Congratulations! You have just been awarded time on XPDF at Diamond.

This page is designed to highlight some important steps that can be performed at your home institution before you arrive for your beamtime. It also contains tips to help your beamtime run as smoothly and be as productive as possible.

Admin

As soon as you receive a successful result from the panel, the User Office will be in touch. You will be encouraged to complete several sections of an online form on the UAS, including safety forms, lab forms, accommodation reservations, and further details regarding experimental team. Please return these forms by the deadlines given by the User Office.

There are limited spaces within the on-site user accommodation (Ridgeway House). There are additional venues available (commonly the Premier Inn in Didcot), though these are not as convenient. To have the best chance of being allocated accommodation in Ridgeway House it is advised that you complete the investigators section on the UAS ASAP. If you need to come for a pre-visit then please schedule this with your local contact, contact the user office to confirm and update the UAS where necessary.

Please include all samples that you wish to run on the ERA (even if they are compositionally similar) as only samples that have been approved by the health and safety team can be mounted onto the beamline. If additional samples come to light after the ERA has been submitted then please discuss these with your local contact as they will need to be assessed by the health and safety team separately. If the experiment that you wish to perform has changed from that outlined in the proposal then this should be discussed with your local contact ASAP.

Please confirm with your local contact the number of ex situ / in situ samples that you intend to analyse and an indication of priority. This will help the beamline staff to plan any sample environment changeovers accordingly.

When completing the lab form make sure you highlight any lab equipment that you will require, such as a fume hood, glove box, powder handling unit, ultrasonic bath or compressed gas. This form will be sent to the lab facilities team, who will book you into the closest lab that is available and meets your requirements. You should also include adequately described procedures for the sample preparations you intend to carry out in these labs. Please also include any additional chemicals/equipment that you require such as conc. HCl or gas mixtures.

Whilst we do have access to some basic chemicals, these are intended more for unanticipated scenarios. Users are encouraged to bring their own chemicals wherever possible. It is also good practice to inform you local contact of any requirement so that they can ensure that you are booked into an appropriate lab in advance of your arrival. We currently do not have gas mixing capabilities on the beamline and so any special gas mixes must be ordered at least 8 weeks in advance. It is essential that you local contact is informed even if only common gases are required (e.g. CO₂) so that stocks can be maintained and delivery can be arranged from the EHCs.

Posting Samples and Equipment

When sending goods to Diamond please include the name of your local contact and arrange delivery to the following address;

Diamond Light Source Ltd
DLS Goods Handling, Zone 8
Synchrotron Stores
Harwell Science and Innovation Campus
Didcot
Oxfordshire
OX11 0DE

Inform your local contact of any packages that you are sending and provide them with information such as tracking numbers and estimated delivery dates.

Know Your Samples

It is important to characterise the samples for a PDF experiment as comprahensively as possible before the beamtime. The three key properties that are required are;

Sample composition - Quantitative analysis should be performed to identify the most accurate composition possible for the samples. This is the full composition for the sample, including any water, binder or support materials that may be present, not just the composition of the material of interest.
Density - The density of the sample should be known in either g cm^-3 or atoms Å^-3.
Packing fraction - This is a value between 0-1 and is often estimated to be ca. 0.6.

The sample composition, density and packing fraction are essential parameters that should be known as accurately as possible in order to perform the data reduction step and generate the PDFs.

There are additional factors that should be considered regarding the samples, such as;

Are there any peaks at low Q? This may require the beamstop to be moved further from the sample. If you have a peak at Q ≤ 1 Å-1 then your local contact should be made aware before the experiment and given a friendly reminder at the start of your beamtime. Q is defined as;

Have you simulated the pdf and the scattering data for comparison?
Do you have .cif files that you can bring with you?
Which of your samples are likely to be the most strongly scattering? This can be effected by the concentration of highly scattering elements, the crystallinity of the sample and the presence of large crystallites in your powder.
Is your sample a "good" powder? Are there likely to be larger crystallites that need further grinding to give a good powder average?
Have you packed as many capillaries as you can at your home institution? We will post empty capillaries to you where necessary. Please refer to the "Know Your Setup" section and discuss with your local contact.

All samples should be labelled with the visit number and a suitable description of the material (i.e. the full composition including any support materials/binders)

Know Your Setup

The vast majority of experiemnts on XPDF are run in glass capilaries that are supplied by the beamline. We offer both borosilicate and fused quartz capillaries in a range of sizes, outlined here. It is important that you do not pack your samples into different capillaries without discussing this with your local contact. Consistency is very important here in order for an accurate background subtraction to be made. Borosilicate capillaries are adequate for experiments where the sample will be at a temperatue < 500°C, otherwise for higher temperature experiments fused quartz capillaries should be used.

If you are using one of the sample environments provied by the beamline then you should discuss the setup with your local contact. This may include;

Temperature profiles - i.e. ramp rates, dwell times etc.
Data collection strategy - continuous collection during ramps or only collecting during hold.
Maximum/minimum temperature capabilities for the cell.

If you are providing your own cell then this needs to be discussed in detail with the local contact in order to fabricate mounting brackets and discuss sample geometry etc. In some cases a pre-visit may be required during a shutdown to check that the cell can be mounted. Alternatively the cell can be shipped in advance of the beamtime to check this.

If you are bringing your own cell this should be brought to the attention of the local contact and discussed in detail. This should be done well in advance of the beamtime to address any issues that may become evident.

It's time for you to return to your home institution with high quality PDF data in hand.

The following section is designed to walk you through the beamline checkout process.

When one experiment ends it is very likely that there will be another group waiting and ready to do some more science on XPDF. To help with the changover process there are some important points that we would like to highlight in advance of your beamtime. Most of these are outlined in the "Beamline Policy" section. Before you depart please check that;

All of your samples are packed to be taken off site with you when you leave.
All of your equipment and chemicals are boxed up ready for collection by courier at a later date.
You have disposed of any gloves, bench protectors and waste through the appropriate route.
All equipment is clean and returned to the appropriate storage location, including pestle and mortars, spatulas etc.

Preparing For Beamtime