General beamline description and specifications
The PHOENIX (PHotons for the Exploration of Nature by Imaging and XAFS) beamline is dedicated to X-ray Absorption (micro-) Spectroscopy (XAS) and imaging in the tender X-ray energy range of 0.4 to 8 keV. Due to this special energy range, PHOENIX is devoted to the study of light elements (K-edges of O-Fe, L –edges of Ca-Gd), providing unique research opportunities for material science, biology, energy research, environmental science, chemistry, catalysis or cultural heritage.
Opportunities for medical and biological research at the PHOENIX beamline
The PHOENIX beamline offers imaging on a micrometer scale and X-ray spectroscopy to analyze the chemical composition of a sample. Using the tender X-ray range, PHOENIX is well suited to perform X-ray micro spectroscopy on elements (O, N, F, Na, Mg, Al, Si, P, Cl, K, Ca, .., Fe), which are relevant to biological systems. This technique can be used to decipher the chemical role (oxidation state, type of chemical bonding, speciation, etc. with micrometer spatial resolution) of these elements in a biological system. For example, the chemical structure of Sulfur and Phosphorous has been studied in cancer tissues. (https://journals.sagepub.com/doi/10.1177/0003702815620128).
With the current COVID-19 health crisis, we invite in particular research proposals tackling these problems. Currently, there is an open rapid access call for research projects on COVID-19: https://www.psi.ch/en/sls/scientific-highlights/priority-access-call-for-work-on-combating-covid-19
Brief specifications of the PHOENIX beamline
|Energy range|| 0.8 - 8.0 keV PHOENIX I
0.4 - 2.0 keV PHOENIX II
|Photon source||elliptical APPLE II undulator for linear and elliptical polarization|
|Flux (3keV)||1 x 1011 ph/s/0.1%BW/400 mA|
|Energy resolution||1 x 10-4|
|Focused spot size||2.5 µm x 2.5 µm|
|Sample environments|| - solid samples, pellets
- measurement in vacuum or helium
- possible heating to 450 C, cooling to 90K
- titration cells, flow-through liquid cells
- liquid microjet (in collaboration)
|Fluorescence detectors||4 element and 1 element silicon drift diode (SDD) energy dispersive detectors|
X-ray absorption spectroscopy (XAS) and chemical imagingPHOENIX offers opportunities for high quality spectroscopy (i.e. EXAFS) and imaging of light elements, with the possibility of studying samples with low concentration. The beamline is equipped with two different end-stations providing state-of-the-art equipment to conduct X-ray micro-spectroscopic measurements (µ-XAS and µ-XRF) using fluorescence, absorption and total electron yield as detection methods. Chemical imaging of bulk samples can be done with spatial resolution in the micrometer range using x-ray scanning microscopy.
X-ray emission spectroscopy (XES)A von Hamos spectrometer for tender x-rays is available for emission spectroscopy (current energy range 2.25-2.8 keV, 0.5 eV energy resolution). The energy range will be extended to cover the range 2.1 to 4.5 keV. The spectrometer is completely integrated into the x-ray scanning microscope, and hence can be coupled to imaging applications. To use the spectrometer please contact beamline scientist (firstname.lastname@example.org) prior to proposal submission.
Sample environmentsStandard solid samples can be measured in vacuum or helium atmosphere. Heating to 450 C and cooling to 90 K is possible. Measurements can be conducted in different sample environments including but not limited to liquid micro-jet, liquid flow cell and in situ titration cells.
Upon request dedicated sample environments can be developed within scientific collaboration.
Research examples performed at the PHOENIX beamlineResearch at PHOENIX covers various fields, such as environmental sciences, catalysis, energy research, electrochemistry, cultural heritage and characterization of novel materials. For a complete list see PHOENIX publications.
The capabilities of the beamline can be demonstrated by these publications.
- A liquid microjet has been used to decipher the mechanism of carbonate nucleation (Henzler et al., SLS highlight) and the structure of molecules in solutions (Pin et al.).
- Examples for using micro focussing and micro spectroscopy include studies about the state and distribution of sulfur species in shells (Fichtner et al.), or the distribution of sulfur and phosphorous species in biological tissue (Czapla-Masztafiak et al.).
- The beamline is suited for cultural heritage studies. Examples include studies of the discoloring of famous paintings (Cato et al.), or the colour of ancient carpet hair (Meyer et al.).
- A speciality of the beamline is to make high quality XAS measurements (XANES and EXAFS) for low-Z elements. This includes the study of Aluminium in zeolites (Vjunov et al., Fulton et al.), the structure of Sodium ions in solutions (Galib et al.) or the study of UV radiation damages in biological samples (Czapla-Masztafiak et al.).
- User supplied in situ cells can be used at the beamline, as it has been done to study the charging cycles of sulphur-based batteries (Gorlin et al.), or phosphorous containing batteries (Schmidt et al.).