Abstract: A process and apparatus for producing polycrystalline silicon ingots. A crucible is arranged in a process chamber and filled with solid silicon material. At least one diagonal heater is located laterally offset to and generally above the silicon ingot to be produced. The silicon material is heated to form molten silicon in the crucible, and thereafter cooled down below the solidification temperature of the molten silicon. A temperature profile in the silicon material during the cooling phase is controlled at least partially via the at least one diagonal heater. The apparatus includes a process chamber, a crucible holder, and at least one diagonal heater. The diagonal heater is located laterally with respect to the crucible holder and generally above a polycrystalline silicon ingot to be formed in the crucible. The diagonal heater is stationary with respect to the crucible holder when the process chamber is closed.

Abstract: A crucible is filled with silicon material and is arranged in a process chamber. The silicon material in the crucible is melted and is subsequently cooled below the solidification temperature. During a time period, a plate element that has at least one passage may be arranged over the molten silicon in the crucible, and a gas flow may be directed onto the surface of the molten silicon at least partially via the at least one passage. Alternatively a crucible arrangement includes a crucible and a holding ring arranged on or above a crucible filled with silicon material. Additional silicon material may be received and held above the crucible by the holding ring. During the heating of the silicon material in the crucible and the holding ring, molten silicon is formed in a crucible, which is subsequently cooled below the solidification temperature of the silicon.

Abstract: An optical system for shaping an incoming beam having a divergence with an angular distribution at least in a first direction comprises at least one angle selective optical element for clipping the angular distribution in the at least first direction. The approach according to the present invention bases on using an angle-selective device operated by the principle of total internal reflection to reduce divergence of the incoming beam, in contrast to a spatially-selective device as for example a field-stop or slit. The method according to the present invention has the advantage that no physical sharp edges have to be exposed at high energy densities. Thus, thermal impact and demands on the optical elements to withstand a high power laser beam are significantly reduced.

Abstract: An optical system for shaping an incoming beam having a divergence with an angular distribution at least in a first direction comprises at least one angle selective optical element (26,28) for clipping the angular distribution in the at least first direction. The approach according to the present invention bases on using an angle-selective device (25,32) operated by the principle of total internal reflection to reduce divergence of the incoming beam, in contrast to a spatially-selective device as for example a field-stop or slit. The method according to the present invention has the advantage that no physical sharp edges have to be exposed at high energy densities. Thus, thermal impact and demands on the optical elements to withstand a high power laser beam are significantly reduced.

Abstract: An optical system for shaping an incoming beam having a divergence with an angular distribution at least in a first direction comprises at least one angle selective optical element for clipping the angular distribution in the at least first direction. The approach according to the present invention bases on using an angle-selective device operated by the principle of total internal reflection to reduce divergence of the incoming beam, in contrast to a spatially-selective device as for example a field-stop or slit. The method according to the present invention has the advantage that no physical sharp edges have to be exposed at high energy densities. Thus, thermal impact and demands on the optical elements to withstand a high power laser beam are significantly reduced.