Well, the world hasn't been sucked inside out... yet. The Large Hadron Collider at CERN was finally switched on today for its first full-circuit test, though as it was just to fire a clump of protons in one direction, the experiment hasn't yet reached the stage where the much-feared "micro black hole" could theoretically appear and devour us all. Which is nice.
The BBC article on the subject hints at amazing powers on the part of Lyn Evans, the project leader. Apparently, shortly after the switch was flicked, Lyn remarked "There it is" as the proton beam completed its first lap. Wow. According to the same article, the proton beam ultimately goes round the circuit in about 1/11,000 of a second - so my initial thought was that Lyn must have amazingly fast reflexes.
Then I looked into it a little further on the excellent LHC Outreach site, here, and found this handy description of the various stages which would precede a full circuit of the collider:
How long does it take for a proton to go from zero to 14 TeV ?
When a proton leaves the source, it crosses the linac and reaches the
PSB in a few microseconds. In the PSB it is accelerated from 50 MeV to
1.4 GeV in 530 ms, then after less than a microsecond it is injected in the PS where it can either:
- be accelerated/manipulated/extracted in 1025 ms
- or wait for 1.2 more seconds before being accelerated, if it's part of the first PSB batch to the PS.
Then it is sent to the SPS where it waits for 10.8, 7.2, 3.6, or zero
seconds whether it's part of the first, second, third, or fourth PS
batch to the SPS. The SPS accelerates it to 450 GeV in 4.3 seconds, and sends it to the LHC.
So the time it takes from the source to the exit of the SPS is between
0.53 + 1.025 + 4.3 = 5.86 seconds
and
0.53 + 1.2 + 1.025 + 10.8 + 4.3 = 17.86 seconds
Then our proton has to wait up to 20 minutes on the LHC 450 GeV
injection plateau before the 25 minutes ramp to high energy, and these
45 minutes dominates [sic] the transit time.
The 450 GeV mentioned is, as it were, the 'entry speed' onto the collider. Thereafter, the 'ramp to high energy' consists of successive 'kicks' which bring the circulating proton beam up to its full close-to-light speed of 7 TeV. Through the wonders of the Web, I am able to tell you that TeV stands for Teraelectrion volts, and that
7 teraelectron volts = 1.12152352 × 10-6 joules
If you need/want to know what electron volts are, I suggest you look on Wikipedia... I gave up Physics when I was 15 ;^)
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Oh, Robin, you smartass!
I see your reaction to this event is similar to mine. A scary thought. ;-)
I failed the famous Miliken Oil Drop experiment, and thus gave up my future as a rocket scientist.
However, I do take offense when someone says, "This is not rocket science".
I always want to retort, "But, I am a rocket scientist!"
;-)
Posted by Carolyn on September 10, 2008 at 01:55 PM GMT+00:00 #
I've been following news updates on BBC Radio 4 as best I could today, and was *so* pleased to hear that both beams are already completing full circuits of the LHC ring :-).
(Aside: I (mis-?)spent my youth doing more Physics than was probably good for me, and having been a mere glint in Dad's eye when Neil Armstrong stepped foot on the moon, the LHC is probably the most significant scientific endeavour to reach fruition, in my lifetime so far.)
"Mini Black Holes" are about as major a nonsense as Torchwood's neutron-munching monsters, if Schwarzschild was correct. However, I'm in intuitive agreement with Hawking, in that I don't think LHC will find the Higgs; the Standard Model just has too many tweaks and exceptions in it, for it to be the hoped-for Grand Unified Theorem, even with the Higgs details added.
If current terminology has been preserved, it's also amusing to hear that previous particle-smashers may well have been preserved and re-purposed; back in the '80s, the Super Proton Synchrotron was CERN's principal experiment; today, the "SPS" was described as the source of the beams which feed the LHC. I wonder :-).
Finally, hats-off to all the LHC folk, on the day their experiment successfully starts its equivalent of pen-testing.
Posted by Dave Walker on September 10, 2008 at 09:03 PM GMT+00:00 #
@Carolyn; take heart.
My eyes have always been sufficiently shot, that I could never track those oil drops either (also bear in mind, that it sent Millikan blind); still, a rocket scientist once told me that "'rocket science' isn't rocket science".
:-)
Posted by Dave Walker on September 10, 2008 at 09:08 PM GMT+00:00 #