HV bus issues and ideas: Mind the gap From Vic Guarino's - PowerPoint PPT Presentation

HV bus issues and ideas: Mind the gap From Vic Guarino's presentation at ProtoDUNE SP CPA and Field Cage meeting Wednesday https://indico.fnal.gov/conferenceDisplay.py?confId=11862 ● Design Challenges: – Thermal contraction results in .9mm gap between CPAs – Offset loading from FC results in significant rotation of frame ● Looking at connecting two CPA’s together at top and bottom bars of frame so that they act as one. – Balanced loading – Requires top supports to beam to be able to slide .9mm for thermal contraction. ● Need flexible connection to beam to accommodate roof distortion. [Roof distortion is 3 mm.] 1

Mind the gap ● Need flexible HV bus connection that can accommodate 3 mm roof motion, changes in gap width, survives dynamic changes during FC swing out. ● Also want to avoid exposing connection points to field in gap ● Known problem, various ideas. 2

F r o m B o ' s 7 - M a r - 2 0 1 6 t a l k : H V B u s I n t e g r a t e d i n t o a C P A M o d u l e This concept needs to be modifjed to allow for a few mm of vertjcal relatjve movement between CPA modules to accommodate roof defmectjon: • Change the circular pin and socket into rectangular ones • Or use screw and wire lug to connect the bus together. 3

F r o m B o ' s 2 3 - M a r - 2 0 1 6 t a l k : A Variant to Allow Vertjcal Movement The pin and slot connectjon should allow a few mm of vertjcal movement between CPAs caused by roof motjon without breaking electrical contact.

A n o t h e r i d e a Loose but captured protruding magnetic plug, fixed recessed magnetic socket Resistive material Embedded magnet near contacts Mated, on-axis with 9mm gap Mated, 4 mm gap, 3 mm vertical shift 5

Another thought ● Resistive strips around Fiberglass channel (63x63x6mm) frame should cover gap Resistjve panel (3mm thick) Resistjve strips with a ● Large strip on one CPA difgerent bias could cover gap and 1.15 frame of next CPA over. m ● Then we could have bigger gap, shielded region in which to run bus wires. 6

Fiberglass channel (63x63x6mm) Resistjve panel (3mm thick) Resistjve strips with a difgerent bias 1.15 Fiberglass channel m (63x63x6mm) Resistjve panel (3mm thick) Resistjve strips with a difgerent bias 1.15 m 7