From narrow to wide band normalization for orbit and trajectory measurements

The beam orbit measurement (BOM) of the LEP collider makes use of a narrow band normalizer (NBN) based on a phase processing system. This design has been working fully satisfactory in LEP for almost 10 years. Development work for the LHC, requiring beam acquisitions every 25 ns, has led to a new idea of a so-called "Wide Band Normaliser" (WBN) which exploits most of the P.U.'s differentiated pulse spectrum. In the WBN the beam position information is converted into a time difference between the zero crossing of two recombined and shaped electrode signals. A prototype based on the existing NBN unit has been developed and tested to prove the feasibility of this new idea. For this the B.P. filters and the 90° hybrids are replaced by L.P. filters and delay lines.