News from B180: DC-DC Stavelet with HV MUX

1. News from B180:DC-DC Stavelet with HV MUX Carlos Garcia Argos Giulio Villani Matt Warren Todd Huffman Peter Phillips One hybrid shows ~20ENC extra noise, others much the same. Not yet understood - investigations continue

2. News from B180:DC-DC Stavelet with HV MUX Carlos Garcia Argos Giulio Villani Matt Warren Todd Huffman Peter Phillips A little more variation – nothing too significant

3. News from RAL:New SP Stavelet • EoS mounted • BCC terminations removed / changed to 56R • Several flavours of “PPB” in hand • CofH PPB (with components) • CofM PPB (no components) • CofM STAR PPB replacement (filtering but no shunts) • Stavelet now aligned under module placement system • Alignment took a long time, see over • Bottom line: • Ready and waiting for modules

4. Lacking kaptons that are ‘correctly placed’ or of the correct size, there is simply no way to accurately position modules onto the stave(let). • Need to build to gaps between the shield pads • Assembly optics designed to pick up small fiducials with high accuracy • Not good with “long” straight edges, especially if they’re not actually straight • On the current stavelet kapton the edges of the etched aluminium are not suitable for alignment purposes • Gold plated copper layer has good detail, but that’s the wrong layer • Future stave(let)s need one or more fiducials to be added. A survey can then be made once with more appropriate optics (eg large area smartscope) and thereafter the build may proceed wrt the fiducials. • Unless it’s possible to add fiducials on the Aluminium layer? Gold Plated Copper Edge Aluminium Edge

5. Preparations for the (DC-DC) Stave:Build options • Plan to use new assembly system • Four module placement bridges 90% complete • Expect to be ready in a few weeks. • Need engineering drawing of stave including all PCBs • Need mechanical stave(let) for trials • Request >~5cm pipe external to stave • Shall investigate temporary pipe extension to more robust pressure connector • Shall stavelet have continuity test before it arrives here?

6. Preparations for the (DC-DC) Stave:Service options Low Voltage • We have one TTi TSX1820P PSU. We could buy two more and power each segment separately • We have one EA PSU rated at 100A. We could use this via some kind of current monitor / fuse panel akin to the way Geneva power the supermodule. High Voltage • We could use 12 channels of SCTHV, one per module • We could use (say) 3 channels of SCTHV, each one fed to four modules (= one DC-DC segment) though a multiplexer. • Both options would require a simple PCB or equivalent to be made, but for the 12 channel case we also need more cables. DCS • Do we need additional T monitoring? • The stave must run cold, and may do so before all modules have been fitted • Propose to add “one wire” T sensors at a few locations along the power tape • Humidity Monitoring • Matt is working on firmware to read SHT71 sensors through HSIO.

7. Preparations for the (DC-DC) Stave:Service options Environmental Enclosure • Plastic covers with o-ring seals built into assembly frame? CO2 Cooling • Blow off cooling system exists at RAL • will need to be relocated • Outdoor “Gas Hut” on order • to be fitted next month • Further investigation & adaptation may be needed • Scales to weigh bottles, readable from inside? • Humidity and pressure Interlocks? • Plan to have internal meeting within the next few weeks

8. Tandem DC-DC • Latest provisional layout from Georges and Isaac • Bond pads aligned to power bus • Star point is now on the PCB Area in which one wire T sensors could be mounted