APAC 2007, session 7 Accelerator Technology RRCAT, Indore, India, - - PowerPoint PPT Presentation

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APAC 2007, session 7 ‘Accelerator Technology’ RRCAT, Indore, India, Jan 28 - Feb 2, 2007 http://recycle.lbl.gov/apac2007/ Problems worthy of attack show their worth by hitting back.

• Piet Hein (1905-1996), Danish polymath

Analog, Digital, or Hybrid Controller Plant single or multiple cavities ring or linac pulsed or CW normal or superconducting Measurement noise System noise

Σ Σ

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• 20

20 40 60 80 100 1 10 100 1000 10000 100000 1e+06 1e+07 Gain (dB) Frequency (Hz) cavity responses, bandwidths 50 Hz to 50 kHz pole-zero cancelling controller responses

Gain = KP + KI s A complex system that works is invariably found to have evolved from a simple system that worked.

• John Gall, U.S. author

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• 20

20 40 60 80 100 1 10 100 1000 10000 100000 1e+06 1e+07 Gain (dB) Frequency (Hz)

Gain = KP 1 + sτ + KI s

Conditioning Signal Conditioning Signal Conditioning Signal

housekeeping and custom functions FPGA

Conditioning Signal

DAC DAC ADC ADC Host CPU or PHY Host I/F Network

The cheapest, fastest and most reliable components

• f a computer system are those that aren’t there.
• Gordon Bell (1934-), U.S. computer engineer

Embrace simplicity. Put others first. Desire little.

• Laozi (4th century BC?), Chinese philosopher

housekeeping and custom functions FPGA DAC DAC ADC ADC Host CPU or PHY LO Clock Host I/F Network

Programmable digital logic device Yes Yes Major suppliers uncountable 2 Glue-less hookup to most DAQ hardware

• Yes

Guaranteed low-latency processing

• Yes

Good programming languages Yes

• Good programming requires thought and experience

Yes Yes

4-input look-up table Flip Flop

1536 (US$10) to 178176 (US$6000) cells, plus routing, carry chains, multipliers, RAM, input, and output VHDL was written by a bunch of software guys who knew nothing about designing hardware. We beat on it until you could do hardware with it. Verilog was written by a bunch of hardware guys who knew nothing about designing software. We beat on it until you could do software with it. Neither does the job they were originally intended to do, but they work.

• David Bishop, Engineer

When someone says ‘I want a programming language in which I need only say what I wish done,’ give him a lollipop.

• Alan Perlis (1922-1990), U.S. computer scientist

ADC ADC ADC DAC DAC LO LO LO LO LO

RF to Klystron Modulated Calibration Line phase reference Cavity 1 Field Cavity 2 Field

Σ Σ Σ

Be patient, man. I’m trying to be linear.

• A.L.F., fictional TV alien, 1986-1990

cavity ADC

CORDIC SetR

DAC to Klystron

Setθ+nωT +

• A

θ r x y

cavity ADC

CORDIC SetR

DAC to Klystron phase reference ADC

Phase

Σ

Setθ+nωT

S/H

+

• A

θ r x y Measure

Σ

cavity ADC

CORDIC SetR

KP+KI/s

DAC to Klystron phase reference ADC

DDC CORDIC

Σ

Setθ+nωT

S/H

(or predictive filter) θ r x y θ r x y

Σ Σ

cavity ADC

Setpoint Waveform

1-z-2

DDC

∫

DUC (complex)

Σ

KP+KI/s

DAC to Klystron

DDR output cell z-1 z-1

Σ

z-1 z-1 Σ z-1 z-1

γ δ γ’ δ’

Σ Σ

z-1 z-1 z-1

• z-1

z-1

Σ

z-1 z-1

Σ

ν

z-1 z-1

Σ

ν

z-1 z-1 z-1

Σ

z-1 z-1

Σ

z-1

Σ

z-1 z-1 ADC z-1 Setpoint Waveform z-1

What’s the difference between hardware and software? Hardware keeps getting cheaper, faster, and smaller.

• Rick Cochran, U.S. system analyst

Test Bench Driver Code Model Physics Model Physics Driver Code Test Bench Language simulator Global Controls FPGA hardware Language simulator code FPGA code FPGA code FPGA with controller Physics Model

LLRF

Phase Reference High Power RF Interlocks Beam Diagnostics Machine Timing Global Controls Additional mandatory features:

• cavity detune measurement
• self-test, self-cal
• exception handling

It is easier to move a problem around than it is to solve it.

• Ross Callon, U.S. network engineer

2001 2006

ADC ADC ADC DAC DAC LO LO LO LO LO

RF to Klystron Modulated Calibration Line phase reference Cavity 1 Field Cavity 2 Field

Σ Σ Σ

Σ cavity ADC

CORDIC SetR

KP+KI/s

DAC to Klystron phase reference ADC

DDC CORDIC

Σ

Setθ+nωT

S/H

(or predictive filter) θ r x y θ r x y

Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

• Antoine de Saint-Exup´

ery (1900-1944), French writer and aviator

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Alex Ratti Brian Chase Mark Champion Taylor Davidson Hengjie Ma Chip Piller Stefan Simrock John Staples Yubin Zhao Image credits: Wikipedia, Wiley Miller This talk is online at http://recycle.lbl.gov/apac2007/ I have only made this letter rather long because I have not had time to make it shorter.

• Blaise Pascal (1623-1662), French mathematician and philosopher