High pressure and shock wave research in BARC was initiated in late 1960s.
Over a period of few decades, the division has set up several experimental facilities and has extensive theoretical skills for in depth investigations of materials under high pressures.
Divisional Mandate:
• Study of variations in physical properties of materials when subjected to extreme conditions of pressure, temperature etc.
• Determination of reliable equation of state of materials.
• Development of beamlines at Indus synchrotron radiation sources for facilitating in-situ studies of materials under extreme conditions.
In situ studies under severe plastic deformation at high pressures, employing shear diamond anvil cells, have recently gained much
\r\ninterest in the high-pressure community owing to their potential applications in material processing methods, mechanochemistry, and geophysics. These studies, combined with multi-scale computational simulations, provide important insights into the transient hierarchical microstructural evolution, structural phase transitions, and orientation relationship between parent and daughter phases and help establish the kinetics of strain-induced phase transitions under severe plastic deformation. The existing SDACs are mostly used in axial x-ray diffraction geometry due to geometrical constraints providing less reliable information about stress states and texture. Their asymmetric design also poses serious limitations to high-pressure shear studies on single crystals. To overcome these limitations, a new compact symmetric
\r\nshear diamond anvil cell has been designed and developed for in situ high-pressure torsion studies on materials. The symmetric
\r\nangular opening and short working distance in this new design help obtain a more reliable crystallographic orientation distribution function and lattice strain states up to a large Q range.
The cluster "MARS" at HP&SRPD is made up of 10 BOSTON X86 Servers with dual processor 14- core Intel Xeon processors, 132 GB RAM and 8 TB SATA disks inter-connected through a high speed infiniband network. The file server has a storage space of 48 TB, with 8 disks arranged in a raid 2 array. This provides data security in case of disk failure. Benchmarking using LINPACK tool with Open MPI parallelization and Intel math kernel libraries gave average performance rating of 10 TFlops.
Laser shock laboratory at HP&SPRD is equipped with 30 J / 300 ps and 2J / 8ns laser, along with with several high resolution ultra-fast diagnostics for time resolved investigations under dynamic compression. These include-1) x-ray pinhole camera with 15 µm and 25 µm resolution, 2) X-ray transmission grating spectrometer with a spectral resolution of 3.18 Å, 3) X-ray crystal spectrometer using TAP crystal with 25 mÅ resolution, 4) X-ray semiconductor diode arrays for x-ray spectral regions covering a range from 100 eV to 16 keV, 5) Fast response (150 ps rise time) seven channel x-ray vacuum photodiode array with a large x-ray spectral detection range, 6) Ion collector and Langmuir probe arrays to measure angular distribution of ion emission, 7)Time of flight Ion collectors (Faraday Cup) to resolve fast ion components from laser produce plasma, 8) Electrostatic Ion Energy Analyzer (IEA) for evaluation of energy spectrum and the abundance of charge states, 9) High resolution Thomson parabola for ion charge states and energy distribution in each charge states measurement, 10) Optical streak camera technique to study Laser induced multi-megabar shock pressure, 10) Multiframe optical shadowgraph to study the foil free surface (particle) velocity and foil acceleration 11) X-ray streak camera with resolution of 10 ps and single frame camera, 12) x-ray backlighter for the imaging of shocked materials and absorption spectroscopy of the laser heated materials, 13) interferometry system for the free surface velocity measurement, 14) Time resolved Raman spectroscopy set up for the studies of materials at molecular level facility etc.
The Laser Heated Diamond Anvil Cel (LHDAC) facility at HP&SRPD is capable of simultaneous generation of pressure and temperature up to ~ 100 GPa and 6000 K respectively. The salient feature of the LHDAC facility is an angular geometry with an off-axis incidence of the near infrared (NIR) laser beam on the sample enabling independent control over the size of the hot spot at the sample position, minimizing the radial temperature gradient.
Material synthesis facilities at HP&SRPD include arc melter, tubular furnace, box furnace, inert environment furnace and toroid press. The Arc Melter is water cooled copper hearth arc melter and can be used to melt sample (~10-20 gms) with sample temperature nearly 3500°C. The tubular furnaces with tube diameter 1.5 inches and 3 inches which can be operated up to 1000°C and 1400°C respectively. The toroid press can be used for high pressure-high temperature sample synthesis with pressure up to around 6 GPa and temperature up to 900°C.
The ECXRD beamline with HP&SRPD is a dedicated X-ray diffraction beamline for structural investigations under extreme conditions at BL-11 port of Indus-2 synchtorton. The beamline utilizes tunability of synchrotron radiation from 10 - 30 keV X-rays and has capabilities of both angle dispersive and energy dispersive x-ray diffraction measurements. The beamline is being routinely used by several national users for a variety of investigations.
The rotating anode X-ray generator based XRD facility at HP&SRPD is equipped with MAR345 imaging plate detector for recording 2D-XRD images. General specifications of the facility are as follows:
18 KW rotating anode X-ray generator (RAG) (Rigaku Rotaflex RU-300) with
Mo target operating at 50 KV and 60 mA (power 3 KW), rotating speed of 6000 rpm.
X-ray beam size: ~0.1 mm x 0.1 mm
Monochromator: graphite (002)
X-ray wavelength: Mo Kα (0.7107 Å)
Detector: Image plate area detector- Marresearch (Mar345)
2θ Range: ±40°
2D diffraction image resolution:
There are two selectable pixel sizes viz., 150x150 μm or 100x100 μm.
At HP&SRPD, electrical properties of materials under pressure are measured using four probe techniques.
The Bridgman anvil set up uses a pyrophillyte gasket of ~200 μm thickness and talc as pressure transmitting medium for pressures upto 10 GPa. The sample size in this apparatus is 2x1x0.1 mm^3.
For measurements at higher pressures a clamp type diamond anvil is used where the electrical leads of 20 μm diameter are manually placed on the surface of one of the diamond with diameter 400 μm. The sample size in this is 100x50x10 μm. Metallic gaskets carefully insulated with alumina powder is used for sample containing. Measurements upto 30 GPa are routinely done using this techniques.
A 7 Tesla SQUID Magnetometer facility at HP&SRPD is used for high pressure based DC and AC magnetization and magneto-resistance measurements. The facility is used to explore exotic physical properties (electronic and magnetic) in novel transition metal compounds under high pressure. Salient features of of the facility are as follows:
Low Temperature Resistance measurements under high pressure (using Optical Cryostat)
T range 1.4 – 300K, P ~ up to 30 GPa
Study of Magnetic properties under high pressure (using 7T SQUID magnetometer)
T range 2 – 300K, P ~ up to 10 GPa, Magnetic Field B ~ up to 7 Tesla
T range (0.3 – 700 K) with B up to 7 Tesla at ambient pressure
The high pressure - low temperature magneto-transport measurement facility at HP&SRPD is equipped with reservoir type optical cryostat with vacuum control mechanism and can be used for DAC based resistance measurements up to ~45 GPa, in the T range 1.4- 300K. Magneto-resistance measurements are performed in a field of 0.5 Tesla.
The optical absorption spectroscopy facility at HP&SRPD is used for in-situ high pressure investigations in DAC. The weak signals from inside the DAC are detected using Standford Research SR530 lock-in-amplifier. The setup is equipped with monochromatized UV enhanced Xe arc lamp. The absorption spectra are recorded using a photo-multiplier tube detector.
The confocal micro-Raman system at HP&SRPD is configured around a single stage ANDOR (model no SR-500i-C-R) spectrograph of focal length 500 mm where excitation Laser beam is focused by 10X/20X infinity corrected Mitutoyo objective. The confocal arrangement facilitates depth sensitive Raman scattering measurements. The facility is equipped with motorized sample stages and viewing arrangements for alignment in submicron precision.
The resonance Raman spectroscopy facility at HP&SRPD is configured around a Jobin Yvon T64000 triple-stage spectrograph which can be operated in additive or subtractive modes providing high resolution Raman spectra very close to Relaigh line. With several excitation lasers viz. Argon ion laser (multiple wavelengths), 532 nm DPSS and 633 He-Ne, the facility can be used for resonance Raman spectroscopy. General specifications of this facility are as follows:
Microscope Objectives: 10x, 20x, 50x, 100x
Spectral Range: 200 nm to 800 nm
Resolution: < 0.15 cm-1 (In additive mode)
~ 2 cm-1 (In subtractive mode)
Detector: Peltier cooled CCD
The Brillouin scattering spectroscopy facility at HP&SRPD is a unique facility configured around tandem 3+3 pass Fabry-Perot Interferometer to estimate elastic constants and photo-elastic coefficients of materials by measuring sound velocities (acoustic phonons) along the crystallographic axes. This facility can be used for high-pressure as well as low-temperature in-situ measurements. Probing of low energy excitation (E<1 meV) is possible using this setup with an instrumental resolution better than 10^(-3) meV. For low temperature measurements, a 9K Oxford Cryo-systems closed cycle refrigerator has been installed with this setup.
The Fourier tranform Raman spectrometer (FT-Raman) at HP&SRPD is MultiRAM Stand Alone FT-Raman Spectrometer from M/s Bruker. It is equipped with 1064nm Nd:YAG IR excitation laser and LN2 cooled Ge (Range: 65 – 3800 cm^(-1)) detector. This facility provides high resolution accurate Raman spectra and can be used for samples with high laser-induced fluorescence.
The infrared (IR) beamline with HP&SRPD has been installed at the 10 degree port of dipole chamber-4 of Indus-1 synchrotron radiation source at RRCAT, Indore. The acceptance angle at Indus-1 allows utilization of mid-IR (600 – 6000 cm-1) part of SR light. With the focused spot size of nearly 300 microns at sample, the facility can be used for in-situ high pressure as well as low/high temperature (4.2K to 500K) IR absorption spectroscopy.
The high resolution FTIR spectroscopy facility at HP&SRPD is configured around Bruker FTS125 HR FTIR system with maximum resolution of 0.0012 cm-1 and covers spectral range from 10 to 40000 cm^(-1). Various gas absorption cells and auxiliary facilities for emission/ absorption studies have been developed around the instrument.
IR spectroscopy beamline (BL-06) at Indus-1 Synchrotron
200 TW laser facility
Brillouin scattering facility for in situ high-pressure elastic constant studies
Extreme conditions X-ray diffraction beamline (BL-11) at Indus-2 Synchrotron
Indigenously developed diamond anvil cells by HP&SRPD
Pressure range of interest for high-pressure studies
