Gas adsorption equipment for x-ray scattering

A closed cycle kryostat combined with an gas adsorption station allow full automatic in-situ gas adsorption measurements combined with XDR and SAXS-investigations. The equiment has been established at BESSY in with the BMBF and theTU Dresden.

Closed cycle cryostat (ARS DE-202AG):

  • Temperature range with saphire heater stage: 10 K - 450 K
  • Beryllium sample cell and -windows for 2π-scattering angle
  • 2 gas supply cappillaries (for static and continuous sorption methods)

Gas adsorption station (BELSORP-MAX):

  • Volumetric gas dosing up to 130 KPa
  • Integrated trigger-automatic for usage with SPEC-controlled x-ray instrumentation

In-situ XRD with BELSORP-MAX and ARS-cryostat at MAGS-beamline

In-situ XRD with BELSORP-MAX and ARS-cryostat at MAGS-beamline

Specifications of system
Pressure Range 130 kPa
Sample Space Dia./Height 5 x 5 x 1 mm^3
Insert suitable to cryostat
Temperature Range 6 K - 450 K
Thermometry Sensors Si-Diode

The automated gas dosing system Belsorp-Max is connected by a flexible capillary to the cryostat DE-202AG, which allows measurements between 6 K and 450 K, and the attached sample chamber that is closed by a small Be-dome (figure). In addition to measurements in static gas atmosphere also measurements in gas flow are possible via a second capillary. The sample holder is built of aluminum comprising a U-cut-out that is permeable for X-rays. The sample can be placed between two Kapton foils. A thickness of about 1 mm of a loose powder packed bed is achieved.

In the synchrotron version for the MAGS an KMC-2 beamlines of BESSY II a trigger between the gas dosing system and the SPEC controlled diffraction system is possible: At first, an appropriate amount of gas is added into the capillary and the attached sample chamber. Then, the system waits for equilibrium and subsequently sends a trigger signal to the diffraction system. Now, the measurement of the diffraction pattern starts, followed by another trigger signal to the adsorption system to continue with the next adsorption step and so on.