...that's where I get all my planetary science news! not. also. also. Why do people do this? This is the internet, not your local morning paper. You can go wherever you want to get this information. WHY NOT GO DIRECTLY TO THE SOURCE!?
Yes, yes, it's Slashdot and supposedly the blind leading the blind on this question. r-d-r-r. I get it. But I've been enjoying this site for a full decade now (late 20s) and I find that whenever these sorts of non-tech/science questions come up, the responses are often some of the most highly thoughtful and interesting on offer. So as long as we're all here and considering justshootme's question of "where do you meet fellow geeks -- preferably including some of the opposite gender", I would like to ask about fellow geeks interested in meeting the SAME gender for said purposes implied in the original question. I find that this exceptionally difficult, as there are very few other gay dudes willing to tolerate discussions about supersymmetry or the history of thermodynamics or mediaeval history for more than a few milliseconds at most. Should I resign myself to the fact that my demographic is simply to narrow and settle? I am beginning to think so.
It's literally entirely harmless. Tritium is a pure beta emitter (electrons). The maximum energy of a beta particle from a decaying T atom is 18.6 KeV. A beta particle of 18 KeV can penetrate no more than about 5mm in air or 6-7 MICROmeters in water (or your skin). Exactly zero beta particles are escaping the phosphor coated glass ampoule (let alone the plastic outer case). ok so now what about bremsstrahlung. Well the percent of incident 18 KeV betas on the glass ampoule that actually produce bremsstrahlung is VERY low, 0.1% at absolute most and remember, the number of betas emitted that are >than even 15 KeV is VERY low (few percent). This ampoule likely contains about 10 millicuries of T or ~370 million betas emitted per second. We can assume (extremely) roughly that 10K X-rays of >15KeV are produced every second from this source then. The half value layer of 20 KeV x-rays is 1mm for aluminum, so 3mm of aluminum will block ~90% of a 20 KeV x-ray source, I assume the thickness (mass) of the glass of the ampoule and the lucite plastic is at least roughly equal to 3mm of Al so now we're down to 1,000 x-rays per second emitted isotropically (500 per second toward you, ~half of which would be absorbed merely while penetrating your skin alone). Even this, though it's very tiny, has got to be a ridiculous over estimate. How do I know? Because fortunately someone has taken the time to measure the emanation from a HUGE tube of this sort taken from an emergency exit sign. What did he find? It was giving off 60 counts per MINUTE of x-rays. An utterly, totally trivial amount of radiation. You will get thousands of times this sort of dose from cosmic rays on a half hour plane ride.
Well you probably should be unimpressed by the project from the point of view of power generation, since it was never designed with the objective of generating power in mind. And in the very long term I DO think this is going to be cheaper than fission since its fuel source is water an pinch of lithium. Additionally, it will burn radioactive waste from fission plants.
There's several videos floating around with him too that are definitely worth watching. He is a very sharp mind and it pleases me greatly to see his urgently needed skeptical analysis getting the press coverage it so thoroughly deserves.
The noise is very unique. If you are near the laser bay the noise you hear is a LOUD BANG from the thousands of enormous Xe flashlamps going off simultaneously. The capacitor bay that discharges to fire the lamps produces deeper thud. The noise that comes from the target bay is very different. It's very similar to the quick fsss you hear when opening a can of soda (minus the click), but louder and more resonant. I suspect this has to do with the fact some residual IR light is absorbed by the backplanes of the turning mirrors, so this noise may not be present on all ICF lasers. The target in the implosion chamber itself can make almost no noise at all or a moderate muffled bang, depending on the target type and laser energy used for the shot. there used to be a recording of the GEKKO XII system in Osaka firing, but that site is gone now.
"That might explain why they carry on for decades without a sign of anything working."
Right, right, yeah exactly because they definitely didn't just report on their website being able to deliver >1 MJ of UV light to the target chamber like last month or anything like that. clueless.
Those Wired pictures are nice and all but if you want wallpaper, why don't you just go to the source, LLNL's Flickr page? As an aside, as someone who works at the US's other major laser fusion facility (there aren't many, I'll leave it to you to figure out), I can tell you that all the scaled implosions we've been doing for the past 10 years here validate the expectation that NIF will achieve fusion ignition, burn, and high gain when they go to 2MJ cryogenic DT ice implosions next year. We are extremely excited. This will be the first time nuclear fusion breakeven and ignition will have been achieved in a laboratory. I want you to think for a little while about what the long term implications of fusion energy on technologically advanced human civilization will be. I still don't think very many people realize that this experiment is a MAJOR step in that ultimate goal.
Translation: "Fuck! D-zero's collected like 6 inverse femtobarns of integrated luminosity and we're just sitting on our asses looking at cosmic ray hits!!! Who gives a shit about power $$$?! Switch the fucker on!!"
NIR would be inappropriate for this application. If you're looking for contaminant poisons in drinking water you need to have exquisitely sensitive detection thresholds in the part per billion level. A NIR spectrometer using conventional (quartz) fiber optics would be forced to look at the second and third overtones of the fundamental molecular absorption lines in the mid-IR. These overtones have a mere thousandth or hundredth of the relative absorption intensity as the fundamental lines and therefore your signal for extremely low concentrations of contaminants is going to be waaaaay below the noise in your detector. NIRS is best suited for detection of percent level deviations in chemical mixtures, not trace analysis. What this guy from Israel has done is use drawn fibers of silver chloride/bromide, which have spectacular transmittance in the mid-IR, to detect the fundamental absorption bands of trace contaminants using the evanescent waves of IR light that poke slightly outside the surface of a fiber optic. I wish I could find his latest paper that this press release is about though.....
Can someone on this project tell us what took so long with Planck? I remember seeing a picture of it under construction in a cleanroom in the accompanying book to the PBS show "Stephen Hawking's Universe"....... in 1998!
Not the first. Maybe the first X-ray FEL (maybe) but not the first X-ray laser proper. The first X-ray lasers were created in nickel and samarium plasmas created by few ns long, multi Kj, UV light pulses of LLNL's Novette laser (predecessor of the Nova laser) in the early '80s. The work was probably done with SDI in mind.
"Will we be getting real time videos of enzymes in action?"
No, enzymes in action must be in solution and not locked into a regular crystalline lattice of the sort required to diffract X-rays of comparable wavelength with the spatially encoded information of said molecular structure which is necessary to do diffractometry.
gosh I don't know, maybe NASA's slightly more interested in getting plain facts out instead of hyping every latest piece of new information to maximum sensationalistic mediagasm proportions?
Well it would be simillar to that. aluminum is not magnetic so you wouldn't notice anything when getting into the machine, but as soon as the scan started, the ultrafast sweeping of the gradient magnet's fields that's needed to perform echo sequences with the time resolution relevant to fMRI would create HUGE ohmic heating in the conductive metal and severely burn you, if not light your hair on fire.
Is it possible that the parameter space remaining to be excluded could still contain a supersymmetric higgs? There is a video showing Lisa Randall talking about the possibility of finding photinos at the Tevatron but could a SUSY higgs could be found first?
Dear sir, I take extreme issue with your assertion that "target implosion fusion is never going to put a watt onto the grid". That statement is unreasonable.
(disclaimer: I work in an INERTIAL fusion lab (I'm not telling which one but suffice it to say there aren't very many here and I don't work at NIF) and while I'm not a pacifist, I don't generally like H-bombs and don't like that my field is associated with them..... but T.S., it IS associated with them and there's nothing we can really do about that for now)
The hyping of NIF as a potential power source is, admittedly, a little over the top (LIFE nonsense on the website, etc.), but I assure you that I have delved very, very deep into the literature on both sides of this little magnetic versus inertial debate we fusion people like to have, and I am at a genuine loss to say which technology will eventually be the one to produce usable, economical power. Your magnetic confinement method has HUGE problems with neutron flux degradation of the superconducting solenoid coils that will be needed for a DEMO scale reactor, with divertor heat flux management, with massive tritium loading of the vacuum vessel, with plasma facing wall heavy element ablation poisoning the reaction, it goes on and on. So you shouldn't be presenting MFE as the 'one and only true possibility' for economical fusion. Yes IFE has its problems too; final optics destruction, ion flux degradation of the inside of the target chamber, laser medium heat extraction, beam energy to target coupling efficiency, hydrodynamic fuel instability during implosion and on and on. But you seem to ignore or are unaware of the recent advances in laser fusion in your assessment of its supposed unfeasibility. Namely the use of chirped pulse, petawatt scale lasers for "fast ignition" inertial fusion, where the driver laser can be reduced in size from something like a NIF scale to an order of magnitude less. I'm not the only one convinced that this has a real shot at energy production. Are you unaware that the Europeans are going ahead with HiPER, a laser fusion / fast ignition scheme designed to demonstrate power production using diode pumped laser media? This device will have NO APPLICATION in nuclear weapons research and will certainly cost much less than ITER. We know it will not be used for weapons research because France is building their own NIF already called Laser Megajoule for that military purpose. No one knows who's going to win this thing. NO ONE, neither me or you. All I'm hoping for is to live long enough to see it happen either way, I don't care how it's eventually actually done, that's irrelevant. What's important is that it IS done and that human civilization enters the next stage of its evolution that such an achievement will most assuredly deliver.
Slashdot Mirror
The Birth of the Transistor. Circuits In Stone. watch and learn, kid.
You are wrong.
lol, VERY well done. Mr. Sokal? Is that you?
...that's where I get all my planetary science news! not. also. also. Why do people do this? This is the internet, not your local morning paper. You can go wherever you want to get this information. WHY NOT GO DIRECTLY TO THE SOURCE!?
I have read your post several times now and I confess to still not being able to tell if you are referring to a type of drug and sex fueled adventure or a type of pc bus architecture automatic self-configuration. I suspect that this is the first time in history that this particular confusion has occurred. :))
Yes, yes, it's Slashdot and supposedly the blind leading the blind on this question. r-d-r-r. I get it. But I've been enjoying this site for a full decade now (late 20s) and I find that whenever these sorts of non-tech/science questions come up, the responses are often some of the most highly thoughtful and interesting on offer. So as long as we're all here and considering justshootme's question of "where do you meet fellow geeks -- preferably including some of the opposite gender", I would like to ask about fellow geeks interested in meeting the SAME gender for said purposes implied in the original question. I find that this exceptionally difficult, as there are very few other gay dudes willing to tolerate discussions about supersymmetry or the history of thermodynamics or mediaeval history for more than a few milliseconds at most. Should I resign myself to the fact that my demographic is simply to narrow and settle? I am beginning to think so.
It's literally entirely harmless. Tritium is a pure beta emitter (electrons). The maximum energy of a beta particle from a decaying T atom is 18.6 KeV. A beta particle of 18 KeV can penetrate no more than about 5mm in air or 6-7 MICROmeters in water (or your skin). Exactly zero beta particles are escaping the phosphor coated glass ampoule (let alone the plastic outer case). ok so now what about bremsstrahlung. Well the percent of incident 18 KeV betas on the glass ampoule that actually produce bremsstrahlung is VERY low, 0.1% at absolute most and remember, the number of betas emitted that are >than even 15 KeV is VERY low (few percent). This ampoule likely contains about 10 millicuries of T or ~370 million betas emitted per second. We can assume (extremely) roughly that 10K X-rays of >15KeV are produced every second from this source then. The half value layer of 20 KeV x-rays is 1mm for aluminum, so 3mm of aluminum will block ~90% of a 20 KeV x-ray source, I assume the thickness (mass) of the glass of the ampoule and the lucite plastic is at least roughly equal to 3mm of Al so now we're down to 1,000 x-rays per second emitted isotropically (500 per second toward you, ~half of which would be absorbed merely while penetrating your skin alone). Even this, though it's very tiny, has got to be a ridiculous over estimate. How do I know? Because fortunately someone has taken the time to measure the emanation from a HUGE tube of this sort taken from an emergency exit sign. What did he find? It was giving off 60 counts per MINUTE of x-rays. An utterly, totally trivial amount of radiation. You will get thousands of times this sort of dose from cosmic rays on a half hour plane ride.
Well you probably should be unimpressed by the project from the point of view of power generation, since it was never designed with the objective of generating power in mind. And in the very long term I DO think this is going to be cheaper than fission since its fuel source is water an pinch of lithium. Additionally, it will burn radioactive waste from fission plants.
There's several videos floating around with him too that are definitely worth watching. He is a very sharp mind and it pleases me greatly to see his urgently needed skeptical analysis getting the press coverage it so thoroughly deserves.
The noise is very unique. If you are near the laser bay the noise you hear is a LOUD BANG from the thousands of enormous Xe flashlamps going off simultaneously. The capacitor bay that discharges to fire the lamps produces deeper thud. The noise that comes from the target bay is very different. It's very similar to the quick fsss you hear when opening a can of soda (minus the click), but louder and more resonant. I suspect this has to do with the fact some residual IR light is absorbed by the backplanes of the turning mirrors, so this noise may not be present on all ICF lasers. The target in the implosion chamber itself can make almost no noise at all or a moderate muffled bang, depending on the target type and laser energy used for the shot. there used to be a recording of the GEKKO XII system in Osaka firing, but that site is gone now.
"That might explain why they carry on for decades without a sign of anything working."
Right, right, yeah exactly because they definitely didn't just report on their website being able to deliver >1 MJ of UV light to the target chamber like last month or anything like that. clueless.
Those Wired pictures are nice and all but if you want wallpaper, why don't you just go to the source, LLNL's Flickr page? As an aside, as someone who works at the US's other major laser fusion facility (there aren't many, I'll leave it to you to figure out), I can tell you that all the scaled implosions we've been doing for the past 10 years here validate the expectation that NIF will achieve fusion ignition, burn, and high gain when they go to 2MJ cryogenic DT ice implosions next year. We are extremely excited. This will be the first time nuclear fusion breakeven and ignition will have been achieved in a laboratory. I want you to think for a little while about what the long term implications of fusion energy on technologically advanced human civilization will be. I still don't think very many people realize that this experiment is a MAJOR step in that ultimate goal.
Translation: "Fuck! D-zero's collected like 6 inverse femtobarns of integrated luminosity and we're just sitting on our asses looking at cosmic ray hits!!! Who gives a shit about power $$$?! Switch the fucker on!!"
NIR would be inappropriate for this application. If you're looking for contaminant poisons in drinking water you need to have exquisitely sensitive detection thresholds in the part per billion level. A NIR spectrometer using conventional (quartz) fiber optics would be forced to look at the second and third overtones of the fundamental molecular absorption lines in the mid-IR. These overtones have a mere thousandth or hundredth of the relative absorption intensity as the fundamental lines and therefore your signal for extremely low concentrations of contaminants is going to be waaaaay below the noise in your detector. NIRS is best suited for detection of percent level deviations in chemical mixtures, not trace analysis. What this guy from Israel has done is use drawn fibers of silver chloride/bromide, which have spectacular transmittance in the mid-IR, to detect the fundamental absorption bands of trace contaminants using the evanescent waves of IR light that poke slightly outside the surface of a fiber optic. I wish I could find his latest paper that this press release is about though.....
nary a sunspot
no faculae here at all
last chance to see this
Can someone on this project tell us what took so long with Planck? I remember seeing a picture of it under construction in a cleanroom in the accompanying book to the PBS show "Stephen Hawking's Universe"....... in 1998!
jebus you're right. unbelievable.
Not the first. Maybe the first X-ray FEL (maybe) but not the first X-ray laser proper. The first X-ray lasers were created in nickel and samarium plasmas created by few ns long, multi Kj, UV light pulses of LLNL's Novette laser (predecessor of the Nova laser) in the early '80s. The work was probably done with SDI in mind.
"Will we be getting real time videos of enzymes in action?"
No, enzymes in action must be in solution and not locked into a regular crystalline lattice of the sort required to diffract X-rays of comparable wavelength with the spatially encoded information of said molecular structure which is necessary to do diffractometry.
uhhhhh are you sure you know what a twink is, cuz.....
gosh I don't know, maybe NASA's slightly more interested in getting plain facts out instead of hyping every latest piece of new information to maximum sensationalistic mediagasm proportions?
Well it would be simillar to that. aluminum is not magnetic so you wouldn't notice anything when getting into the machine, but as soon as the scan started, the ultrafast sweeping of the gradient magnet's fields that's needed to perform echo sequences with the time resolution relevant to fMRI would create HUGE ohmic heating in the conductive metal and severely burn you, if not light your hair on fire.
Is it possible that the parameter space remaining to be excluded could still contain a supersymmetric higgs? There is a video showing Lisa Randall talking about the possibility of finding photinos at the Tevatron but could a SUSY higgs could be found first?
um no. IFE has existed since the 60's.
Dear sir, I take extreme issue with your assertion that "target implosion fusion is never going to put a watt onto the grid". That statement is unreasonable.
(disclaimer: I work in an INERTIAL fusion lab (I'm not telling which one but suffice it to say there aren't very many here and I don't work at NIF) and while I'm not a pacifist, I don't generally like H-bombs and don't like that my field is associated with them..... but T.S., it IS associated with them and there's nothing we can really do about that for now)
The hyping of NIF as a potential power source is, admittedly, a little over the top (LIFE nonsense on the website, etc.), but I assure you that I have delved very, very deep into the literature on both sides of this little magnetic versus inertial debate we fusion people like to have, and I am at a genuine loss to say which technology will eventually be the one to produce usable, economical power. Your magnetic confinement method has HUGE problems with neutron flux degradation of the superconducting solenoid coils that will be needed for a DEMO scale reactor, with divertor heat flux management, with massive tritium loading of the vacuum vessel, with plasma facing wall heavy element ablation poisoning the reaction, it goes on and on. So you shouldn't be presenting MFE as the 'one and only true possibility' for economical fusion. Yes IFE has its problems too; final optics destruction, ion flux degradation of the inside of the target chamber, laser medium heat extraction, beam energy to target coupling efficiency, hydrodynamic fuel instability during implosion and on and on. But you seem to ignore or are unaware of the recent advances in laser fusion in your assessment of its supposed unfeasibility. Namely the use of chirped pulse, petawatt scale lasers for "fast ignition" inertial fusion, where the driver laser can be reduced in size from something like a NIF scale to an order of magnitude less. I'm not the only one convinced that this has a real shot at energy production. Are you unaware that the Europeans are going ahead with HiPER, a laser fusion / fast ignition scheme designed to demonstrate power production using diode pumped laser media? This device will have NO APPLICATION in nuclear weapons research and will certainly cost much less than ITER. We know it will not be used for weapons research because France is building their own NIF already called Laser Megajoule for that military purpose. No one knows who's going to win this thing. NO ONE, neither me or you. All I'm hoping for is to live long enough to see it happen either way, I don't care how it's eventually actually done, that's irrelevant. What's important is that it IS done and that human civilization enters the next stage of its evolution that such an achievement will most assuredly deliver.