Quarknet oregon
This presentation is the property of its rightful owner.
Sponsored Links
1 / 13

QuarkNet Oregon PowerPoint PPT Presentation


  • 49 Views
  • Uploaded on
  • Presentation posted in: General

QuarkNet Oregon. Ray Frey, Dept of Physics, UO. What is QuarkNet? National program, funded by NSF and DoE High-energy physics and the public (and our government) SSC  LHC Getting the public (schools) involved in (HEP) inquiry Demystification of basic science research

Download Presentation

QuarkNet Oregon

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Quarknet oregon

QuarkNet Oregon

Ray Frey, Dept of Physics, UO

  • What is QuarkNet?

    • National program, funded by NSF and DoE

  • High-energy physics and the public (and our government)

    • SSC  LHC

    • Getting the public (schools) involved in (HEP) inquiry

    • Demystification of basic science research

    • Familiarity with the forefront research questions being studied

  • QuarkNet Oregon

    • HEP at UO  HS teachers  students

    • Research questions and methodologies

    • Activities surround annual 1 week workshops

      • Lectures and tours

      • Cosmic ray detectors for each involved teacher

      • Participation in national QuarkNet events

    • Looking for new teachers to get involved !

QuarkNet Oregon 2008, R Frey


Quarknet oregon

  • Supports learning by inquiry.

  • Provides teachers and students with real research opportunities in particle physics.

  • Encourages national and international collaboration among students, teachers and scientists.

QuarkNet Oregon 2008, R Frey


The large hadron collider lhc

The Large Hadron Collider (LHC)

  • CERN, Geneva; startup 2008

  • collisions of 7 TeV protons and 7 TeV protons

  • a billion collisions/second

  • The Standard Model of HEP appears to break down at E1 TeV

  • We anticipate New Physics but don’t know in what form it will appear

  • The Oregon HEP group collaborates on the Atlas experiment at the LHC

  • A goal of QuarkNet is to help bring the excitement of the LHC to the classroom

QuarkNet Oregon 2008, R Frey


Cosmic rays

Cosmic Rays

  • Outside earth’s atmosphere, these are charged particles, 86% protons

  • These primary cosmic ray particles interact with air high in the atmosphere (15 km), creating showers of secondary particles

  • By time the secondaries reach sea level, muons dominate the flux

  • The detectable (vertical) rate at sea level is 1/cm2/min (e.g. in CRDs)

  • Throughout our galaxy, CRs have an energy density of 1 eV/cm3

    • Starlight: 0.6 eV/cm3

    • CMB: 0.26 eV/cm3

  • 30% of natural radiation (sea level)

  • Provide charge and seeds for lightning

from QuarkNet CRD manual

QuarkNet Oregon 2008, R Frey


Energy and origin of primaries

energy and origin of primaries

  • Steeply falling, power law energy spectrum

  • For E1014 eV, spectrum and flux are consistent with acceleration by shock waves from supernovae (“Fermi acceleration”)

  • For larger energy, mechanism is unknown (black hole at galactic center??)

  • For E1019 eV, protons would not be captured by galactic magnetic field (310-10 T)

    • pt [GeV] = (0.3q/e)B[T] R[m]

  • So higher energy CRs must be extra-galactic... but GZK cutoff...

QuarkNet Oregon 2008, R Frey


Auger cr observatory www auger org

Auger CR observatorywww.auger.org

  • Sites in Mexico and Argentina

  • Array of detectors: (40x1.5 km)x(40x1.5 km)

  • GZK: extragalactic CRs attenuated:

    p +  (CMB)  +  p + , n + +

    • 411 CMB photons/ cm3 ; E=k2.7K=2.410-4 eV

    • No protons >1020 eV from further than 5 Mpc

  • Summer 2007: No excess above GZK cutoff

  • Fall 2007: UHE CRs associated with AGNs

QuarkNet Oregon 2008, R Frey


The cosmic ray showers

The cosmic ray showers

  • Primaries interact in the atmosphere – the maximum production of pions and muons is at z15 km, making showers of (mostly) short-lived particles.(e.g. pion () lifetime is 2.610-8 s)

  • Characteristic shower angle:

      pt / pL  0.2 GeV/E

  • The long-lived secondaries are:

    • e, photons: mostly absorbed

    • neutrinos (): practically invisible

    • muons (): =lifetime is 2.210-6 s

  • Without time dilation, muons would travel dc=660 m, with a survival fraction

    e-0.66/15 10-10

  • Instead, for a 10 GeV muon, 10/0.1=100, then mean distance is 66 km. (OK)

QuarkNet Oregon 2008, R Frey


Cosmic rays at earth s surface

cosmic rays at earth’s surface

  • Predominantly muons

  • Detectable (vertical) flux is 1/ cm2/ min

  • Mean energy  4 GeV

  • Originate at altitude of 15 km, on average

  • The very low energy muons (1-3 GeV) mostly decay

    • 15 km decay length corresponds to a 2.4 GeV muon

  • The higher energy muons lose about 2 GeV (on average) due to ionization in the atmosphere

    • and about 4 MeV / cm in concrete

QuarkNet Oregon 2008, R Frey


Quarknet oregon

QuarkNet Oregon 2008, R Frey


Quarknet oregon

QuarkNet Oregon 2008, R Frey


Quarknet cosmic ray detectors

QuarkNet cosmic ray detectors

  • 4 scintillator paddles and photomultiplier tubes

  • requires only wall plug power

  • GPS receiver

  • electronics card and computer interface

  • measure cosmic ray rates in various configurations

  • datasets written to computer

  • combine with other setups

  • muon lifetime experiment

QuarkNet Oregon 2008, R Frey


A community of cosmic experimenters

a community of cosmic experimenters

  • A “minimum ionizing particle” (MIP), e.g. a typical cosmic ray muon, passes through a plastic scintillator, depositing (on average) about 2 MeV / cm (ionization of the plastic)

  • Typically, the scintillation yield is 1 photon per 100 eV of ionization  2104 photons/ cm for each muon

  • Some fraction of the photons are collected at the photomultiplier tube (PMT) – depends on geometry and indices of refraction

  • The photocathode of the PMT converts a blue photon to an electron with efficiency of 10%

  • The PMT multiplies an electron by a factor 106

    • depends on high voltage setting, number of stages N (N=10 to 12 typically), and geometry

    • Gain  (few)N

QuarkNet Oregon 2008, R Frey


A community of cosmic experimenters1

a community of cosmic experimenters

QuarkNet Oregon 2008, R Frey


  • Login