Beamline parameters

The ICON beamline consists of evacuated neutron flight-tubes looking through a pinhole on the cold neutron source in the SINQ moderator tank. This implements a pinhole optic forming an almost "parallel" neutron beam, where beam divergence decreases with increasing distance from the pinhole. Due to this divergence a geometric unsharpness in the images results. The unsharpness is in the order of ug = lsample2detector / (L/D) . In a flight-tube neutron flux decreases with increasing distance from the pinhole and is proportional to the pinhole area and the proton current (~1.5 mA) irradiating the SINQ target. ICON can select among 5 different apertures (1, 10, 20, 40, and 80 mm), in the table below only the 20 mm aperture is considered.

Position for experiments 2 3
Distance from the n-aperture L [mm] 6864 12083
Neutron flux / cm2 / sec / mA 1.3 107 3.9 106
Collimation ratio L/D 343 604

These parameters depend on many factors like lens type, camera, scintillator etc. Below only some combinations are provided. If the conditions for your specific need are not listed, please contact the beamline staff.

Position Camera box Field of view [mm] Nominal pixe size [mm] Exposure time [sec]
2 Micro 27.5 x 27.5 0.0135 90
  Midi 150 x 150 0.024 - 0.058 12
3 Maxi 306 x 306 0.15 8