  For the ITER-like wall, the JET mirror link divertor spectroscopy system was
redesigned to fully cover the tungsten horizontal strike plate with faster time
resolution and improved near-UV performance. Since the ITER-like wall project
involves a change in JET from a carbon dominated machine to a beryllium and
tungsten dominated machine with residual carbon, the aim of the system is to
provide the recycling flux, equivalent, to the impinging deuterium ion flux,
the impurity fluxes (C, Be, O) and tungsten sputtering fluxes and hence give
information on the tungsten divertor source. In order to do this
self-consistently, the system also needs to provide plasma characterization
through the deuterium Balmer spectra measurements of electron density and
temperature during high density. L-Mode results at the density limit from Stark
broadening/line ratio analysis will be presented and compared to Langmuir probe
profiles and 2D-tomography of low-n Balmer emission [1]. Comparison with other
diagnostics will be vital for modelling attempts with the EDGE2D-EIRENE code[2]
as the best possible data sets need to be provided to study detachment
behaviour.
