We report results of a BeppoSAX observation of the low-mass X-ray binary ( LMXB ) dipping source XB 1916 - 053 .
The source joins the small group of LMXB detected at energies \mathrel { \hbox { \hbox to 0.0 pt { \lower 2.365 pt \hbox { $ \sim$ } } \kern - 3.0 pt \raise 1. % 72 pt \hbox { $ > $ } } } 100 keV .
The non-dip spectrum is well fitted by an absorbed blackbody with a temperature of 1.62 \pm 0.05 keV and an absorbed cut-off power law with a photon index of 1.61 \pm 0.01 and a cut-off energy of 80 \pm 10 keV .
Below 10 keV , where photoelectric absorption is dominant , the dramatic spectral changes observed during dips can be simply modelled by progressive covering of the blackbody and cut-off power law components .
The blackbody component is very rapidly absorbed during dips , consistent with it being point-like , while the cutoff power law is more gradually absorbed , consistent with it being extended .
The most likely locations for the blackbody component are the surface of the neutron star or the boundary layer between the neutron star and the accretion disk .
The extended emission most probably originates in an accretion disk corona .
Above 10 keV , dipping is detected up to \sim 40 keV , and there is some evidence for an energy-independent reduction in intensity of up to 15 % .
This reduction could be caused by electron scattering or obscuration .
In the first case , the change is consistent with an electron column density of \sim 2.9 \times 10 ^ { 23 } { cm ^ { -2 } } , several times smaller than the average hydrogen column measured simultaneously .