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The Military Science

US Nuclear Weapons Lab Discovers How To Suppress the Casimir Force 112

Posted by Soulskill
from the requires-application-of-Casimir's-Oil dept.
KentuckyFC writes "One of the frustrating problems with microelectromechanical (MEM) devices is that the machinery can sometimes stick fast, causing them to stop working. One of the culprits is the Casimir effect — an exotic force that pushes metallic sheets together when they are separated by tiny distances. Now physicists at the Los Alamos National Laboratory in New Mexico have worked out and demonstrated how to suppress the Casimir force. The trick is to create a set of deep grooves and ridges in the surface of one sheet so that the other only comes close to the tips of the ridges. These tips have a much smaller surface area than the flat sheet and so generate much less force. That could help prevent stiction in future MEMs devices. But why would a nuclear weapons lab be interested? MEM devices are invulnerable to electromagnetic pulse weapons that fry transistor-based switches, and so could be used as on-off switches for nuclear devices."
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US Nuclear Weapons Lab Discovers How To Suppress the Casimir Force

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  • by Toad-san (64810) on Friday October 11, 2013 @03:16PM (#45103997)

    "MEM devices are invulnerable to electromagnetic pulse weapons that fry transistor-based switches,"

    I don't know why that would be true. We're talking about a very small mechanical switch, right? Two metallic surfaces (presumably at the end of wires or traces) that connect to close a circuit? The high voltage surge usually associated with an EMP would jump (and weld) micro-teensy-tiny switches just as easily as big ones. You've never seen a mechanical switch welded by an unexpected high voltage or amperage surge? I have. No reason why that won't happen with an MEM device. I'll have to see a better reference to proof of that surge invulnerability before I buy into this.

  • Re:brilliant! (Score:5, Insightful)

    by sycodon (149926) on Friday October 11, 2013 @03:49PM (#45104207)

    So they didn't really suppress anything, they just prevented the circumstances that would be subject to the effect.

    Wouldn't it be the case that if they actually manipulated a fundamental nuclear force that it would be a very notable achievement? Rght up there with negating gravity or something.

  • Good old LANL (Score:5, Insightful)

    by Animats (122034) on Friday October 11, 2013 @04:00PM (#45104277) Homepage

    Ah, Los Alamos. Once it had more great scientists in one place than anywhere else in the world. There was a tradition in the early days that the head of Los Alamos must have a Nobel Prize. That ended in the 1980s when Ronald Reagan put a lawyer in charge.

    The US has a strange approach to "national laboratories". The original ones (Los Alamos, Lawerence Livermore, Sandia, Oak Ridge, Savannah River, etc.) were originally all Atomic Energy Commission operations. The Department of Energy got the AEC operations when it was formed. So the US still has a huge nuclear weapons R&D operation, despite the fact that the US hasn't built a new nuclear weapon in decades.

    This project sounds more like an excuse for funding basic research than a component needed in a nuclear weapon. EMP shielding isn't that hard. This MEMS device doesn't seem to be a likely choice for the firing switch in a nuclear weapon. Nuclear weapons require a symmetrical implosion squeeze, which is initiated with multiple detonators, all of which have to go off at the same time within 1ns or so. This is done with a setup like a photoflash, but more powerful - a capacitor bank is charged up, and then dumped into thin wire detonators when the discharge switch closes. It's a few KV at a few thousand amps for a nanosecond or so. That discharge switch is what the article probably refers to.

    The classic device for that is a krytron. Although using a gas-filled tube is kind of retro, it works. It's probably possible to build some MOSFET device to replace krytrons, as this work at SLAC [fnal.gov] indicates. But a microscopic MEMS device? Too tiny to handle the current.

  • by taylorius (221419) on Friday October 11, 2013 @05:18PM (#45104859) Homepage

    So, to paraphrase quite a few comments on this article:

    "Duh, Los alamos are so stupid - less material in contact, less force, just like friction. I can't believe they only just worked that out. I mean DUH, they could've asked me THAT. Oh, and they make nukes. Eurgh, I hate them!"

    Really? You seriously think that's all there is to it? I only read the abstract, and it states that the decrease in the Casimir force is far beyond theoretical predictions. But pffth, they probably got that wrong too, right?

    I dunno, the misplaced arrogance I read on here sometimes really depresses me.

  • by mbkennel (97636) on Friday October 11, 2013 @06:00PM (#45105191)
    http://www.lanl.gov/about/facts-figures/budget.php#.UlhzcVCshcY

    NNSA Weapons programs 57%: 1.263B
    NNSA Nonproliferation (also about nuclear weapons): 9% 210M
    NNSA Safeguards & Security (also about nuclear weaopns) 7% 152M
    DOE Environmental Management (cleanup junk) 8% 187 M
    DOE Energy and other Programs, 4% 84M (unclear, nuclear reactors perhaps?)
    DOE Office of Science, 4% 94M
    Work For Others, 4%, 98M
    Work For Others (National Security), 7% 154M

    So by far most of LANL's budget involves nuclear weapons, and cleaning up from producing and testing nuclear weapons. Then after that unspecified work for "National Security", which is probably scientific services to the Intelligence Community.

    Then, there's the 4% which is basic science like "particle physics, it works on biofuels, and proteins, and medicine" and there may be some science in the 4% of "DOE Energy and Other Programs".

    I too was pretty surprised how small the basic science budget is, and I'm a physicist.

    Calling LANL a "Nuclear Weapons Laboratory" is about as correct as calling Microsoft a "software company", even though they do make keyboards and mice and a tablet.

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