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intro. We are investigating the consequence of removing one heater strip from mqxb07 protection, i.e. One heaee circuit with 3 out of 4 strips (one quadant uncovered), one circuit normal. Quadrant 2 will be the one uncovered. Orientation of Q1,Q2, Q3 leads. DFBX. To IR.

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  1. intro We are investigating the consequence of removing one heater strip from mqxb07 protection, i.e. One heaee circuit with 3 out of 4 strips (one quadant uncovered), one circuit normal. Quadrant 2 will be the one uncovered. BUS WORK 2 April 2001

  2. Orientation of Q1,Q2, Q3 leads DFBX To IR Q1 and Q3 are MQXA, Q2a,Q2b or MQXB. Q2 forms a single unit with focus, Q1 and Q3 both defocus relative to Q2. Leads of Q3 and Q2a face towards IR, Q2b and Q1 face towards DFBX. For magnets facing same direction (face to back), connecting “A to B” in series would give relative focusing and “A to A” or “B to B” would give relative defocus. Since Q2a and Q2b are “back to back” you have to connect “B to B” (or A to A) to get a net focus. Similarly, to get Q3 to be defocused relative to Q2B and Q2a to be defocused relative to Q1, you have to connect A to B since they are “face to face” BUS WORK 2 April 2001

  3. Bussing of a mqxb -magnet leads originate from inner coil midplane of inner coils of quadrant 3 and 4. -Quadrant 4 is the “B” lead , the lead that connects q2a to q2b, quadrant 3 is the ‘a’ lead which connects to q1 or q3.. -Bussing sequence, inner 3, outer 3, inner 1 outer 1, outer 2, inner 2, outer 4, outer 4 Inner to outer connections are done in pole turns, quadrant to quadrant splices done on midplanes. X Current into paper • Current out of paper Leads L3 and L4 come out here in this direction xx • • • • xx To machine center BUS WORK 2 April 2001

  4. Cases to consider a)case where one heater circuit on each q2a,q2b (like standard test on model magnets and prototype b) case with q2b two good circuits, q2a one good, one special c) case with q2b two good cicuits, q2a one special d) case with q2b one good circuit, q2a one special case a) is nominal will be used as bench mark case b is judged to be much simpler than case c and d and not considered. BUS WORK 2 April 2001

  5. Areas of concern -What is peak voltage to ground -What is max quadrant to quadrant voltage -will missing a segment affect inductance of heater circuit? BUS WORK 2 April 2001

  6. anaylsis Use files from model program -each heater strip (I.e. up and back) can be connected -try two case: normal ie. Two heaters, 4 strips, each strip covers ½ of each quadrant Case 2 Two heaters, 4 strips, one strip covers ½ of quadrant 2,one strip covers ½ of quad 4, 2 strips cover quad 1, NO strips cover quadrant 3 Use input files for hqq08 BUS WORK 2 April 2001

  7. method use a step wise approach to reproduce current decay BUS WORK 2 April 2001

  8. method -using idot coil and coil inductance, separate out resist and induct voltages -using measu R(t) and inductance… and initial current BUS WORK 2 April 2001

  9. Predicting voltages -combine the files from two files to build a full length -Inductance and resistance scale with length -Resistance profile should scale, as long as current decay profile doesn’t change too much (I.e. driven by MIIT’s(t) -Simple compensation for double, no heater cases To use asymetric case in need to reduce resistance scale for “double heater quduadrant” BUS WORK 2 April 2001

  10. Case one two heaters in q2b, one heater in q2a -how to scale two heater vs one. -data from hgq08 studies suggest ratio between 1.7 and 1.3. Using ‘1.5’gives voltages to ground that match data from LQXB01 studies BUS WORK 2 April 2001

  11. Case 1 one heater in q2a, two heaters in q2b - BUS WORK 2 April 2001

  12. Case one two heaters in q2b, one special heater in q2a Quadrant 2 in q2b is missing a strip BUS WORK 2 April 2001

  13. BUS WORK 2 April 2001

  14. Quadrant to quadrant voltage Consider Vdiff between physically adjacent quadrants. Consider inner and outer coils separately. b a g e d BUS WORK 2 April 2001

  15. Quadrant voltages Using notation on previous slide Quadrants Inners Outers 1-2 b-e g-g 2-3 e-a g-b 3-4 a-d b-e 4-1 d-b e-g Approx. Voltage to Gnd from: a 0 b -9 g -43 e -346 d -358 Conclude worst case is about 350 volts quadrant to quadrant BUS WORK 2 April 2001

  16. Conclude We used data from HQG program plus simple model to predict voltages to ground and quadrant to quadrant voltages Voltage to ground is about 450V for case with “special heater circuit on Q2a, two heater circuits on Q2b. Note this is to be compared with 350 V to ground for case of one heater circuit in q2a and two heater circuits in q2b. In q2a quadrant to quadrant voltage is worst case 350 V. Conclude: Voltage imbalance not is not a serious problem BUS WORK 2 April 2001

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