Tag Archives: sapphire PEARL diffractometer neutron fast-neutrons gammas

Sapphire filter

Last week Stettler (CH) has delivered the Sapphire filter that will be installed in front of the diffractometer to reduce the flux of fast and epi-thermal neutrons and the gamma flux. Our colleagues  from PSI have done some testing on the reduction factor for fast neutrons and here at the RID we now have measured the transmission of the filter for the (wanted) thermal neutrons: ~84% for 1.67AA neutrons.

A tilt of a few degrees of the crystals in the beam makes no difference in the transmission.

transmission of Sapphire filter

transmission of Sapphire filter for thermal neutrons as measured at the RID beam line.