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

PANDA

Cold three-axes spectrometer

PANDA scheme PANDA scheme

The cold three-axes spectrometer PANDA spectrometer is located in the experimental hall of the FRMII at the SR2 beam-tube. By neutron guide elements in the beam tube, a short source to monochromator distance and the double-focusing monochromator and analyzer, high flux is achieved and the instrument is further optimized for low background.

In addition to standard cold TAS mode, the achievable energy transfer overlaps with thermal three-axes spectrometers, a high Q-resolution setup as well as a polarized setup is available and an up-to-date sample environment offers high magnetic fields and low temperatures.

The performed experiments typically include the investigation of spin waves and crystal field excitations, phonons, excitations in low-dimensional systems as well as quasi-elastic scattering and diffraction with energy analysis. The obtained results give often decisive input for the research of unconventional superconductivity, strongly correlated electron systems, magnetically frustrated and magnetism in low-dimensional systems, but also for lattice dynamics and material science.

Typical Applications

Magnetic properties

  • Spin-waves
  • Crystal field excitations
  • Excitations in low dimensional systems
  • Magnetic vs nuclear scattering

Lattice dynamics

  • Phonon dispersion
  • Anharmonic effects
  • Polarisations vectors

General

  • Critical scattering at phase transitions
  • Magnon – phonon interaction
  • Soft mode
  • Central peak
  • Diffraction:
    • without analyser: integral E method
    • with analyser: dE close to 0, high E & Q resolution

Sample Environment

The sample table of PANDA allows for a variety of sample environment and may easily be adapted to user specific devices. Among other PANDA disposes routinely operated sample environment for:

Low temperature:

  • Closed cycle cryostat: (3 K < T < 300 K)
  • Variox cryostat: (1.5 K < T < 100 K)
  • Dilution insert: (50 mK < T < 6 K)
  • 3He insert: (450 mK < T < 300 K)

typical dimensions for sample space: Ø 50 mm, h = 70 mm

Vertical magnetic field:

  • Cryomagnet V15T with optional 3He-4He dilution insert
    • Hmax = 13.5 T (50 mK) 1.5 K < T < 100 K
    • max. sample diameter: (12 mm) 19 mm
    • split of coils 20 mm
  • Closed-cycle magnet V7.5T
    • Hmax = 7.5 T
    • Closed-cycle cryostat and high temperature furnace inserts available
  • Shielded cryomagnet V5T
    • Hmax = 5 T
    • 1.5 K < T < 100 K

High temperature:

  • High temperature furnace:
    • 300 K < T < 2100 K
    • sample space: Ø 50 mm, h = 50 mm

Pressure cells:

  • if provided by users, can be adapted for low temperatures within the space limits of the cryostats

Technical Data

Main parameters:

  • distance from source: 7.8 m
  • highest energy resolution: 20 µeV
  • energy transfer range: < 25 meV
  • momentum transfer range: < 6 Å-1
  • flux at sample position (1.5 Å-1): 1.9 × 107 n cm-2 s-1
  • beam at sample position: approx. 1 × 1 cm2
  • Be-, BeO-, PG-filter
  • nonmagnetic shielding
  • inelastic background with sample environment: (2…0.5) cts/minute

Monochromators:

  • PG002 (d = 3.355 Å)
    • 20° < 2ΘM < 132°
    • 1.05 Å-1 < ki < 4.0 Å-1
    • variable horizontal and vertical focussing
  • Heusler (d = 3.35 Å, polarised neutrons)
    • 20° < 2ΘM < 120°
    • 1.1 Å-1 < ki < 4.0 Å-1
    • variable vertical focussing
  • Si (111) (d = 3.135 Å)
    • 20° < 2ΘM < 132°
    • 1.15 Å-1 < ki < 4.0 Å-1
    • variable horizontal and fixed vertical focussing

Analysers:

  • PG002
    • -130° < 2ΘA < 100°
    • 1.05 Å-1 < kf
    • variable horizontal focussing
  • Heusler (polarized neutrons)
    • -130° < 2ΘA < 100°
    • 1.05 Å-1 < kf
    • variable horizontal focussing

Detectors:

Single 3He-tubes

  • 1” (focused mode)
  • 2” (collimated mode)

Instrument Scientist

Dr. Astrid Schneidewind
Phone: +49.(0)89.289.14749
E-Mail:

Dr. Petr Cermak
Phone: +49.(0)89.289.11773
E-Mail:

PANDA
Phone: +49.(0)89.289.14869

Operated by

JCNS

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PANDA
PANDA

MLZ is a cooperation between:

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