Nicolas Delerue LAL CNRS On behalf of the

Nicolas Delerue (LAL, CNRS) On behalf of the Thom. X collaboration Thom. X, a Compton X-ray source project in Orsay I POSIPOL, N 2 P 3 August 2011 Les deux infinis 1

The Thom. X collaboration • Thom. X is a collaboration between several French laboratories: • LAL (Orsay), HEP lab • SOLEIL, Synchrotron source • CELIA, Laser lab • C 2 RMF, archeology/museum lab • ESRF, Synchrotron source • NEEL, X-rays instrumentation • INSERM, medical research • Funding from “equipex”, IN 2 P 3/CNRS, Université Paris-Sud XI, Région Ile de France, … • Full funding approved • Project leader: A. Variola, deputy: A. Loulergue Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 2

The machine 50 Me. V electrons Size ~10 mx 7 m will be located in Orsay Optical resonator ~50 Me. V electrons X rays INAC L ) z GH nd (3 S-ba Photo gun Pixel det. Im. Xgam èFrom ATLAS/CPPM 09/09/2020 Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 3

Thom. X at LAL Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 4

ies Ba ies Vid g Ma g Dia Ba ies Ba ll Sa er as el e urc e ) (v 1 RF So Mur de blindage FP Salle climatisée Flux class 100 Blocs de béton Ligne X Blocs de béton Coolin g RF anneau X Ampli RF Salle Strea k Kicker Extension possible urc So F e. R ) (v 2 Septu m 0 Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 • xxx 5 10 5

Main parameters • Electrons: - 20 -70 Me. V (nominal: 50 Me. V) - 1 n. C - 20 ps rms • Laser: - 30 m. J/pulse => 100 k. W in Fabry-Pérot cavity - 1 ps rms • X-rays: - 6 -92 ke. V - 1011 to 1013 ph/s Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 6

Predicted flux Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 7

RF Gun • Based on LAL experience: design similar to that built for CTF 3 (CLIC) • 2. 5 cells, 80 MV/m, 6 MW, 3 GHz • Q=14400 Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 8

RF Gun (2) • CTF 3 RF Gun was designed, built and brazed at LAL. • Also using LAL’s experience with its own RF-Gun (PHIL) Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 9

Linac Gun s ectio • • n Rep. rate = 50 Hz 5 Me. V to 70 Me. V (nominal 50 Me. V) S-Band (2998, 55 MHz – European standard) One LIL accelerating structure (nominal: 12. 6 MV/m; can reach 18. 3 MV/m). • Total length: 6. 45 m LIL a ccele Nicolas. Delerue@lal. in 2 p 3. fr ratin g sec tion POSIPOL, August 2011 10

Transfer line (from A. Loulergue) Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 11

Ring injection • • Injection angle: 150 mrad Septum: 1 k. A – 150 V (50 ns) Injection angle compensated by kicker Currently studying a scheme with injection and extraction Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 12

Ring Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 13

Ring optics Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 14

Beam dynamics • CBS makes the beam lifetime very short => beam stored for only 20 ms • Damping is very long (1 -2 s) • Injected bunch is very short (4 ps) => turbulent process to fill the bucket (20 ps) • Strong collective effects (CSR, Resistive walls, …) (from A. Loulergue) Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 15

Beam dynamics (2) Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 16 (from A. Loulergue)

Main diagnostics • Energy spread measurement prior injection • Bunch length measurement before injection (Cerenkov) and in the ring (SR) using a streak camera • Longitudinal and transverse feedback to minimise instabilities using BPM information • Laser follows the e- beam position • Extraction dump: Imaging station to allow beam dynamics studies Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 17

Extraction • • Nicolas. Delerue@lal. in 2 p 3. fr Beam will be extracted after 20 ms. Reduces radiation Diagnostics on extracted beam Details still under study POSIPOL, August 2011 18

Lasers system • Based on our experience with Mighty. Laser • Fibre amplification • Lower rep. rate: 37. 7 MHz (instead of 178 MHz) => Larger oscillator cavity… • Higher power (Goal 100 W) • => Much higher energy per pulse: 281 n. J => 2. 6 u. J • Need to address carefully non linear effects => larger fibre, more stretching • Using advanced R&D done at CELIA Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 Chirped Pulse Amplifier Master (low power) Oscillator 200 m. W Stretcher Power amplifiers 100 W Compressor 19

Fabry-Pérot cavity • • Also based on our experience with Mighty. Laser 4 -mirror cavity but with a planar geometry Lower frequency requires longer path (8 m) Digital feedback will use the same principle but using a home-built system (better control) • A first in-air prototype has been tested this summer at LAL. Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 20

Fabry-Pérot cavity (2) Optical path : ~ 8, 4 meters (40 Mhz) Spherical Mirror 1 e- d ra m 0 2 ton p m e) Co l g n fa (hal Spherical Mirror 1 Flat Mirror 2 Laser Flat Mirror 1 ~ 2100 mm Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 21

Interaction area • Design of the interaction area is challenging - Elliptical beam pipe -2 degrees crossing angle - Laser and X-rays slits (R 4, 5 x 45 mm et R 3 x 27 mm) Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 22

Vacuum issues • Ion trapping will be exacerbated by the high repetition rate. • This induces an increase of the relative pressure seen by the beam and some charge shielding. • => Important to have a very good vacuum • However these tight vacuum requirements conflicts with the Fabry-Pérot cavity feedback requirements => R&D in progress to see what can be achieved. Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 23

X-ray line • Several instruments to caracterize the X-rays (focalisation, position, profile, intensity…) during comissioning. • Radiation safety still under study. Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 24

Applications • Heritage applications (Collaboration with C 2 RMF / Musé du Louvres) - Structural and chemical studies of artefact - Compact source can be installed in a museum => Imaging of artefact in situ • Medical application (Collaboration with ESRF) - Imaging using k-line of elements - High energy radiotherapy (specific tumors) - Radiotherapy with radiation enhancement (Cis. Pt) => Thom. X is more flexible then ESRF Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 25

Application to positrons • Thom. X energy is too low for positron production • However the experience gained operating Thom. X will be applicable to a Compton based positron source. • In particular this will be an opportunity to study the dynamics of a beam undergoing strong Compton interactions. • Thom. X is a step toward the demonstration of Compton based polarised positrons sources. Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 26

Thank you Nicolas. Delerue@lal. in 2 p 3. fr POSIPOL, August 2011 27