SXM-II Sample preparation

Dry solid samples

In the case of dry solid samples, the sample is mounted on a circular flat plate drilled with one or several central holes (A), the plate is then screwed on the ring (B), which is then inserted in the sample stage (C). The sample is preferably mounted on the front side of the plate, but if needed, it can also be mounted on the back side, provided it fits in the 22 mm diameter.

The sample can be glued on the holder or clamped between 2 plates. The sample holder hole can also be covered with thin Ultralene film (SPEX-CERTIPREP) to maintain the sample without glue.

Insertion of the sample holder in the sample stage from rear side

Standard sample holders

The following table describes the available sample holders, the materials available (PEEK, SS: Stainess steel, or Al: Aluminum), number and dimension of their holes and a link to their technical drawings.

Keep in mind that only part of the holder is accesible with the motors and only a partial section of the holder is accesible in transmission.

                         Areas accesible to the stage motors (in red) and accesible for transmission measurments (in blue).       

Large samples can also be  sealed between two ultralene (SPEX-CERTIPREP) films, using a "clip" sample holder.

                                    Sample mounting between ultralene foils and accessible area after mounted.

Block samples

Samples embedded in a block of resin can also be mounted on special sample holders with a large aperture and maintained by lateral screws. The surface of the sample ideally needs to be polished (or at least to be as flat as possible) and to be aligned with the top of the holder, so that it falls in the correct focal plane in the X-ray microscope.

Holders for samples embeded in resin blocks or large samples.

Sample mounting

1. The sample is laid between two ultralene foils interposed between two-discks. Alternatively sulfur-free tape (FLUXANA GmbH) of kapton can be taped in the back of one disk, the sample deposited on it and then covered with the ultralene on the second disk.

2. Place the disks on the peek ring of the sample holder (use rings of either 0.3 mm or 1 mm spacing depending of the material of the disks). 

3. Screw the disks onto the peek ring.

Step by step showing the process of mounting disks onto the sample holders.

For the sample to be on the focal plane, the disk should coincide with the peek ring basis: neither exceed it nor be sunken. Peek rings have different indentations (0.3 or 1 mm) to match the thickness of the different disk materials. Choose the adecuate one!.

                                                          As shown in the picture the focal plane should coincide with thewith the peek ring basis.

Sample preparation for Cryo X-ray microspectroscopy

Fragile or frozen samples may require to be kept at low temperature during data acquisition.  To understand which sample preparation technique to use, we refer to the following image, extracted and modified from the this review.

A short video showing how to prepare plant tissue to be cryo-microtomed at the beamline. A dry-shipper which allows the transport of LN₂ frozen samples is available upon resonable request.

(VIDEO OF SAMPLE PREPARATION FROM HIRAM?)

The use of chemical reagents for dehydration, fixation or embedding steps makes protocols marked with X not recommended for speciation experiments.

The SXM is equipped with a cryo-stage and special sample holders maintaining the sample temperature down to 110K , please contact beamline staff for further details.