1 0.1-nm Hard X-ray XFEL  Project Period: 2011 ~ 2015  Total Budget: 400 M$  10-GeV Electron Linac (Normal Conducting S-band, 60 Hz)  Total Length: 1.1 km 4-th Generation Light Source: PAL-XFEL Pohang Light Source (3 GeV /400 mA) Experimental Hall Undulator Hall Linac Heung-Sik Kang, on behalf of PAL-XFEL Team

SASE XFEL Power Growth & Temporal Profile The SASE radiation starts from initial shot noise in the beam, with the resulting radiation having an excellent spatial coherence, but a rather poor temporal one Bandwidth : Transversely coherent -10 billions times brighter than 3-rd generation source -Femto-second long radiation pulse

LCLS-1SACLAEU-FELPAL-XFELSwissFELMaRIE Electron Energy, GeV Max. Photon energy, keV Accelerator Type NCRF (S-band) NCRF (C-band) SCRF (L-band) NCRF (S-band) NCRF (C-band) NCRF (S-band) Repetition rate , Undulatorout-of- vacuum, fixed gap In-vacuum, variable gap out-of- vacuum, variable gap out-of- vacuum, variable gap In-vacuum, variable gap out-of- vacuum, variable gap First lasing Proposal Operation mode SASE, Self- seeding SASE, Self- seeding SASE, Self-seeding SASE, Self- seeding SASE Hard X-ray FEL Facilities Large facility LCLS-1, MaRIE High intensity Small facility SwissFEL, SACLA Low intensity, high stability Medium size PAL-XFEL High intensity, high stability

Undulator Lines Undulator LineHX1SX1 Wavelength [nm] 0.06 ~ 0.61 ~ 4.5 Beam Energy [GeV] 4 ~ (2.57) Wavelength Tuning [nm] 0.6 ~ 0.1 (Beam Energy) 0.1 ~ 0.06 (Undulator Gap) 4.5 ~ 3 (Beam Energy) 3 ~ 1 (Undulator gap) Undulator Type Planar variable gap, out- vacuum Planar + APPLE II variable gap, out- vacuum Undulator Period / Gap [mm] 26 / / 8.3 Operation Mode SASE (2016) Self-Seeding (2017) SASE (2016) Main parameters e - Energy 10 GeV e - Bunch charge pC Repetition rate 60 Hz Pulse duration 5 fs – 100 fs Number of bunch 1 (Phase-1) 2 (Phase-2) SX line switching DC (Phase-1) Kicker (Phase-2)

Project Schedule  Test Facility (ITF, ATF)  Site Preparation  Building Construction  Install  Linac RF conditioning  Linac Commissioning  FEL Commissioning now

6 July 20, 2013 Construction site

7 26 October 2014

HXU Hall SXU Hall 11 m 8.5 m Tunnel View Linac Tunnel

PAL-XFEL Layout Key devices No. of quantities S-band accelerating structure (3 m) 175 S-band klystron (80 MW, 4 us, 60 Hz)50 S-band klystron modulator (200 MW, 60 Hz)50 S-band low level RF controller50 S-band Solid-state amplifier50 Undulator (5-m length, 8.3 mm gap)26

Issues of XFEL Photon flux : > 1 x photons/pulse Limited number of beamlines Large bandwidth (10-3) Radiation pulse stability 10 High beam energy : 10 GeV Self-seeding and undulator tapering : > 100 GW power Undulator hall is long (250 m) enough to install 28 undulators Five undulator lines & Branch line for soft X-ray Two bunch & Simultaneous operation of Soft & Hard X-ray Beamline 10-5 by self-seedig Ultra-stable pulse RF system Klystron beam voltage stability : 30 ppm Linac Stability  Beam energy jitter : < 0.02 %  Beam arrival time : < 20 fs  Emittance growth : < 10%  Beam current change: < 10% L1XL2L3, L4 Linac RF Phase [degrees] Linac RF Amplitude [%]

Challenge: Linac RF Stability S-bandX-band Frequency [GHz] RF phase stability Goal [degrees] Klystron beam voltage stability [ppm]  Because of the pulse nature of the normal conducting Linac, RF stability is determined by klystron modulator stability PLS Linac klystron modulator stability : 1,000 ppm in rms

Undulator Layout SX undulator hall Tune-up dump Main dump Chicane for Self- Seeding 12 ea 6 ea Source point HX Undulator hall Main dump 8 ea Chicane for Self- Seeding 28 undulator space for HX1: 18 undulators for Phase-1  15 undulator space for SX1 : 6 undulators for Phase-1 Tune-up dump Source point EPU

Challenge : Undulator Parameter  P i /P 0 tolerance Launch Angle,  rad % Cell Phase, degree6599 %7.9 Phase Shift, degree6599 %9 Break Length, mm %0.6  K/K (gap control, 1  m) % Quad position,  m %1.232 Seg. Ver. Pos.,  m mm %139.9 Jaw Pitch,  rad 2195%6.726 Undulator Stability Field accuracy: < 2 x 10-4 Gap setting accuracy: < 1 um PAL-XFEL Undulator Error Budget for 0.1 nm

How to Achieve the Stability Goal PAL-XFEL should be world’s best in terms of FEL performance –Requires the best performance devices –But, lacks in man power and technology at PAL To achieve this high stability requirement that was not realized before Strategy 1: We have experience and expect the best performance achievable Do it by ourselves by  collaboration with industrial partner for S-band RF system  adopts EU-FEL design for udulator Strategy 3: adopts the advanced ideas and concepts developed by leading group : 1) self-seeding scheme Strategy 2: world best performance not achievable by ourselves Just buy it from outside  Event timing system, BPM control system from SLAC  diamond crystal monochromator for self-seeding from Argonne lab.

How we collaborate with Industrial Partner  We started the collaboration one year before the official start of project –Selection process for Industrial partner Public offering for Partners Qualification examination by Review Committee –Contract with company for collaborative R&D work Klystron modulator: 2 companies LLRF : 2 companies Accelerating structure : 1 company W/G and SLED : 1 company  Design & simulation : PAL and Company Fabrication & engineering : Company Test and Evaluation : PAL 15

50-ppm Stability Inverter PS-type Modulator a. Front view Ross Probe(5,000:1) RC Snubber Current Limit Reversal Tail R Heat exchanger #1 EOLC

Modulator Performance Rms Stability : 21 [ppm] Peak Stability : 303 [ppm] Klystron beam voltage requirement : When the collaboration start, it was 100 ppm in rms Confirming the capability of LOCAL COMPANY, PAL changed it to the design goal, 50 ppm in rms rms Stability : 17.1[ppm] Peak Stability : 120.0[ppm] PAL encouraged the company to achieve a higher goal of 150 ppm in pKpK.

Collaboration for S-band Structure

Prototype Undulator Undulator Measurement Room Hall Probe System and Prototype Undulator stable temperature control of ±0.1°C EU-XFEL undulator design is benchmarked. A MOU to use the EU-XFEL design is agreed on 2011 June between PAL and EU-XFEL. PAL modified the design including the new magnetic design, EPICS IOC, and updated tolerances reflecting new parameters. A fully assembled HXU prototype was delivered in Dec 2012 and measured at the undulator measurement lab.

Field Measurement & Gap Reproducibility Errors Gap Reproducibility Errors The peak fields from 5 measurements are overlapped. Between each measurement, gap is opened to 100 mm and closed to measurement gap. 1.5 Gauss difference translates to 1.0 μm gap error. The peak fields from 5 measurements are overlapped. B errors are about ±1.0 G. Orbit error from the measurements is less than 1 um. Field Measurement Errors

Procurement Status  Linac  SLED (42) and W/G : contracted with Vitzro-Tech in July 2013  Accelerating structures : contracted with MHI (120) and Vitzro-Tech (57)  High precision Inverter type modulator : 51 modulators contracted with POSCO-ICT and Dawon-Sys in June 2013  High precision LLRF systems : 55 units contracted with Mobiis in March 2014  S-band Solid-state Amplifier : 55 units contracted with Mobiis in July 2014  Undulator  Variable gap out-vacuum HX undulator: 18 units contracted with SFA in 2013  Variable gap out-vacuum SX undulator: 6 units contracted in 2014  Diagnostics & Control  Event timing system (SLAC design) : delivered in February 2014  Stripline BPM control system (mTCA based ) : contracted with SLAC in October Evaluation of Performance of prototypes was successfully done for Linac RF system and undulators.

Install and FEL Commissioning FEL Commissioning Schedule  Linac RF conditioning / Injector commissioning ( ~ )  1 st FEL commissioning ( ~ ) : 0.3 nm Hz  2 nd FEL commissioning ( ~ ) : 0.1 nm HX 3.0 nm 10Hz JFMAMJJASONDJFMAMJJASOND ITF operation Injector install in XFEL, S&A Other component install, S&A Injector beam commissioning Linac RF conditioning (10 Hz) Linac beam commissioning FEL commissioning Maintenance

Do Our Best for A successful FEL commissioning in 2016!! Thank you for your attention