Principle

In cryo configuration, a copper cold finger is mounted on the sample stage and linked via copper braids to the cooled base plate of the LN2 dewar. The cold finger is thermally insulated from the sample stage mechanics by a Polyetheretherketone (PEEK) support. Measurements both in fluorescence and transmission modes are possible thanks to this new configuration. Good thermal contact is ensured due to the conical shapes of the cold finger and sample holder. Initial cooling of the cryo-stage requires 1 hour before settling in thermal equilibrium with a 100 K temperature on the cold finger.  The system offers an autonomy of 3.5 hours and a semi-automatic refilling procedure can be manually activated or integrated in data acquisition macros.

 

 


Picture of cryostage mounted on the SXM and the desing of the cold finer and cryo sample holder (Design by E. Gagliardini, ESRF ISDD)

Sample holders

The sample holder is machined in a copper block providing sufficient thermal inertia during sample transfer. Samples are usually deposited on TEM grids, Si3N4 membranes (frame size 5 x 5 mm)  or between ultralene films. The sample is deposited on the holder, maintained by a drilled copper plate and covered with a thin polymer film (Ultralene, Spex-Certiprep) which limits its sublimation. This stack is maintained by a “clip” cover plate which facilitates mounting.

Picture of the cryo sample holder and its copper lid.