Attendees

Lia Merminga presented a first draft of an RF commissioning plan for the IRFEL.
The plan is divided into 4 phases:
Phase I: RF Commissioning - No beam
Phase II: RF Commissioning of Cryounit with Beam
Phase III: First Light
Phase IV: Energy Recovery with FEL OFF and ON.

For each phase dates, goals, test plans and hardware and software requirements were presented and two action items were identified.

Phase I: RF Commissioning - No Beam
Starting Date: April 1, July 1 (FEL)
Completion Date: October 1

Goals: 1. Establish stable gradient of 10MV/m (on average) in cryounit & 8 MV/m in cryomodule
2. Demonstrate reliable tuning of cavities
3. Verify gradient and phase (long and short term) stability without beam.

Test Plans: 1. Measure microphonic noise in all cavities
2. Measure Qext in all cavities
3. Measure klystron saturation curves (including phase)
4. Test magnetostrictive tuner operation/reliability
5. Test tuning algorithm (?)
6. Measure gradient & phase stability w/out beam, and slow phase drifts
7. Test new interlocks for 50KW klystrons
8. Obtain a comparison database with CEBAF
9. Cavity performance tests

Software Requirements:
1. Magnetostrictive tuner software
2. Tuning algorithm
3. Auto-reset: Maybe Master Reset?

Hardware Requirements:
1. Magnetostrictive tuner hardware

Phase II: RF Commissioning of Cryounit with beam
Starting Date: Oct. 1
Completion Date: Nov. 15

Goals: 1. Demonstrate stable pulsed (1.1mA) and CW (5mA) operation.
2. Demonstrate reliably/reproducibly algorithm for current increase and from pulsed to CW.

Test Plans:
1. Calibrate gradients with beam
2. Tune cavities
3. Phase cavities (15 degrees and 20 degrees) - Test phasing algorithm (?)
4. Test detuning angle compensation for beam loading
5. Determine/test how to go from pulsed (1.1mA) to CW to 5mA.
Scenario must be compatible with energy recovery and optics vs. space charge related issues.
6. Measure beam-induced transients in amplitude & phase as function of beam current and gains.
7. Measure/verify gradient and phase stability with beam.

Software Requirements:
1. Detuning angle compensation for beam loading.
2. Cavity phasing
3. Gradient calibration with beam
4. Start-up algorithm

Phase III: "First Light"
Starting Date: Nov. 15
Completion Date: Mar. 1

Goals: 1. Demonstrate stable pulsed and CW operation at 1.1mA, off-crest and off-resonance.
2. Investigate limits of control vs beam loading.

Test Plans:
1. Initial steps same as Phase II
2. Emphasis here:
a. Operate stably off-crest and off-resonance
b. Klystron saturation: Is available power sufficient for 8MV/m, 1.1mA and possibly increased microphonics? (With 8kW klystrons should be OK)
c. Do we need stub tuners?

Phase IV: Energy Recovery @ 5mA with FEL off and FEL on!
Starting Date: Apr. 1
Completion Date:

Goals:
1. Demonstrate energy stability
2. Test start-up/recovery algorithm
3. Test energy stability theory of recirculating, energy recovering linacs

Test Plans: 1. Start up/Recovery algorithm
2. Ensure/verify stability in phase and amplitude, in the presence of two nearly canceling beam vectors.
3. Perform energy stability experiments with varying M56 and beam loss.
4. Test on stability of FEL/RF system.

Actions:
1. What has been important in the high current/high gradient runs at CEBAF? (Doolittle/Tiefenback)
2. Which parts of high level application software do we need/want to carry over?

Feedback from audience:
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Benson pointed out that one of the goals for Phase I should be achieving 32 MV across the cryomodule with one cavity off. A well defined bypassing procedure must be developed for the bypassed cavity.

Krafft pointed out the need to use CEBAF's experience with high current run to decide on measurements to make on the FEL cavities in advance.

Magnetostrictive tuner algorithm and beam loading compensation algorithm must be integrated into present tuning algorithm.

Dr Shu suggested that cavity performance tests are carried out and uptime specification is determined.

We need to determine which tests need to be done in both places.

Legg suggested that in Phase III we use high charge per bunch in pulsed mode to investigate rf stability limits.

Benson reminded us that a decision needs to be made soon on stub tuners.

Krafft pointed out the need to communicate our software needs to software people as soon as possible.

Action Items
1) Figure out beam loading compensation of tuning angle algorithm. Communicate with Fugitt and Doolittle for the development of the tuning software (Merminga)
2) Do we need stub tuners (Merminga)
3) Call a meeting with the subsystem leaders to communicate the RF commissioning plans to them, the requirements on their system and deadlines (Merminga)
4) Start writing test plans (All)