ZEBRA: Thermal Single Crystal Diffractometer

The thermal neutron single crystal instrument ZEBRA is a flexible monochromatic diffraction instrument for applications in magnetism and classical crystallography, covering fields such as materials science, multiferroics, highly correlated electron systems. The short (1.18Å) and long (2.32Å) wavelength, the flexible computer controlled inpile-collimation, the two detectors (single tube, 160mm x 160mm area detector with a radial collimator) and the possibility to tilt both detectors individually are key components for covering these needs and opening a wide flexibility going beyond a classical single crystal instrument. Mid 2017, an analyzer unit will be available as an upgrade option for very low background experiments.

Operating in 4-circle mode (5K up 800K, < 20 GPa) or tilting mode (50 mK up to 1200 K, fields horizontal up to 11 Tesla, vertical up to 15 Tesla, pressures up to 100kbar) gives access to the full temperature and pressure range available at PSI. Special sample environment brought-in by the user can also be easily installed.

Complicated modulated structures can be investigated by the possibility to switch from the single detector to the area detector by one turn. Dedicated software allows analyzing complete datasets in a fast way, making them ready in formats commonly used refinement programs. Two dimensional data can be investigated with our own in-house software anatric and trics3d.

Details of the instrument can be found in the description section, in particular the instrumental parameters and the available dedicated sample environment for the 4-circle mode.

ZEBRA is operated by the Laboratory for Neutron Scattering and Imaging, LNS.

Beam Optics

Beam Tube SINQ, thermal beam tube R42, H2O-scatterer
Monochromators Ge311 (λ = 1.177 Å) and PG002 (λ = 2.317 Å), both vertical focusing
Monochromator = 38.8o (fixed)
In-pile Collimation computer controlled (80', 40', 20')
Resolution Δd/d > .005
Flux at Sample max. 1.00x106 n/cm2/sec (spring 2011, 1.5mA on SINQ)
Crystal Size 3-5 mm3
xyz-Adjustment x,y:+/- 15mm, z:+/- 30mm
(smallest crystal investigated: crystal structure NaOs2O6: 0.8mm3, 5.8mg, magnetic structure CuSeOCl: 0.2x1.8x4 mm3, 5mg, 1mB)

Secondary Instrument

- 2D He3-area-detector, 160 mm x 160 mm (oscillating radial collimator)
- 1D single He3-tube (soller collimator: 80', 40', 20') |
max. momentum transfer

- 2D/1D: 6o< 2Θ <130o, λ=1.18Å: max.sinΘ/λ=0.77 Å-1, λ=2.317 Å: max.sinΘ/λ=0.39 Å-1

Operation modes

ZEBRA is operated in two operation modes: 4-circle equatorial geometry (γ = 0o) and tilting geometry(-14.5o< γ <15o)

Equipment for 4-circle-mode
  • cryogenics 15-450 K (APD), 4.5-300K (CCR3)
  • cryogenics (1.7-300 K, JT-CCR)
  • pressure cell (20 kbar, T > 4.5 K)
  • photocrystallography (400-800 nm, 100mW/cm2, T > 50 K)
  • vacuum furnace (300K-800K)
Equipment in tilting mode
  • magnetic field (H 15 Tesla vertical, 11 Tesla horizontal)
  • cryogenics (T > 50 mK (dilution stick))
  • furnaces (<2000K)
  • any other equipment available at PSI


Visualisation of 2D detector data:
trics3d - a software based on the root-software-package of CERN - is now available in addition to cami4psd