Compton Collision Scheme of E-Gammas Proposal for ELI-NP Luca Serafini – INFN Milan ELI-NP: third Pillar of Extreme Light Infrastructure (large European Initiative on Extreme Light, 900 M€), devoted to Nuclear Photonics One of the two Main Components of ELI-NP: advanced Gamma Source - Bright, Mono-chromatic (0.3%), High Spectral Flux (> 10 4 ph/sec. eV), Tunable (1-20 MeV), Highly Polarized Tender is open for Best Proposal (60 M€): Egammas European Collaboration is preparing to submit Innovative solution for Compton  -ray Source based on advanced C-band RF Linacs in multi-bunch mode and New Concepts for Laser Recirculation: maximizing Luminosity of Compton Source SAPPHiRE Day, CERN, Feb 19th 2013

Extreme Light Infrastructure (ELI) Gerard Mourou 1985: Chirped Pulse Amplification (CPA) ELI Courtesy of Victor Zamfir

Extreme Light Infrastructure ELI on ESFRI list ELI-PP December 2009 (EC) 3 Pillars (Structural Funds): CZECH Rep: Beamlines HUNGARY: Short Pulses ROMANIA: Nuclear Physics Courtesy of Victor Zamfir

ELI-Nuclear Physics “White Book” (100 scientists, 30 institutions, eds. Habs et al.) ( Feasibility Study: 293 Meuro w/o VAT “Extreme Light” : two 10 PW APOLLON-type lasers brilliant γ beam, up to 20 MeV, BW:10-3 produced by Compton scattering on a 700 MeV electron beam

ELI-NP γ beam

SAPPHiRE Day, CERN, Feb 19th 2013 The Tender for ELI-NP Gamma System was published in early Dec. 2012: deadline March 10th 2013 The Challenge we are facing: design the most advanced Gamma Beam System based on state-of-the-art components, to be commissioned and delivered to users by mid 2017, reliable, cost-effective (60 M€ Total Cost), compatible with present lay-out of ELI-NP building Prototype of a New Generation (Light) Gamma-ray Sources: Bright, Mono- chromatic (0.3%), High Spectral Flux (> 10 4 ph/sec. eV), Tunable (1-20 MeV), Highly Polarized, based on Compton Back-Scattering of High Phase Space Density Electron Beams by Lasers The EGAMMAS European Collaboration has been preparing its Proposal since Sept Plus 6 Industrial Partners and Sub-Contractors: [Amplitude, Thales, Alsyom] (F), Comeb (I), RI (D), Danfysik (Dk)

SAPPHiRE Day, CERN, Feb 19th 2013 Because of Budget/Space-available/Implementation-schedule Constraints we were obliged to discard Super-Conducting Technology for the Linac. The Baseline is therefore based on a room temperature low rep rate (100 Hz) 700 MeV Linac, delivering maximum phase space density of bunches generated in trains, coupled to a High Average Power (100 Hz, 100 W) psec J-class Laser system, recirculated at each collision to collide with all the electron bunches in the train.

SAPPHiRE Day, CERN, Feb 19th 2013 We built a set of criteria for optimal design of the Gamma Beam System, based on the concept of Spectral Luminosity, i.e. Luminosity per unit bandwidth electrons laser 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 f

Gamma Beam System Characteristics 1-2 Orders of magnitude better than state of the art HiGS (bdw 3%, sp. dens. 10 2, E < 8 MeV) SAPPHiRE Day, CERN, Feb 19th 2013

Back-scattering Radiation on-axis Thomson factor Compton red shift ELI  =10 -2 Negligible recoil Dominant quantum effects 1/  0 2 1/  0

Compton Recoil  = electron relativistic factor  = angle of observation (  = 0 -> photon scattered on electron beam propagation axis) = laser frequency  = frequency of the scatterd (X,  ) photon a 0 = dimensionless amplitude of the vector potential for the laser e.m. field, a 0 =eE 0 /(  L mc)

Total Scattered Photons f RF = RF rep rate n RF = #bunches per RF pulse U L = Laser pulse energy Q = electron bunch charge h  = laser photon energy [eV]  x = electron bunch spot size at collision point  = collision angle (<<1)  = 0 for head-on collision  t = laser pulse length  all sigma’s and angles are intended as rms, all distributions are assumed as gaussians in (phase) space and time

SAPPHiRE Day, CERN, Feb 19th 2013 The Luminosity based description of Compton Back-scattering allowed us to develop a simple powerful analytical model predicting with great accuracy the number of photons generated within the desired bandwidth (Spectral Luminosity) and all related quantities like Spectral Density, photon beam emittance, Brilliance, etc CAIN results

RMS bandwidth, due to collection angle, laser phase space distribution and electron beam phase space distribution electron beam laser

CAIN (quantum MonteCarlo) Run by I.Chaichovska and A. Variola TSST (classical) Developed by P. Tomassini Comp_Cross (quantum semianalytical) Developed by V.Petrillo COMPARISON between classical (TSST), quantum semianalytical (Comp_cross) and quantum MonteCarlo (CAIN) Number of photons bandwidth V. Petrillo et al., NIM-A693 (2012) 109

(a)CAIN (b)Comp_Cross (c)TSST Quantum  shift  E A part from the quantum shift, the spectra are very similar

SAPPHiRE Day, CERN, Feb 19th 2013 Outstanding electron beam quality: ultra-high phase space density in single bunch beam dynamics

First multi-bunch start-to-end with HOM damped C-band cavities No significant emittance dilution observed from beam break-up SAPPHiRE Day, CERN, Feb 19th 2013

General procedure we would like to follow: input/output couplers are fabricated separately and joined to the cells by a vacuum flange The fabrication of a prototype with a reduced number of cells is necessary to: A.Test the effectiveness of the dipole mode damping including the test the absorbing material performances B.Test the vacuum properties of the structure with absorbing material C.Perform the low power tests and the tuning of the structure D.Test the high gradient performances of the structure ELI Damped structure: Mechanical drawings, realization and prototype

SAPPHiRE Day, CERN, Feb 19th 2013

WORKSHOP 2012 European Proposal for ELI-NP Gamma Beam System: the Machine and the Experiments Milan, Italy May Palazzo delle Stelline ELI-NP Bucharest (Magurele) Romania for ELI ELI-NP Bucharest (Magurele) Romania for ELI Chairs INFN Angela Bracco (Univ. Milano and INFN) Luca Serafini (INFN Milano) Chairs INFN Angela Bracco (Univ. Milano and INFN) Luca Serafini (INFN Milano)

SAPPHiRE Day, CERN, Feb 19th 2013

N.B. in the Thomson limit

SAPPHiRE Day, CERN, Feb 19th 2013 Thanks for your attention Thanks to: F. Zomer and K. Dupraz (Univ. Paris Sud and Orsay/LAL) & Alsyom for Laser Recirculator V. Petrillo (Univ. of Milan and INFN/Milan) for gamma ray Spectra C. Vaccarezza (INFN/LNF) for Beam Dynamics D. Alesini (INFN/LNF) for C-band HOM Damped Acc. Structures N. Bliss (STFC) for Lay-out

SAPPHiRE Day, CERN, Feb 19th 2013

Detailed description of the diagnostics instrumentation for electron beam throughout the linac. Mature design for the collimation at low and high energy beam lines. Advanced study for monitoring and characterizing the gamma ray beam by means of luminometers and calorimeters. SAPPHiRE Day, CERN, Feb 19th 2013

320 MeV the floor level is at MeV 360 MeV 720 MeV Scan the Dynamic Range SAPPHiRE Day, CERN, Feb 19th 2013

Set the Parameter Table

SAPPHiRE Day, CERN, Feb 19th 2013