NuMI Magnet Power Supply System

1
NuMI Magnet Power Supply System

• WBS 1.1.3 Power Supply System
• Level 3 Manager
• Nancy Grossman
• FNAL
• July 11, 2001

2
Outline

• Overview and Specifications (Nancy Grossman, 20)
• Conventional Power Supplies and Cables (PS)
• Kicker Power Supply and Cables (PS)
• Status of Refurbished PS (Steve Hays, 30)
• Status of Kicker PS (Chris Jensen, 30)
• Status of Cooling System for PS (Dave Pushka,
  30)
• Cost/Schedule/Concerns (Nancy Grossman, 10)

3
Overview of the Magnet Power Supply System

• Conventional Power Supplies (PS) (all existing
  PSs to be refurbished or bought from FNAL spares
  inventory Steve Hays, Bob Ducar)
• Ten 500 KW PS
• 1 Main Ring PS
• Three 240 KW PS (one used at MI8 for testing
  horns)
• Ten 20 KW PS
• PS for 12 Main Injector trim magnets
• 1 Kicker PS (to be designed, built and tested
  Chris Jensen)
• AC (480 panel to PS) and DC Power Supply Cables
  and Connectors (Steve Hays, Bob Ducar)
• All large power supplies are ramped.
• All quad and trim PSs are DC and have their own
  PS.

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Refurbished Magnet Power SuppliesSpecifications

• Conventional Power Supplies and Cables (Steve
  Hays, Bob Ducar)
• Must provide reliable, stable power to beamline
  elements while minimizing power consumption.
• The NuMI facility is expected to be operational
  for of order ten years, and the power supply
  system has been designed with this in mind.
• Power supplies must accommodate a repetition
  period of 1.9 seconds (1 msec flatop).
• Want PS to stabilize at flatop, read it to check
  current and have time to still extract.
• Personnel safety must be assured from possible
  electrical, mechanical and radiological hazards
  during installation and operations.
• Voltage and current requirements for the various
  beamline elements determine what power supplies
  and cables will be needed.
• Table summarizes these requirements and indicates
  the chosen power supply for each case.
• For beam tuning and focusing, each trim and
  quadropole magnet has its own power supply.
• Bend circuits use several 500 kW supplies in
  series (or for the V105 circuit a Main Ring Power
  Supply) in order to obtain the desired voltage
  levels.

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Refurbished Magnet Power SuppliesMI60
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Technical Progress Status HV101 PS at MI60
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Technical Progress Status V100, LAM60 and
Quad PS MI60
8
Refurbished Magnet Power SuppliesMI62
9
Refurbished Magnet Power SuppliesTarget Hall
Service Building
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Refurbished Magnet Power Supply Regulation

• Power supply regulation requirements shown
  below
• Groundwater irradiation
• Stability of beam on target
• 720 Hz line ripple effect on the PS currents is
  shown in the table below.
• Need filters on all bend strings

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Refurbished Magnet Power Supply Regulation

• Simulations were run for the NuMI V105 string,
  assuming a constant reference voltage.
• 5 change in line voltage was easily corrected
  for at the level of 25 ppm
• with standard voltage regulation. (most
  variation one would expect)
• 5 load change (resistance) gave a 240 ppm
  current variation.
• Corresponds to about a 100 C change in the copper
  in the magnet or the LCW changing 150C
• Need additional regulation.
• HOLEC transductor (5K/string) Special FNAL
  regulation electronics (5K/string)
• Both are designed and installed in the Main
  Injector
• This combination of electronics would give
  another factor of 2 120 ppm

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Refurbished Magnet Power Supply Regulation
Three strings are still above the required
specifications. So now what?
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Refurbished Magnet Power Supply Regulation

• Bandwidth
• Each string will be tuned for maximum bandwidth.
• 20 Hz is assumed in the previous calculations, 40
  Hz may achieved (but not guaranteed).
• Gives a factor of 2 in current stability.
• Auto-tune
• Load changes are typically slow changes and thus
  Auto-tune can correct for these.
• One could then argue why do you need the extra
  power supply regulation too?
• Auto-tune does not always work.
• Needs beam and working beam position monitors to
  work.
• Assumes next beam pulse like the previous one.
• Experience at FNAL where significant beam control
  is needed says do both.
• Since the power supply regulation is also driven
  some by groundwater concerns, we want something
  that is always working.

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Refurbished Magnet Power Supply Regulation

• NuMI bend string power supply regulation levels
  will be achieved by
• Filters on all 7 strings.
• HOLEC and FNAL Electronics on all 7 strings.
• Auto-tune.
• Tuning for maximum bandwidth.
• Quadropole power supplies (20 KW PEIs)
• Standard regulation is at /- 0.05 of the
  maximum current (100 or 200 amps)
• Corresponds to up to /-0.44 variation in
  operating current.
• Believed to be sufficient.
• Main Injector Trim Magnet power supplies
• Standard regulation is at /- 0.1 of the maximum
  current (15 amps)
• Believed to be sufficient.

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Refurbished Magnet Power SuppliesStatus

• Conventional Power Supplies and Cables (Steve
  Hays, Bob Ducar)
• MI60 Power Supply Cables
• DC cable pulls complete (except kicker PS),
  including termination on PS side.
• AC cabling of power supplies is complete (except
  kicker PS).
• MI62 Power Supply Cables
• AC cabling done except for Main Ring PS.
• Conventional Power Supplies
• 9 refurbished, 4 for Target Hall still need to be
  refurbished.
• Ones in existing construction are also in place
  (except MR PS and Kicker PS).
• 6 large power supplies, 7 quads and 12 trim power
  supplies.
• Testing of the PS will begin shortly.
• Filter chokes and the Main Ring PS need to be
  installed (not behind schedule).
• Scheduled to happen soon.
• All ahead of schedule and within budget.

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Specifications for the Extraction Kicker

• Minimum Integrated Field 2.24 kG - m
• Kick Angle _at_ 120 GeV 563 µrad to inside of
  ring
• Field Rise Time (1-99) 1.30 µs
• Field Fall Time N/A
• Field Flattop Time 9.78 µs minimum( 6 batches)
• Flattop During Pulse 1
• Flattop pulse to pulse 1
• Repetition Rate 1.9 seconds
• Required Charging Time 1.5 seconds
• Magnet Location Immediately Downstream Q602
• Power Supply Location MI-60 Service Building,
  South Power Supply Room

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Kicker Power Supply

• Kicker Power Supply - based on MI-52 kicker
  design (Chris Jensen)
• Design modifications to change polarity of
  supply. (Significant design effort.)
• Pulse Forming Network driving two (or three
  series/parallel) magnets in parallel.
• PFN has 32 sections, 33 nF/section, 825
  nH/section, 46 kV at minimum kick
• Increase coupling of Pulse Forming Network
  (versus MI-52)
• Longer lifetime capacitors for PFN (versus MI-52)

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Kicker Power Supply

• Work on the charging power supply specification
  is in progress.
• Drafting is in progress
• Design is 40 complete
• Swtich tube enclosure 50 complete.
• Some long lead time parts ordered
• End of line clipper diodes
• Controls parts
• Kicker controls are 30 complete.
• Much of the design is delayed due to magnet
  design questions (ceramic tube)
• Much of the kicker construction, machining and
  purchase orders will be delayed to FY2003.
• Due to funding profile with re-baseline
• Still allows several months of float in the
  kicker construction, testing and installation.

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Other Presentations

• Overview and Specifications (Nancy Grossman, 20)
• Conventional Power Supplies and Cables (PS)
• Kicker Power Supply and Cables (PS)
• Status of Refurbished PS (Steve Hays, 30)
• Status of Kicker PS (Chris Jensen, 30)
• Status of Cooling System for PS (Dave Pushka,
  30)
• Cost/Schedule/Concerns (Nancy Grossman, 10)

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Costs

• Refurbished Power Supply Cable Costs
• Total Budget 900K
• Percent Complete48
• Cables, MR PS, regulation/filters, testing
• Kicker Power Supply and Cables
• Based on 2 magnet design.
• Total Budget 534K
• Percent Complete 40
• Need new cost estimate based on 3 magnet design -
  in progress.

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Schedule Milestones
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Concerns/Summary

• Refurbishing of conventional PS and installation
  of their AC and DC cables is ahead of schedule
  and within budget.
• Regulation requirements are tight, but doable
• Concerned about integration of the power supply
  regulation/readout into the NuMI Beam Permit
  System
• Kicker Magnet Power Supply
• On schedule and budget so far, but
• Will the magnet design change to 3 magnets versus
  two due to having to use a shorter ceramic tube?
• Cost/schedule implications of that are in
  progress and nearly complete.