Unified Data Sheet

P02.1 - Powder Diffraction and Total Scattering

Beamline P02.1 offers two operating modes: powder X-ray diffraction and total scattering (for PDF studies). In both modes a wide range of sample environments are available for investigating structural changes on application of external stimuli. Additional support laboratories are also available at the beamline for users to prepare their samples.

The following tables compares the key features of these two modes: the first provides common beam parameters, whilst the second details beamline hardware available for all experiments. The further tables below contain technical specifications of the beamline.

 

Common beamline parameters

Photon Energy / keV

~ 60

Photon Wavelength / Å

~ 0.207

Beam size at sample (FWHM, Horiz. × Vert.) / mm

0.5 × 1.1

Photon flux at sample / ph s-1

4 × 1010
 
Standard beamline hardware

Diffractometer

3 circle (2 × θ; 1 × ω) (all 3 axes fitted with encoders)

Diffractometer Sample Stage

Diffractometer Huber: x (20 mm), y (20 mm), z (40 mm) (all 3 axes fitted with encoders)
- Capillary spinner stage
- Sample mass up to 5 kg

Alternative Sample Stages

Table z: (200 mm vertical travel)

Small Huber: x (20 mm), y (20 mm), z (16 mm)

Large Huber: x (25 mm), y (25 mm), z (20 mm)
- Sample mass up to 50 kg

Detector

Standard detectors:

Varex XRD 4343CT (150×150 µm2 pixel size, 2880 x 2880 pixel area)
(CsI scintillator directly deposited on amorphous Si photodiodes)

Pool detectors:

Perkin Elmer XRD1621 CN3 - EHS (200×200 µm2 pixel size, 2048 x 2048 pixel area)
(CsI scintillator directly deposited on amorphous Si photodiodes)

Dectris Pilatus3 X CdTe 2M (172x172 µm² pixel size, 1475 x 1679 pixel area)
(device shared between several beamlines; contact beamline staff for details)

Detector Stage

x (2700 mm; consists of stages)
y (400 mm)
z (400 mm)

Automatic Sample Exchange Robot

300 capillary samples
- N.B. robot is currently only available for capillaries measured under ambient conditions. Please contact beamline staff for details.

Beamline Operating Modes

The table below compares three different experiments in terms of the 2θ and Q ranges/resolutions that are achieveable. The selected Sample to Detector Distances (SDDs) are typical values for Powder Diffraction and Total Scattering modes, and these determine the differences between the two set-ups. For Powder Diffraction geometry, two examples are given (one collecting full diffraction rings, the latter collecting only half rings). These can be used as guides for discussion with beamline staff.

 

Data collection ranges for the Perkin Elmer XRD1621 at two typical SDDs

Powder Diffraction (Full Rings)

Powder Diffraction (Half Rings)

Total Scattering (PDF)

Sample to Detector Distance (SDD) / mm

2000

2000

200

2θ min. / °

0.430

0.430

0.43

2θ max. (Full rings) / °

8.240 (5.846)

11.574

55.37 (45.68)

2θ resolution / °

0.005

0.005

0.06

QMin / Å-1

0.228

0.228

0.23

QMax / Å-1

3.102

6.133

23.61

Q resolution / Å-1

0.003

0.003

0.03

Powder Diffraction (Full Rings) and Total Scattering (PDF) assume the beam centre is at the centre of the detector. Powder Diffraction (Half Rings) assumes the beam centre is on one side of the detector, half way up. For comparison with a standard laboratory intrument fitted with a Cu Kα1 tube, the QMax for Powder Diffraction (Full Rings) equates to a 2θ max. of 44.703°, whilst that of Powder Diffraction (Half Rings) equates to a 2θ max. 94.505°.

The beam centre can be positioned anywhere on the detector to achieve the desired 2θ max./QMax and resolution.

Source

P02.1 uses the P02 U23 undulator as the source of synchrotron radiation. The undulator is shared with P02.2 and full technical specifcations of the device are available in Barthelmess et al. [1].

 

Insertion device specifications [1].

Insertion Device

U23 undulator

Insertion Device Length / m

2

Period Length / mm

23

Max. Power Output / kW

1.7

Source size (Horiz. × Vert.) / mm

140 × 5.6

Divergence (Horiz. × Vert.) / µrad

7.9 × 4.1

Source brilliance 

1019 ph / s / 0.1% bw / mA

Polarisation

Linear, horizontal

Beamline Optics

To allow simultaneous operation of the P02.1 and P02.2 endstations, P02.1 is equipped with an in-house developed double Laue crystal C(111)/Si(111) monochromator. This offsets the main and side station beams by approximately 1.7 m. Details of the optic are given in Dippel et al. and in the table below [2].

In the experiment hutch, beam shaping is achieved using two slit systems (a beam defining aperture and a guard slit) and two pinholes. A selection of absorbers is available to beamline users to reduce the beam intensity (if needed).

 

Monochromator specifications [2].

Photon Energy / eV

60 000

Energy Bandwidth / eV

16

Energy Bandwidth (δE/E)

2.5×10-4

Divergence (Horiz. × Vert.) / µrad

8 × 9

References

[1]   M. Barthelmess, U. Englisch, J. Pflüger, A. Schöps, J. Skupin and M. Tischer, in Proceedings of the 11th European Particle Accelerator Conference, Genoa, Italy, 2008, pp. 2320–2322.

[2]   A.-C. Dippel, H.-P. Liermann, J. T. Delitz, P. Walter, H. Schulte-Schrepping, O. H. Seeck and H. Franz, J. Synchrotron Radiat., 2015, 22, 675–687.

 

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