A slow neutron chopper time-of-flight spectrometer at the reactor R2 in Sweden

Abstract

A slow neutron time-of-flight spectrometer for studies in the solid and liquid state physics has been constructed at the light water moderated reactor R2. The thermal spectrum emerging from the used channel has been measured and found to be a Maxwellian. The spectrometer has a semi-monochromatizing chopper working in conjunction with a beryllium filter. The transmitted neutron spectrum has a half value width of ≈0.3Å at 4 Å. The time resolution corresponds to 12μsec/meter or 1.2% at 4 Å. A full description of the equipment with the collimator plug and the shielding house of the chopper will be given. A comparison is made with the time-of-flight spectrometer at R1.