Detached operation close to the density limit is a preferred mode of operation in ITER because it allows the reduction of the power load and the average energy of particles on the divertor targets by radiating a significant part of the power in the divertor volume. It is important to understand the physical processes in the divertor that give rise to the electromagnetic radiation and to the power loss by neutral particles that are produced by charge-exchange (CX) processes. Details of the radiation and neutral-particle loss have been studied in the past by bolometer tomography in the JET MkI [1] and MkIIA divertors [2,3]. This study is now extended to the JET MkIIGB divertor with improved tools: high-resolution bolometer tomography by plasma sweeps and CCD-camera tomography.