1. LINAC PROTON SOURCE MODULATORS
FERMILAB
LINAC PROTON SOURCE MODULATORS
4/27/2019
Dan Wolff/Howie Pfeffer

2. Dan Wolff/Howie Pfeffer
MODULATOR SPECS
Output Voltage: kV
Output Current: amps
Output Pulse Length: ms
Pulse Rate: Hz
Input Voltage: VAC
Spark Energy Limit: joules
Regulation (incl. slope): % (?)
Design should minimize cost for upgrade
to 10 Hz pulse rate at 1.5 ms pulse width.
4/27/2019
Dan Wolff/Howie Pfeffer

3. 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
4/27/2019
Dan Wolff/Howie Pfeffer

4. FNAL Bouncer-type 4.5 ms Modulator “Simplified” Schematic
4/27/2019
Dan Wolff/Howie Pfeffer

5. 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
4/27/2019
Dan Wolff/Howie Pfeffer

6. 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.
4/27/2019
Dan Wolff/Howie Pfeffer

7. 4.5 ms Modulator Design Features that minimize 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.
Charging Power Supply
Assuming boost converter regulation works, the same charging PS could be used to power 3 of the 1.5 ms modulators.
4/27/2019
Dan Wolff/Howie Pfeffer

8. 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
In your opening, establish the relevancy of the topic to the audience. Give a brief preview of the presentation and establish value for the listeners. Take into account your audience’s interest and expertise in the topic when choosing your vocabulary, examples, and illustrations. Focus on the importance of the topic to your audience, and you will have more attentive listeners.
TOTAL: $420K
4/27/2019
Dan Wolff/Howie Pfeffer

9. 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
4/27/2019
Dan Wolff/Howie Pfeffer

10. 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
Determine the best close for your audience and your presentation. Close with a summary; offer options; recommend a strategy; suggest a plan; set a goal. Keep your focus throughout your presentation, and you will more likely achieve your purpose.
TOTAL:
Inflation Since 1996 (8 yrs at 2.5%/yr) = 22%
1.22 x ($735k-$125k) = $745k
4/27/2019
Dan Wolff/Howie Pfeffer

11. 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
Original Modulator Costs Scaled to 4.5ms Modulator
SCR Controller: $ 7k
Machine shop: $ 7k
Bouncer Choke: $ 6k
Bouncer Caps: $ 6k
Power Resistors: $ 6k
Klystron Fil. PS $ 5k
Solenoid PS: $ 4k
480VAC Contactor: $ 4k
HV Diodes: $ 4k
Ignitron Tubes: $ 4k
Other: $ 72k
Total: 269k
TOTAL parts: $650K
4/27/2019
Dan Wolff/Howie Pfeffer

12. 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
4/27/2019
Dan Wolff/Howie Pfeffer

13. ESTIMATED SIZE ! Simple scaling, no attempt to optimize
4/27/2019
Dan Wolff/Howie Pfeffer

14. 4.5 ms Modulator Project 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.
4/27/2019
Dan Wolff/Howie Pfeffer