Challenges and Opportunities of high intensity X/g photon beams for Nuclear Photonics and Muon Beams

1
Challenges and Opportunities of high intensity
X/g photonbeams for Nuclear Photonics and Muon
Beams
Luca Serafini INFN-Milan, EuroGammaS
scientific coordinator V. Petrillo, C. Curatolo
Univ. of Milan

• Physics/Technology Challenges of
  electron-(optical)photon colliders as X/g beam
  Sources using Compton back-scattering
• Need of high peak brightness/high average current
  electron beams (cmp. FELs drivers) fsec-class
  synchronized and mm-mrad-scale aligned to high
  peak/average power laser beams
• Main goal for Nuclear Physics and Nuclear
  Photonics Spectral Densities gt 104
  Nph/(s.eV) (state of the art HigS 300,
  bremsstrahlung sources 1) photon energy range
  1-20 MeV, bandwidths 10-3 class

2

• Main goal for MeV-class g - g and TeV g -
  nucleon colliders Peak Brilliance gt 1021
  Nph/(s.mm2.mrad2.0.1) 109ltNphlt1013 Source spot
  size mm-scale (low diffraction, few
  mrad) Tunability, Mono-chromaticity, Polarization
  (H,V,C)
• ELI-NP-GammaBeamSystem in construction by
  EuroGammaS as an example of new generation
  Compton Source
• Photon-Photon scattering ( Breit-Wheeler pair
  creation in vacuum) is becoming feasible with
  this new generation g-beams
• Interesting new option for low emittance pion and
  muon beams generation using X-FELs and LHC beams
  (demonstrator based on Compton Source and SPS
  beams)

3
If the Physics of Compton/Thomson back-scattering
is well known.
the Challenge of making a Compton Source running
as an electron-photon Collider with maximum
Luminosity, to achieve the requested Spectral
Density, Brilliance, narrow Bandwidth of the
generated X/g ray beam, is a completely
different issue/business !
Courtesy L. Palumbo
4
Compton Inverse Scattering Physics is clear
recall some basics
3 regimes a) Elastic, Thomson b) Quasi-Elastic,
Compton with Thomson cross-section c) Inelastic,
Compton, recoil dominated
Courtesy V. Petrillo
5
g-g Colliders
Polarized Positrons
X/g MeV
FELs (pure g2)
Nuclear Photonics
D
Thomson X-rays
1 GeV
1 TeV
Te MeV
6
We need to build a very high luminosity
collider, that needs to maximize the Spectral
Luminosity, i.e. Luminosity per unit bandwidth

• Scattered flux
• Luminosity as in HEP collisions
• Many photons, electrons
• Focus tightly
• ELI-NP

f
cfr. LHC 1034, Hi-Lumi LHC 1035
7
300 mrad 60 mrad
Courtesy M. Gambaccini
8
Bandwidth due to collection angle, laser and
electron beam phase space distribution
9
ELI-NP ? beam the quest for narrow bandwidths
(from 10-2 down to 10-3)
Courtesy V. Zamfir ELI-NP
10
Spectr. Density 1
Spectr. Density gt 103
11
courtesy of G. Travish (UCLA)
12
ELI-NP GBS (Extreme Light Infrastrucutre Gamma
Beam System) Main Parameters
outstanding electron beam _at_ 750 MeV with high
phase space density (all values are projected,
not slice! cmp. FELs)
Back-scattering a high quality J-class ps laser
pulse
13
Accelerator and Equipments in ELI-NP Building
14
109 Authors, 327 pages published today on
ArXiv http//arxiv.org/abs/1407.3669
15
Optical system laser beam circulator (LBC)for
J-class psec laser pulses focused down to mm spot
sizes
Electron beam is transparent to the laser (only
109 photons are back-scattered at each collision
out of the 1018 carried by the laser pulse)

• Circulator principle

• PARAMETERS OPTIMIZED ON THE GAMMA-RAY FLUX

• 2 high-grade quality parabolic mirrors
• Aberration free
• Mirror-pair system (MPS) per pass
• Synchronization
• Optical plan switching
• Constant incident angle small bandwidth

• Laser power state of the art
• Angle of incidence (f 7.54)
• Waist size (?0 28.3µm)
• Number of passes 32 passes

30 cm
2.4 m
courtesy K. Cassou
16
(No Transcript)
17
ELI-NP-GBS High Order mode Damped RF structure
Unlike FELs Linacs, ELI-NP-GBS is a multi-bunch
accelerator, therefore we need to control the
Beam-Break-Up Instability to avoid complete
deterioration of the electron beam emittance,
i.e. of its brightness and phase space density
courtesy David Alesini
18
C-BAND STRUCTURES HIGH POWER TEST SETUP
The structure has been tested at high power at
the Bonn University under RI responsibility.
Successfully tested at full power (40 MW)
courtesy David Alesini
19
Brilliance of Lasers and X-ray sources
12.4
1.24
0.124
l (nm)
ELI
BELLA
FLASH
Outstanding X/g photon beams for Exotic Colliders
20
A MeV-class Photon-Photon Scattering Machine
based ontwin Photo-Injectors and Compton Sources

• g-ray beams similar to those generated by Compton
  Sources for Nuclear Physics/Photonics
• issue with photon beam diffraction at low energy!
• Best option twin system of high gradient X-band
  200 MeV photo-injectors with J-class ps lasers
  (ELI-NP-GBS)

21
optical transparency of the Universe
courtesy E. Milotti
22
courtesy E. Milotti
23
courtesy E. Milotti
24

• We evaluated the event production rate of several
  schemes for photon-photon scattering, based on
  ultra-intense lasers, bremsstralhung machines,
  Nuclear Photonics gamma-ray machines, etc, in all
  possible combinations collision of 0.5 MeV
  photon beams is the only viable solution to
  achieve 1 nbarn-1 in a reasonable measurement
  time.
• Colliding 2 ELI-NP 10 PW lasers under
  construction (ready in 2018), hn1.2 eV, f1/60
  Hz, we achieve (Ecm3 eV) LSC6.1045, cross
  section 6.10-64, events/sec10-19
• Colliding 1 ELI-NP 10 PW laser with the 20 MeV
  gamma-ray beam of ELI-NP-GBS we achieve (Ecm5.5
  keV) LSC6.1033, cross section10-41, events/sec
  10-8

25

• Colliding a high power Bremsstralhung 50 keV
  X-ray beam (unpolarized, 100 kW on a mm spot
  size) with ELI-NP-GBS 20 MeV gamma-ray beam
  (Ecm2 MeV) we achieve LSC6.1022, cross
  section1 mbarn, events/s 10-8

4) Colliding 2 gamma-ray 0.5 MeV beams,
carrying 109 photons per pulse at 100 Hz rep
rate, with focal spot size at the collision point
of about 2 mm, we achieve LSC2.1026, cross
section 1 mbarn, events/s2.10-4,
events/day18, 1 nanobarn-1 accumulated after 3
months of machine running.
26
Luminosities of Colliders involving Photon
Beams at various c.m. energy

• Compton Sources L1035 cm-2s-1 at 1-100 keV
  c.m. energy (ELI-NP-GBS like)
• g-g colliders for photon-photon scattering
  experiment and Breit-Wheeler L1026 cm-2s-1 at
  0.5-2 MeV c.m. energy
• Photonphoton collider with 2x10 PW ELI Laser
  (most powerful of this decade) L1045 cm-2s-1 at
  3 eV c.m. energy
• LHC proton (7 TeV) XFEL photon (20 keV)
  collider ultimate Luminosity (1013 p 200ns,
  TW-FEL as for LCLS-II SC-CW) L1038 cm-2s-1 at
  1.2 GeV c.m. energy C.Pellegrini et
  al., PRSTAB 15, 050704 (2012)

production of low emittance p/m/n/ beams
27
Not a new idea.. but A.Dadi and C.Muller analyzed
a multi-photon reaction and didnt make
evaluations of the phase spaces for the generated
pion/muon beams
28
2 Ingredients to make a Collider Source of a low
emittance (high phase space density, high
brilliance) secondary beam

• Large Lorentz boost to collimate within narrow
  solid angle (in the Lab frame) all reaction
  products, i.e. gcm gtgt 1
• Energy available in c.m. frame as momentum of
  secondary particles much smaller than their
  invariant mass energy

29
hn 20 keV FEL photon is seen as a 2. gp. hn
300 MeV by the proton in its rest frame (max
total cross section of pion photo-production 0.25
mbarn)
30
Momentum in laboratory frame
nF
nB
pF
pB
Large Lorentz boost gcm 5830
31
Phase Space Distribution Results of a montecarlo
event generator with (upper) and without (lower)
LHC proton beam emittance (proton rms transv.
momentum 200 MeV, sx 20 mrad)
20 mrad
32
Populating the Phase Space combination of p-beam
transverse emittance (temperature) and stochastic
transverse temperature increase due to decay
sequence (p, hn) -gt (p, n) -gt (m,n) n
33
outstanding pion beam emittance lt 10 mm.mrad
thanks to 7 mm emitting source spot-size and low
p rms trans. momentum (150 MeV ppx /mp1)
34
Luminosity issues and pion/muon/neutron/neutrinos
fluxes
a) Assuming LHC p-beam at 1013 intensity and 5
MHz rep rate vs. 1013 photons/pulse SC-CW XFEL
(run in long 200 fs pulse and tapering), focused
down to 7 mm rms spot size, we can get 6.104
pions per bunch crossing (no collective beam-beam
at IP w.r.t. p-p collisions) b) We have a pion
photo-cathode how to match the pion beam into a
storage ring / transport line is an open
problem c) Assuming the low p-beam emittance can
be preserved, we can accumulate muons over half
ot their life-time (10-60 ms), reaching Nm3.109
, which is enough, at 5 MHz rep rate, to reach a
muon collider luminosity of about 1031 cm-2s-1,
without need of cooling nor acceleration.
35
d) Life-time of p-beam is about 10 hours (taking
into account also p0, e/e- and Compton
events) e) p- production requires deuteron beams
(simultaneous production of p and p- thanks to
pion-photoproduction quasi-symmetric cross
section on deuteron) f) Potentials for highly
collimated neutrino and neutron beams in the 10
GeV 1 TeV range
Is it going to be an interesting alternative
option for m-collider?
Using FCC beams we would need 3 keV X-rays -gt
simpler and cheaper FEL (5-6 GeV Linac vs. 15-18
GeV Linac for 20 keV photons and larger number of
photons)
36
A Compact (10 m, 10 M) Demonstrator at SPS of
a Pion Photo-cathode
37
Thank you for your kind attention
Special Thanks to C. Meroni, A. Ghigo, D.
Palmer on the pion beams. E. Milotti, C.
Curceanu for material on the photon-photon
scattering. D. Alesini, N. Bliss, F. Zomer, K.
Cassou, A. Variola and the whole EuroGammaS
collaboration on the ELI-NP-GBS Project.
38
(No Transcript)
39
hn 12 keV FEL photon is seen as a 2. gp. hn
180 MeV by the proton in its rest frame (max
total cross section of pion photo-production 0.1
mbarn)