The D0 inter-cryostat detector, massless gaps and missing E{sub T} resolution

The inter-cryostat detector and massless gaps are located in the intermediate rapidity regions between the central and end calorimeters of the D0 detector and are designed to improve energy measurements in those regions. Results are presented from test beam and collider data showing the improvement of single particle and jet energy resolutions with the inclusion of the inter-cryostat detector and massless gaps. The calorimeter missing E[sub T] resolution in collider data is presented.