ONSET OF THE QUANTUM REGIME KRISTOFFER K. ANDERSEN DEPARTMENT OF - - PowerPoint PPT Presentation

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ONSET OF THE QUANTUM REGIME KRISTOFFER K. ANDERSEN DEPARTMENT OF - - PowerPoint PPT Presentation

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22. FEBRUARY 2013 EXPERIMENTAL INVESTIGATIONS OF SYNCHROTRON RADIATION AT THE ONSET OF THE QUANTUM REGIME KRISTOFFER K. ANDERSEN DEPARTMENT OF PHYSICS AND ASTRONOMY, AARHUS UNIVERSITY QUANTUM SYNCHROTRON RADIATION 22. FEBRUARY 2013

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KRISTOFFER K. ANDERSEN DEPARTMENT OF PHYSICS AND ASTRONOMY, AARHUS UNIVERSITY

  • 22. FEBRUARY 2013

QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

EXPERIMENTAL INVESTIGATIONS OF SYNCHROTRON RADIATION AT THE ONSET OF THE QUANTUM REGIME

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

MOTIVATION

› Test of quantum mechanical calculations of synchrotron radiation. › Relevant for linear colliders, astrophysical

  • bjects like magnetars,

heavy ion collisions and more.

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Magnetar SGR 1900+14

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

BEAMSTRAHLUNG

›Electric field from one bunch boosted by 2g2-1 as seen by particles in the other bunch

Small beams, high Lorentz factors => Strong electromagnetic fields => Beam focusing Increase of luminosity Beamstrahlung

The electric field of the oncoming bunch is seen as a magnetic and electric field in the rest frame of the first bunch.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

SYNCHROTRON RADIATION

›Typical radiated energy is ›The strong field parameter ›The critical field is

B photons electrons

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

SYNCHROTRON RADIATION

.0 1 .0 1 .1 1 1 1 1 1 1 .0 1 .0 1 .1 1 1 Critica l e n e rg y

Classical synchrotron radiation

In cid e n t e n e rg y, E

e=1

G e V S ta n d a rd ma g n e t, B = 1 T, 1 m S i <1 1 >max, B

equiv = 2

5 .0 T, 0 .1 mm

dN/d

Photon energy [M eV]

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

BEAMSTRAHLUNG PARAMETERS

›For colliders the strong field parameter is given by ›And the luminosity is without disruption. › separates the classical from the quantum regime.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CLIC PARAMETER

›For CLIC we get ›However due to disruption of the beam the averaged parameter is

From the CLIC conceptual design report

›For ILC this is

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CLIC LUMINOSITY

›Large reduction due to beamstrahlung but even worse if the quantum suppression was not present-

From the CLIC conceptual design report

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

MAGNETARS

›B = 10 GT > B0 ›Neutron star of radius 20 km and greater mass than the sun. ›Gamma and X-ray emitters

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On the surface of quark stars

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE NA63 EXPERIMENTS

›Use crystalline fields to measure the quantum corrections to synchrotron radiation.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

EXPERIMENTAL SETUP

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DC1 DC2 Krystal

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

GERMANIUM CRYSTAL

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Random orientation axis

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CONTINUUM MODEL

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CRYSTAL POTENTIAL AND FIELD

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Strong field parameter Remark the figure shows the potential energy for a positron along the crystal axis

The potential is taken from Baier et al.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

ACCESSIBLE PHASE SPACE

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The potential energy at a given distance from the axis The transverse kinetic energy The particle is free to move between different axes. Well channelled particles have extremely small entrance angles.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE CONSTANT FIELD APPROXIMATION

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Radiation emission angle: Deflection angle:

Criterium for constant field approx.

Magnetic bremsstrahlung

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE CONSTANT FIELD APPROXIMATION

›Classical synchrtron radiation ›The constant field approximation ›Two changes: Spin and recoil

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE CONSTANT FIELD APPROXIMATION

›Spin contribution:

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NIMB 119 (1996) 2

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CRYSTAL RADIATION

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Average over positions in crystal. Strong field parameter For germanium

Baier et al.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

RADIATION ENHANCEMENT

›Radiation emission is enhanced compared to bremsstrahlung. ›Bethe-Heitler formula:

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

DEFLECTION AND DETECTION

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DC2 DC3 Crystal MBPL magnet LG

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

PILE UP AND CALOMETRIC EFFECT

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Lead glass detector Multiphoton effects: Less photons at low energies

A slight increase at high energies Photon energy

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

PAIR SPECTROMETER

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DC5 DC6 Cu conver- siontarget MDX magnet

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

GEOMETRIC CONSTRAINTS

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MDX DC5 DC6 e+ e- Drift chamber width: 15 cm 2.0 m 3.2 m q+ q- DC6 angle constraint: corresponding to Energy threshold: for DC6.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

GEOMETRIC CONSTRAINTS

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

MONTE CARLO SIMULATIONS OF PS

›Compare the background measurements to the Bethe-Heitler formula.

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PRD 86, 072001 (2012)

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

MONTE CARLO SIMULATIONS OF PS

›The goal is to verify measurements of Bethe-Heitler radiation and determine the efficiency of the pair spectrometer.

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PRD 86, 072001 (2012)

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

PAIR SPECTROMETER EFFICIENCY

›From the Monte Carlo simulations we deduce the efficiency of the pair spectrometer from the incident photons and the measured spectrum.

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› Depends on:

Detector geometry Conversion probability Internal structure

  • f detector

Drift chamber efficiency

PRD 86, 072001 (2012)

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

RADIATION SPECTRA

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PRD 86, 072001 (2012)

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

RADIATION SPECTRA

› Full theoretical calculation › Single field CFA fit with and without the spin correction. › Classical synchrotron radiation

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PRD 86, 072001 (2012)

100 GeV data

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

ENHANCEMENT

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Quantum suppression of synchrotron radiation

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

SPIN FLIP TRANSITIONS

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

SPIN FLIP TRANSITIONS

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’Polarization time’

PRL 87, 054801 (2001)

For a 100 GeV electron in χ = 1 field ct becomes 10 μm or t = 32 fs

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE CONCEPT OF FORMATION LENGTH

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› The distances the emitted photon travels before it is separated by a Compton wavelength from the emitting electron.

High particle energy, low photon energy: Long formation length 250 GeV e-, 1 GeV γ: lf = 0.1 mm

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THE CONCEPT OF FORMATION LENGTH

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› For synchrotron radiation one can relate the magnetic field to the formation length.

For a 100 GeV electron in a 1 kT field this corresponds to a 9 GeV photon.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

A SIMPLE GRAPHICAL EXPLANATION

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

DIRECT MEASUREMENT OF LF

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› 45 μm target separation › Small excess around 400 MeV › Data has a preference for the Blankenbecler and Drell theory with the delta correction term.

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SLIDE 38

QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CRYSTALLINE UNDULATORS

› Periodically bent crystals consisting of silicon and germanium and made by molecular beam epitaxy. › Amplitude a > d › Stable channelling › Many periods › Low radiative loss

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

CRYSTALLINE UNDULATORS

›Measured at MAMI ›270 MeV electrons in planar channelling for a flat crystal (blue) and crystal undulator (red). ›The excess is seen around the 1st harmonic at 70 keV.

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QUANTUM SYNCHROTRON RADIATION KRISTOFFER K. ANDERSEN

  • 22. FEBRUARY 2013

THANKS TO

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the CERN NA63 collaboration in which this work was done.

And thanks for your attention!

Aarhus University: Group of Ulrik Uggerhøj;

Helge Knudsen Heine Thomsen Jakob Esberg Søren Andersen

Other members of NA63

Pietro Sona Alessio Mangiarotti Sergio Ballestrero Tjeerd Ketel

Aarhus University: Technical staff:

Per Christensen Poul Aggerholm