challenges and opportunities of high intensity x/ photon beams for nuclear photonics and muon beams...

Challenges and Opportunities of high intensity X/ photonbeams for Nuclear Photonics and Muon Beams

Luca Serafini – INFN-Milan, EuroGammaS scientific coordinatorV. Petrillo, C. Curatolo – Univ. of Milan

• Physics/Technology Challenges of electron-(optical)photon

colliders as X/ beam Sources using Compton back-scattering

• Need of high peak brightness/high average current electron

beams (cmp. FEL’s drivers) fsec-class synchronized and m-

rad-scale aligned to high peak/average power laser beams

• Main goal for Nuclear Physics and Nuclear Photonics:

Spectral Densities > 104 Nph/(s.eV) (state

of the art: HiS 300, bremsstrahlung sources 1) photon

energy range 1-20 MeV, bandwidths 10-3 classFuture Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015

• Main goal for MeV-class and TeV - nucleon

colliders: Peak Brilliance > 1021 Nph/(s.mm2.mrad2.0.1%)

109<Nph<1013 Source spot size m-scale (low diffraction,

few rad) 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 -beams

• Interesting new option for low emittance pion and muon beams

generation using X-FEL’s and LHC beams (demonstrator

based on Compton Source and SPS beams)Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015 Courtesy L. Palumbo

If the Physics of Compton/Thomson back-scattering is well known….

the Challenge of making a Compton Source running as anelectron-photon Collider with maximum Luminosity, to achieve the requested Spectral Density, Brilliance,narrow Bandwidth of the generated Xray beam,

is a completely different issue/business !

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015

Compton Inverse Scattering Physics is clear: recall some basics

Courtesy V. Petrillo

3 regimes: a) Elastic, Thomson b) Quasi-Elastic, Compton with Thomson cross-section c) Inelastic, Compton, recoil dominated


€

ν =4ν 0

1

2γ 2 1+4γhν 0

mc 2

⎛

⎝ ⎜

⎞

⎠ ⎟ ⇒ + collective effects

€

Thomson ∝ γ 2

€

Compton

FELs (pure

)

Thomson

X-rays

Nuclear

Photonics

€

σCompton

σThomson

X/[MeV]

Te [MeV]

€

ν0 = 2.4 eV (λ 0 = 500 nm)

1 GeV 1 TeV

Polarized

Positrons

€

ν ≈4ν 0γ

2

1+ γ 2θ 2 + a02 2

1 − Δ( )

€

=4γhν 0

mc 2 Δ <<1 Compton recoil

€

σCompton = σThomson 1− Δ( )

Colliders


We need to build a very high luminosity collider,that needs to maximize the Spectral Luminosity,

i.e. Luminosity per unit bandwidth

negligible diffraction0 crossing angle

electrons laser

€

LS ≡L

Δνγ

• Scattered flux• Luminosity as in HEP

collisions– Many photons, electrons– Focus tightly

– ELI-NP

• Scattered flux• Luminosity as in HEP

collisions– Many photons, electrons– Focus tightly

– ELI-NP

σ T =8π

3re

2N =LσT

L =NLNe−

4πσ x

€

σT = 0.67 ⋅10−24 cm2 = 0.67 barn

f

€

L =1.3⋅1018⋅1.6⋅109

4π 0.0015cm( )2 3200(s−1) = 2.5⋅1035cm−2s−1

cfr. LHC 1034, Hi-Lumi LHC 1035

Courtesy M. Gambaccini

300 rad60 rad


€

ν =ν4γ 2

1+ γ 2θ 2 + a02 2

1 − Δ( )

Bandwidth due to collection angle, laser and electron beam phase space

distribution

€

2θ 2 ≅ γ 2ϑ 2 + γ 2ϑ e2 ≅ γ 2ϑ rms

2 + (σ p⊥/mc)2 ≅ γ 2ϑ rms2 + 2(ε n /σ x )2

€

ν

ν

≅ (γϑ )rms4 + 4

Δγ

γ

⎛

⎝ ⎜

⎞

⎠ ⎟

2

+2ε n

σ x

⎛

⎝ ⎜

⎞

⎠ ⎟

4

+Δν

ν

⎛

⎝ ⎜

⎞

⎠ ⎟2

+M 2λ L

2πw0

⎛

⎝ ⎜

⎞

⎠ ⎟

4

+a0 p

2 /3

1+ a0 p2 /2

⎛

⎝ ⎜ ⎜

⎞

⎠ ⎟ ⎟

2

€

Optimized Bandwidth ≅ 2(ε n /σ x )2

€

Maximum Spectral Density ∝ Luminosity /(ε n /σ x )2 ∝ Q /ε n2

€

Maximum Spectral Density ∝ Phase Space density€

ϑ =normalized

collection angle

electron beam laser

€

=4γ hν mc 2

1+ 2γ hν mc 2 Δ <<1 Compton recoil

ELI-NP γ beam: the quest for narrow bandwidths (from 10-2 down to 10-3)

Courtesy V. Zamfir – ELI-NP



Spectr. Density > 103

Spectr. Density = 1

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015 courtesy of G. Travish (UCLA)

€

−ray 1− 20 MeV ; rms Bandwidth 3.− 5. 10−3

€

Spectral Density : 103 −104 photons /s⋅ eV

needs 3.105 photons / pulse @ 3 kHz rep rate

€

rms divergence 30 < 300 μrad

linear or circular polarization > 98%


ELI-NP GBS (Extreme Light Infrastrucutre Gamma Beam System) Main Parameters

€

Q = 250pC ; ε n = 4.10−7 m⋅ rad ; Δγ γ = 5⋅10−4

outstanding electron beam @ 750 MeV with high phase space density(all values are projected, not slice! cmp. FEL’s)

Back-scattering a high quality J-class ps laser pulse

€

UL = 400 mJ ; M 2 =1.2 ; Δν

ν= 5⋅10−4 not

sustainableby RF, Laser!

Accelerator and Equipmentsin ELI-NP Building

109 Authors, 327 pagespublished today on ArXiv

http://arxiv.org/abs/1407.3669

CIRCULATOR PRINCIPLE• 2 high-grade quality parabolic mirrors

– Aberration free

• Mirror-pair system (MPS) per pass

– Synchronization

– Optical plan switching Constant incident angle = small bandwidth

PARAMETERS = OPTIMIZED ON THE GAMMA-RAY FLUX

• Laser power = state of the art

• Angle of incidence (φ = 7.54°)

• Waist size (ω0 = 28.3μm)

• Number of passes = 32 passes

Optical system: laser beam circulator (LBC)for J-class psec laser pulses focused down to m spot sizes

2.4 m

30 cm

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)

courtesy K. Cassou 15

Unlike FEL’s Linacs, ELI-NP-GBS is a multi-bunch accelerator, therefore we need to control the Beam-Break-Up Instability to avoid complete deteriorationof the electron beam emittance, i.e. of its brightness and phase space density

ELI-NP-GBS High Order mode Damped RF structure

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015 courtesy David Alesini

C-BAND STRUCTURES: HIGH POWER TEST SETUPThe structure has been tested at high power at the Bonn University under RI responsibility.


Successfully tested at full power (40 MW)

courtesy David Alesini

FLASH

12.4 1.24 0.124 (nm)

Thomson/Compton Sources

Brilliance of Lasers and X-ray sources

BELLA


€

B =N ph

2πσ t M 2λ( )2 Δλ

λ€

N ph =1019 −1020

σ t =10 − 20 fs

ELI

€

N ph =1011 −1013

σ t =10 − 200 fs

€

BCompton ∝ γ 2

€

N ph =108 −109

σ t =100 fs − 5ps

Outstanding X/photon beamsfor Exotic Colliders

A MeV-class Photon-Photon Scattering Machine based ontwin Photo-Injectors and Compton Sources

• -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)


peak cross-section, ≈1.6 µbarn at

cross-section for unpolarized initial state (average over initial polarizations)

optical transparencyof the Universe

Tunability!Narrow bdw!

courtesy E. MilottiFuture Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015 courtesy E. Milotti

threshold of theBreit-Wheeler process

1 nb-1

10 pb-1

integrated luminosity corresponding to a bare minimum of about 100 scattering events (total).

ECM ≈ 630 keV

ECM ≈ 880 keV

ECM ≈ 13 MeV

ECM ≈ 140 MeV

threshold of theBethe-Heitlerprocess

Future Res. Infrastr., Challenges and Opportunities, Varenna, July 9th 2015 courtesy E. Milotti

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), hν=1.2 eV, f=1/60 Hz, we achieve (Ecm=3 eV): LSC=6.1045, cross section= 6.10-64, events/sec=10-19

•Colliding 1 ELI-NP 10 PW laser with the 20 MeV gamma-ray beam of ELI-NP-GBS we achieve (Ecm=5.5 keV): LSC=6.1033, cross section=10-41, events/sec = 10-8


3)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 (Ecm=2 MeV) we achieve: LSC=6.1022, cross section=1 barn, 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 m, we achieve: LSC=2.1026, cross section = 1 barn, events/s=2.10-4, events/day=18, 1 nanobarn-1 accumulated after 3 months of machine running.



Luminosities of Colliders involving Photon Beamsat various c.m. energy

• Compton Sources: L=1035 cm-2s-1 at 1-100 keV c.m. energy

(ELI-NP-GBS like)

• colliders for photon-photon scattering experiment and

Breit-Wheeler: L=1026 cm-2s-1 at 0.5-2 MeV c.m. energy

• Photon–photon collider with 2x10 PW ELI Laser (most

powerful of this decade): L=1045 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) L=1038 cm-2s-1 at 1.2 GeV c.m. energy*C.Pellegrini et al.,

PRSTAB 15, 050704 (2012)

production of low emittance πν/ beams…Is it of any interest?


Not a new idea.. but A.Dadi and C.Muller analyzed a multi-photon reaction and didn’t make evaluations of the phase spaces for the

generated pion/muon beams

2 Ingredients to make a Collider Source of a low emittance (high phase space density, high brilliance) secondary beam

Emittance of secondary beam generated in collision: combination of

emittance of momentum-dominant beam (protons for LHC-FEL,

electrons for Compton Sources) and transverse momentum in c.m. frame (-> transverse momentum is invariant

to Lorentz boost, i.e. transverse temperature/emittance is also

invariant to Lorentz boost)

€

εn ≡ σ xσ px ; σ px ≡ p x2

p x ≡px

mc= βxγ

€

εnpLHC ≅1.5 μrad ; σ x

pLHC = 7 μm ⇒ σ pxpLHC =

1.5

7938 = 200 MeV (σ ′ x =19 μrad)

• Large Lorentz boost to collimate within narrow solid angle (in

the Lab frame) all reaction products, i.e. cm >> 1

• Energy available in c.m. frame as momentum of secondary

particles much smaller than their invariant mass energy


hν 20 keV FEL photon is seen as a 2.p. hν = 300 MeV by the proton in

its rest frame (max total cross section of pion photo-production 0.25 mbarn)

Momentum in laboratory frame:

0,00 0,05 0,10 0,15 0,20 0,250

1

2

3

4

5

6

7

|p| π,

|p| n(T

eV/c

)

π angle (mrad)

πF

nF

nB

πB


Large Lorentz boost : cm = 5830

Phase Space Distribution Results of a montecarlo event generatorwith (upper) and without (lower) LHC proton beam emittance

(proton rms transv. momentum 200 MeV, σx’ = 20 rad)

20 rad

260 GeV/cπ 48 s

2.5 TeV/cπ 0.5 ms

2.5 TeV/c 50 ms

150 GeV/c 5 ms

stop-band at =20 rad(200 MeV p transv. mom.)

Populating the Phase Space: combination of p-beam transverse emittance (temperature) and stochastic transverse temperature increase due to decay

sequence (p, hν) -> (π+, n) -> (,ν) n


outstanding pion beam emittance < 10 mm.mrad thanks to 7 m emitting source spot-size and low π+ rms trans. momentum (150 MeV: pπx /mπ=1)


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 m 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 π-beam emittance can be preserved, we can

accumulate muons over half ot their life-time (10-60 ms),

reaching N=3.109 , 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.


d) Life-time of p-beam is about 10 hours (taking into account also

π0, e+/e- and Compton events)

e) π- production requires deuteron beams (simultaneous production

of π+ and π- 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 -collider?

Using FCC beams we would need 3 keV X-rays -> simpler and cheaper FEL (5-6 GeV Linac vs. 15-18 GeV Linac for 20 keV photons and larger number of photons)

A Compact (10 m, 10 M€) Demonstrator at SPS of aPion Photo-cathode

Compton Source: 109 hν/pulse @ 350 keV vs. 400 GeV protons-> measure diff. cross. sect., phase space accumulation (1 π / b. cross.)


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.


hν 12 keV FEL photon is seen as a 2.p. hν = 180 MeV by the proton in

its rest frame (max total cross section of pion photo-production 0.1 mbarn)

challenges and opportunities of high intensity x/ photon beams for nuclear photonics and muon beams...

Documents

class future

elinp building slide

x beam sources

laser pulse courtesy

travish ucla slide

laser beam circulator

electron beam emittance

eli outstanding x photon