A Multipurpose Modular RF Amplifiers System

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15 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

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A U.S. Department of Energy

Office of Science Laboratory

Operated by The University of Chicago

Argonne National Laboratory

Office of Science

U.S. Department of Energy

A Multipurpose Modular RF
Amplifiers System

A. Nassiri and G. Pile

Advanced Photon Source

HPSL
-
2005 Workshop

May 23
rd

2005, Naperville, Illinois

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

2

OUTLINE


Motivation


Requirements


Technical Approach


Mechanical Layout


Anticipated Benefits


Technical Challenges


Summary




Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

3

Motivation


Explore the development of a robust and flexible modular RF
amplifiers system. With RIA RF systems in mind.


Integration of multipurpose devices into a modular system.


Provide the ultimate re
-
configurable RF amplifiers.


Collaboration between national laboratories and small
businesses benefits both. SBIR Program.


Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

4

Requirements


Cover operating frequencies from VHF to UHF.


Provide operating output power from 5 kW to 30 kW CW.


Smart digital control system configuration.


Utilizing solid state technology.



Power Amplifier

S. M. Power Supply


Control System


System Interlocks

Wall
Power

RF Output
Power

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

5

Technical Approach


Develop modular RF amplifier family using a small number of
commercially available Vacuum Electronic Devices (VEDs).


Develop a series of CW amplifiers with the main focus on the rf
requirements for the RIA project.

Operating frequencies

12.125, 24.25, 48.5, 57.5, 115, 345, 805 MHz

Output power

5 to 30 kW CW

Power adjustment range

25% to 100%

Input drive

0 to 10 dBm

Amplitude stability

< 0.05 dB (1% amplitude variation)

Phase stability

<0.2 degrees

Spurs and harmonics

-
40 dB below main frequency

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

6


For all but the 805 MHz amplifier, tetrodes will be used as the
main amplifying element.


Being inherently wideband devices, either one or two VEDs will
cover the entire range of amplifiers from 10


400 MHz.


For the UHS (805 MHz) amplifier, an Inductively Coupled
Output (IOT) tube will be used


commonly used in the
broadcast television industry.


The standard RF tube transmitter (RF power generator)
operates the output device in class “C” which maximizes the
transmitter efficiency but highly nonlinear in amplitude.


Changing the operating conditions to make the output vary
more linearly with input drive has a large penalty in efficiency
as the operating mode changes to class “B” or even class “A”.


Technical Approach

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

7


Novel solution for a light source, although it has been adopted
for new machines in construction. Few applications in the
scientific field.


Widely used in UHF TV applications due to the higher basic
efficiency and the moderate loss of efficiency at reduced power
level. In this field they have almost completely replaced the
klystrons as the preferred electron tube for the final stage.


In TV operation, their lifetime is approaching or similar to
klystron’s.



Could combine two or three IOTs to achieve higher CW.


Efficiency is in the range from 65 to 70%.



Technical Approach

IOT

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

8

Technical Approach

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

9


In TV operation the power is modulated according to the TV
signal. TV linearity is more demanding.



Peak power is higher in TV operation, but average power is lower.


Efficiency is higher for a CW operation than for a TV operation.


Collector dissipation is lower in cw operation, due to the
increased efficiency. Also electron peak power loading on the
collector should be lower (more evenly spread on the collector
surface).


Output cavity cooling should be increased for CW operation.



Technical Approach

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

10

Technical Approach

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

11

Technical Approach

Reference
RF in
High Frequency
Switching Power Supplies
(Plate, filament, grid, focus magnet, ion pump, etc.)
Low speed
faults,
interlocks &
status monitor
High speed
faults
(RF, tube,
power supply)
Solid State
Driver amp
VED
Power amp
RF output
(RF sample
couplers, load
matching)
Amplitude
and phase
feedback
control
Forward & reverse
power
Accelerator
Cavity
PLC controller
Local
Man
-
machine
Interface
Remote
control
RF power path
RF sample path
AC & DC power
and bias
Status and control
Coolant and bias
faults, cabinet
interlocks, etc.
External
interlocks
Power supply ripple sample
(for active ripple cancellation)
Forward and reverse power sample
Cavity RF sample
Status & tuning
Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

12

Mechanical Layout


A double
-
wide rack


Power supplies, controls, and LLRF and drive
in one rack


High power RF amplifier unit in the second
rack

Modular Multipurpose Amplifier

Courtesy of Diversified Technologies, Inc.
May 2005

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

13

Mechanical Layout

Modular multipurpose amplifier with tetrode module and IOT module

Courtesy of Diversified Technologies, Inc.
May 2005

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

14

Mechanical Layout

RF amplifier modified to be a C
-
band pulse transmitter

Courtesy of Diversified Technologies, Inc.
May 2005

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

15

Anticipated Benefits


Provides a modular design approach.


Integration of solid state switch mode power supply to
eliminate crow bar system.


Ability to build multiple RF amplifiers at different range of
frequencies.


Using common designs, components, controls, interlocks.


Turn
-
key approach.


Easier for faults detection and troubleshooting.



Potential cost savings to RIA.


Potential benefits ( system integration and cost savings) to
future accelerators.


Commercial applications.

Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

16

Technical Challenges


Control system bandwidths of


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Amplitude and Phase stabilities.


Stability and regulation of HV system.


Control of HV ripple and jitter.


System integration, Interlocks, Control, LLRF, and HLRF.


Impedance matching, parasitic oscillations.


Reflection of dynamically changing load impedance from SC
cavities.


Pros and cons of operating the amplifiers in different
configuration class.


Pioneering

Science and

Technology

Office of Science


U.S. Department

of Energy

A. Nassiri HPSL 2005 Naperville Illinois May 23
rd

2005

17

Summary


This offers an opportunity to develop an integrated modular
multipurpose RF amplifiers system for future accelerators RF
systems.


This approach will eliminate significant HV components that
limit the demanding high performance RF and beam quality
requirements.


This approach is most suited for RIA RF system.


This provide more flexibility for system configuration and
operation of the RIA RF systems.


Can be adapted to other rf configurations requirements such
as Proton Drivers and ILC RF systems.


Provides significant cost savings incentives.


-

Approximately 10 to 15 M$ RF cost savings to RIA


Helps to promote collaboration between national laboratories
and small businesses.