Frank
Laboratory
of Neutron Physics

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DN-6

Responsible for the facility:

Lukin Evgenii
tel. +7(49621) 6-20-47
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Main research areas:

1.Crystal structure of materials in a wide range of pressures.
2.Reconfiguration of the magnetic structure of materials at a high pressure.
3. Research of the crystal and magnetic structure of compounds with a small volume using neutron diffraction in a wide temperature range.
4. Phase analysis of microsamples.

Facility layout

Main view of facility

Sample environment

Description of DN-6

Neutron diffraction is a powerful technique that provides information about both the crystal structure and the magnetic properties of matter. Research at high pressures is the only direct method for controlled changes in physical properties due to variations in interatomic distances and valance angles. Such research provides a unique opportunity to study the structural aspect of the formation of the physical properties of compounds, including magnetic ones.

The staff of the Frank Laboratory of Neutron Physics of JINR (Dubna, Russia) has more than twenty years of experience in developing high-pressure neutron scattering methods. In recent years, a new high-luminosity diffractometer DN-6 has been developed, combining a higher incident neutron flux and a wide aperture of the detector system. The DN-6 diffractometer includes a neutron beam chopper in phase with the reactor pulse, a curved neutron guide based on supermirrors with a parabolic focusing section to ensure a high neutron flux on the sample and a detector system with a large solid angle that allows to carry out neutron diffraction experiments with extremely small volumes (about 0.01 mm3) of samples under research. High pressure chambers with sapphire and diamond anvils are used on a specialized neutron diffractometer DN-6 to study microsamples. The available pressure range extends up to 50 hPa.

Diffractometer experiments are carried out in axial geometry, when an incident collimated neutron beam passes through a sapphire single crystal anvil and scatters on the sample. Scattered neutrons are registered separately using each of the detector ring counters. To obtain low temperatures, a closed cycle helium refrigerator is used. The high pressure chamber is loaded into a cryostat that allows to carry out further research on the structures and magnetic phase diagrams of a wide range of objects at various temperatures and pressures.

Main characteristics

Neutron flux on the sample

(gold foil activation method)

~3.5 × 107 n/cm2/c

Typical TOF distance

30.5 m

Attained dhkl

Scattering angle 2q = 90°:

Scattering angle 2q = 42°:

 

0.5–5.7 Å

1.8–11.2 Å

Resolution Dd/d (for d = 2 Å)

at 2q= 90°:

at 2q = 42°:

 

0.025

0.030

 

Typical exposure time:

Sample under normal conditions, V~50 mm3

Sample in high pressure chamber

with sapphire anvils, V~1 mm3

 

Sample in high pressure chamber

with diamond anvils, V~0.01 mm3

 

0.1 h

2–4 h

 

20–40 h

Pressures achieved in the experiment

High pressure chamber

with sapphire anvils

 

High pressure chamber

with diamond anvils

 

12 hPa

 

50 hPa

Temperature range

Cryostat based on a helium refrigerator

 

5–320 K

Sample environment:

  1. Cryostat based on a closed cycle helium refrigerator. Temperature range 4-320 K.
  2. High pressure cells based on sapphire and diamond anvil technology.

References:

  1. Kozlenko D.P., Kichanov S.E., Lukin E.V., Savenko B.N. "The DN-6 Neutron Diffractometer for High-Pressure Research at Half a Megabar Scale", Crystals, 8(8), 331 (2018). doi: 10.3390/cryst8080331
  2. P. Kozlenko, S.E. Kichanov, E.V. Lukin, B.N. Savenko “High-Pressure Neutron Diffraction Study of the Crystal and Magnetic Structure of Materials at the Pulsed Reactor IBR-2: Current Opportunities and Prospects” Crystallography Reports, 66, 2, 303-313 (2021)
  3. P. Kozlenko, O.N. Lis, S.E. Kichanov, E.V. Lukin, N.M. Belozerova, B.N. Savenko “Spin-induced negative thermal expansion and spin–phonon coupling in van der Waals material CrBr3”, npj Quantum Materials, 6, 1, 1-5 (2021)
  4. O. Golosova, D.P. Kozlenko, E.V. Lukin, S.E. Kichanov, B.N. Savenko, ‘High pressure effects on the crystal and magnetic structure of 160Gd metal’, Journal of Magnetism and Magnetic Materials, 540, 168485 (2021)
  5. Kozlenko D.P., Dubrovinsky L.S., Kichanov S.E., Lukin E. V., Cerantola V., Chumakov A. I., SavenkoB. N. Magnetic and electronic properties of magnetite across the high pressure anomaly, Scientific reports. V. 9. P. 1. (2019) 
  6. P. Kozlenko, V. Yu. Yushankhai, R. Hayn, M. Richter, N.O. Golosova, S.E. Kichanov, E.V. Lukin, B.N. Savenko “Pressure-induced structural transition and antiferromagnetism in elemental terbium”, Physical Review Materials, 5, 3, 034402 (2021)