Cosmic Hot Interstellar Plasma Spectrometer external stop delay board: An alternative to bulky and massive coax for long (>100 ns) time delays

The Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) utilizes a typical microchannel plate detector with a cross delay line event readout anode. A CHIPS delay line was predicted to approach a time delay of 80 ns. Therefore an added time delay of 100 ns was required for the stop channels. Implementation of such a delay using conventional coax cable was deemed too bulky and massive. After exploring other alternatives, which failed to meet specific requirements, a stripline delay printed circuit board was developed. This approach eventually proved to be a superior alternative to coax cable for the CHIPS detector. This article outlines and details the development of the CHIPS external stop delay board from basic microwave circuit theory to design and testing. Discussion of the mathematical and computer models used for design are contained in the Appendices.