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Introduction
The Dispersive Extended X-ray Absorption Fine Structure (DEXAFS) beamline has been set up by Applied Spectroscopy Division, BARC at the Indus-2 synchrotron radiation source.
The DEXAFS Beamline (BL08) at Indus-2 is dedicated to X-ray absorption spectroscopy in the transmission mode, using dispersive optics. In this beamline a bent crystal (Si 111) polychromator is used to select a band of energy from the white synchrotron beam which is horizontally dispersed and focused on the sample. The crystal is bent in the shape of an ellipse in such a way that source & sample positions are at two focii of the ellipse. The transmitted beam intensity from the sample is recorded on a position sensitive CCD detector, thus enabling recording of the whole EXAFS spectrum around an absorption edge in a single shot (typical acquisition time of one spectrum is ~300 msec). A mirror is used prior to the polychromator for vertical focusing and higher harmonics rejection.
Optical layout |
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Beamline specifications
Source |
Bending magnet (2.5 GeV Indus-2 Source) |
Energy Range |
5-20keV |
Acceptance |
1.5 mrad horizontal x 0.2 mrad vertical
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Pre-Mirror |
Rh coated meridional cylindrical mirror with fixed radius of curvature of 1319m, Horizontally mounted for vertical focusing and higher harmonic rejection |
Monochromator |
Elliptically bent Si(111) Polychromator
Vertically mounted on a mechanical bender
Mean Radius variable between 2 m to 20 m |
Post mirror |
NA |
Observed Spot size @sample position |
250microns(H) x 500microns(V) at 20keV |
Observed Resolution |
5 x 103 @ 20 keV |
7.5 x 103 @13 keV |
8.5 x 103 @ 11 keV |
Photon flux |
1012 photons/sec/1000eV bandwidth |
Typical acquisition time for one EXAFS spectrum |
300 msec |
Sample Environment |
Mount available for various forms of samples viz., powder, pellets, liquids etc.
High temperature (450º C) reaction cell to study in-situ kinetics for pellet samples |
Experimental station
The experimental station consists of a θ-2θ goniometer with a telescopic 2θ arm on which sample and detector stages are mounted. The polychromator is mounted on the θ axis. Both θ and 2 θ motions are independently controlled through a PC. The telescopic arm moves on a granite slab with pneumatic air pads. Sample and detector stages are provided with remote controlled X-Y-Z and tilt mechanisms. Sample stage has facility to mount 12 samples (maximum sample dia: 25mm) at a time; any sample can be brought into the beam path for transmission measurement remotely. Generally samples in pellet or powder form can easily be mounted on the sample holder. Liquid samples confined in a proper cell with x-ray transmission window can also be mounted. A high temperature (upto 750K) cell, which can accommodate sample up to 12mm dia, is available for temperature dependent EXAFS studies. A low temperature sample environment will also be inducted soon in the beamline.
Features
| Angular resolution of goniometer |
18arcsec |
| 2 θ range |
-5 to 45 degree |
| Sample and detector manipulations |
X, Y (±15mm), Z (-10 to 35mm), tilts(±50) |
| Sample environment |
Air/vacuum |
| Sample temperature range |
300 to 750 K |
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Publication
- A comparative study of the spectra recorded at RRCAT synchrotron BL-8 dispersive EXAFS beamline with other beamlines
Abhijeet Gaur, B. D. Shrivastava, S. N. Jha, D. Bhattacharyya, &A. Poswal
Pramana, (2012) In Press.
- One-pot thioetherification of aryl halides with thiourea and benzyl bromide in water catalyzed by Cu-grafted furfural imine-functionalized mesoporous SBA-15w
John Mondal, Arindam Modak, Arghya Dutta, Sohini Basu, Shambhu Nath Jha, Dibyendu Bhattacharyy and Asim Bhaumik
Chem. Commun., 2012, 48, 8000-8002.
- Chemical shifts of K-X-ray absorption edges on copper in different compounds by X-ray absorption spectroscopy (XAS) with Synchrotron radiation
D. Joseph, S. Basu, S.N. Jha, D. Bhattacharyya
Nuclear Instruments and Methods in Physics Research B 274, 126-128(2012).
- Eu3+ assisted structural collapse of GaOOH nanorods: Probed through EXAFS and vibrational techniques
S. Basu, B.S. Naidu, M. Pandey, V. Sudarsan, S.N. Jha, D. Bhattacharyya, R.K. Vatsa, R.J. Kshirsagar
Chem. Phys. Lett. 528 (2012)21.
- X-ray Absorption Spectroscopy of doped ZrO2 systems
S. Basua, Salil Varma, A.N. Shirsatb, B.N. Wani, S. R. Bharadwaj, A. Chakrabarti, S.N. Jha and D. Bhattacharyya
Journal of Applied Physics, 111 (2012) 053532.
- EXAFS measurements on PbMoO4 crystals prepared under different conditions
A.K. Poswal, D. Bhattacharyya, S.N. Jha, Sangeeta and S.C. Sabharwal
Bull. Mater. Sci., 35 (2012) 103.
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On the method of calibration of the energy dispersive EXAFS beamline at Indus-2 and fitting theoretical model to the EXAFS spectrum
Abhijeet Gaur, Ajita Johari, B. D. Shrivastava, D. C. GAUR, S. N. Jha, D. Bhattacharyya, A. Poswal and S. K. Deb
Sadhana, 36, 339-348(2011).
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EXAFS study of binuclear hydroxo-bridged copper(II) complexes
Abhijeet Gaur, B. D. Shrivastava, D. C. Gaur, J. Prasad, K. Srivastava, S. N. Jha, D. Bhattacharyya, A. Poswal and S. K. Deb
Journal of Coordination Chemistry, Vol. 64, 1265-1275(2011).
- X-ray absorption spectroscopy of PbMoO4 single crystals
D. Bhattacharyya, A.K. Poswal, S.N. Jha, Sangeeta and S.C. Sabharwal
Bull. Mater. Sci., 32, 1-5( 2009).
- First Results From a Dispersive EXAFS beamline developed at INDUS-2 Synchrotron Source at RRCAT, Indore, India
D.Bhattacharyya, A.K.Poswal, S.N.Jha, Sangeeta and S.C.Sabharwal
Nuclear Instruments and Methods in Physics Research A, 609, 286-293(2009).
- Focussing properties of Energy Dispersive EXAFS Beamline at INDUS-2 SRS using Aditional Optical Elements
N.C. Das, D. Lahiri and D.Bhattacharyya
Journal of Optics, 36 (2007) 8.
- Optimisation of cooling configuration of different components of the EXAFS beamline at INDUS-II Synchrotron source
D.Bhattacharyya, S.N. Jha, N.C. Das, Vishnu Verma, S.G. Markandeya and A.K. Ghosh, Sadhana
30 (2005) 735
- Design, Fabrication and Testing of Elliptical Crystal Bender for the EXAFS Beam Line at INDUS-II Synchrotron Source
N.C.Das, S.N.Jha, D.Bhattacharyya, A.K. Poswal, A.K.Sinha and V.K.Mishra, Sadhana
29 (2004) 545.
- Design of the Extended X-ray Absorption Fine-Structure (EXAFS) Beam Line at INDUS-II Synchrotron source
N.C. Das, S.N. Jha, and D.Bhattacharyya
AIP Conference Proceedings of Eighth International conference on Synchrotron Radiation Instrumentation (SRI-2003), Aug 24-Aug 29, 2003, San Francisco, USA, Vol.705, 179-186, 2003.
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Contact Number : 244 2508/ 244 2104
Contacts |
| Dr. D. Bhattacharyya |
dibyendu(at)barc.gov.in
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| Dr. Biplab Ghosh |
biplab(at)rrcat.gov.in
phone 244 2509/ 244 2175
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| Sh. A.K. Poswal |
anshu(at)barc.gov.in
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