Friday, February 05, 2010

The LHC Proton Source

Yesterday, we had a very nice colloquium by Jonas Strandberg from the University of Michigan on "The startup of the LHC and the very first collisions in the ATLAS detector" (abstract and video here). If you have an hour time, watching the video is a good way to spend it. Here, I just want to pick out one image he showed because it got stuck in my head.

As you might know the protons the LHC is circulating are accelerated in various stages. From a duoplasmatron, they are first injected into a linear accelerator (up to 50 MeV), then in the first small circular accelerator, the Proton Synchroton Booster (50 MeV -> 1.4 GeV), then in the Proton Synchroton (1.4 GeV -> 26GeV) and then in the Super Proton Synchroton (26 GeV -> 450 GeV). Only after this are they injected into the LHC tunnel for the real kick (450 GeV -> 7 TeV).


[picture source]


But where do the protons come from? Rather banally, out of a bottle of hydrogen:


[picture source]


I find it amazing, the contrast between that hydrogen bottle and the mighty LHC complex necessary to accelerate the protons.

50 comments:

Riccardo Campana said...

It would be interesting to see also the source of lead ions...

Bee said...

Laser ion source heads for new life

Bee said...

Meant to add: I suppose it looks somewhat like the photo in that article.

Phil Warnell said...

Hi Bee,

Thanks for the post and to marking the video which I will definitely watch when time allows. Also I never thought about the source of the protons before as to imagine it being just an everyday bottle of gas. I’m left curious of what is done first strip to the gas of its electrons and then decouple and segregate the hydrogen atom’s neutrons from their protons to just become raw protons. Also as realizing being so striped these paricles would be highly reactive as being both electron and neutron denied I imagine the completeness of the vacuum within all the step up tubes and the final one must be as close to void of particles as one could imagine. It then eaves one to wonder the what and hows of the process that are responsible for particles of even higher energies that enter our atmosphere daily.

Oh yes it is times like this I wished such talks were live on the interenet with perhaps even some moderator selecting a question or two from the remote audience. They had such a setup at Perimeter’s for their last festival lecture event and I had several of mine selected to be answered. Not that the questions asked would be ultimately important to the researchers, yet might serve useful to some of the onlookers as being things asked which are not so obvious to non professionals.

Anyway thanks once again.

Best,

Phil

Phil Warnell said...

Hi Bee,

Oh yes there’s one other thing I was going to mention and that was how sorry I feel for these poor protons, for after all that going around and around they must end up quite dizzy not to mention flatter the pancakes and time being all but brought to a halt; that is until there eventually have a head on collision with another of their kind. This would be enough to give anything the hiccups; sorry I forgot you want them to get the higgups instead :-)

Best,

Phil

Georg said...

Hello Bee,
a Kipp-Generator with Zink granules
and sulphuric acid would be
even more of an eye-catcher :=)
The hydogen from such a generator
could be sold to visitors as
"bio-hydrogen".
Georg

Steven Colyer said...

Phil, that's an interesting problem. I imagined that the raw protons, being H+, are steered into the proton launch facility by magnets.

A little research later .... yes, click here to see an example of the magnets they will be using. Rest assured that if this were an American Defense Contractor in charge of procurement, the Federal Government would be charged $100,000 a piece for those puppies.

Nails not included.

Uncle Al said...

That is by far the most wonderful science picture ever published!

1) Lecture bottle of hydrogen.
2) ?
3) Universal understanding!

Management's first task must be to replace the cylinder of hydrogen molecules with a cylinder of hydrogen atoms - to cut the cost in half.

Bee said...

Hi Phil,

It takes far less energy to ionize an atom than to break apart a nucleus, thus your guess that ionization happens first is a good one. And well, yeah, it's not healthy to sit in an electron, proton or neutron beam, but than the average person rarely runs in high risk of that to happen. Best,

B.

Georg said...

and then decouple and segregate the hydrogen atom’s neutrons from their protons to just become raw protons

Hello Phil,
Are You kidding and my knowledge
of English language is insufficient?
Georg

LastAncientGreek said...

Phil,

The universe was kind enough to store its neutrons in other elements than Hydrogen.

Since I'm pretty sure you knew that, i have to figure that some neurons got crossed when you composed your comment. ;)

Maybe you were thinking of Deuterium ?

Jérôme CHAUVET said...

The philosophy of this is to me that the Nature is simple, but not the explanation of it. It's like an equilibrium : in order to transform the proton from an unexplained form into an explained form, you have to transfer it from a small bottle to a huge particle collider. An explanation of it make it simplier in the mind, but it requires in turn to be put in a more complicated form or situation in the real world...

Could this be some kind of equilibrium theory applied to the information about the proton? Each one of us can make up his own mind about this...

Best,

Jérôme CHAUVET said...

Er... Sorry, I meant "conservation theory" instead of "equilibrium theory".

Now it makes a little more sense :)

Best,

Wayne Farmer said...

Phil raised an interesting question, though; does the H2 bottle contain only the lightest isotope of hydrogen? I'd guess that there are some deuterium or tritium atoms in there as well, and that there must be some provision in the LHC system, either inherent or provided, that excludes those atoms or their nuclei so that deuterium or tritium nuclei don't become part of the collision stream.

Wayne Farmer said...

Follow-up: A Google search for "pure protium" brings up interesting results.

stefan said...

It would surprise me if off-the shelf hydrogen gas was isotopically pure. So I would expect 150 ppm of deuterium in the initial stuff from the cylinder.

However, the charge over mass ratio is so different that protons and deuterons will separate at the first bend. And 19th century technology and a few keV probably are sufficient for that.

Cheers, Stefan

LastAncientGreek said...

Hi Wayne,

I am inclined to agree with you that Phil must have had deuterium contamination in the hydrogen bottle in mind and simply failed to mention the words deuterium or contamination ...

... just as i failed to mention the word " ... other 'isotopes' and elements ..." in my comment.

Bee will probably tell us at some point whether or not it is a bottle of purified hydrogen which was an assumption on my part.

stefan said...

Dear Bee,


the photo is hilarious! That's really a surprisingly low-tech initial source of the protons :-)

I also like the concept that the protons while being accelerated retrace the "evolution" of particle accelerators - the PS and SPS all have been, some time back in the past, the top-end of available accelerator power.

Cheers, Stefan

LastAncientGreek said...

Ah, Thanks Stefan, so no purification needed in advance.

stefan said...

Hi Riccardo,

It would be interesting to see also the source of lead ions...

in the link Bee has given you can find a drawing of the lead source that has been used for the SPS heavy ion program at CERN over the last 15 years. And here is a photo of the apparatus.

Essentially, solid lead is vaporized by heating. Ionization happens stepwise: First, a few electrons are stripped off, the ions are accelerated in the Linac and shot through thin carbon foils, which strips off more electrons. Then they are further accelerated in the PS, and completely ionized only before injection into the SPS.

It seems there are a few technical upgrades and changes in this process (see this PDF) for the heavy ion program at the LHC, but the principal steps will be the same as for the old SPS heavy ion experiments.

You can find more details here and here (in French).

Cheers, Stefan

Uncle Al said...

Lead (boiling point 1749 °C) was perhaps not the most clever choice of heavy nucleus for its multiple isotopes. Monoisotopic bismuth (bp 1564 °C) is charming (and non-toxic).

Phil Warnell said...

Hi Bee,

Would you happen to know what media player this lecture video you linked to here is supported by since it doesn’t seem to load up ?

Best,

Phil

kaleberg said...

That's pretty funny having a "high tension" warning. That's a reference to the tension on the ether associated with the electric field. You'd think that they'd have given up on the old ether theory these days, at least at the LHC, or do they know something they aren't telling?

Bee said...

Hi Phil,

It's a wmv fil, it runs with the windows media player. I gather the improvement of the recording/online features is a topic of discussion here. They are at least 3 years behind PI though (and if they continue that pace are unlikely to ever catch up.) The most annoying part is that they don't have the slides online. Best,

B.

Bee said...

Hi Kaleberg: Well, Volt didn't call the voltage voltage. In fact, in German there's no specific referral to Volt beyond the unit convention; the word for voltage is the same as that for tension: "Spannung" (which incidentally also means suspense). But yeah, I'm pretty sure they know some things they're not telling us ;-) Best,

B.

Bee said...

Dear Stefan,
Yes, it's historically interesting how they stack older accelerators. I believe the clever use of the PS and SPS rings is the reason why the LHC was affordable at all. (The photo btw seems to show a display bottle, the picture caption was somewhat vague on the details.) Best,

B.

Phil Warnell said...

Hi Wayne & LastAncientGreek and Stefan,

It was nice of you to attempt in letting me off the hook, yet as Georg suspected I was having one of those burnt out synapse moments with my reference to the hydrogen atom having neutrons to be concerned about. Its true I know that hydrogen is normally just a proton with an electron yet for that instance I was thinking of the normal situations as being Deuterium. This of course brings up an interesting question regarding the early universe as Deuterium being stable why is protium the overwhelmingly dominant isotope of hydrogen. That is energy can’t be the only issue as supposedly there was a lot of helium and lithium formed in the early universe as well I wonder if Stefan could lend some insight here.

Best,

Phil

Phil Warnell said...

Hi Stefan,

Your explanation of how the other isotopes of hydrogen could be distiquished from one another sound quite reasonable yet it doesn’t have them removed from the system so I suspect then they also could be envolved in collissons within the detectors although at a much reduced rate. Also with the heavier isotopes being a lot slower one could imagine a few rear end collisions involving the lighter ones, even within the rings while not in the detectors. So I would be still curious to know how all this is dealt with.

Best,

Phil

Bee said...

Phil: They never make it into the beam. The bending of a particle in an electromagnetic field depends, as Stefan says, on the charge over mass ration. It doesn't take much to separate out particles with different charge to mass ratio than a proton. Even if one miraculously made it into a synchroton, it would literally run into the wall. Best,

B.

Phil Warnell said...

Hi Bee,

So are you saying that the magnetic confinement is tuned to a specific mass. Not that I’m doubting you yet I would have thought such a magnetic field as being so powerful couldn’t be so selective. That coupled with the fact as the protons increase in velocity so does their relativistic mass. I’m sorry yet I still remain confused.

Best,

Phil

Bee said...

Phil: We're talking about the first stage of the acceleration. The magnets in that case aren't particularly strong. But when it comes to the LHC, think about it, you need to keep your protons on a 27km ring within some mm accuracy (at least). If the bending is only a tiny bit off, the particle won't make it into the next magnet. Best,

B.

Phil Warnell said...

Hi Bee,

Thanks, again I was having another one of those moments as I forgot that the field is used as much to accelerate the particles as they are to confine it. You could say its a little like that rabbit leading those poor gray hounds around the track. This also serves to remind how sophisticated the computer control of the whole process is in repect to the power levels and the switching of the magnets. It certainly standa as a testimony to human ingenuity, to be able to have it to work at all.

Best,

Phil

stefan said...

Hi Phil,

separating protons from deuterons is not that difficult - it uses the principle of mass spectroscopy, which has been around before the first accelerators have been build. And the relative difference in e/m by a factor 2 is larger for protons/neutrons than for any other pair of ions, so it requires not a high mass resolution.

Actually, it's not necessary to take into account "relativistic mass" in a simple mass spectrometer, Coulomb and Lorentz forces acting on charges do the job, all classical. And the voltages involved and thus energies are not so high that relativity must be taken into account for protons or nuclei (for electrons, this is different, but their mass is 2000 times smaller).

BTW, at RHIC there has been a program of deuteron-gold collisions (I guess deuterons because it's an isospin singlet with equal numbers of up and down quarks), so they have indeed selected deuterons instead of protons out of their hydrogen cylinders ;-)

Cheers, Stefan

Phil Warnell said...
This comment has been removed by the author.
Phil Warnell said...

Hi Bee,

Another thing that had me think yesterday after your post was to imagine how the world would present itself from perspective of these protonsbin terms of the geometry of the citcular track, as well as the ever changing (acieration and angular momentum induced) gravity vector presented. Now this would certainly be a strange place in deed if one could manage to survive it.

Best,

Phil

Phil Warnell said...

Hi Stefan,

Thanks for the explanation, yet must admit I’ll have to think a bit as to why the relativistic mass increase you say as not being significant, as at 7 Tev would have a proton mass being that of a mosquito. As for the deuterium being used in the RHIC I guess you are referring to having this in terms of a system being a Boson and the implications that has in terms of such experiments in relation to matter condensates.

Best,

Phil

stefan said...

Hi Phil,

sorry, didn't want to confuse use... of course, over the whole high-energy acceleration process, relativity is important, at least after the linear accelerator.

The point is, separation of protons and deuterons happens at much lower energies, of a few keV. it is the very first step, even before acceleration in the LINAC. In such an accelerator, electric and magnetic fields have to been very precisely tuned, and with one set of machine parameter, this works only for one type of ions.

Cheers, Stefan

Phil Warnell said...

Hi Stefan,

Thanks again, so it’s in the ramp up stages all this is weeded out. I must admit this LHC has me fascinated and reminiscent of my visiting the space center in Florida shortly after they erected the building that houses a Saturn 5 rocket mounted horizontally. I spent more the four hours in that building, with my spouse patiently waiting with her not being able to go outside as the mosquitoes were so thick that day they could eat you alive. To be truthful I could have spent a couple of days there rather the hours. I hope to one day be able to visit the LHC for it presents to me the same sense of fascination and wonder.

Best,

Phil

Phil Warnell said...

Hi Bee,

I thought I’d relay I’m still having trouble to be able to watch that video stream. It seems to be some conflict between Windows viewer and Realtime. It appears to want to load it up under RealTime rather than the windows program and theirin prompting a error message. I think I’ll try dumping Realtime viewerfrom the system and see how that works out. It’s times like this that has me ever closer to ditching this Microsoft, pin cushioned and band aided junk to get a Mac as I’m finding I’m getting to old and impatient to enjoy the computer geek stuff:-)


Best,

Phil

Georg said...

Hello Kaleberg,

That's pretty funny having a "high tension" warning. That's a reference to the tension on the ether associated with the electric field.

If You have a close look You will
see that the tension is shared with
the French "haute".
With the word "voltage" that is not
possible.
Regarding "ether", I think You are not right.
The wording goes back to to the
analogies to steaming water, and
tension is still used for force/area
in civil engineering
(same as in German for Spannung).
I dont know, why this laymanlike
"voltage" (why not amperage,
why not ohmage ?)
is the common expression in
(american?) Enlish today.
Some other example of such wording
is the name "capacitor" for those
electronics parts having a capacity, strange, isn't it?
Georg

Phil Warnell said...

Hi Bee,

I finally figured out what the problem was in not me being able to watch the video. It wasn’t anything to do with my system or the link you provided, yet rather the link that’s provided in the window which it leads to at Nordita that is to be clicked on. In checking the link it reads mms://videos.nordita.org/colloquia/2010/2010-02-04-Strandberg.wmv which isn’t an internet protocol as beginning with mms: yet should read http://videos.nordita.org/colloquia/2010/2010-02-04-Strandberg.wmv which is. In other words it was your Nordita computer geeks that had it screwed up :-) Never the less I enjoyed the lecture.

Best,

Phil

Bee said...

Hi Phil,

You're right! I also replaced the mms with http, but then completely forgot about it, sorry about that. Best,

B.

Plato said...

You know with my bias I couldn't help interject this explanation as to what one can hope comes out of the LHC while we examine the results quite closely.

I know this concept has not formed in a lot of heads yet I know as time progresses it will eventually make sense for some:)


Missing Energy Kicks New Physics Models Off The Board

The signature of large missing energy and jets is arguably one of the most important avenues for the study of potential new physics signatures at today's hadron colliders.

The above concept marks an interesting turn of events: the years of the glorification of charged leptons as the single most important tools for the discovery of rare production processes appears behind us. The W and Z discovery in 1983 by UA1 at CERN, or the top quark discovery by CDF and DZERO in 1995 at Fermilab, would have been impossible without the precise and clean detection of electrons and muons. However, with time we have understood that missing energy may be a more powerful tool for new discoveries.

Missing energy arises when a violent collision between the projectiles -protons against antiprotons at the Tevatron collider, or protons against protons at the world's most powerful accelerator, the LHC- produces an asymmetric flow of energetic bodies out of the collision point in the plane orthogonal to the beams: a transverse imbalance. This is a clear signal that something is leaving the detector unseen. And it turns out that there is a host of new physics signals which can do precisely that.

A large amount of missing transverse energy may be the result of the decay of a leptoquarks into jets and neutrinos, when the latter leave undetected; or from the silent escape of a supersymmetric neutral particle -the neutralino- produced in the chain of decays following the production of squarks and gluinos; or it may even be due to the escape of particles in a fourth dimension of space -an alternative dubbed "large extra dimensions". see more in linked title above)


Best,

Plato said...

"Death, so called, is but older matter dressed
In some new form. And in a varied vest,
From tenement to tenement though tossed,
The soul is still the same, the figure only lost." Poem on Pythagoras, Dryden's Ovid.


So what about the Missing Energy?

When your looking at ICECUBE, SuperCDms, or thinking about the extension of the LHC on muon detection for Gran Sasso you have to know "what the causes were first" in order to understand the full scope of the collision process as the full particle plethora is looked at.

Best,

Phil Warnell said...

Hi Bee,

I trust you will inform them they need to repair their link and as you said they have a little ways to go io catch up with how Perimeter now presents it, with the slides being displayed separately as not having to darken the room as to have them be seen. One thing they could all improve on is the acoustics of the lecture rooms as the echo has it sometimes hard to make out what’s being said, especially if the speaker is talking in Germenglish or Swenglish:-) Then again I shouldn’t complain at all for at least now I can be that fly on the wall that I was never able to be before, for which I’m truly grateful.

The one thing I found out that I wasn’t clear on before is they will be concentrating on the collisions relative to the top quark in order in looking for the signature of the Higgs. All very fascinating yet so much data to analyze its amazing they can sort any of it out to know anything. Personally I’m hoping they will run across something that will totally have all left scratching their heads. I’m mindful of the Quark soup with the RHIC which many are still struggling to have each other convinced is still consistent with the standard model as it’s certainly not what was expected.

Best,

Phil

Bee said...

Hi Phil,

I believe what the speaker said, if I recall correctly, is that prior to being able to see any Higgs signature they will likely produce a higher number of top-quarks than the TeVatron has in its whole lifetime. I don't know what you mean with "concentrating on the collisions relative to the top quark in order in looking for the signature of the Higgs." Best,

B.

Phil Warnell said...

Hi Bee,

Sorry perhaps I had it wrong as to what the speaker was aluding to in respect to top quark production as it had me mindful that in theory the Higgs boson binds strongly to it so that in decay it creates two anti-quark pairs as to having this being the signature they are looking for.

Best,

Phil

Bee said...

Hi Phil,

Well, some of the decay channels include quark-antiquark pairs, but I'm not aware of top being a relevant signature. You find a plot with decay channels here. Best,

B.

Bee said...

Oh, yeah, you are right, there's a tt there coming up in the high mass end!

Chuck said...

Is it a commercial duoplasmatron? Which one?