a link to a nutjob page where the title was something like: "CERN found something so disturbing they had to shut down immediately".

The nutjob article (yes, I did read it, LOL) suggested that they had found some universal truth maybe about God or aliens or something, and it scared them so much they just noped out of the science business to prepare themselves for the inevitable revealing of the "truth".

It is truly no wonder that so much of society is so fundamentally fucking stupid when their trusted information sources are so full of obviously false bullshit.

I can't wait until the LHC is back online zipping tiny things around the ring again in a cosmic demolition derby to find the smallest specs of our reality and give them all whimsical names.

sieste - 3 hours ago

I treat these nutjob articles as a subgenre of science fiction and when they're somewhat well written find them very entertaining. The author cosplaying investigative journalist, one part of the audience acting as if it's a real discovery and another part playing debunking and outrage, is all part of the performance and it's hilarious. Check out the flat earth movement, it's great entertainment all around!

pif - 3 hours ago

Luminosity, not power!

cheschire - 12 hours ago

by Tim the Particle Man Taylor

sigmar - 10 hours ago

I visited CERN last July. Was lucky enough to get into a group tour. The tour guide was a postdoc researcher who said the only times that public tours are allowed to take an elevator down is during long shutdowns. So while they do this work on LHC might be the best time to swing by for a tour (I might even try to return).

Even without the descent, my tour was great with showing the 70 year timeline, historical early particle accelerator equipment, and a cool view of the ATLAS control room. The facility is awe inspiring and a testament to Europe's willingness to make long-term commitments to furthering science research for the public good.

buildbot - 8 hours ago

I worked on a tiny, tiny part of the research for the insertable B layer in ATLAS during long shutdown one as an undergraduate - the 3 year period allowed all the detectors to be upgraded significantly! It will be interesting to see how the current systems are upgraded during this shutdown. Sounds like the ITK for ATLAS is absolutely _insane_ compared to the insertable B layer - 5 billion channels, up from 8 million. I wonder if ITKpix is at all similar to the T3MAPs cmos or FEI4 sensors we worked with…

Edit Looks like it’s very different; and really cool: https://cds.cern.ch/record/2928802/files/ATL-ITK-PROC-2025-0...

xAlecto - 1 hour ago

For anyone interested in doing some very special visits this will be a good timing. Long Shutdowns are the only moments where a lot of usually inaccessible places can be visited.

There should be (not yet officially confirmed) an open days after summer next year, just like there was in 2019. Short time frame but for a few days everything(-ish) is accessible, including going down in the LHC tunnel, but many more crazy places.

In the meantime there are still permanent exhibitions and guided tours for those interested. Come have a look at the cool science (made with your taxes)!

charmd - 1 day ago

I've read that CERN is storing more than 1 exabyte of collisions data these days (up from 600PB during the last long shutdown https://information-technology.web.cern.ch/sites/default/fil...). Not too shaby...

DiabloD3 - 14 hours ago

All using ZFS, too

tempay - 12 hours ago

No they're not. At CERN physics data is on:

* CTA for tape storage: https://cta.docs.cern.ch/v5/

* EOS for disk storage: https://eos-web.web.cern.ch/eos-web/

There is a large CEPH cluster as well but that isn't really used for physics data.

dcrazy - 11 hours ago

More specifically, from the EOS page:

> Data is stored natively in XFS filesystems on hard disks or SSDs or on virtualised back-end storage (e.g. RADOS block devices) or distributed filesystems like Lustre or CephFS.

DiabloD3 - 10 hours ago

Interesting, they used to be the largest ZFS user.

Hard to Google for it without getting AI slop on it, but apparently they built their own stack in 2019.

Not sure I like their solution, "Meta-data is persisted in RocksDB databases using a proprietary KV store called QuarkDB." Unless QuarkDB has magically removed RocksDB's amazing ability to corrupt and lose data frequently, this whole thing sounds like a bad idea.

Also, their data is not stored on any one system (local XFS, Ceph, Lustre), a recipe for disaster.

scheme271 - 4 hours ago

There's at least 3 copies of all the data and possibly more spread around the world at different Tier1 and Tier2 centers. The T1 and T2 centers are very likely using different filesystems and everything is checksummed pretty much at every major step (data generation, before and after any network transfers, before analysis, etc).

dijit - 14 hours ago

uhoh, can only store 1000 of that dataset then. D:

DiabloD3 - 13 hours ago

In one pool, sure.

You can have more than one pool.

pjmlp - 1 day ago

Having done my little contribution to ATLAS TDAQ/HLT in the early 2000's, it is an interesting feeling to see the next steps taking shape.

kristopolous - 13 hours ago

The typo that sometimes got through in official literature still makes me giggle

https://www.google.com/search?q=site%3Acern.ch+%22large+hard...

modeless - 13 hours ago

https://web.archive.org/web/20170814124609/http://largehardo...

pryelluw - 9 hours ago

Maybe some enterprising Las Vegas citizen will jump at the opportunity to turn that idea into a hard asset.

archimedes237 - 14 hours ago

Hopefully no sophons appear.

kridsdale1 - 13 hours ago

You don’t want an ocular alarm clock?

underlipton - 12 hours ago

Hyperstrategic origami.

lyu07282 - 5 hours ago

[dead]

drybjed - 13 hours ago

El Psy Kongroo.

ursuscamp - 13 hours ago

Too late, damage is already done. We have been on the wrong timeline for years at this point.

zombot - 2 hours ago

The LHC is dead, long live the HiLumi LHC!

ComputerGuru - 8 hours ago

Am I the only one that feels three/four years is a mighty ambitious timeline for the upgrade? It seems to be a very significant undertaking…

xAlecto - 1 hour ago

Keep in mind this is for the hardware work. We have been working on the HL-LHC from the physics / beam dynamics / everything else side for close to a decade now.

The other machines in the complex, which we call "injectors" from our mighty tower, have already undergone their own upgrade to be ready for HL-LHC, the LIU (https://home.cern/accelerator-chain-prepares-high-luminosity...).

Nonetheless there are plenty of things to be done and a lot of technologically engaging challenges ahead so this 3-4 years is still ambitious ;)

scheme271 - 3 hours ago

It's been in the planning stages for at least 5-8 years at this point. The instruments and upgrades have been tested and validated so it's just putting stuff together and then validating/calibrating. Stuff can still happen like the splice issue and repairs.

usernamed7 - 12 hours ago

I was surprised to see .cern as a TLD - i would not expect it to need a family of websites in the way .gov or .mil do.

oliyoung - 11 hours ago

To be fair, if any org deserves a vanity TLD it's CERN

saghm - 5 hours ago

Yeah, given that the web was basically invented there, it seems pretty reasonable

Cockbrand - 2 hours ago

I was too, and I was going to ask whether this is a good use of taxpayer money, as the ICANN fee for registering a TLD is $227,000. But given the fact that the Web was invented at CERN, I could imagine that they got a special deal.

Happy to learn about details if someone knows more!

pezezin - 10 hours ago

CERN is so big that they have their own IXP: https://cixp.net/

Also, the web was invented at CERN, so like the other comment said, if someone deserves at gTLD is them.

gojak - 4 hours ago

Actually, in the 2000's CERN was the biggest internet exchange point in Switzerland, while the physical datacenter was not in Switzerland but in France xD

andrewf - 11 hours ago

It's a brand gTLD, like .microsoft and .google. https://en.wikipedia.org/wiki/Generic_top-level_domain#Brand...

s5300 - 3 hours ago

[dead]

nok22kon - 13 hours ago

bad timing with the price of RAM and NAND

tempay - 12 hours ago

Maybe not that bad, stopping the accelerator means the storage requirements drop now that data is no longer being taken. Storage is instead just used for simulation and reprocessing which is small in comparision.

So long as the market recovers before HL-LHC starts and the data volume increases it'll be okay. If it doesn't...

gojak - 4 hours ago

They will buy the hardware last, at the end of LHC to get the best hw possible. Helium is a bigger problem, since CERN is the biggest Helium cryo-installation in the world...

servo_sausage - 6 hours ago

The LHC is such a crazy thing; kilometres of strange infrastructure, thousands of people, all for what seems like pure scientific curiosity.

I think only surpassed by the SETI program in terms of doing it because many nerds think it's really cool.

otabdeveloper4 - 5 hours ago

Politicians think it's a moonshot project at finding another nuclear bomb type of thing. (None of this would ever be funded without the tenuous nuclear weapons connection.)

KeplerBoy - 4 hours ago

That doesn't sound like something one would want to do in cooperation with the entire rest of the world.