Deep images of cluster radio halos

New radio data are presented for the clusters A401, A545, A754, A1914, A2219 and A2390, where the presence of diffuse radio emission was suggested from the images of the NRAO VLA Sky Survey. Sensitive images of these clusters, obtained with the Very Large Array (VLA) at 20 cm confirm the existence of the diffuse sources and allow us to derive their fluxes and intrinsic parameters. The correlation between the halo radio power and cluster X-ray luminosity is derived for a large sample of halo clusters, and is briefly discussed.