Merlin technical information
17 Oct 2008



Merlin Specifications

MERLIN detector bank
Beamline S4/5
Moderator 300 K dedicated water moderator centrally poisoned with Gd
Neutron guides supermirror converging m3 guides
Incident energy 7-2000 meV
Energy Resolution Depends on the choice and speed of Fermi chopper
Δhω/Ei=4-7 % FWHM at the elastic line  
Primary flight path 11.8 m
Secondary flight path 2.5 m
Fermi chopper

10 m from the moderator

50-600 Hz phased to ISIS pulse ±0.1ms

  • Sloppy package is available optimised for high flux and medium resolution
  • Alternatively Gd chopper package enables operation in RRM mode, but places upper limit of 200 meV on incident energy.
Background chopper 8.5 m at 50 Hz
Sample position 11.8 m from the moderator
Beam size at the sample 50x50 mm, motorized jaws can define a smaller beam size
Detectors 2.5 m from the sample position
Position sensitive 3He tubes (10 bar partial pressure) 2.5 cm diameter, 3 m long, resolution 21 mm along the tube
Angular range: -45° to 135° horizontal
                        ±30° vertical direction
Smallest scattering angle 3°
Intensity at the sample(Ei= 45 mev, Δhω/Ei=5%) 6x104 (n ·cm-2·s-1)
Detector Pixels 69632
Solid Angle (Sr) 3.1
Sample environment Accepts all standard sample environment
Instrument tank constrains maximum magnetic field available:
4 T in 7.5 T standard magnet
2 T in wide angle 9 T magnet