MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich
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MLZ (eng)

Lichtenbergstr.1
85748 Garching

SAPHiR (under construction)

Six Anvil Press for High pressure Radiography and diffraction

The instrument provides extreme pressure and temperature environments for time-of-flight neutron diffraction and neutron radiography of polycrystalline and liquid samples. The instrument shares a thermal neutron beamline (wavelength range 1-2.4 Å) with the upstream instrument POWTEX. The centrepiece is a six-ram multianvil press that is placed on a positioning and rotation table for sample adjustment, and surrounded by detectors for neutron diffraction and radiography. The six independently adjustable rams provide a combined pressing force of up to 23.5 MN (2400 tons) that is transferred via a set of smaller second stage anvils to a cubic sample assembly. A ca. 20 mm3 sample capsule can be subjected to P and T conditions of up to 15 GPa (150 kbar) and > 2000°C with the aim of increasing the pressure to >20 GPa. Aided by an anvil positioning and advancing system with a precision in the sub-micron range, samples can be deformed at strain rates varying from ca. 10-3 to 10-7 s-1 for in situ stress and strain measurements. An elliptical neutron guide with a variable supermirror coating of m = 1.5-4 will guide and focus the neutron beam between POWTEX and the press due to the sample cross-section of 3×3 mm. For radiography part of the guide can be exchanged by an absorbing end-piece; combined with different pinhole widths L/D ratios larger than 500 are attainable at reasonable neutron fluxes so that a resolution better than 100 μm can be achieved.

Typical Applications

Radiographic applications:

  • Critical behaviour and miscibility of fluid-silicate melt and melt-melt systems
  • Melt/fluid distribution in crystalline silicate systems.
  • Falling sphere viscosimetry
  • Sintering kinetics

TOF neutron diffraction:

  • Crystal structure and stability of water bearing high pressure phases
  • Phase diagrams and transformation kinetics of light materials
  • Sintering kinetics
  • Equations of state at extreme conditions
  • Structure of silicate melts
  • Cathion ordering
  • Magnetic ordering
  • Rheological flow laws of high-pressure materials
  • Elastic properties of materials at high pressure and temperature

Sample Environment
  • 10/7 cubic multianvil setup: 10-12 mm diameter cubic sample assemblies with dewatered pyrophyllite pressure medium compressed by 7 mm truncation Ni-bound tungsten carbide anvils
  • Internal platinum or rhenium foil furnace (up to > 2000°C)
  • Cylindrical Pt or Re sample capsules for solid (polycrystalline) or liquid/molten samples with a typical diameter and height of 2-4 mm (ca. 20 mm3 sample volume)
  • Sample adjustment: ±10 cm in x-y-z direction and ±15° rotation of the press relative to the beam on a positioning table.
  • 1.5-3 mm wide anvil gaps for entering and escaping neutrons at low and high 2 Θ angles and at 90°.
Technical Data

Neutron beam and guide

  • SR5 (NL-Halle Ost) thermal neutrons downstream from POWTEX.
  • TOF Neutron wavelength range: 1-2.4 Å.
  • Elliptical neutron guide, length 10 m, supermirror coating m = 1.5 – 4
  • Entering and exit width ca. 7 mm

Chopper

Puls chopper frequency (POWTEX):200 s-1
Press chopper frequency:100 s-1
Chopper disc diameter:750 mm
Pulse width:10 μs

Collimation and flux (numerical modelling with VITESS)

  • TOF diffraction (100 s-1 chopper frequency): ~107 n s-1cm-1 on a 3×3 mm sample.
  • Radiography (continuous beam): ~5×108 n s-1cm-2 (L/D = 250), ~4×107 n s-1cm-2 (L/D = 500)

TOF Detectors (current planning)

  • 3He 8 mm tubes at 2 Θ ~90° and ~10-35°
  • Scintillator banks at large 2 Θ angles 135-170°
  • Angular range of detector banks (2 Θ): ~10-35°, ~85-95°, and ~135-170°, Q ≈ <1-10 Å-1

Instrument Scientists

Prof. Dr. Hans Keppler (project leader)
Phone: +49 (0)921 5537-44
E-Mail:

Dr. Nicolas Walte (instrument scientist)
Phone: +49 (0)921 5537-19
E-Mail:

Operated by

BGI

Publications

Find the latest publications regarding SAPHiR in our publication database iMPULSE:

impulse.mlz-garching.de

Gallery

SAPHiR
SAPHiR

Multianvil press SAPHiR

SAPHiR
SAPHiR

Multianvil press SAPHiR in detail

MLZ is a cooperation between:

Technische Universität München> Technische Universität MünchenHelmholtz-Zentrum Geesthacht> Helmholtz-Zentrum GeesthachtForschungszentrum Jülich> Forschungszentrum Jülich