Speaker
Description
A new experimental setup, which includes a highly photon sensitive spectrometer based
on superconducting transition edge sensors (TES) is under commissioning at BESSY II.
The setup is dedicated to XAS, XES and RIXS experiments in the soft X-ray regime with a
strong emphasis on the study of low concentration systems, which can be divided into two
main themes: 1) solids and low dimensional systems and 2) molecular systems in solution.
The principle of a TES detector is based on the abrupt normal metal –
superconductor transition edge of a superconducting sensor as an energy dispersive and
ultrasensitive photon detector with a collecting efficiency orders of magnitude higher than
grating-based spectrometers [1,2]. The present detector consists of an array of 256
sensors in a compact design mounted on a closed-cycle dilution refrigerator to reach the
operation temperature of 53 mK, and targets an energy resolution of 0.5 eV FWHM for
energies below 1 keV. The experimental setup is installed at the UE52-SGM beamline with
full polarization control. The relatively large (1-6 mm 2) beam size at the sample position
allows low sample damage measurements of fragile systems. The dedicated UHV sample
chamber is designed for the preparation of low-dimensional solid state systems as well as
for the insertion of molecular systems in frozen solutions.
In this presentation, after an introduction on the principle of the TES technology, I
will show the specific characteristics of the spectrometer deployed at BESSY II and the
results of the first tests with the full experimental setup.
