Higher Order Suppressor (HOS) for the PolLux Microspectroscope Beamline at the Swiss Light Source SLS

Frommherz, U.; Raabe, Jörg; Watts, Benjamin; Stefani, R.; Ellenberger, U.; Garrett, R.; Gentle, Ian R.; Nugent, Keith A.; Wilkins, S.

doi:10.1063/1.3463232

Cited by 36 publications

(29 citation statements)

References 4 publications

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“…NEXAFS investigations were performed ex situ at the PolLux beamline (X07DA) of the synchrotron radiation facility SLS at the PSI, using STXM with an energy resolution of E/DE 4 3000 for the 270-350 eV energy range. 44,[60][61][62] The NEXAFS measurements were performed under normal incidence in the ''line-scan'' mode in each region of interest with a length of 25 mm. On each position, the transmitted photon flux I was measured in an energy scan with varying energy step sizes for different regions of the spectrum (270-282 eV, 0.5 eV step; 282.1-293.0 eV, 0.2 eV step; 293.25-300.00 eV, 0.25 eV step; 301-350 eV, 1 eV step; dwell time 100 ms) was recorded.…”

Section: Discussionmentioning

confidence: 99%

Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Bespalov

Witte

et al. 2020

J. Mater. Chem. C

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Section: Discussionmentioning

confidence: 99%

Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Bespalov

Witte

et al. 2020

J. Mater. Chem. C

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“…STXM/NEXAFS measurements were performed at the PolLux endstation located at the Swiss Light Source (SLS) to obtain the Fe oxidation state of particles between 0.2-2 µm in diameter (Flechsig et al, 2007;Frommherz et al, 2010;Raabe et al, 2008).…”

Section: Chemical Characterization By Stxm/nexafsmentioning

confidence: 99%

Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Dou¹,

Alpert²,

Arroyo³

et al. 2020

Preprint

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Abstract. Iron(III) carboxylate photochemistry plays an important role in aerosol aging, especially in the lower troposphere. These complexes can absorb light over a broad wavelength range, inducing the reduction of iron(III) and the oxidation of carboxylate ligands. In the presence of O2, ensuing radical chemistry leads to further decarboxylation, and the production of ·OH, HO2·, peroxides, and oxygenated volatile organic compounds, contributing to particle mass loss. The ·OH, HO2·, and peroxides in turn re-oxidize iron(II) back to iron(III), closing a photocatalytic cycle. This cycle is repeated resulting in continual mass loss due to the release of CO2 and other volatile compounds. In a cold and/or dry atmosphere, organic aerosol particles tend to attain highly viscous states. While the impact of reduced mobility of aerosol constituents on dark chemical reactions has received substantial attention, studies on the effect of high viscosity on photochemical processes are scarce. Here, we choose iron(III)-citrate (FeIII(Cit)) as a model light absorbing iron carboxylate complex that induces citric acid (CA) degradation to investigate how transport limitations influence photochemical processes. Three complementary experimental approaches were used to investigate kinetic transport limitations. The mass loss of single, levitated particles was measured with an electrodynamic balance, the oxidation state of deposited particles was measured with X-ray spectromicroscopy, and HO2· radical production and release into the gas phase was observed in coated wall flow tube experiments. To quantitatively compare these experiments and determine important physical and chemical parameters, a numerical multi-layered photochemical reaction and diffusion (PRAD) model that treats chemical reactions and transport of various species was developed. We observed significant photochemical degradation, with up to 80 % mass loss within 24 hours of light exposure. Interestingly, we also observed that mass loss always accelerated during irradiation, resulting in an increase of the mass loss rate by about a factor of 10. When we increased relative humidity, the observed particle mass loss rate also increased. This is consistent with strong kinetic transport limitations for highly viscous particles. The PRAD model was tuned to reproduce all experimental results and captured the essential chemistry and transport during irradiation. In particular, the photolysis rate of FeIII, the re-oxidation rate of FeII, HO2· production, and the diffusivity of O2 in aqueous FeIII(Cit)/CA system as function of relative humidity and FeIII(Cit) / CA molar ratio could be constrained. Photochemical degradation under atmospheric conditions predicted by the PRAD model shows that release of CO2 and re-partitioning of organic compounds to the gas phase may be very significant to accurately predict organic aerosol aging processes.

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“…Similar systems have been described elsewhere (e.g. Waki et al, 1989;Frommherz et al, 2010;Bulicke et al, 1997).…”

Section: Introductionmentioning

confidence: 87%

Efficient high-order suppression system for a metrology beamline

Sokolov

Сертсу

Gaupp

et al. 2018

J Synchrotron Radiat

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High-quality metrology with synchrotron radiation requires in particular a very high spectral purity of the incident beam. This is usually achieved by a set of transmission filters with suitable absorption edges to suppress high-order radiation of the monochromator. The at-wavelength metrology station at a BESSY-II bending-magnet collimated plane-grating monochromator (c-PGM) beamline has recently commissioned a high-order suppression system (HiOS) based on four reflections from mirrors which can be inserted into the beam path. Two pairs of mirrors are aligned parallel so as not to disturb the original beam path and are rotated clockwise and counter-clockwise. Three sets of coatings are available for the different energy ranges and the incidence angle is freely tunable to find the optimum figure of merit for maximum suppression at maximum transmission for each photon energy required. Measured performance results of the HiOS for the EUV and XUV range are compared with simulations, and applications are discussed.

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Higher Order Suppressor (HOS) for the PolLux Microspectroscope Beamline at the Swiss Light Source SLS

Cited by 36 publications

References 4 publications

Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Photochemical degradation of iron(III)-citrate/citric acid aerosol quantified with the combination of three complementary experimental techniques and a kinetic process model

Efficient high-order suppression system for a metrology beamline

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