The Lux is the SI unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square metre. Lux meter is generally using for measure the intensity of solar and UV light.

The problem has been probably solved, but a good suggestion was Delta Ohm instruments, which work pretty well and may be coupled to different sensors of variable wavelength (UV-A, UV-B,...). Portable equipments with PAR and UV-A sensors can be in the order of a few hundreds of $ (depending on the model). You can probably find many more suppliers.

thank you Espana