I’ve fired one of America’s most powerful lasers—here’s what a shot day looks like

The laser was used to study the physics of stellar interiors and fusion energy, among other things.

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[Cryxx]

The laser is in an area that is shut down, but makes you wonder how often it's checked to ensure everything is there and secure? The ones who would know were the ones working on it. They are not there or off doing other things. A lock only keeps out those that follow the rules.

 

[spopepro]

It seems everything is bigger in Texas, including the lasers and budget cuts. I’m surprised this was cut because of both the real world defense applications, and one of the subsystems in the golden moron’s Golden Dome fantasy are laser dazzlers and destroyers.

Edit to ablate excess words with a laser

I think the budget situation may be complicated and extremely political, but not in the way other commenters are assuming.

The Dept of Energy under Bush II opened up the national lab contracts under the guise of “improving efficiency” but it was really to break the University of California’s control of most of the labs. Controversially, many administration contracts went to the University of Texas. Questionable both because of the location of the school and the president, but also because UT had no standing capability to actually staff and supervise their labs. Lab subversion is now more diversified, and the trend seems to be to make joint ventures between university systems and sometimes private partners. But UT’s involvement with national lab administration has been dramatically reduced, so their ability to conduct DoE work in system is also very likely reduced.

 

[kaced]

I read a book about the history of chemistry to learn more about how they figured out that oxygen and nitrogen are different things given the tools available 300-400 years ago. The invention of the vacuum chamber was the key development. So why was it invented? To study gases, not for any commercial purpose. Being more of an engineer than a scientist myself, it’s interesting to me how to this day how scientific instruments like this one have to be built by scientists, who also have to be engineers themselves. I’m sure this laser wasn’t designed and built by one person, but the physicists behind it clearly need to know a lot about machines and their components. The guy with the coffee cup studying matter doesn’t need to know the intimate details of how it works, but the people building it definitely need to know a lot about physics. If you want to build many of something, you probably hand it off to a team of engineers to make it easier to replicate, but scientists themselves have to design the things they need.

 

[el_oscuro]

So much this. I've seen how AI's tend to construct complex sentences; they're just parroting back all the grammar they've been trained on. They do tend to spit out grammatically complicated passages without much attention pacing and rhythm though. But too many people eager to pounce on suspected AI writing don't or won't notice and just randomly accuse writers who have a good college-level writing style.

Em-dashes aren't a guaranteed tell for AI writing.

I never understood the whole em-dash thing, given that Microsoft Word by default converts regular dashes to em-dashes. So if you write a word doc, it will likely have them. It has been this way for at least 10 years.

This has been a royal PITA for me as I write and review Unix SOPs and these em-dashes screw up all of the Unix command options in them.

 

[Mungus the Unhyphenated]

I never understood the whole em-dash thing, given that Microsoft Word by default converts regular dashes to em-dashes. So if you write a word doc, it will likely have them. It has been this way for at least 10 years.

This has been a royal PITA for me as I write and review Unix SOPs and these em-dashes screw up all of the Unix command options in them.

MS Office autocorrect is both a boon and a bane, depending on the nature of what you're typing.

As a senior-level analyst in IT, it's a particular issue because in a single email or document, I may be communicating both non-technical and highly technical information. The narrative has to be formatted to be readable, and technical segments have to be unambiguous and safe to easily copy-and-paste into a command window or a scripting environment/IDE.

I make a point to switch to a proper monospace font for any code lines or commands, even mid-sentence. MS products at least respect that that and generally don't try to do advanced formatting on things like Courier and Consolas.

It also drives home the difference between when I'm explaining stuff and when what's on the page is what belongs on the screen/command line/in the PowerShell script, etc.

 

[Angstroman]

It seems like just one speck of dust on some of the optical elements would cause a problem. I'm wondering how they keep 'em clean. Windex?

It has been quite a while since I ran a high powered laser with enough power ("only" tens of gigawatt vs the TPW) to damage coatings and optics. But in those days the final clean was done with dry (so not water spotting) technical ethanol using only the capillary force of a lint-free tissue dragged across the surface. This was done in a clean environment. After cleaning there was also a very slight dry nitrogen purge near the optical surface to prevent infiltration of any dust that managed to get in the clean environment. It only takes one speck of dust to star an optical surface when it explodes in the beam. I suspect the current technique is similar.

 

[ReadandShare]

"which is currently closed due to funding cuts..."

And yet, we've to build that stupid arch and ballroom! Instead of doubling down on STEM investments, we have collectively chosen to rally behind fascism and leader worship as the path to making America 'great' again.

 

[Photon_plumber]

The laser is in an area that is shut down, but makes you wonder how often it's checked to ensure everything is there and secure? The ones who would know were the ones working on it. They are not there or off doing other things. A lock only keeps out those that follow the rules.

If you’re worried about theft, those items are very unique and ownership is quite documented. Of course, surplus items come up for sale occasionally. I have a rather massive Nd:glass rod that was used in Livermore laser fusion experiments in the late 80s in my collection.

 

[void&]

Word automatically converts single dashes ('-') to en-dashes ('–'). They are particularly insidious — it's hard to tell visually when a shell script or code sample has been corrupted. Word converts double hyphens ('--') to em-dashes ('—'). They are annoying, but it is a little easier to spot the lack of a gap. </pedantic>

 

[Speakertoanimals]

The deeply unpopular MD of a company I worked for came to see the demonstration of a prototype carbon dioxide laser. The guy who designed and built it thought H&S applied to other people and didn't even insulate the caps of the capacitor bank, relying on a "Danger high voltage" warning sign. This is early 1980s.
The said managing director decided to poke around while waiting and put his hand out towards one of the capacitor terminals. The Chief Engineer instinctively knocked his arm away. The MD stormed off (he would later sack the Chief Engineer.) As the MD slammed the outer door behind him, my boss said quite audibly "What did you do that for?"

Can you imagine the paperwork and meetings that would result from an "Accident" like that? Plus the clean-up of the remnants of the former carbon-based life form?

 

[Erbium168]

Can you imagine the paperwork and meetings that would result from an "Accident" like that? Plus the clean-up of the remnants of the former carbon-based life form?

Plenty of witnesses, all of whom liked both the Chief Eng and the Technical Director.

You reminded me though of the friend of one of the in-laws who was in charge of a surface to air anti-terrorist missile station on top of a block of flats during the London Olympics. I asked him if he hadn't secretly hoped that there would be a terrorist aircraft attack and his lads would be the ones to shoot it down.
"Oh no," he said, "I'd still be doing the paperwork."

 

[Erbium168]

I read a book about the history of chemistry to learn more about how they figured out that oxygen and nitrogen are different things given the tools available 300-400 years ago

Oxygen was only definitely identified a couple of hundred years ago due to the major screwup by Boyle who started the hare of the phlogiston theory, which held things up for a century.
For some reason I have a copy of the 1915 history of chemistry written by an FRS. The prestige of Boyle was so immense that even then, in explaining how he got it so wrong, the author was circumspect about it. Boyle is called in England the "father of chemistry" but it was Lavoisier who did the heavy lifting.
Oddly the discovery of nitrogen nd hydrogen preceded the definite identification of oxygen.

 

[GitM]

The link to the TPW web page has the energy as 140 J in a 140 fs (140×10 ^-15s) pulse which is 10¹⁵ W

Let's see... If light travels 11.8 inches in a nano-second, that'd make the pulse roughly 1.652 inches long. I don't know what frequency the laser operates at, but for visible light, I'm coming up with 5 x 10²⁰ to 2.7 x 10²⁰ photons in each pulse.

According to the Boom Table, 140 Joules would be roughly equal to 70 milligrams of black powder or 33.6 milligrams of TNT or 1.4 firecrackers. Which doesn't sound too bad, but if you kept that pace up for an entire second...

1 billion/.14 = 7 1/7 billion * 33.6 milligrams = 240 billion milligrams = 240 million grams = 240,000 kilograms = 240 metric tons = .24 killotons per second. Yeah, that would sting. (Roughly 20 Mother Of All Bombs per second.)

 

[Erbium168]

You'll never guess what ChatGPT is trained on, or as you put it, whose output it imitates.

No I wouldn't guess...I know how it works.
As new material is added to its training material, changes in style caused by adaptation of human authors to AI will incresingly find their way into AI until, like the mythical poot bird, it will fly in ever decreasing circles and disappear up its own cloaca.

 

[JohnDeL]

(Roughly 20 Mother Of All Bombs per second.)

A geophysics professor I used to work with liked to quote Vader whenever he would visit the labs and they'd start bragging about how "powerful" their lasers were:
"Don't be too proud of this technological terror you've constructed."

IRIS Earthquake Energy Equivalent chart:

 

[NdYAG]

It has been quite a while since I ran a high powered laser with enough power ("only" tens of gigawatt vs the TPW) to damage coatings and optics. But in those days the final clean was done with dry (so not water spotting) technical ethanol using only the capillary force of a lint-free tissue dragged across the surface. This was done in a clean environment. After cleaning there was also a very slight dry nitrogen purge near the optical surface to prevent infiltration of any dust that managed to get in the clean environment. It only takes one speck of dust to star an optical surface when it explodes in the beam. I suspect the current technique is similar.

Impurities in the glass itself can also cause self-focusing and damage.

 

[AdamM]

So much this. I've seen how AI's tend to construct complex sentences; they're just parroting back all the grammar they've been trained on. They do tend to spit out grammatically complicated passages without much attention pacing and rhythm though. But too many people eager to pounce on suspected AI writing don't or won't notice and just randomly accuse writers who have a good college-level writing style.

Em-dashes aren't a guaranteed tell for AI writing.

Especially since you’ll find em-dashes in a news article, a children’s book, and the writings of someone with a Grammarly account.

 

[bratkitty]

I sure hope they don't. A hyphen and an emdash have different grammatical purposes.

A hyphen joins words or word fragments, while an emdash sets off additional information or indicates a pause. Some word processors will turn a double hyphen into an emdash, but I haven't relied on that for years as on MacOS an emdash can be easily typed with "option-shift-hyphen" and on iOS you hold down the hyphen until a selection menu pops up giving you access to a variety of different dashes.

MS Word will turn a space-hyphen-space into an em-dash, since it's super rare that you'd have spaces bracketing a hyphen that should remain a hyphen.

 

[SomewhereAroundBarstow]

No I wouldn't guess...I know how it works.
As new material is added to its training material, changes in style caused by adaptation of human authors to AI will incresingly find their way into AI until, like the mythical poot bird, it will fly in ever decreasing circles and disappear up its own cloaca.

No writer who treats writing as a craft is going to imitate AI. If anything they'll go to greater pains to make sure they retain their own distinctive voice. What will happen is people who don't have any respect for the craft will increasingly outsource writing to AI and that output will then be ingested by AIs and thus AI output will become more and more homogeneous as the volume of AI-generated writing buries the human-generated writing. This will have the effect of making human writing stand out even more amidst the sea of dreck. Yet there will still be people saying "I can tell this is AI because it uses emdashes and the word 'quiet'."

To bring this back on topic, I am working on a grant proposal to put Sam Altman in a vacuum chamber and shoot him with a laser.

ETA: Nothing quite like writing about writing and using "their" instead of "there." Sheesh.

 

[JohnDeL]

No writer who treats writing as a craft is going to imitate AI.

Unless the point is to show why we shouldn't trust AI. At all.

While "The Machine Stops" may be the original version of this, I much prefer Dickson's "Computers Don't Argue" for its nigh-well perfect mixture of pathos and bathos.

 

[SomewhereAroundBarstow]

MS Word will turn a space-hyphen-space into an em-dash, since it's super rare that you'd have spaces bracketing a hyphen that should remain a hyphen.

I've thankfully not touched Word in well over a decade and I'm gathering from these comments that particular one is a newer trick. Or maybe I never ran into it because if you are putting a space before or after a hyphen you are not using hyphens correctly. I was trained by a style guide to set emdashes off with spaces but I'm sometimes inconsistent about that in my own writing.

At that same job, for a while I had to take what I'd written in Word and mark it up as HTML. In Word. Thankfully I got a real text editor after a while because that was misery.

 

[JoHBE]

It hurts to type this, but that may literally be the case. There was a hit on the word “diverse” and it got shut down.

Can it vaporize schoolkids? Yes?

They'll be ok...

 

[wagnerrp]

Many people are saying a Petawatt laser could fill at least a dozen high school gymnasiums full of popcorn. But only if mounted in a B21 Raider. The B1 B does not have Petawatt laser receptacles.

Mentioned already, it's 160J per shot, or about half the energy needed to pop a single kernel of corn.

 

[JohnDeL]

ETA: Nothing quite like writing about writing and using "their" instead of "there." Sheesh.

There, their, they're. Nobody is mad about it...

 

[the cave troll]

Could someone more knowledgeable than I explain to me the difference between this device and NIF?

 

[NeutrinoSunset]

Don't get me wrong - I am very impressed.

But I also immediately want a neutrino version.

What would that do? The defining characteristic of neutrinos is that they don't interact with anything.

 

[spopepro]

Could someone more knowledgeable than I explain to me the difference between this device and NIF?

It’s much smaller, but similar. This project is somewhat more like the Nova project that preceded the NIF. But there are lots of applications for high energy lasers with regards to particle physics and it is beneficial to have labs that are working at different pulse durations and frequencies to run different experiments.

 

[FranzJoseph]

What would that do? The defining characteristic of neutrinos is that they don't interact with anything.

Not even with sunsets? ;-)

From a sci‑fi point, a modulated neutrino stream could at least make for some nice interstellar comms device. A cloud of dust in your comms pathway? No problem!

Detecting a potentially modulated neutrino stream alien message (it's not ever made clear if it was actually that) was the major plot point of Stanisław Lem's His Master's Voice novel (a really good read, if as usual for Lem it was more concerned with the humanity and the geopolitical, scientific and sociological implications of said message to us as a civilisation than whether it was actually any message or just some semi‑organised random fluctuation). Still a great read, as pretty much anything by Lem.

 

[janhec]

Enjoyed reading this article, thanks.



I found this line amusing, especially in the same paragraph as batteries so large they take up whole room on another floor.

Capacitors take up more space than batteries, I would say, for the same energy content. To get a nearly instantaneous release of energy, batteries are no good. Even overly large capacitors would have a problem, given the intended timescale (1 picosecond). So, there must be some specific laser magic, like in the earlier charging stages. Which deserves imo more attention in the article. Now the article is really nice, but mostly a scaling story, how large (energy) and how concentrated (time) it is designed to be, and the clearly needed organization and folklore around it to reliably produce this. But what an unusual workplace story!

 

[archtop]

It seems like just one speck of dust on some of the optical elements would cause a problem. I'm wondering how they keep 'em clean. Windex?

The classic method is to mix up 50% acetone and 50% methanol, wet a special wipe, and lightly drag the wipe across the optic at a medium speed. Surely this method has been superseded for these laser optics (and LIGO optics, etc.).

 

[anneoneamouse]

No image of the target getting vaporized?

 

[archtop]

Hmmm...

Quiet! I can't think with you humming like that.

 

[anneoneamouse]

Don't get me wrong - I am very impressed.

But I also immediately want a neutrino version.

Why? They wouldn't interact with the target.

 

[markgo]

I sure hope they don't. A hyphen and an emdash have different grammatical purposes.

A hyphen joins words or word fragments, while an emdash sets off additional information or indicates a pause. Some word processors will turn a double hyphen into an emdash, but I haven't relied on that for years as on MacOS an emdash can be easily typed with "option-shift-hyphen" and on iOS you hold down the hyphen until a selection menu pops up giving you access to a variety of different dashes.

It’s faster to just hit the hyphen twice—as I just did—which works on iOS, MacOS and reportedly Microsoft Word on all platforms as well.

 

[Bongle]

This was a fantastic article, thanks for describing an extremely unique job and experience.

Ars/Conversation/commenters: I'd love to read a similar article about the LHC, ITER, or any other research machinery.

 

[SomewhereAroundBarstow]

It’s faster to just hit the hyphen twice—as I just did—which works on iOS, MacOS and reportedly Microsoft Word on all platforms as well.

I'm not sure about faster but I am sure -- having confirmed it just now in this reply -- that it doesn't work in Firefox on MacOS.

 

[jonbob_newcastle]

Could someone more knowledgeable than I explain to me the difference between this device and NIF?

Thankfully this organisation doesn’t try to pretend they’re doing meaningful work on peaceful fusion power. The NIF do fusion weapons research, and no amount of greenwashing press releases will ever change that.

 

[no_great_name]

Anyone else find it hilarious to accuse someone of using AI to communicate highly specific technical information that AI probably does not have in its training corpus?

“Ok, ChatGPT, ARS has asked me for an article and I want to save time by having you do it. So let’s spend several hours (days? weeks?) to augment your capacity to understand the operating procedures of this one particular high energy pulse laser.”

 

[FranzJoseph]

The classic method is to mix up 50% acetone and 50% methanol, wet a special wipe, and lightly drag the wipe across the optic at a medium speed. Surely this method has been superseded for these laser optics (and LIGO optics, etc.).

For cleaning some photographic lenses, we used diethyl ether. Of course it tends to form nastily explosive peroxide crystals at the slightest provocation. Most probably not the very best substance to clean optics, after all...

 

[jonbob_newcastle]

For cleaning some photographic lenses, we used diethyl ether. Of course it tends to form nastily explosive peroxide crystals at the slightest provocation. Most probably not the very best substance to clean optics, after all...

A colleague of mine used to clean delicate things - mostly watches, I think - by hanging them over an open container of carbon tet. How she is still alive I will never know.