Beamline overview
X-ray diffraction (XRD) is a versatile, non-destructive technique that reveals detailed information about the chemical composition and crystallographic structure of different materials. There are two main variants of x-ray diffraction technique viz. angle dispersive x-ray diffraction (ADXRD) and energy dispersive x-ray diffraction (EDXRD) technique. Both the techniques have their own merits and demerits. EDXRD technique has an advantage when sample is in constrained geometry and diffraction data is required to be collected in large Q range. Since the data is displayed online, this technique can be gainfully employed for kinetics studies as well. An EDXRD beam line has been designed, fabricated and installed at bending magnet port BL-11.
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| EDXRD beamline at Indus-2 |
Experimental Station
The front end for EDXRD beamline delivers a 1 mrad white beam. This beam is transported to the experimental station through various components viz. beam stopper, primary slit, evacuation chamber and precision slit. Primary slit and precision slit cut down the size of synchrotron radiation (SR) to 100µmX100µm at the sample. A custom made 8-axis sample stage goniometer from Huber is installed for sample mounting. This goniometer has maneuverability of XYZ translation, rotation and tilt. The data acquisition system comprises of a high resolution HPGe detector mounted on a detector arm attached to the 2θ stage of the goniometer. The detector is preceded by a cleaning slit and a point slit. Diffraction angle is defined by cleaning slit and point slit within the precision of ~0.001º. Cleaning slit also helps in reducing the background arising from the Compton scattered x-rays. All the vital components of beamline are motorized and can be remotely controlled through indigenously developed TCP/IP based server-client control softwares. This beam line has been specially optimized for carrying out high pressure experiments in diamond anvil cell (DAC).
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EDXRD beamline experimental station |
Parameters
| SR source: |
Bending Magnet 1.5T |
| Energy range: |
10-70 KeV @ 2.5 GeV, 300 mA |
| Angular range for diffraction: |
± 25 ° |
| Q Range: |
1.3 to 9.2 Å-1( for 2θ =15° ) |
| Detector resolution: |
145 eV at 5.9 KeV; 475 eV at 122 KeV |
| Geometrical resolution: |
2% |
| Spot size at sample: |
~ 100x100 µm (which can be increased up to 5x5 mm) |
| Total Flux at sample: |
1011 photons/s (for 300 mA @ 2.5 GeV and 100x100 µm spot size) |
Facilities
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Experiments that can be carried out at BL-11 (EDXRD) beam line:
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High pressure powder and single crystal x-ray diffraction experiments can be carried out using the diamond anvil cells (DAC). These cells are based on modified designs of the Mao-Bell, Merrill Basset and Edinburgh diamond anvil cells.
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High temperature studies can be carried upto 450° C using Aluminum capillary holder, Nichrome (NiCr) heating wire and PID based temperature controller. We are in the process of installing another high temperature setup which would raise the sample temperature up to ~1200° C.
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Preliminary sample characterization can be done using x-ray fluorescence and diffraction.
Utilization
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Study of phase transitions under high pressure
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Equation of state of high Z materials
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Temperature stability of high Z materials
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Kinetics studies of materials with varying thermodynamic parameter viz. pressure or temperature
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Characterization of samples at ambient conditions using x-ray fluorescence
Recent studies
Elemental Diffraction
Resolution of diffraction peaks at this beamline is limited by the energy resolution of HPGe detector
EDXRD patterns have been recorded from several elemental metals i.e. Au, Ag, Al, W, Mo etc. for benchmarking.
| Peak details |
ΔE/E |
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| Au Lα1 (9.713 keV) |
0.021 |
Au Lβ1 (11.442 keV)
Au Lβ2 (11.584 keV) |
0.026 |
| Au (111) |
0.014 |
| Au (200) |
0.013 |
| Au (220) |
0.012 |
| Au (311) |
0.011 |
High temperature experiments
Powder x-ray diffraction patterns of BaTiO3 at different temperatures |
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High pressure experiments
Stacked powder EDXRD patterns of Dy2O3 at different pressures |
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Contacts
Dr Surinder M. Sharma
Email: smsharma (at) barc.gov.in
(Head, High Pressure & Synchrotron Physics Division, BARC)
Address: Purnima Labs. Bhabha Atomic Research Centre Trombay
Mumbai-400085
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MCD/PES (BL-1)
GIXS(BL-13) (To be commissioned soon)