Electromagnetic radiation transmitter/reflector device, apparatus and process implementing such a device

An electromagnetic radiation transmitter/reflector device comprising a straight transparent quartz electrode tube with an end-to-end bore for retaining an ionising gas under pressure, extending elongate around an axis and defining a radiation transmitter beam, and a surface for reflecting the transmitted radiation comprising two longitudinal side wings symmetrical in relation to an axial plane of the bore, said reflecting surface being at least partially secured to the transmitter tube and presenting a transverse cross section at least partially strictly or appreciably parabolic or elliptic, wherein a diameter of the bore surface of the tube is smaller than or equal to about 9 mm, and a portion of the reflecting surface corresponding to the side wings and presenting a transverse cross section at least partially parabolic or elliptic belong to a curve whose generating line at the peak is situated at a distance d from the axis of the bore, in the axial plane of symmetry such that:

• d=f and 0<d<r+e+1 mm, where:
• f:
• distance between the focal point of the parabola or ellipse and the corresponding generating line at the peak,
• r:
• distance between the axis and the internal surface of the bore in the axial plane, on the same side as the generating line at the peak, and
• e:
• thickness of the tube in the axial plane, on the same side as the generating line at the peak.