# Presentation: 596592

## MI RF UPGRADE – DUAL PA’s

- John Reid
- March 16 , 2005

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Outline

- Summary of RF System Parameters
- Advantages of Two PA Approach
- Limitations of Two PA Approach
- Modifications Required to Existing 53 MHz System
- R&D
- Cost
- Conclusion

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## RF System Requirements - 1 

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## RF System Requirements - 2

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Advantages of Two PA’s

- Will double the available current.
- Could accelerate up to ~ 1e14 protons, not considering stability issues.
- With added external cavity load (Robinson stability), for beam power equal to cavity power, could accelerate ~ 8e13 protons (88% of amplifier capability).
- Prototype system currently under fabrication.
- Minimum design required, prototype can use existing parts for proof of operation.
- Install a prototype system in MI by Fall 2005.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Disadvantages of Two PA’s

- Not sufficient power to accelerate 1.5e14 protons.
- Does not increase cavity voltage, only available current.
- More voltage is required for faster ramp rates, must add cavities (only 21 rf cavities exist, 18 installed).
- Duty factor limited to ~ 50 % due to cooling limitations in present cavity design.
- Transient beam loading will be challenging at these intensities, especially during beam gymnastics.
- May need to dissipate additional cavity power for Robinson stability, feedback & feed forward may not be completely sufficient.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Standard MI RF Cavity

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- March 15-17, 2005

## Standard MI RF Cavity

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- March 15-17, 2005

## Modified MI RF Cavity

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- March 15-17, 2005

## Cavity Issues

- Modifications
- Fabricate new rf coupling loop for two PA operation
- Prototype loop is fabricated and ready for testing
- Measure spurious modes, coupling ratio (step-up ratio) , cavity tuning range.
- Implement  optional external rf loading to cavity.
- Lifetime issues
- Cavities are 35 years old, water leaks are the biggest  concern.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Coupling Loop for 2 PA’s

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- March 15-17, 2005

## Modulators

- Design & Fabricate 20 new Series Tube Modulators
- Required to supply 40 amps at 21 KV to 2 PA’s.
- Short R&D program is necessary for prototype.
- Requires new higher power series tube.
- New floating deck.
- New grid, screen, filament supplies for series tube.
- Additional grid, screen, filament supplies for 2nd PA.
- Equipment gallery can tolerate slightly larger modulator footprint.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Present Series Tube Modulator

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- March 15-17, 2005

## RF Sources

**RF Power Amplifier**
- Fabricate 20 additional 200 Kwatt Power Amplifiers.
- Identical to present Amplifiers in MI.
**8 Kwatt Solid State Driver Amplifier**
- Fabricate 20 additional solid state driver amplifiers.
- Identical to present Amplifiers in MI.
**Local Station RF Controller**
- Modifications to existing design required for two PA’s.
- Fabricate 20 controller chassis.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Anode Supplies

- Modify 3 existing Anode Supplies for:
- Higher power main rectifier transformers
- Higher power rectifier stack
- Increased capacitor bank
- Higher power interphase reactor
- Higher power water resistor
- Possible upgrade to step start 13.8 KV contactor
-               OR
- Build 3 more supplies – similar to existing
- Requires civil construction for block buildings.
- Requires procurement of all parts.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## Utilities

- LCW – Requirements
- 95 degree rf equipment system
- Present system supplies ~ 2200 gpm to equipment.
- Upgrades would increase flow to ~ 4100 gpm
- 90 degree Cavity system
- Present system supplies ~ 750 gpm
- Upgrades would increase flow to  ~ 1000 gpm
- Upgrade costs would be required for both systems.
- Power Distribution
- Sufficient 480 V power available for additional equipment.
- 13.8 KV feeder for Anode Power supplies may require upgraded capacity.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## R&D

- Continue work to get one cavity modified with two PA’s.
- Low level measurements; cavity tuning range, spurious mode properties, dampers.
- Implement optional rf loading to cavity by coupling power to an external water load.
- Immediately start a prototype modulator utilizing higher power series tube.
- Fabricate rf station LL RF controller for 2 PA operation.
- Test two PA cavity in MI-60 test station.
- Install in MI tunnel for testing with beam.
- Accumulate actual running time with beam.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005

## M&S Costs

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- March 15-17, 2005

## Conclusions

- Two PA approach not suitable for 1.5e14
- Two PA’s would at best accelerate ~1.0e14, ignoring stability issues.
- Worth while to complete, document, and test a prototype two PA system.
- R&D efforts should be concentrated on new rf system.

- Your Name  - Proton Driver Director's Review

- March 15-17, 2005