LHC

• http://www.scienceinschool.org/2008/issue10/lhchow

  • CERN-Brochure-2008

  • beam parameters

• 26659 m circumference and 3.8 m wide tunnel about 100 m underground, 4243 m radius
• Beam tube 6.3 cm diameter (2.5 inch is 6.35 cm)
• 1e-13 bar
• 3e14 protons in two beams
• Acceleration cavity 5 MV/m
• 1.1e11 protons per bunch
• each beam consists of 2808 discrete bunches, seven meters between bunches
• After 20 minutes, they reach their final energy, while doing 11 245 circuits of the LHC ring per second.
• 3e14 protons per beam
• 0.999999991 c
• 7 TeV
• 9300 magnets, 1232 dipoles, 16 m long, 35 mt, 8.33 tesla maximum, 11700 A
• -271.3°C (1.9K), superfluid helium has very high thermal conductivity
• 96 tonnes of helium, 8 refrigerators at 18kW at 4.5K ?
• 120 MW
• niobium/titanium superconductors
• CMS magnet system contains 10,000 tonnes of iron
• 4 crossing points (8 possible?)

  • CMS Compact Muon Solenoid also TOTEM Total elastic and diffractive cross section measurement

  • beam dump

  • .

  • LHCb LHC beauty experiment

  • ATLAS also LHCf LHC forward

  • ALICE A Large Ion Collider Experiment

  • .

  • .

• 20 particle collisions occur per bunch crossing
• 600M collisions/s = 20 x 2800 bunches x 11 245 turns per second at each crossing
  • 4 crossings, 2.4 billion collisions per second
• 100 KJ/bunch
• 350 MJ in each beam, 400 tonne TGV travelling at 200 km/h is 620 MJ Magnet energy is 11 GJ
  • Freight train: class 4, 97 km/h (27 m/s), 3000 to 8000 to 13000 tons? 5000 tonnes at 25 m/s is 156 GJ
• normally a millimeter in diameter, bunches squeezed by special magnets to 16 µm diameter and 80 mm length at collision points
• 150 million sensors, 40 Ms/s
• 31.6 MHz bunch crossing rate, with gaps allowing for kicker magnet response time to dump beam
• a beam might circulate for 10 hours, 10.8 billion kilometers, Neptune and back
• 15 petabytes annually

LHC, Particles Books

The Large Hadron Collider

Unraveling the Mysteries of the Universe

Martin Beech, CENTRAL 539.7376 B4143L 2010

LHC is one of my favorite machines; micrometer precision at kilometer scale, at 0.999999991 of the speed of light. The stored proton energy is a tiny fraction of a launch loop rotor, but in most other ways it far exceeds the necessary precision, drag, and control accuracy necessary for a launch loop or power loop ambit. Launch loops could use superconducting magnets, but the expense and risk is unnecessary for the ambits, ordinary iron and copper electromagnets will suffice for a 1.5 Tesla deflection field. 4 Tesla high field superconducting magnets for the vertical deflectors could reduce the ocean depth of those magnets from hundreds to tens of meters.

The Beech book was written soon after the 2008 September 10 turnon and the September 19 sector 3-4 magnet quench, which vented 1000 kg of helium and delayed restart until 2010, with full power operation (and full magnet field strength) delayed until 2011. Thus, most of the story, and the detection of the Higgs, occured after this book went to press. So most of the book is about related physics.

• This particular MultCo copy has a lot of pencilled margin notes by an opinionated ass ("OA"). For example, on page 57 the book responds to the author's statement "there is no specific maximum energy that a particle can have" (my emphasis) with nattering about the Planck length and photon energy, apparently not understanding the word specific in a real physical context. No particle can have more than the 1.2e19 GeV Planck energy, but there may be other lower limits, not yet discovered or postulated. There may not be any particle with a rest mass heavier than the top quark ( 172 GeV/c² ) and with a mean lifetime of 5e−25 seconds, there may not be any heavier measurable fundamental particles. Hypothetical composite particles like Unbinilium (element 120 eka-radium) nuclei might have a mass of 299 AMU or 278 GeV/c², and have much higher relativistic velocities in an accelerator. There being no "specific" length for an physical accelerator, there is no "specific" maximum particle energy. Hence, OA doesn't understand what the author intended, and may be unfamiliar with the use of qualifying adjectives.

• p44 Octant map:

  • 1 ATLAS (A Toroidal LHC Apparatus) beam crossing

  • 2 ALICE (A Large Ion Collider Experiment) beam crossing

  • 3 Beam cleaning
  • 4 RF Beam booster

  • 5 CMS (Compact Muon Solenoid) beam crossing

  • 6 Beam Dump
  • 7 Beam Cleaning

  • 8 LHCb (Large Hadron Collider beauty) beam crossing

• p52 Photo of the hydrogen supply cylinder feeding a tiny trickle of protons to CERN, 2 ng per day.
• This feeds a series of faster and larger machines with increasing diameters and exit energies:

• 1 LINAC 2 proton accelerator, exit energy 50 MeV, 1978.

• 2 PSB Proton Synchrotron Booster,four 50 m rings, 1.4 GeV, 1972.

• 3 PS Proton Synchrotron, 2 00m, 25 GeV, 1959.

• 4 SPS Super Proton Synchrotron, 2.25 km, 400 GeV, 1976.

• 5 LHC Large Hadron Collider, 8.6 km, 6.5 TeV per beam after 2015 upgrade.

• The counterrotating beams produce a collision energy of 13 TeV
• LHC will be shut down for two years of upgrades, increasing luminance and improving detectors, with target energies of 14 TeV in 2021.

• A high luminosity (5x improvement) upgrade, HL-LHC, is scheduled for 2026.

• p54 LHC@home uses BOINC (Berkeley Open Infrastructure for Network Computing) and VirtualBox and CERNVM

. The project does not use the graphics coprocessor (GPU), which would be more energy efficient.

• p62 Tbe cryogenic beam boosting and beam shaping station is at octant 4, 5 MV/m, 500 MHz. Run time 10 hours after acceleration and before beam dump in octant.
• p62 Stray photons are removed at beam cleaning stations in octants 3 and 7.

• p140 Fig 5.14 Rotation velocity vs distance for Milky Way resembles this image

• p141 Fig 5.15 Composite of rotation curves for 21 galaxies measured by Vera Rubin et al, perhaps sourced from this image

Particle Physics

A Very Short Introduction

Frank Close, Central 539.72 C645pp 2004

This is a startlingly well written book, and provides explanations of the standard model and the evolution of particle detectors. I would love to find a 2019 version of it, updated by the successful operation of the Large Hadron Collider, the Higgs discovery, and the lack of higher energy discoveries supporting the notion of supersymmetry, dark matter, axions, etc. etc.

Our models of the very early universe assume cosmic inflation and other postulations to flatten things out, as well as dark matter to explain deuterium abundance. Perhaps the early universe was far more chaotic than this. Symmetries lead to the Higgs field hypothesis, and the 125 GeV signal that is attributed to the Higgs.

However, our models of the universe are mostly built from observations through a murky atmosphere, deep in the Earth and Sun gravity wells, with a handful of "small" sensors in space. When we build vast observatories in solar orbit, and someday far from the Sun, we may capture some weak "anomalous" signals incompatible with our elaborate models and their associated unobservables.

Without data, medieval cartographers drew mermaids and sea monsters in the blank areas of their maps, because their patrons weren't paying for blank paper. I wonder if SUSY and the hypothetical dark matter zoo are the sea serpents of our age, just as the ether and phlogiston were the sea serpents of the 19th and 18th centuries.

Lets put some of the theorists to work designing clever space probes, and measure the universe in new and different ways; if we strive to be surprised, we will be ready to listen to nature again.