High Pressure

HP 400 kN press

HP 400 kN press

Specifications

• compressive force: 450 kN
• repulsive force: 220 kN
• dynamic pressure up to 10 Hz possible

Cryostat CC-11-P to be used with HP 400 kN press

Specifications

• Temperature range: 20 K – 600 K
• Cool-down time RT – 20 K: 4 h
• Diameter of sample space: max. 16 mm
• Total height of sample space: 10 mm
• Pressure range: 200 MPa for Ø 16 mm anvil

Cut through CC-11-P

A special challenge is to go to low temperatures at high pressures. The newly constructed high-pressure cryostat allows one to apply and vary the force in situ, even at low temperature. The sample cell is operated externally by the hydraulic HP 400 kN press. It can be mounted in a dewar and cooled down to below 10 K within four hours. With a piston-in-cylinder cell and a piston diameter of 16 mm a maximum pressure of 2.0 GPa (20 kbar) can be achieved at a sample size up to 30 mm length and 16 mm diameter. Reducing the piston diameter and the sample volume the pressure can be increased up to 100 kbar. Using anvil cells the pressure range extends to 30 GPa (300 kbar) and above. In addition, a dynamic pressure can be superimposed on the static pressure with a frequency of up to 10 Hz.

To load gas pressure cells the MLZ provides a gas compression unit for inert gas pressure up to 10 kbar. The unit can be operated either manually or remote controlled. The remote controlled operation allows for individually programmable pressure time profiles. The measurement system includes a high-precision manometer and a pressure transmitter that cover the range up to 10 kbar.

Specifications

Pressure range 10⁵ Pa ≤ p ≤ 10⁹ Pa

• 10⁵ Pa ≤ p ≤ 7 · 10⁸ Pa Heise high-precision
  manometer; resolution 0.1 % ME
• 7 · 10⁸ Pa ≤ p ≤ 10⁹ Pa transmitter; resolution 9 · 10⁶ Pa

Clamp cells for neutron scattering at pressures up to 1.2 Gpa - Dimensions Clamp cells for neutron scattering at pressures up to 1.2 Gpa - Dimensions © FRM II / TUM

Clamp cells for neutron scattering at pressures up to 1.2 Gpa - Dimensions © FRM II / TUM

The cells are loaded in a hydraulic press and then clamped by locking nuts. They allow to study samples as single crystals, powders, or liquids. The body of the cells is made of the CuBe alloy. The pressure transmitting medium could be fluorinert or deuterated alcohols. The sample capsules are made of the AlMg5 alloy, teflon, or lead. The pressure inside the cells is determined using the internal NaCl standard (Cell M1) and/or ruby luminescence through the diamond optical window in one of the locking nuts (Cell M2). The cells fit into various cryostats at MLZ.

The cells could be operated in the panoramic or transmission modes. In the first case, the incident and scattered beams pass through a gasket that is usually soft CuBe. In the latter one, both beams pass through diamonds. The transmission cells could be used for combined high-pressure neutron and X-ray diffraction studies. All the cells are made of the CuBe or NiCrAl alloys. The pressure transmitting media are deuterated alcohols. The highest pressure depends on the sample volume that is not larger than 0.1 mm3. For this reason, only studies on very strongly scattering samples with high symmetry are feasible. The panoramic cells fit into the cryostats on the beamlines HEiDi and POLI. They are also compatible with the magnets at POLI. Currently, the transmission cells are operated at room temperature.