Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSY<sup>VSR</sup>

Jankowiak, Andreas; Wüstefeld, G.

doi:10.1080/08940886.2013.791212

Cited by 18 publications

(18 citation statements)

References 9 publications

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“…The underlying 10 ps time scale renders this transient peak shift an ideal cross-correlator for ps-pulsed X-ray sources like the normal single bunch of 3rd generation synchrotrons (approximately 75 ps at BESSY II), 13,14 synchrotrons in low- α mode (approximately 10 ps at BESSY II) 24 and even below that such as for the currently developed BESSY-VSR mode 24 . Moreover, the ns recovery of the peak shift yields efficient detectability of this transient signature and can also be utilized for optimizing the spatial overlap between pump and probe pulses since the transient signal change is proportional to the excitation fluence in the probed region.…”

Section: Resultsmentioning

confidence: 99%

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Schick

Eckert

Pontius

et al. 2016

Structural Dynamics

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We present an X-ray-optical cross-correlator for the soft (>150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50% total X-ray reflectivity and transient signal changes of more than 20%.

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Section: Resultsmentioning

confidence: 99%

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Schick

Eckert

Pontius

et al. 2016

Structural Dynamics

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“…Another example experiment with PPRE switched ON and OFF is depicted in Fig. 5c,d, where the ring is operated in hybrid mode with only one camshaft pulse, but under low-a condition 15 . The clean spectrum in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Bunch lengths of B2-3 ps (r.m.s.) have been available for many years using BESSY II's low-a mode 14,15 or even shorter bunches at lowest currents 16 . To test PPRE with ultra-short bunches, a special fill pattern with a bunch current of o100 mA of the camshaft bunch was created depicted by the blue curve in Fig.…”

Section: Resultsmentioning

confidence: 99%

Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source

et al. 2014

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Synchrotron radiation facilities routinely operate in a multi-bunch regime, but applications relying on time-of-flight schemes require single bunch operation. Here we show that pulse picking by resonant excitation in a storage ring creates in addition to the multi-bunch operation a distinct and separable single bunch soft X-ray source. It has variable polarization, a photon flux of up to 10 7 -10 9 ph s À 1 /0.1%BW at purity values of 10 4 -10 2 and a repetition rate of 1.25 MHz. The quasi-resonant excitation of incoherent betatron oscillations of electrons allows horizontal pulse separation at variable (also circular) polarization accessible for both, regular 30 ps pulses and ultrashort pulses of 2-3 ps duration. Combined with a new generation of angularly resolving electron spectrometers this creates unique opportunities for time-resolved photoemission studies as confirmed by time-of-flight spectra. Our pulse picking scheme is particularly suited for surface physics at diffraction-limited light sources promising ultimate spectral resolution.

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“…Another approach to extend the time resolution of storage-ring X-ray sources to the fewpicosecond regime, while exploiting all of the stored electrons at the full repetition rate, relies on a different stable closed e-bunch orbit with a minimized energy/momentum correlation [186,187]. The momentum-compaction factor, α c , relates differential changes in electron orbital path length ( L) with differential changes in electron energy ( E) as given by: L/L = α c E/E.…”

Section: (B) Low-α Operationmentioning

confidence: 99%

“…ignoring collective electron effects), the nominal e-bunch length scales as: σ e-bunch ∼ α c /V , where V is the temporal gradient of the accelerating RF voltage. The scaling of e-bunch length with α c and e-bunch current is illustrated by the red curves in figure 12, taking the example of BESSY II [187]. The interaction of electrons with their own coherent synchrotron radiation (CSR), and with the impedance of the storage-ring vacuum chamber, leads to a nonlinear increase in σ ebunch with e-bunch current.…”

Section: (B) Low-α Operationmentioning

confidence: 99%

Recent advances in ultrafast X-ray sources

Schoenlein

Elsaesser

Holldack

et al. 2019

Phil. Trans. R. Soc. A.

120

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Over more than a century, X-rays have transformed our understanding of the fundamental structure of matter and have been an indispensable tool for chemistry, physics, biology, materials science and related fields. Recent advances in ultrafast X-ray sources operating in the femtosecond to attosecond regimes have opened an important new frontier in X-ray science. These advances now enable: (i) sensitive probing of structural dynamics in matter on the fundamental timescales of atomic motion, (ii) element-specific probing of electronic structure and charge dynamics on fundamental timescales of electronic motion, and (iii) powerful new approaches for unravelling the coupling between electronic and atomic structural dynamics that underpin the properties and function of matter. Most notable is the recent realization of X-ray free-electron lasers (XFELs) with numerous new XFEL facilities in operation or under development worldwide. Advances in XFELs are complemented by advances in synchrotron-based and table-top laser-plasma X-ray sources now operating in the femtosecond regime, and laser-based high-order harmonic XUV sources operating in the attosecond regime. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

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Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSY^VSR

Cited by 18 publications

References 9 publications

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source

Recent advances in ultrafast X-ray sources

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Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSYVSR

Cited by 18 publications

References 9 publications

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Versatile soft X-ray-optical cross-correlator for ultrafast applications

Single bunch X-ray pulses on demand from a multi-bunch synchrotron radiation source

Recent advances in ultrafast X-ray sources

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Low-α Operation of BESSY II and Future Plans for an Alternating Bunch Length Scheme BESSY^VSR