Temperature environments for KMC2

A particular strong point of KMC-2 is the wide range of sample environments available for both stations. Besides various high-temperature furnaces and gas-loading devices, of particular interest for crystallographers are the newly developed temperature environments (see table below), which allow experiments in a wide temperature range in vacuum or in controlled gas atmospheres:

CCR-XRD is based on a Gifford-McMahon (GM) closed-cycle cryocooler equipped with a high temperature stage, which covers the temperature range from 15 K to 450 K for samples in vacuum. For temperatures lower than 320 K an optional Kapton cupola can be used to keep the sample at inert or exchange gas conditions. In particular, this allows seamless studies of phase transitions around ambient temperature. Exchanging the Kapton cupola for a Beryllium dome allows investigating samples at controlled gas atmospheres up to pressures of 150 kPa up to 450 K. The equipment can be used both in transmission or reflection during diffraction studies and in transmission or fluorescence XAS experiments.

For small samples, several capillary setups are available. The CRYO-GAS-JET system applies a cryogenic generated gas jet to a glass or Kapton sample tube in a setup designed to prevent ice condensation. This system allows a temperature range of 20 - 300 K.  An AROUND-AMBIENT- and a HOT-AIR-JET setup use special gas thermalized capillary environments designed to provide very homogenous temperature profiles, in the temperature ranges 250 – 320 K and 300 - 800 K, respectively. All capillary systems allow sample rotation for enhanced particle statistic, and also allow applying a continuous flow or static gas atmospheres up to 10.000 kPa to the sample.

All sample environments are available to users of KMC-2 @ BESSY II. They have been successfully utilized in a wide range of experiments and are under constant development.

[1] M. Többens, S. Zander, Journal of large-scale research facilities, 2, A49 (2016)

 Overview of provided Equipment:

Name T-range [K] p-range [kPa] description cell windows sample holder
CCR-XRD 15-450 0-150 closed cycle cryostat for different sample cells and gas adsorption option Kapton (x-gas-cell), Beryllium (gas adsorption cell) powder transmission and reflection, single crystals
N-HELIX CRYO-GAS-JET 20-600 0-10000 closed cycle cryo-jet for small samples in glass capillaries

quartz and Kapton tubes  (0.1mm - 2 mm)

continuous flow, and static gas atmospheres
THERMO-AIR-JET 200 - 400 0-10000 thermalized N2-gas jet

quartz tubes (0.1 mm - 1.0 mm)

continuous flow, and static gas atmospheres combined with  sample rotation
HOT-AIR-JET 300-800 0-10000 heated N2-gas jet

quartz tubes (0.1 mm - 1.0 mm)

continuous flow, and static gas atmospheres combined with  sample rotation
HTF-KMC2 300-1000 <0.01