Abstract: A powder bed fusion apparatus arranged to irradiate a powder bed using a charged particle beam is provided, the apparatus comprising a neutralising particle source operable to provide neutralising particles of an opposite charge to the charged particle beam, and a neutralising particle focusing system arranged to weakly focus a beam of the neutralising particles from the neutralising particle source on to the powder bed in the vicinity of the irradiation position of the charged particle beam on the powder, such that the neutralising particles neutralise charging of the powder bed by the charged particle beam. A method of additive manufacture using a powder bed fusion apparatus is also provided, wherein a part is formed as a series of layers, each layer being formed by scanning the charged particle beam over a layer of the powder bed to melt the powder according to a predetermined pattern.

Abstract: A personal computer comprising a housing, and placed in the housing a motherboard that is at least provided with one central processor unit, which computer is provided with input and output connections for peripheral equipment such as VDU, keyboard and mouse. A heat sink is provided whose capacity is geared to the heat generation of the central processor unit, wherein the housing is embodied without fan and without an accessory fan drive, wherein the heat sink is an integral part of the housing, and the motherboard is mounted in the housing in such manner that the central processor unit is stably positioned against the heat sink.

Abstract: An ion implanter for implanting ions into a semiconductor wafer comprises means for generating an ion beam, means for receiving charged particles ejected from the ion beam, first means for rejecting those of the received charged particles below a first predetermined energy, second means for rejecting those of the received charged particles above a second predetermined energy, the first predetermined energy being lower than the second predetermined energy. The ion implanter further comprises means to count the number of received charged particles between the first and second predetermined energies, and scanning means for scanning the first and second predetermined energies to determine the energy at which the number of received charged particles between the first and second predetermined energies is a maximum.