Introduction
SINQ has an extensive selection of high-pressure instruments that can be combined with neutron scattering to probe multiple materials. Here we list the available equipment with the relevant properties. The key to successful high-pressure experiments is preparation. Often the outcome of such complicated experiments is determined already before the neutron shutter is open. Therefore below we provide the guidelines for planning your experiments.
Available equipment
The following high-pressure equipment is available for high-pressure experiments. Clicking on the relevant class of equipment will take you to the dedicated page.
Gas-loading pressure cells
(extremely high hydrostaticity, in-situ tuning)
Clamp cells
(Only ex-situ pressure change)
Paris-Edinburgh press
(Highest pressures, in-situ pressure change, but smallest volumes and T down to only 6 K)
Uniaxial Pressure Device
(In-situ tuning, limited angular coverage)
Preparation for a high-pressure experiment
For all experiments:
Up to 2 weeks before the proposal deadline: Discuss the feasibility of the experiment with the high-pressure responsible (G. Simutis) and the corresponding instrument scientists at SINQ. This will enable you to judge the feasibility, to choose the correct cell, and determine the appropriate measurement times. Moreover, it is important to know how the real pressure at measurement temperatures will be determined. Is the equation of state known for the sample? Or does a calibrant need to be added? What is the pressure-transmitting medium that will be used for the experiment? What is the activation of the sample and the pressure cell?
The detailed preparation for the experiment, once the beamtime is granted will depend on whether you will be doing single-crystal or powder experiments.
For single crystal experiments, the following tasks must be completed before the experiment starts:
- How will the crystal be mounted? Is special holder needed? If yes, this should be produced.
- Does the crystal fit into the required dimensions? If needed, it must be cut to the right shape and size.
- What is the scattering plane required for the experiment?
- The sample needs to be aligned on its own (Users can book a diffractometer at PSI for a day or more)
- Further, the sample alignment must be checked once it is inside the cell (for most cases, this should also be done on a separate diffractometer, in exceptional cases – already on the main instrument)
- Pay attention to any dark angles (pillars in the PE press, opening window in the uniaxial press)
- For uniaxial experiments it may be important to polish the sample before the experiment and it has to be glued with enough time left to dry before the experiment starts.
For powder experiments, the following tasks must be completed before the experiment starts:
- The expected (or ideally measured) diffractogram must be simulated (For example with FullProf) to gauge the intensities and the peaks of interest need to be identified.
- If a separate pressure indicator is used (NaCl powder for example), it is important to further simulate the pattern of the sample+indicator. Are the key peaks not overlapping? Is the intensity of the indicator strong enough to determine the pressure? This step will allow you to know which indicator to use and how much of it to put in.
Projects and collaboration
Please get in touch with Gediminas Simutis if you are interested in working with us in terms of student projects (Bachelor or Master works) or internships. We also host Marie-Curie fellows as well as the SNSF Postdoctoral fellowship holders.
We also collaborate with other laboratories to create specialized equipment for dedicated science cases, do not hesitate to contact us.
The old website with pressure cell information can be found on our Wiki:
http://lns00.psi.ch/sinqwiki/Wiki.jsp?page=PressureDevices