Results are reported for analysis of the extensive Rosat observation of the dipping low mass X-ray binary XB 1916-053 .
Dipping is 100 % deep showing that the emission regions are completely covered by the absorber .
A good fit to the non-dip spectrum is obtained using a model consisting of a blackbody with { kT _ { BB } } = 1.95 { { } ^ { +0.74 } _ { -0.34 } } keV and a power law with photon index 2.32 \pm 0.04 .
These components are identified with emission from the neutron star , and Comptonized emission from an extended accretion disk corona ( ADC ) .
Dip spectra are well-fitted by rapid absorption of the blackbody , and progressive covering of the extended component , as the absorber moves across the source , with a covering fraction that increases smoothly from zero to \sim 1.0 .
Progressive covering shows that the Comptonized emission region is extended , consistent with it originating in the accretion disk corona .
The strong unabsorbed component in the dip spectra is well-modelled as the uncovered part of the Comptonized emission at all stages of dipping .
There is no detectable change in the low energy cut-off of the spectrum in dipping which supports the identification of the unabsorbed part of the spectrum with the uncovered part of the ADC emission .
The absorbed part of the ADC emission is rapidly removed from the 0.1–2.0 keV band of the PSPC , which therefore selects only the uncovered part of the emission , and so the spectral evolution in dipping as viewed by the PSPC depends only on the covering fraction , determined by the geometric overlap between the source and absorber .