LINAC PROTON SOURCE MODULATORS

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LINAC PROTON SOURCE MODULATORS
FERMILAB
 
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MODULATOR SPECS

• Output Voltage 120kV
• Output Current 140 amps
• Output Pulse Length 4.5 ms
• Pulse Rate 3 Hz
• Input Voltage 480 VAC
• Spark Energy Limit 20 joules
• Regulation (incl. slope) 1 (?)
• Design should minimize cost for upgrade
• to 10 Hz pulse rate at 1.5 ms pulse width.

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POTENTIAL MODULATOR TECHNOLOGIES

• FNAL (Bouncer-type) with Updated Technology
• Higher Voltage IGBTs, New Caps, New Controls

• SNS High Frequency Switcher
• Small Size
• Being commercially produced
• - As yet, unproven operational reliability
• - Passive circuit on secondary to control
  spark energy
• deserves further investigation
• - HV/HF Transformer is tricky. Is it
  reliable?
• - Pulse flattening yet to be demonstrated

• Miss-Matched PFN Russian Idea, not
  demonstrated
• No Bouncer Needed
• Interesting, might be more reliable
• - Need to build one

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FNAL Bouncer-type 4.5 ms Modulator Simplified
Schematic
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Bouncer-type Modulator with Updated Technology

• IGBT Switch
• Using New Higher Voltage Devices
• 50 reduction in cost and physical size

• Main Capacitor Bank
• Using New HAZY Self-Healing Polypropylene
  Capacitors
• 50 Reduction in Cap Cost and Physical Size

• Modulator Controls
• Using Lab G type SM Components, fewer cable
  interconnects
• 25 reduction in parts, 50 reduction in labor

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Bouncer-type Modulator - New Features

• Redundant IGBT Switch Design
• - Eliminating the Backup Switch 20
  reduction in cost
• - BUT Requires redundancy in number of switch
  devices and gate controls
• - Replaces Ignitrons with less expensive SCRs
  in crowbar circuit
• - Eliminates very high current crowbars and
  associated noise
• - Maybe a zero gains feature but better
  reliability

• Boost Converter Regulation
• - Goal is to achieve /- 5
  control/regulation
• - Allows for multiple modulators fed from one
  charging power supply.

• Smoothing Choke
• - Series choke of sufficient size to limit AC
  line fluctuations to /- 1
• (present Linac area AC lines 15Hz voltage
  distortion).
• - If new Linac fed from dedicated 345kV
  transformer, above
• requirement could be relaxed.

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4.5 ms Modulator Design Features thatminimize
1.5ms upgrade costs

• 2 parallel IGBT Switches
• Main Cap Bank designed to separated into 3.
• RMS current based on 10 Hz 1.5 ms operation
• Bouncer Caps and Inductors designed to be
  separated into 3.
• RMS current based on 10 Hz 1.5 ms operation

• Charging Power Supply
• Assuming boost converter regulation works, the
  same charging PS could be used to power 3 of the
  1.5 ms modulators.

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Original FERMI TESLA MODULATOR Parts Cost

• Pulser Parts Cost

• Pulse Transformer 108k
• Pwr Transformer 50k
• Main Cap Bank 31k
• Cabinet 15k
• Other 126k
• Subtotal 330k
• IGBT Switch Subtotal 50k
• Modulator Controls Subtotal 40k

• TOTAL 420K

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Original FERMI TESLA MODULATOR Total Cost

• PULSER PARTS ESTIMATE 420k

• RF MODULES (Spark Detection) 12k
  (AWAG)

• LABOR ESTIMATE
• (Total parts cost) (Pulse Transformer)
• 422k - 108k 314k

• TOTAL (1996 s) 735k

• TOTAL
• Inflation Since 1996 (8 yrs at 2.5/yr) 22
• 1.22 x 735k 900k

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Original Fermi TESLA Modulator Updated
Technology cost savings

• IGBT Switch
• Using New Higher Voltage Devices and eliminating
  the backup switch
• 60k savings in labor and parts

• Main Capacitor Bank
• Using New HAZY Self-Healing Polypropylene
  Capacitors
• 30k savings in labor and parts
• 5k savings in Cabinet, Reduced Service
  Building Size!

• Controls Upgrade
• 30k Savings in parts and labor

• Total updated technology savings 125k

• TOTAL
• Inflation Since 1996 (8 yrs at 2.5/yr) 22
• 1.22 x (735k-125k) 745k

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4.5 ms Modulator Cost Estimate

• Pulse Transformer 108k x sqrt(3)
  190k
• Pwr Transformer 50k same 50k
• Main Cap Bank 31k x1/2
  x3 50k
• Cabinet 15k x8/5
  25k
• Other 126k see
  notes 270k
• 
  Subtotal
  585k
• IGBT Switch Subtotal 50k x
  4/10 x2 40k
• Modulator Controls Subtotal 40k x 5/8
  25k

• TOTAL parts 650K

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4.5 ms Modulator Cost Estimate Total Cost

• PULSER PARTS ESTIMATE 650k

• RF MODULES (Spark Detection) 12k
  (AWAG)

• LABOR ESTIMATE
• (Total parts cost) (Pulse Transformer)
• 650k - 190k 460k

• TOTAL parts and labor (1996 s) 1122k

• TOTAL
• Inflation Since 1996 (8 yrs at 2.5/yr) 22
• 1.22 x 1122k 1370k

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ESTIMATED SIZE !Simple scaling, no attempt to
optimize
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4.5 ms ModulatorProject Organization

• Project Leader Howie Pfeffer
• Magnetics Chris Jensen
• Controls Jim Biggs ( P. Prieto)
• Switch, Cap Bank, Bouncer, Misc., Leon Bartelson
• and construction
• Computer Simulations Dan Wolff

• Estimated project time
• Design, construction, and commissioning 18
  months
• after s available.