Resistor Divider Chain With Beam Plug Cheng-Ju Lin LBNL HV Test @ PC4 Weekly Meeting 18-Aug-2016
• We (Glenn, Bo, Thomas, and I) have been finalizing the resistor values for the FC voltage divider • Preference is to use two parallel paths of 1G ! resistors for the nominal FC • For stage 2 test, the resistor divider of the beam plug is tied to field cage profile # 5 • Need to compensate the divider network to maintain the nominal voltage drop of 3kV across all profiles • Instead of replacing the nominal boards, we (Glenn’s idea) plan to attach a second resistor divider board in parallel with the nominal board for the first 5 profiles near the CPA
ProtoDUNE RESISTOR DIVIDER CHAIN CPA Field Shaping 178.5kV FC0 FC1 FC2 FC3 FC4 FC5 FC6 FC7 FC8 FC9 FC10 FC20 FC30 FC40 FC50 FC58 APA -180kV -177kV -174kV -171kV -168kV -165kV -162kV -159kV -156kV -153kV -150kV -120kV -90kV -60kV -30kV -6kV GND … … … … … R2 R3 R3 R3 R3 R4 Rf R1 R1 R2 R2 R2 R3 R3 R3 R3 R3 R3 … … … … … R1 R1 R2 R2 R2 R2 R3 R3 R3 R3 R3 R3 R3 R3 R3 R3 R4 Rf Vf (-1.5kV) R6 R6 R5 R6 R6 Main resistor board: Parallel resistor R1 R2 R3 R4 Rf Beam board VALUE (M ! ) 500 1000 1000 1500 500 R7 R7 Plug CURRENT ( " A) 3.0 3.0 3.0 3.0 3.0 R7 R7 Parallel resistor board (when beam plug is installed): R7 R7 R5 R6 VALUE (M ! ) 800 800 R7 R7 CURRENT ( " A) 3.7 3.7 R7 R7 Beam plug resistor chain: R7 Total Current Draw = 9.6 " A R7 R7 VALUE (M ! ) 15000 C.-J. Lin 18-Aug-2016 CURRENT ( " A) 1.8
RESISTOR DIVIDER CHAIN CPA Field Shaping 178.5kV FC0 FC1 FC2 FC3 FC4 FC5 FC6 FC7 FC8 FC9 FC10 FC20 FC30 FC40 FC50 FC58 APA -180kV -177kV -174kV -171kV -168kV -165kV -162kV -159kV -156kV -153kV -150kV -120kV -90kV -60kV -30kV -6kV GND … … … … … R2 R3 R3 R3 R3 R4 Rf R1 R1 R2 R2 R2 R3 R3 R3 R3 R3 R3 … … … … … R1 R1 R2 R2 R2 R2 R3 R3 R3 R3 R3 R3 R3 R3 R3 R3 R4 Rf Vf (-1.5kV) R6 R6 R5 R6 R6 Parallel resistor Beam board Ideal resistor value for R5 and R6 is 818 M ! R7 R7 Plug Using stock value of 800 M ! , the resulting voltage drops are: R7 R7 R1 R2 R3 R4 Rf R7 R7 VOLTAGE DROP (V) 1488 2976 3002 4403 1501 27519 R7 CURRENT ( " A) 3.0 3.0 3.0 3.0 3.0 1.8 R7 R7 R7 R7 Voltages are within ~1% of the nominal values R7 R7 C.-J. Lin 18-Aug-2016
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