We present the analysis and interpretation of a sample of eight ASCA observations of Broad Absorption Line Quasi-Stellar Objects ( BALQSOs ) .
This is the first moderate-sized sample of sensitive BALQSO observations above 2 keV , and the BALQSOs in our sample are among the optically brightest known ( B = 14.5–18.5 ) .
Despite the ability of 2–10 keV X-rays to penetrate large column densities , we find BALQSOs to be extremely weak sources above 2 keV , and we are only able to add two new 2–10 keV detections ( 0226–104 and IRAS 07598+6508 ) to those previously reported .
By comparison with non-BALQSOs of similar optical continuum magnitudes , we derive the column densities needed to suppress the expected X-ray fluxes of our BALQSOs .
In several cases we derive column densities { \raise - 2.15 pt \hbox { $ \buildrel > \over { \sim } $ } } 5 \times 10 ^ { 23 } cm ^ { -2 } for a neutral absorber with solar abundances .
These are the largest X-ray column densities yet inferred for BALQSOs , and they exceed ROSAT lower limits by about an order of magnitude .

Optical brightness does not appear to be a good predictor of 2–10 keV brightness for BALQSOs , but our data do suggest that the BALQSOs with high optical continuum polarizations may be the X-ray brighter members of the class .
For example , the highly polarized object PHL 5200 appears to be unusually X-ray bright for a BALQSO given its optical magnitude .

We discuss the implications of our results for future observations with AXAF and XMM .
If the objects in our sample are representative of the BALQSO population , precision X-ray spectroscopy of most BALQSOs will unfortunately prove difficult in the near future .