alessandro fabris – 10 july, 2015 future research infrastructures: challenges and opportunities,...

Alessandro Fabris – 10 July, 2015Future Research Infrastructures: Challenges and Opportunities, Varenna (I) 2

ELETTRA AND FERMI PERSPECTIVES

A.Fabris, E. Karantzoulis, M. Svandrlik

on behalf of the Elettra and FERMI Teams

Alessandro Fabris – 10 July, 2015Future Research Infrastructures: Challenges and Opportunities, Varenna (I)

OUTLINE

Elettra Sincrotrone Trieste overview

Elettra Status Short term developments Elettra 2.0

FERMI Status Short term upgrades Long term upgrades

Summary

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Elettra Sincrotrone Trieste

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Who we are

No profit shareholder company recognized of national interest. Shareholders: Area Science Park, Friuli Venezia Giulia Region,

CNR, Invitalia. Established in 1987 to build and manage synchrotron light

sources to be open internationally.

What we do

Our mission is to promote cultural, social and economic growth through basic and applied research in relevant fields, technical and scientific training, and technology transfer.


Elettra Sincrotrone Trieste in brief:2 complementary Light Sources

FERMIElettra


Elettra

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Linac +Booster (114 m)

Storage Ring (259.2 m)

Third generation light source, open to external users since 1994

The machine complex is now made of a storage ring ( generally operated at 2.0 or 2.4 GeV) and a full energy injector (2.5 GeV booster plus 100 MeV linac)


Elettra in brief

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Operating modes for users: Top-up 2.0 GeV, 310 mA for 75 % of users time Top-up 2.4 GeV, 160 mA for 25 % of users time Filling patterns: multibunch 95 % filling or hybrid. Other filling patterns, as single

bunch, few bunches or other multinbunch fillings can be provided. 28 beam lines In 2014: 947 proposals (10 % increase with respect to 2013) Oversubscription rate from 1.5 to 3 depending on the beamline.

6400 hours per year on 24 7/7 basis. 5000 hours for users Availability in 2014: 97.1 % / 98.5 % excluding external electricity power failures

Since May 2010 Top-up


Elettra short term developments

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Elettra has been upgraded during the years to keep the performance competitive to the new light sources being built in the recent years.

Studies are going on to exploit the margins for other relatively low impact upgrades to extend the performance to the ultimate limits allowed by the present machine also in terms of operability and stability.

Some possibilities:

Energy increase to 2.5 GeV, 140 mA

Reduction of the emittance, presently closest to the theoretical limit for a DBA, with a new optics.

Unifying space in the arcs, to integrate the two separated shorter straight section in a 2.5 m straight to provide possibilities for new insertion devices. This require replacing one defocusing quadrupoles by two smaller ones shifted from the center.

E. Karantzoulis et al, “Elettra Status and Future Prospect”, IPAC 2015, Richmond, May 2015


Elettra short term developments

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Beam emittance reduction Although Elettra emittance (7 nm-rad) is already the closest

to the theoretical limit for a DBA lattice, possibilities to reduce the beam emittance without additional costs. have been investigated studying alternative optics

Abandoning the achromat condition, thus introducing dispersion in the straight sections, a new optic can be created which a 2.8 nm-rad theoretical emittance, a 30-60% reduction in spot size and an average factor of two in brilliance increase.

When taking into account the 3.5 T superconducting wiggler reduction is limited when Including also this device at full field, the effective emittance is only 20 % lower than the nominal one.

Energy increase Magnets and power supplies for Elettra were designed with wide safety margins, and

this is one of the reasons that allowed to operate at a higher energy than the designed.

An analysis of the limits in the operating energy of the machine has shown that it can be still increased to 2.5 GeV.

Since the users’ community has expressed some interest even in this small energy increase, now studies are going to investigate the implementation in the machine with stored current around 140 mA.

E. Karantzoulis et al, “Elettra Status and Future Prospect”, IPAC 2015, Richmond, May 2015


Elettra 2.0

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Conceptual design study to investigate a successor to the machine, Elettra 2.0

Based on latest trends in this field, i.e. next generation, ultimate light sources (ULS):

Much higher brilliance (at least one order of magnitude at low photon energies, e.g. 1 keV),

High level of coherence in both planes (3rd generation sources have only high vertical coherence),

Smaller spot size and divergence,

Higher flux and a variety of insertion devices.

E. Karantzoulis, “Evolution of Elettra towards an Ultimate Light Source”, IPAC 2014, Dresden, June 2014, p. 258 (2014); http://www.JACoW.org


Elettra 2.0 requirements

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The requirements for the new machine have been developed based on the interaction with the users’ community and considering costs optimization.

A dedicated workshop on the future of Elettra was held in April 2014 to examine the different scenarios

Design boundary conditions

keep the same building and the same ring circumference (259-260 m), beam energy: 2 GeV, keep the same beam intensity keep the same filling patterns: multibunch, hybrid, single bunch, few bunches, emittance: to be reduced by more than 1 order of magnitude, electron horizontal beam size: less than 60 µm, existing ID beam lines and their position should be maintained, free space available for IDs: not less than that of Elettra keep the existing bending magnets beam lines use the existing injectors, that means off-axis injection.

E. Karantzoulis , “Elettra2.0-The Next Machine”, IPAC 2015, Richmond, May 2015


Elettra 2.0 Lattice

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BASE SOLUTION IS A 6 BEND ACHROMAT

LATTICE 1 6-bend achromat base solution

Notes The dipole field is not sufficiently high to be used

for the present bending magnets beamlines. A solution could be installing a short wiggler in

one of the short straights. However, this requires a 7 °shift in the present location of the beamline.

LATTICE 2 Second and fifth dipole replaced by a strong 1.3 T

permanent magnet with a 5.6° bending angle This solution allows to provide light to the bending

magnets beamlines from the 1.3 T dipoles with almost no shift of the beamline.

It also noted that this lattice provides also the possibility to install a short wiggler in the short straight section available.

E. Karantzoulis , “Elettra2.0-The Next Machine”, IPAC 2015, Richmond, May 2015


Comparison

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Elettra 2.0 brilliance

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Graph by B. Diviacco

Super ESCA @ 2 GeV 100 mA

Brilliance W14 400 mA

1.00E+15

1.00E+16

1.00E+17

1.00E+18

1.00

E+03

1.77

E+03

2.54

E+03

3.30

E+03

4.07

E+03

4.84

E+03

5.61

E+03

6.37

E+03

7.14

E+03

7.91

E+03

8.68

E+03

9.44

E+03

1.02

E+04

1.10

E+04

1.17

E+04

1.25

E+04

1.33

E+04

1.41

E+04

1.48

E+04

1.56

E+04

1.64

E+04

1.71

E+04

1.79

E+04

1.87

E+04

1.94

E+04

eV

ph

oto

ns

/se

c/m

m2 /m

rad

2 /0.1

% b

w

2.0GeV 7nm

2.4GeV 10 nm

2.0GeV 0.25nm

Wiggler@ 2 GeV 400 mA


Elettra 2.0 outlook

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Conceptual design project started During this period optics solution should be fixed with all beam dynamics InIparallel with the theoretical calculations, different technological points are also

being addressed. For example, diffraction limited rings require very strong focusing, which

translates on demanding requirements on the magnets such as high gradient and high precision engineering. For these reasons, the construction of prototypes such as a fixed gap undulator, a short permanent magnet dipole and a strong 0.22 m long quadrupole are planned to confirm the feasibility of the results obtained by the simulations.

Conceptual design report to be released in 5/2016.


FERMI

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50 m

Experim. Hall

100 m

Undulator Hall

200 m

Linac Tunnel +

Injector

Extension

• Seeded FEL, 1.5 GeV, 10 Hz (50 Hz) – First Lasing Dec.13, 2010• Open to external users since 2012 (FEL-1),


FERMI Overview

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Two FEL lines are available. Both FELs are externally seeded. The first FEL line, FEL-1, adopts on a single stage HGHG scheme and covers the

VUV – EUV spectral range 100 – 20 nm starting with a tunable seed laser in the UV. The second FEL line is based on a double stage HGHG configuration that starting

from an UV seed laser can generate powerful pulses covering the EUV to soft X-rays range down to the 20 – 4 nm spectral range.

Three beam lines presently in operation: DiProi, EIS-TIMEX, LDM

FERMI is a single-pass FEL user facility, based on the high gain harmonic generation scheme HGHG.

Advantage of this scheme is the generation of powerful light pulses in the XUV spectral range characterized by a very high degree of coherence both in the longitudinal and transverse plane.

Coherence, tunability, spectral stability with pulses close to the Fourier limit, very low time jitter synchronization to an optical pump laser are among the distinctive features that make FERMI a very attractive facility for the scientific community. The capability of controlling the radiation polarization is another of the unique characteristics of FERMI


FERMI Layout

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FEL1

FEL2I/O mirrors & gas cells

PADReS

EIS

DIPROI

LDM

Photon Beam Lines

slits

experimental hall

undulator hall

Transfer Line

FEL1

FEL2

L1

X-band

BC1

L2 L3 L4

BC2

Electron linear accelerator tunnel

PI

Laser Heater

Pump&Probe

Autocorrelator


FERMI – electron beam parameters

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FERMI – photon beam parameters

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FEL-2 single shot spectral image and relative line-width distribution over about 500 spectra.The harmonic conversion from 260 nm is 12x4, the 1st stage lasing at 21.7 nm and the 2nd stage tuned at its 4th harmonic


FERMI – Status

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FEL-1: open to external users since December 2012. Nominal performance of FEL -2 reached in September 2014 FEL-2 open to external from the first users period of 2015.

OPERATING HOURS DISTIBUTION (2014)

Total operating hours 6640

User operation 2848 43 %

Machine tuning 1120 17 %

Commissioning 2672 40 %

Four calls from 2012 so far: 193 proposal, 76 on DiProI, 55 on EIS-TIMEX and 62 on LDM

At the last call for proposal deadline in January 2015, 68 proposals were submitted, 30% of them on FEL-2.

The oversubscription factor is about 3.5 (was 3.1 for the 3rd call).

M/Svandrlik et al. , “The FERMI Seeded FEL Facility: Operational Experience and Future Plans”, IPAC 2015, Richmond, May 2015


FERMI – Special Users’ Modes

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Generation of coherent radiation from FEL-1 at 12 nm, well below the nominal spectral range, and users experiments were performed at 12 nm with 10 µJ energy per pulse.

A new FEL configuration allowing two colour operations with a wide spectral separation between the two FEL pulses has been proposed and successfully used for experiments on DiProI by M. Sacchi (CNRS-SOLEIL) in November 2014.

Two seed laser pulses with slightly different wavelength and a controllable delay interact with the same electron bunch. The final radiator is divided in two sections tuned at two different harmonics of the two seed lasers.

Coherent emission is produced by each of the two bunched portions of the beam in only one of the two radiator segments, generating two temporally and spectrally separated pulses .

These and other non-standard schemes are possible thanks to the flexible layout of FEL-1 that allows the generation of pairs of FEL pulses with very high degree of coherence.

E. Allaria et al., “Two-colour pump-probe experiments with a twin-pulse-seed extreme ultraviolet free-electron laser”, Nature Commun. 4, 2476 (2013).L. Giannessi et al. (2012), “First lasing of FERMI FEL-2 (1° stage) and FERMI FEL-1 recent results”, MOOB06, FEL Conference 2012, Nara, Japan.

G. De Ninno et al., “Chirped seeded free-electron lasers: Self-standing light sources for two-color pump-probe experiments”, Phys. Rev. Lett. 110, 064801 (2013).B. Mahieu et al., “Two-colour generation in a chirped seeded free-electron laser: A close look”, Optics Express 21, 22728 – 22741 (2013).M. Sacchi, private communication (2015)


FERMI –short term upgrades -1

The accelerating structures will be 3-meter long, constant gradient, equipped with symmetric input and output couplers.

They will replace the two single feed structures present in the 100 MeV injector part.

The two removed sections will be reinstalled in the high energy part of the LINAC, where space and RF power are already available.

The new sections are built by Research Instruments GmbH

Two accelerating structures will be added to increase the operational margin in the total beam energy budget and to improve the beam quality in the injector part at low energy.

The section will be tested in high RF power in summer 2015.

Final installation is foreseen in the winter shutdown and commissioning of the linac with beam, up to 1.65 GeV, will then start in February 2016.

A. Fabris et al., “Perspective of the S-band Linac of FERMI”, MOPP024, LINAC2014, Geneva, August 2014, p. 105 (2014); http://www.JACoW.org


FERMI –short term upgrades -2

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Third undulator section added to the radiator of the 1st stage of FEL-2. Extract higher energy per pulse from the 1st stage at equivalent seed power or reduce

the required seed power to reach an equivalent seed pulse energy for the 2nd stage. Open the possibility of using a tunable seed laser based on an optical parametric

amplifier on a wider range of seed wavelengths. Relax the stringent requirements on the electron beam quality in favour of long term

stability. The undulator, now being constructed by Kyma srl, will be installed in the tunnel in

January 2016 and commissioning with beam is planned in March 2016.

Addition of a second regenerative amplifier to the seed laser system, sharing the same femtosecond oscillator with the existing amplifier,

Improve the quality of the laser pulse for seeding FEL-2, leading to an improvement of the FEL quality and flexibility.

The main features of the new regenerative amplifier are a shorter pulse duration in fixed wavelength (800 nm) mode, i.e. less than 50 fs FWHM, and a central wavelength tunability within ±2%.

Improve the energy and pulse duration parameters of the optical laser pulse that is delivered with extremely low jitter, less than 7 fs rms, to the experimental stations for pump-probe experiments, removing also any limitation on the optical laser to FEL pulse delay time.

E. Allaria et al., “Tunability experiments at the FERMI@Elettra free-electron laser” New J. Phys. 14 113009 (2012)

M. B. Danailov et al., “Towards jitter-free pump-probe measurements at seeded free electron laser facilities”, Optics Express 22, 12869-12879 (2014).


FERMI –Long term upgrades

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PULSE COMPRESSOR SYSTEM ON TW STRUCTURES Either BOC or SLED are being evaluated

Preliminary tests with a BOC system borrowed form CERN will be done on one plant in the second half of this year to evaluate the technical feasibility of the solution.

The system is now being installed on one RF plant

If a pulse compressor system is implemented on all the structures, the additional energy gain is expected to be around 120 MeV, roughly what can be achieved with two more accelerating structures operated as they are today.

Courtesy of C. Serpico


FERMI –Long term upgrades

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NEW ACCELERATING STRUCTURES A study of a new accelerating module to replace one 6-m BTW structure has started Due to the small iris radius, some of them have to be set off crest in the last part of the

linac with a consequent decrease in the final output energy of the beam to control the impact of longitudinal and transverse wakefield. The loss energy could reach even 130 MeV at 800 pC beam charge.

The scope is to have structures optimized for the needs of FERMI: Parameters are being evaluated to benefit from pulse compression. Better performance in terms of transverse and longitudinal dynamics. The study is made in collaboration with A. Grudiev (CERN)

The preliminary design studies has led to concentrate on a module composed of two 3 m long FTW constant gradient structures with 10 mm iris radius (two times the one of the operating BTW structures)

Longitudinal and transverse dynamics have been also evaluated for this preliminary design

With the new structures at high current the loss with respect to on-crest operation is expected to be reduced to 20 MeV. Courtesy of C. Serpico


FERMI – Energy budget

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Present maximum on-crest energy……………….…………....1550 MeV

Increase with two sections being built………………..………...100 MeV

Expected increase with BOC/SLED on CERN sections……..120 MeV

Total on-crest energy with previous upgrades………………1770 MeV

Further slight margins in energy could be gained if we can push the CERN structures slightly higher and by sledding also the 3m TW sections.

A target peak on-crest energy of 1.8 GeV could be reached, redundancy can be obtained with the exchange of one high energy deflector with an additional accelerating cavity.


SUMMARY

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Elettra In operation since 1994 with excellent reliability and users’ satisfaction. Continuous upgrades have allowed to keep the performance of the

machine at the level of more recent facilities. Study to produce a conceptual design for a new Elettra 2.0 is in course .

FERMI FEL-1 and FEL-2 are in operation for users with excellent performance

and uptime. The offer in terms of experimental stations will be increased from three

to six in 2016. A program to widen the experimental opportunities and flexibility of the

facility is ongoing.


ACKNOWLEDGEMENTS

This presentation reports the work of the people involved in the construction and developments of the accelerators at Elettra Sincrotrone Trieste.

We would like to thank all the colleagues for the fundamental work for the construction, commissioning and operation of the facilities and for the great results achieved.

We would like to thank the Elettra Sincrotrone Management for their support during the construction, commissioning and operation phases of the facilities.

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Thank you!

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alessandro fabris – 10 july, 2015 future research infrastructures: challenges and opportunities,...

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