Large area plasma-enhanced chemical vapor deposition of thin films such as silicon nitride or amorphous silicon is widely used for thin film transistor fabrication in the flat panel display industry. A numerical three-dimensional model to calculate the deposition uniformity over the whole electrode surface for rf rectangular showerhead reactors powered at 13.56MHz is presented. The simulation tool is a commercially available finite-volume software (CDF-ACE®) which solves the multispecies, multireaction chemistry in capacitively coupled rf plasma. In order to simplify the three-dimensional geometry, the injected gas flow distribution across the showerhead is calculated separately and introduced as volumetric source terms for the gas flow and species continuity equations. The model is applied to the particular case of silicon nitride deposition and the results are compared with uniformity profiles obtained in an industrial plasma enhanced chemical vapor deposition reactor. Perturbations due to reactor edges together with nonuniform distribution of voltage due to standing wave effect are investigated as possible sources of the inhomogeneity of the thin film.

The Paul Scherrer Institut operates two meson graphite targets, Target M and Target E, for creating the world's most intense pion and muon beams by using 590 MeV protons and c.w. beam currents of up to 2.4 mA (=1.4 MW). The energy deposit on Target E is 20 kW mA -1 . The proton beam feeds also the spallation neutron source SINQ, which operates in DC mode and produces thermal and cold neutrons. The SINQ target consists of a bundle of lead filled Zircaloy tubes. In this report the continuous developments of both target facilities and their operation are presented.

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Two target stations in the 590 MeV proton beamline of the High Intensity Proton Accelerator (HIPA) at the Paul Scherrer Institut (PSI) produce pions and muons for seven secondary beamlines, leading to several experimental stations. The two target stations are 18 m apart. Target M is a graphite target with an effective thickness of 5 mm, Target E is a graphite wheel with a thickness of 40 mm or 60 mm. Due to the spreading of the beam in the thick target, a high power collimator system is needed to shape the beam for further transport. The beam is then transported to either the SINQ target, a neutron spallation source, or stopped in the beam dump, where about 450 kW beam power is dissipated. Targets, collimators and beam dumps are described.

The high intensity proton accelerator (HIPA) at the Paul Scherrer Institut (PSI) delivers a 590 MeV c.w. proton beam with currents of up to 2.4 mA, i.e. 1.4 MW beam power, which is at the forefront of current particle accelerators. Besides two spallation targets for thermal/cold neutrons (SINQ) and for ultracold neutrons UCN, the beam feeds two meson production targets Target M and Target E used for producing intense pion and muon beams for particle physics and materials science research. The targets consist of graphite wheels of effective thicknesses of 5 mm (Target M) and 40 mm or 60 mm (Target E). One of the target design challenges is to dissipate the power in the targets without damage (20 kW/mA for the 40 mm target). Therefore, the targets are rotating at 1 Hz, which requires a set of bearings surviving sufficiently long in such a harsh radiation environment. Another challenge is the handling of highly activated (several Sv/h) and contaminated materials, when such a target has to be exchanged. This is done with so-called exchange flasks, which are shielded with up to 40 cm steel. Required are well equipped infrastructures such as the hot cell like ATEC facility at PSI, as well as parking slots for the substitute target-inserts. The talk will focus on the two Meson target stations at PSI as well as on the necessary systems and infrastructure.