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From: Jeroen Belleman on 8 Oct 2009 10:29
Jan Panteltje wrote:
> On a sunny day (Thu, 08 Oct 2009 08:46:48 +0200) it happened Jeroen Belleman
> <jeroen(a)nospam.please> wrote in <hak1s3$kue$1(a)aioe.org>:
>
>> harry wrote:
>>>
>>> Unfortunately the relationship between ampere turns and the magnetic
>>> flux generated is not linear. Ie doubling ampere turns does not
>>> double the flux. Also, at some point, the magnetic material
>>> "saturates" and you can add as many ampere turns as you like but flux
>>> will not increase.
>> You may try to sell that argument to our magnet builders here
>> at CERN. ;-) How do you think they get to 10 Teslas?
>
> They dont, it blew up.

Sigh! Indeed it did. And we're still recovering from the blow.

What happened was that a connection *between* two magnets failed,
at just under 9kA. Much of the energy stored in the magnets, and
it's a _lot_, got dumped into that spot, with the results you all
heard about. But the good news is that LHC will soon start up
again. Anyway, in this discussion, that's a side issue.

My point was that even if ferromagnetic material in a coil
saturates, pushing more current will still increase the field,
albeit not by as much as before saturation set in.

Jeroen Belleman
From: Jeroen Belleman on 8 Oct 2009 10:37
TheM wrote:

> Seems it will be fired up again mid-November.
> And full power for Christmas, what a perfect time for armageddon.
> http://www.swisster.ch/en/news/science_tech/cern-experts-begin-testing-lhc-repairs_118-2445479
> "This fault was caused by nothing more technical than a bad soldier joint!" Gillies told Swisster, an oversight that lead to a
> repair bill of some 40 million Swiss francs. The estimated cost of the entire project is thought to be in the region of 10 billion
> francs.
>
> Possibly ROHS problem ;)

The solder used for these joints is a SnAg alloy. Apparently
it is superconductive at the LHC's 1.9K working temperature.

Jeroen Belleman
From: Rich Grise on 8 Oct 2009 13:56
On Thu, 08 Oct 2009 15:55:16 +0200, TheM wrote:
> "Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message
>> On a sunny day (Thu, 08 Oct 2009 08:46:48 +0200) it happened Jeroen
>> Belleman <jeroen(a)nospam.please> wrote in <hak1s3$kue$1(a)aioe.org>:
>>>harry wrote:
>>>>
>>>> Unfortunately the relationship between ampere turns and the magnetic
>>>> flux generated is not linear. Ie doubling ampere turns does not
>>>> double the flux. Also, at some point, the magnetic material
>>>> "saturates" and you can add as many ampere turns as you like but flux
>>>> will not increase.
>>>
>>>You may try to sell that argument to our magnet builders here at CERN.
>>>;-) How do you think they get to 10 Teslas?
>>
>> They dont, it blew up.
>
> Indeed, what's up with that. They've been repairing it for a year now.
>
> So when they finally turn it on again and maybe one tiny part dies we'll
> wait again for a year so they can repair it, re-calibrate it and
> re-establish all temperatures, vacuum and so forth...
>
> Damn expensive toy to just sit there and collect dust.

God's preventing it from being built, because it will make a black hole,
which will immediately fall through the floor, almost to the other side
of the planet, bounce back, and so on, consuming Earth's matter as it goes,
until the whole planet is gone.

Hope This Helps!
Rich

From: harry on 8 Oct 2009 14:02
On Oct 8, 7:46 am, Jeroen Belleman <jer...(a)nospam.please> wrote:
> harry wrote:
>
> > Unfortunately the relationship between ampere turns and the magnetic
> > flux generated is not linear. Ie doubling ampere turns does not
> > double the flux. Also, at some point, the magnetic material
> > "saturates" and you can add as many ampere turns as you like but flux
> > will not increase.
>
> You may try to sell that argument to our magnet builders here
> at CERN. ;-) How do you think they get to 10 Teslas?
>
> Jeroen Belleman

Cryogenics and superconductors I think would be the way forward.
But not for £100 ;-)
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