I15-1 Experimental Timings
Standard Exposure Times
Perkin Elmer 2 (PE2 - Current Detector In Use)
Minimum exposure time: 3 seconds
Standard exposure time: 10 minutes (+2 minutes for robot change/auto filter etc.)
Considerations and extra functionality:
Both can have multiple frames (back-to-back, uninterrupted scans) to allow for quick collections over a physical/chemical process or additional time for weakly scattering samples.
Presleep times (times between collections) are recommended between scans to allow for the detector to cool down and clear the image. Otherwise you may experience ‘ghost’ features from previous samples, especially if they were strongly scattering.
ARC Detector
We are currently commissioning this detector and will be able to update expected exposure times once we have determined the best operating procedure.
Set-up Times
All experiments, from simple ex-situ experiments to complicated in-situ setups. Timings to setup these experiments should be included in your experimental plan. Below shows the timings of many things that we have to do on the beamline to make sure the beamline is as optimally setup for your experiment as it can be!
Essentials (60 minutes)
Detector calibration: 10 minutes
Safety inductions: 30 minutes
Induction on how to operate the beamline: 10-60 minutes
Loading samples onto the beamline: 15 minutes
All of the above is needed for every experiment, meaning that no experiment will start exactly 9am on the starting day. Even if nothing goes wrong, don’t expect to be running your samples before 10:30am, but realistically expect around lunch time.
Temperature Device
Characteristics
Device | Max temperature* / K | Min temperature* / K | Max ramp rate / K/min | Min ramp rate / K/min |
|---|---|---|---|---|
Blower (hot temperature) | 800 | 350 | 300 | 1 |
Cobra (cold temperature) | 450 | 80 | 60 | 0.016 |
Cryostream (cold temperature) | 400 | 100 | 60 | 0.016 |
* - these are the calibrated sample temperatures we can achieve in optimum conditions, they vary on capillary size, air flow, hutch temperature etc.
Ramp rates are applicable in the temperature 200 - 600K ranges for all devices, expect them to slow as they approach the temperature extremes
To do a large temperature range i.e., 100 - 800K we will use both the cold and hot temperature devices to achieve this
Calibrations
All temperature devices require a calibration to ensure your sample is at the temperature that you require. Depending on the range that you require, this can take anywhere from an hour to several hours.
We calibrate by either using lead (low temperature) or a Si/Al2O3 mix (high temperature) and measuring it for 2 minutes at determined temperature points. The temperature device will have an offset between the device temperature and sample temperature (can be up to 200K at the extreme temperatures) and therefore the calibration range will have to be beyond the desired sample temperature. We then run Rietveld refinements to obtain the lattice parameters and determine exact temperatures and apply this on the beamline. From this point forward, temperatures input into the scan will be the temperature your sample will be at.
Hot air blower calibration time (full range): 60 minutes
Cobra/cryostream calibration time (full range): 120 minutes