Sample preparation for non-capillary setups
Furnace Samples
Higher temperatures can be achieved using either the Anton Paar HTK2000 furnace or Stoe capillary furnace.
The beamline is unable to supply Pt and W strips for User experiments. Users intending to use the Anton Paar furnace for their experiments can obtain their own strips in two ways: 1. Purchasing directly from Anton Paar. These strips are supplied with thermocouples attached. 2. Locally by XRF Scientific. If you wish to use a cavity, then you will need to make separate arrangements as XRF Scientific do not machine the cavity. The cavity in the Pt strip is 0.2 mm deep and is approximately 20 mm (L) x 8 mm (W) located in the centre of the strip. S-type (0.35 mm diameter) thermocouple wire will need to be purchased separately. Staff at the beamline are able to attach the thermocouples to your strips. The beamline does not supply thermocouple wire. Hints on the preparation of samples for furnace experiments are provided by Anton Paar and are available here. Additional information regarding the reactivity of samples with platinum is available here; this information should be read carefully, well in advance of the proposed experiment.
The Stoe capillary furnace is capable of heating quartz capillaries from room temperature to 1370 K. The samples are heated using graphite furnace inserts specifically sized for different capillary diameters: 0.3-1 mm. Normal thin-walled capillaries (10 μm) can be used and the capillaries are rotated to improve powder averaging during data collection. To ensure that the sample is in the beam, the capillary must be filled to a depth of 2 cm from the sealed end. There is no need to break off the funnel or shorten the capillary as the full length is required to ensure the capillary is properly housed in the furnace.
High-throughput samples
As with capillary mounted samples, sample preparation for mounting on the high-throughput stage should be done in advance of arriving at the synchrotron, unless exceptional circumstances apply. Samples should be prepared according to the following notes:
Machine multi-well sample cassette; instructions for the plate's manufacture are available here. Cassettes may be 0.5, 0.8, or 1.2 mm thick, however, thicker samples must be used with caution due to the absorption issues that may arise.
Adhere kapton or mylar to one side of cassette, taking care to avoid impinging on a 5 mm border around the edge of the cassette. Polymer film (Kapton or Mylar) should not exceed 25 micron thickness. It is difficult to obtain commercial films thinner than 25 microns with adhesive backing. Thinner films are available (without adhesive) and can be fixed to the cassette using a thin coating of spray adhesive. Films that are 6-12 microns thick have demonstrated both robustness and acceptable levels X-ray absorption.
Place samples in wells. This can be achieved using a very small funnel or a disposable plastic pipette tip. Take care not to press the powders into the wells using spatulas or other flat instruments as unwanted crystallite orientation may result. Powders will need to be finely ground so that the particle size is no more than 10 microns in diameter. Particle statistics are improved during data collection via rocking of the omega axis, however particle size should be as small as possible to maximise the data quality. Eppendorf pipette tips are suitable for loading samples into wells.
Adhere Kapton or Mylar to the other side of the sample cassette, taking care to avoid impinging on a 5 mm border around the edge of the cassette. Minimise cross contamination of sample wells by sealing single or groups of completed wells as you go.
Cryostat samples
Samples are mounted in the cryostat within the sample holder, which can hold up to three samples at once. The samples will be in flat transmission geometry and sealed in each position with Kapton film. Sample changeover requires venting the sample chamber, dismantling the cryostat and then reassembling and pumping down the system after the samples are changed. It is expected that this will take approximately 90 minutes so time should be set aside for this procedure in your experimental plan.