Design, construction, and wire calibration of PAR BPM striplines

The Positron Accumulator Ring (PAR) is part of the APS injection system. It received 24 30‐ns FWHM bursts of 450‐meV positrons, and compresses them into 6‐nC, 290‐ps rms bunches. Striplines were selected as beam position monitors (BPMs) to assure that good position sensitivity is achieved. This paper will describe the design, construction, and wire calibration of the 16 PAR BPMs. It will be demonstrated that all relevant stripline parameters can be determined by solving the two‐dimensional LaPlace equation. This was done numerically using the electrostatic part of the PE2D computer program. The construction of the units will be briefly discussed. Wire calibration data on one of the final units will be compared with theory at four frequencies.