Material deposition was measured in the private flux region of JET by means of a Quartz MicroBalance (QMB) for ~11900 seconds of successive plasma discharges with moderate additional heating (2-3MW). The QMB was located under the Load Bearing Septum Replacement Plate with a view towards the inner divertor. In total a ~270nm thick hydrogenated amorphous carbon layer was measured assuming a density of 1g/cm3 correlated with a fluence of 2.36¥1023 D+ ions into a toroidal section of 1cm length of the inner divertor. The area of the QMB in the private-flux region was deposition dominated when the inner strike point position was on the vertical tiles, line-of-sight with the quartz crystal, and turned into erosion solely by moving the strike point from vertical tile 3 to horizontal tile 4. The most likely reason is a change of the C/D flux ratio of the particles impinging on QMB turning this area from a deposition to an erosion dominated region. Preprint of Paper to be submitted for publication in Proceedings of the 18th Plasma Surface Interactions in Controlled Fusion Devices Toledo, Spain ( 26th May 2008 - 30th May 2008)