Spallation Neutrons and Pressure Diffractometer
SNAP | BL-3 | SNS
SNAP operates a mail-in program for room temperature high-pressure measurements using the Paris-Edinburgh (PE) press. This uses a limited subset of the instrument’s capabilities to provide timely access to high-pressure neutron powder diffraction data, up to ~8 GPa at room temperature.
Announcements
Mail-in slots for cycle 2025-A are full. New mail-in proposals will be allocated for cycle 2025-B, starting in August 2025.
Mail-In Program Overview
- Proposals are accepted at any time.
- Several days are reserved from the General User Program each cycle.
- Experiments are measured on a first-come, first-served basis.
- Mail-in proposals will not be accepted if they directly compete with an approved General User Program proposal.
- Samples should be fully prepared before the mail-in proposal is submitted. Evidence of this is advantageous to the proposal.
- Each mail-in proposal is allocated 12 hrs of beamtime, following one of two preset experiment plans (see below).
- One sample is allowed per proposal.
- The measurements are limited to room temperature only, using the Paris-Edinburgh press.
Loading considerations
-
Sample Loading: Beamline staff will load your sample.
-
Sample Volume: A minimum of 50 mm³ is required—typically 0.2 to 0.5 g depending on your sample’s density.
-
Pressure Marker: A foil of polycrystalline Pb will be added to your sample. This contributes to the diffraction signal and is essential for pressure determination.
- Sample Types: Liquid or polycrystalline solid samples can be accommodated. For solids, powdered form is preferred.
-
Pressure Medium for Solids: A liquid pressure-transmitting medium will be added. By default, a methanol:ethanol mixture is used. If your sample reacts with or dissolves in methanol, a fluorinated oil can be used as an alternative.
-
Liquid Samples: For liquid samples, silica glass wool will be added to promote better powder-averaging upon crystallization.
-
Sample Sensitivity: Air- or moisture-sensitive samples cannot currently be accommodated for mail-in submissions.
Measurement plan options
Pressures achievable: Exact pressures cannot be guaranteed. We offer two approximate pressure-loading protocols:
1) ~0.5 GPa steps up to 5 GPa
2) ~1 GPa steps up to 8 GPa
Instrument Configuration: The instrument will be operated in one fixed configuration. You may choose one of the following measurement options:
A) Full run over the 0.4 – 5.1 Å d-spacing range
B) Split run: Half the time on 0.4 – 5.1 Å, half on 2.8 – 10.5 Å
Mail-In Proposal Process
- Prepare Your Samples: Ensure your sample meets the criteria described above, including volume and compatibility with pressure media.
-
Prepare Your Proposal: Use the SNAP Mail-In Proposal Template (1 page maximum, excluding references). In your proposal, specify the pressure medium compatible with your sample, the desired loading route (Option 1 or 2), and the preferred measurement configuration (Option A or B).
-
Submit Your Proposal: Upload your completed proposal through the IPTS system. Be sure to select "Mail-In" as the proposal type. Mail-in proposals are reviewed continuously and independently from the semi-annual proposal cycle.
-
Proposal Review: If your proposal is accepted, you will receive an email with additional instructions.
-
Ship Your Samples: Follow the instructions and use the address listed on the Shipping Guidance page. Samples will be measured in the order they are received.
-
Measurement and Data Access: You will receive an email notification once data collection is complete. Instructions for accessing your data will be included (see below).
-
Sample Disposal or Return: After 30 days, samples will either be discarded or returned to you, depending on the preference indicated in your proposal.
Data access
- Your data will be automatically reduced. You can access this through the Remote Analysis Service (https://neutrons.ornl.gov/users/remote-analysis).
- Your data will be saved in “/SNS/SNAP/IPTS-XXXXX/shared/SNAPRed/export/” for your relevant IPTS number.
- Data formats include XYE and GSAS files.
Facility acknowledgment
This statement must be included in the acknowledgment section of any publications resulting from, or contributed to by, the mail-in program:
This research [or, A portion of this research] used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The beam time was allocated to SNAP on proposal number IPTS-XXXXX.X.
Notes
Mail-in proposals do not carry-over between cycles. The mail-in proposal will expire given any of the following:
- Samples are not received in a timely manner.
- Samples are not in an appropriate format to load into the press.
- The PE press experiences a ‘blow-out’ – no further loading attempts will be made.
- If the PE press is no longer in commission e.g. due to unplanned maintenance.
- Beam production is reduced or cancelled, undermining the delivery of full experiments.
- We reach the upper cap of mail-in beam days for the current cycle.
Users will be notified of cancellation/expiration and are encouraged to resubmit the proposal.
Help
If you are unsure of any of the details specified above, please contact Chris Ridley (ridleycj@ornl.gov) for further information.
CONNECT WITH US
Oak Ridge National Laboratory is managed by UT-Battelle LLC for the US Department of Energy