Speaker
Description
In order to check the quality of the BPM blocks that will be installed in the ESRF-EBS we have developed a RF characterization bench, which simply measures the transmission between each of the 4 buttons. Every BPM block is measured at least twice: first when they arrive from the manufacturer, and later after being assembled on a girder, with 2 out of 10 of these BPMs also having undergone NEG coating. Thanks to these measurements we were able to detect some dimensional out-of-tolerance BPM blocks and also (more surprisingly) the presence of metallic dust, films or slivers in some of them. This characterization will also possibly be used in determining a first rough value for the BPM block's electric offset, so to minimize these offset at the time of early commissioning when beam-based alignment techniques are not yet possible.
