Damage limitations to scientific experiments at the ...bib-pubdb1.desy.de/record/220205/files/SPIE2015_Lyamayev.pdf · Damage limitations to scientific experiments at the European

Viktor Lyamayev (European XFEL, Hamburg)

Damage to VUV, EUV, and X-ray Optics VPrague,15-16 April 2015

Damage limitations to scientific experiments at the European XFEL

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

European XFEL layout

Injector at DESY campus

Linear Accelerator1.9 km17.5 GeV

Undulator/Photon Tunnels

Experiment Hallin Schenefeld

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

European XFEL

SASE2(= SASE1)

SASE1, λλλλu= 40 mm0.2–0.05 nm SASE3, λλλλu= 68 mm

1.7–0.4 nm

Some specifications

� Photon energy 0.24–24 keV

� Pulse duration ~ 10–100 fs

� Pulse energy few mJ

� Superconducting linac. 17.5 GeV

� 10 Hz (27 000 b/s)

� 5 beamlines / 10 instruments

� Start version with 3 BLs and 6 instruments

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

X-ray pulse structure

X-ray pulse structure of the European XFEL

Average power < 90 WPulse train

(1…2700 pulses)

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

X-ray pulse structure

X-ray pulse structure of the European XFEL

Power of each pulse train: 3 mJ * 2700 pulses / 0.6 ms = 13 kW !!!

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor LyamayevHarald Sinn, Europpean XFEL

Single Particles, Clusters, and Biomolecules (SPB) Instrument

Focusing optics (KB-mirrors)

X-ray beam size 0.1–1 µm

Detectors4 Mp, 4.5 MHz

Sample injectors

Refocusing Be-lenses (CRL)

Beam Stop

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

FEM-analysis of the heat load

The main problem is to combine fine meshing of a small interaction volume (e.g. FWHM = 20 µm) with meshing of much bigger absorbing body (e.g. 50×50×50 mm³).

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

FEM-analysis of the heat load

Heat load on the B4C absorber of the Beam Stop (3 consecutive pulse-trains):

time, ms

T, d

egre

es

850

70

500

0 100 200

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

FEM-analysis of the heat load

Heat load on the B4C absorber of the Beam Stop

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

FEM-analysis of the heat loadThermomechanical stresses in B4C absorber of the Beam Stop

X

Y

Z

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

FEM-analysis of the heat load

Tensile stress in B4C absorber of the Beam Stop

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Alternative materials for the Beam Stop

CVD diamond 70×70×0.3 mm

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Alternative materials for the Beam Stop

CVD diamond 70×70×0.3 mm

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Alternative materials for the Beam Stop

Tensile stress in the Beam Stop (CVD diamond)

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Beam Stop concept

Attenuator (CVD diamondØ80×0.5 mm)

B4C absorber

Aluminium

Steel flange (DN160CF)

x-ray

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Beam diagnostics

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Beam Stop of the SPB Instrument

Damage limitations to scientific experiments at the European XFEL

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor LyamayevHarald Sinn, Europpean XFEL

SPB Instrument

Focusing optics (KB-mirrors)

X-ray beam size 100 nm – 1 µm

Detectors4 Mp, 4.5 MHz

Sample injectors

Refocusing Be-lenses (CRL)

Beam Stop

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Heat load on other instrument components

Compound Refractive Lenses (CRL)

Temperature distribution →

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Heat load on other instrument components

Limitations of Compound Refractive Lenses

FEM

Analytical(adiabatic)

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Thermomechanical stresses in CRL

Stress (along Y-axis) →

D.D.Ryutov, Thermal stresses in the reflective x-ray optics for the LCLS, Rev.Sci.Instrum. 74, 3722 (2003):

� stresses shouldn’t exceed yield strength (for metals)

� otherwise cycling at 10 Hz will lead to cracking

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Thermomechanical stresses in CRL

At heat load leading to T~300 °C compressive stress exceeds yield strength of Be by several times!:

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Damage to VUV, EUV, and X-ray Optics V 15-16 April 2015Viktor Lyamayev

Summary

� X-ray optics and other components of the instruments (CRL, windows, Beam Stop) can potentially limit the science

� Based on comprehensive FEM-simulations optimized Beam Stop design was developed that can withstand full pulse train (2700 pulses)

� Some components show limitation also due to thermomechanical stresses

� 10 Hz cycling should also be taken into account for definition of permissible stresses