An American Family in Geneva

Rudiger Schmidt gives the third of the series on LHC Hardware Commissioning. Here is his abstract:

Unprecedented parameters of the LHC accelerator have a significant impact on operation and machine protection. The energy stored in the magnets is in the order of 10 GJoule when operating at 7 TeV. Each beam carries an energy of about 360 MJoule at nominal beam current. LHC powering operation, and later beam operation must fully rely on a number of protection system.

For powering of the superconducting magnets, the quench detection system, the system to extract the energy and the related interlock systems are required to prevent magnets and other powering equipment to be damaged in case of a quench, or other accidents. During hardware commissioning, the systems must be fully tested. This will not only guarantee that the equipment is protected, but also ensure that the machine is ready for beam and pave the way for the commissioning of beam related protection systems, such as beam interlocks, beam dumping system and beam loss monitors.

The CERN link to this talk is here.

My audio recording of this talk is here.

This is the second in the CERN Academic Lectures on LHC Commissioning.

Here is his abstract:

The cooling of the LHC is produced by eight large cryogenic plants – one per sector - installed in five cryogenic islands. Each plant is able to produce up to 600 kW at 80 K, up to an equivalent capacity of 18 kW at 4.5 K as well as up to 2.4 kW at 1.8 K. After cooling the huge sector mass of 4.6x106 kg from room temperature down to 1.9 K and filling the magnet with up to 15 tons of helium mainly in superfluid state, the cryogenic system must be tuned without current to obtain stable operating conditions over long period. Following this tuning, powering tests with current ramping and de-ramping, fast current discharges and resistive transitions are performed. Fast discharges of the current of the main magnet circuits dissipate up to 3 kJ per meter in the magnet cold-masses which must remain cooled in superfluid helium. Resistive transitions of magnets create fast pressure and temperature rises and flow surges. Following a resistive transition of a magnet cell (107 m), the recovery time to nominal conditions should not exceed few hours.

The CERN link to this talk is here.

The audio for this talk is available here.

Labels: lhc

Dr. Saban just finished an excellent talk on the hardware commissioning for the LHC, as it stands today.

Here is his abstract:

The operation of the Large Hadron Collider relies many systems with technologies often beyond the start of the art and in particular on hundreds of superconducting magnets operating in superfluid He at 1.9K powered by more than 1700 power converters. A sophisticated magnet protection system is crucial to detect a quench and safely extract the energy stored in the circuits (about 1GJ only in one of the dipole circuits of each sector) after a resistive transition.

In order to ensure safe operation, these systems depend on each other and on the infrastructure systems (controls, electricity distribution, water cooling, ventilation, communication systems, etc.). The commissioning of the technical systems together with the associated infrastructures is therefore mandatory.

The complexity of operating this machine stems from the dependence and interplay of the systems, their nominal performance which is often at the technological frontier and on their geographical distribution.

Here is the CERN link to his talk.

Here is a link to the audio recording I made of this lecture.


The conclusion of the talk included this slide, with the current status of the hardware commissioning of the LHC:

Sector	Average Temp (K)	Status
12	300	Flushing
23	22	CoolDown
34	177	Cooldown
45	300	Commissioned to 5 TeV except for the triplet. Inner triplet now connected. Consolidation complete. Cool down starts in two weeks May 26
56	2	Fully commissioned to 5 TeV. Dipoles and quadrupoles being trained to 7 TeV.
67	25	Cooldown
78	2	Partially tested in June, 2007. Inner triplet connected. Power test start tomorrow May 14
81	2	Power tests start in one week May 19.

Labels: lhc

Abstract

An injunction has been filed in the Hawaii courts to halt the startup of the LHC. The basis of this suit is the claim that strange, new particles could be produced by the LHC that could destroy the earth. Several online sources are providing an effective avenue for these objections, raising the concern to such a level that the New York Times has published an article on this topic.

It is my view that it is not possible for the LHC to create a long-lived microscopic black hole. If such a particle was physically possible and dangerous, it would have been created by cosmic ray collisions throughout the Universe and the distinctive signature of the consequences of this particle would have been observed.

This blog article is not a scientific one, that is, I have not completed the full calculations yet. This article is intended as a feasibility study only, and I think that it shows that these harmful black holes do not exist.

Introduction

There have been speculations online that the Large Hadron Collider (LHC) near Geneva, Switzerland, will produce new matter that could be catastrophic for our Planet Earth. One of the more measured surveys of this topic is found at the web site lhcconcerns.com. Here is a list I have taken from that web site of the possible devastations that could be created by the LHC:

• Microscopic Black Holes – The topic of this article.
• Strangelets
• Bubble Nucleation
• Magnetic Monopoles

All of these creations are, admittedly, very unlikely. None has even been observed. But the speculated properties of these new objects could be very interesting.

The ultimate logic goes like this. The risk, R, of something going very wrong is equal to the probability, p, that it could happen times the impact, X, of what could happen:

R = p X

In other words, an unlikely event (small p) with a devastating consequence (large X) leads to a value or risk (R) that is non-zero and worrisome. We assume that the complete destruction of all humanity is an infinite impact! Then any non-zero probability of this leads to a non-zero risk.

This article will only address the impact of microscopic black holes (MBH), created by the LHC, on us.

What Are Critics Saying?

In the Hawking Radiation article in the Wikipedia, you’ll see this interesting line:

In speculative large extra dimension theories, CERN's Large Hadron Collider may be able to create micro black holes and observe their evaporation. In well accepted physics,
there is a nongravitational black hole analog whose formation and evaporation is currently observed at RHIC^[4].

First, let’s examine the second assertion in the quote from the Wikipedia. The footnote to the RHIC “observation” is a BBC News Article from 2005, quoting a Brown University physicist, Horatiu Nastase, who wrote two articles, posted in the arkiv.org database ([1] and [2]). Nastase
suggests that one particularly violent interaction observed at RHIC was the result of a black hole decaying.

I cannot find any evidence that Nastase’s work was peer-reviewed, referenced elsewhere, verified or confirmed by anyone. The only articles in arkiv.org that talk about black holes and RHIC are two from Nastase and one from elsewhere ([3]). Moreover, Nastase left Brown shortly after the publication of this article in 2005 (see his web page).

If Nastase’s article was “well accepted”, I contend that there would be hundreds of authors and lots of references to it.

Therefore I conclude that this article by Nastase is nothing more than speculation.

But this is getting a lot of attention right now. Today, the New York Times reports,

[Two men in Hawaii] think a giant particle accelerator [the LHC] that will begin smashing protons together outside Geneva this summer might produce a black hole or something else that will spell the end of the Earth — and maybe the universe.

LHCConcerns.com, says:

Over 2 thousand Protons in each beam [the design number is 6E14 particles per beam] will pretty much collide roughly in the middle [actually, exactly in the middle of the experiments], although no collision would create a particle exactly dead center, or "still", in a relative sense any MBH or fundamental particle created in such a manner (even with both beams at a speed of .99999999 c) would be in a relative sense, at Rest, or to elaborate the term at rest we mean lower than the necessary escape velocity to escape the Earth's own gravitational pull.

At that point two hypothetical scenarios exist [assuming that Hawking Radiation does not exist]. It would either maintain a rather low orbit within our planet itself, slowly accreting mass at an exponential rate, or it's possible it may "gravitate" to the direct center of the planet in which case would accrete mass very quickly.

A peer-review article, quoted in the CERN Courier in 2004, states:

the 14 TeV centre-of-mass energy of the Large Hadron Collider (LHC) could allow it to become a black-hole factory with a production rate as high as about one per second.

So, after a little while of running the LHC, we will have created lots of long-lived MBH’s, which will devour the earth.

OMG!

Hold on a minute. Let’s look at this more carefully.

Will the Earth survive MBH Creation in the LHC?

First, what do we know?

At the LHC design intensity and assuming the 1 MBH creations per second, that’s one MBH for every 400 million p-p collisions at 14 TeV.

The Tevatron is the largest collider in the world right now, colliding protons and antiprotons at 1.96 TeV. It is achieving interactions at a world-record rate, but still about 300 times smaller than the design LHC level. But they have been running since the early 1990’s, creating about 3 x 10¹⁵ proton-antiproton collisions. If the probability of creating MBH’s at 1.96 TeV was the same as at 14 TeV (which is almost certainly is not), that would have created 7.7 million MBH’s. This has not happened. One can make a similar observation from RHIC at Brookhaven Lab—they have been running for a while and the earth has not been destroyed.

Cosmic Rays

The 14 TeV center-of-mass energy of the LHC is small when compared to cosmic rays, which are bombarding us all the time. So these black holes are being created all the time. But, as LHCConcerns.com says, these could just be passing through the earth, unaffected.

But the earth’s atmosphere is not the only place in the Universe where this would happen. It would happen everywhere a very high-energy cosmic ray hits something. That would include:

• Earth’s atmosphere
• Mars’ atmosphere
• Venus’ atmosphere
• Mercury’s surface
• The moon’s surface
• The sun
• The atmosphere or the surface of every object in the Solar System
• Dust in the Solar System
• The atmosphere or the surface of every object in the our galaxy, the Milky Way
• Dust in the Milky Way
• The atmosphere or the surface of every object in the Universe
• Dust in the Universe
• Free hydrogen in the Universe
  

In other words, everything, everywhere, since the beginning of time would interact with cosmic rays to create microscopic black holes, if they can be created by the LHC.

So, if Hawking Radiation does not exist and if 14 TeV center-of-mass energy is enough to create a MBH, we should be inundated with MBH’s from all over the Universe.

MBH Flux at Earth’s Atmosphere

How many? According to Nima Arkani-Hamed, a particle theorist at the Institute for Advanced Study in Princeton, quoted in the New York Times article, there are 100,000 LHC-like collisions in the earth’s atmosphere every day. That rate converts to 1.2 LHC-like collisions per second. So, every 400 million seconds (12.7 years) and MBH would be created in the earth’s atmosphere.

We can make a reasonable guess on the number of MBH’s made elsewhere. The earth’s mass is about 4 x 10^-5 of the mass of the solar system, so there could be something like a 400,000 MBH’s created in the solar system in 12 years. That converts to a production rate of 1 every
900 seconds in the solar system.

What about all the other solar systems in the Milky Way? There are about 200 billion stars
in the galaxy. So there could be 2 x 10⁸ MBH’s created in the galaxy every second. (That number would probably be increased because of the background gas and dust throughout the galaxy.)

And there are billions (trillions?) of galaxies in the visible universe, and black holes should be coming from there, too.

That’s a lot of MBH’s that are created all the time, everywhere.

Other Effects on MBH Affect?

What happens to an MBH created far, far away as it travels to the earth?

We have assumed that Hawking Radiation does not exist and that this MBH is travelling close to the speed of light when it is created. Thus, it doesn’t get much chance to pick up mass as it zips through all the dust, planets, suns and neutron stars along the way. But it is going to pick up a proton or two from time to time. For each proton that it picks up, it will slow down a little bit, making it a little bit more likely that it will interact with the next proton it encounters.

If the MBH crosses something really big, like a star, it could pick up quite a few protons and slow down quite a bit. Travelling at the speed of light, it will take about ½ second for the MBH to cross a sun-sized star (1.4 x 10⁹ meters across). The center of a star is very tightly packed with protons, alpha particles and electrons. So as the MBH crosses the star, it is encountering a lot of protons.

After a while, the MBH would gain a lot of mass—at some point it would turn into a “real” black hole. One would expect that MBH’s that have grown to some moderate size would be captured by a star, and as they accumulate mass, their orbit would decay, leading to the death of the star

So a MBH created billions of light-years away from us should be capable of devouring the earth, and one would have devoured an observable star by now.

Conclusions

If Hawking Radiation does not exist, black holes would be permanently created at a rate of about 200 MHz (Mega Hertz) in our galaxy, and every other galaxy in the Universe. MBH’s are created far away from a target would have a greater chance of stopping in the target and devouring it. No stars have been observed to disappear in our galactic neighborhood. And, of course, the earth has not been devoured by anything yet.

To paraphrase Enrico Fermi, if there are so many microscopic black holes in the cosmos, “where are they?”

I believe that the same sort of logic would apply to the other speculated exotic particles that critics think could be created by the LHC. If they could be created by the LHC, they would be created at a high rate throughout the Cosmos, and their catastrophic effects would have been seen or felt by now.

Therefore, the Earth will survive the side effects of proton-proton collisions in the Large Hadron Collider.

Labels: lhc

We all know these two important things:

1. The price of gas is a lot higher in Europe than in the US
2. The value of the dollar is falling.

Yesterday I filled up my fuel-efficient Volkswagen Jetta diesel and it cost 91 CHF. Ouch!

The price of diesel has increased to 1.95 CHF per liter from about 1.75 in September--that's an 11% increase.

The value of the dollar continue to fall. This week, it crossed the magic line where the dollar os not less valuable that the franc. Here are a couple of charts from Yahoo. First, "$/CHF" for the last year:
Now, zero in on the last few days:

That's a drop in the value of the dollar by about 20% since we have been here. Remember: the dollar was worth about 1.5 francs a few years ago.

So, I am paying as much to fill up my little 12-gallon Jetta with fuel as my sister pays to fill up her 40-gallon Chevy Suburban in the US.

By the way, why (oh, why?) is the price of diesel higher than the price of gasoline? The answer, for what it is worth, is here. :-(

Update: 13-May-2008
The price of fuel is now 2.14 CHF per liter. But the price of a franc is now 1.048 francs per dollar. So that calculates to $7.76/gallon. Ouch, still!