The main goal of the FINESTLUMI end station is luminescence spectroscopy research under vacuum ultraviolet (VUV) as well as soft X-rays (XUV) excitations. Any materials in solid phase (single crystals, glasses, ceramics, films, powders, etc.) can be studied. The end station consisting of an ultra-high vacuum chamber with a closed-cycle helium cryogenic system provides sample temperatures T = 10 – 350 K. To analyze photoluminescence in the UV to near IR range a Shamrock 0.3 m spectrometer (Andor) equipped with the CCD camera and several photomultiplier detectors is coupled to two optical fibers (working in different spectral ranges), collecting emission from the sample. The possibility to use high-resolution excitation (0.01 nm at 100 nm) in scanning mode and the option of tuneable polarization of the incident light make this beamline very attractive for the field of luminescence studies under VUV and XUV excitations. Additionally to the photoluminescence spectroscopy, the FINESTLUMI end station can be applied to optical spectroscopy experiments examining the reflection signal from flat samples’ surfaces as well as detecting the transmitted light passing through the samples studied. Advanced experiments which include a combination of synchrotron light and some external light sources (for a pump-probe and a photostimulated spectroscopy) are available also if external light sources are provided by users. VUV spectrometer and VUV detection system intended for the study of the luminescence signals at energies higher than 6 eV (below 200 nm) as well as time-resolved registration system are under development and construction.

 

Experimental possibilities:

  • Emission spectra from VUV to NIR spectral range (180 – 1400 nm).
  • Excitation, absorption and reflection spectra with high resolution in 4.3 -1000 eV spectral range.
  • Optical (reflection, transmission) and luminescence spectroscopy under tuneable polarization (vertical/horizontal/elliptic).
  • Temperature dependence of optical and luminescence properties down to liquid helium temperature (10 K).

 

Spectrometer:

Andor Shamrock (SR-303i) 0.3 m spectrometer equipped with a high resolution grating (1200 l/mm, 300 nm blaze) and two lower resolution gratings (300 l/mm) optimized for different spectral regions (300 and 500 nm blaze, respectively). The Andor Shamrock spectrometer collects luminescence from samples with the aid of a fiber optic cable.

Luminescence detectors:

  • The Newton CCD camera (Newton DU970P-BVF model from Andor) is suitable for the spectral range of 200-1100 nm.
  • The set of Hamamatsu photomultipliers (H8259, H8259-01, and H8259-02 photon counting heads) is intended for the spectral range of 1850-900 nm.
  • The thermoelectrically cooled infrared NIR PMT Unit H10330C-45 (Hamamatsu) can be used in the spectral range of 950-1400 nm.

Reflection and transmission detectors:

  • Two AXUV-100G diodes mounted in UHV serve as detectors of either transmitted or reflected radiation from the samples in suitable geometry.
  • The photomultiplier (Hamamtsu H11123 counting head) collecting the luminescence signal from a sodium salicylate covered window excited by reflected light.

Low temperature set-up:

The closed-cycle helium cryostat consists of the ARS DE-204PB cryohead and the ARS-4HW compressor (Advanced Research System). The LakeShore 335 temperature controller allows one to regulate sample temperature in the region of 6 – 400 K.

Sample environment:

The cryostat, mounted on a rotational stage, is installed on an XYZ manipulator (Thermionics) facilitating the alignment of the sample with respect to the incident beam. The size (12×2 cm2) of the two-sided sample holder is large enough to accommodate even dozens of samples on each side. The UHV vacuum chamber is evacuated to the working vacuum level of 10-9 mbar at room temperature by a turbo pump HiPace 300 (Pfeiffer Vacuum) and ion pump (Gamma Vacuum).

Design drawing of the FINESTLUMI showing the measurement geometry. The VUV monochromator shown on the left side has not been implemented yet.

 

 

 

 

 

 

 

 

 

 

 

 

Photoluminescence endstation at FinEstBeAMS.