Proposal for a doubly focusing cold neutron spectrometer at NIST

I propose to build a cold neutron spectrometer with a doubly focusing monochromator viewing the liquid hydrogen moderator at the NBSR reactor at NIST. First I describe a practical formalism for calculating the monochromatic neutron flux at the sample position for various monochromating systems. Then I show that the large solid angle by which a doubly focusing crystal monochromator could view the cold neutron source at the NBSR would allow the construction of an instrument surpassing any current instrument for neutron spectroscopy with 0.1 < ΔE < 0.5 meV and ΔQ ≈ 0.1 Å−1. I contrast the merits of this instrument to those of other neutron spectrometers at NIST and elsewhere and discuss the scientific opportunities that the instrument would provide.