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Phase stability and RF level distribution Requirements
Distribution type & MO location
Cable requirements ( phase versus T° stability & diameter)
Coupling value
T° regulation solution (heater, water, ...)
A PRDS 9m prototype is realized to test several T° regulation
and insulation solution. The tests are in progress.
50 100 150 2000
0.1
0.2
0.3
0.4
Lg 704.4, ( )
Lg 352.2, ( )
Lg 176.1, ( )
0.1
Lg
Christophe Joly*, Sylvain Berthelot, Beng-Yun Ky,Thomas Lester, Wladimir Sarlin, Jean-François Yaniche, Institut de Physique Nucléaire (UMR 8608)- CNRS/ IN2P3-Université Paris-Sud, Orsay, France
Holger Podlech
Johann Wolfgang Goethe Universitaet (Institute of Applied Physics) Frankfurt am Main, Germany
Dirk Vandeplassche
Centre d'études et de recherche Nucléaire (SCK*CEN), Mol, Belgium
LLRF for the RFQ prototype of the MYRRHA project LLRF17 Workshop / Barcelona, Spain /Oct 16-19, 2017
The goal of the European project called MYRTE (MYRRHA Research and Transmutation Endeavour), is to perform research to support the development of the MYRRHA facility
(Accelerator Driven System) with a main topic for the “Accelerator R&D for ADS/MYRRHA” Work Package (WP2): the Injector demonstration. Within this framework, a Low Level
Radio Frequency system for the Radio Frequency Quadrupole (RFQ) is developed by IPNO with an in-house standalone digital board including 2 FMC boards associated to a FPGA
linked to a processor ARM by PCIe. A Phase References generation system has been also realized and tested with the expected performance. This poster presents the project and
focuses to the hardware developments and to some results before the tests with the RFQ planned in May 2018.
This work is supported by the European Atomic
Energy Community’s (Euratom) H2020 Program me
under grant agreement n°662186186 (MYRTE
Project).
Conceptual layout of the MYRRHA Facility
Single SPOKE
352MHz
Double SPOKE
352MHz
Elliptical
704MHz
RFQ + CH
176MHz
Goals :
Build a hybrid reactor demonstrator for transmuting
radiotoxic waste, (ADS).
Radio Isotopes production to medicine
Fundamental research
Parameters of the MYRRHA project
Particles protons
Energy [MeV] 600
Frequency [MHz] 176.1 - 352.2 -704.4
Duty Factor [%] 100 (cw)
I [mA] 4
Beam power [MW] 2.4
MTBF [Hour] 250
Energy stability [%] ±1
Current stability [%] ±2
Reactor power th [MW] ≈60
keff ≈0.95
Fuel MOX
Target Eutectic Pb-Bi
RFQ
LLRF requirements
Amplitude stability [%] ±0.2 rms
Phase stability [Degree] ±0.2 rms
Frequency [MHz] 176.1
Bandwidth [kHz] > 84
RFQ Parameters
RF Structure 4.Rod
Frequency [MHz] 176.1
Beam current [mA] 5
Duty factor [%] 100
Eout [MeV] 1.5
Rp [kWm] 72
RF Power [kW] 113
Specific power [kW/m] 26.5
Voltage [kV] 44
Length [m] 4
Institut für Angewandte Physik
LINAC AG
RFQ assembly in progress at NTG facility
LLRF Requirements
ECR RFQ MEBT-1 CH-cavities MEBT-2 CH-cavities
Injector in
detail
(new design)
Due to beam dynamics studies of the global
accelerator and the RFQ characteristics, the
stabilities requirements will be better than
±0.3% rms and ±0.3° rms.
In this respect, a budget has been defined for
the complete LLRF system composed to the
Master oscillator (MO), the Phase Reference
Distribution System (PRDS) and the LLRF
Feedback loop system.
Then other parameters must be taken into
account as accelerator length, temperature
variation into the tunnel, etc.
LLRF FB System
Master Oscillator
REF Distribution
0.2 - -
0.1 0.1 0.1 Distribution by
subsystem
PRDS MO
LLRF FB loop system
Frequency
[MHz]
Jitter rms
[mDeg]
Jitter rms
[fs]
88.05 1.6 50
176.1 2.0 33
352.2 4.5 36
704.4 8.4 33
Results and [email protected]
X2
X2 X4
X2
704.4 MHz
352.2 MHz
176.1 MHz88.05 MHz
PLL88.05 MHz
Splitter
X2
Multipliers
10 MHz REF for Local oscillator generation
Sampling clock
25kHz bandpass Filter
X N
10MHz Oscillator
Distribution amplifier
The LLRF system for the RFQ is based on a in-house
digital mother board called DALTON using a FPGA linked
to a processor ARM by PCIe, with two FMC slots. For HW and SW details, see P-38 “EPICS and VHDL developments
in the LLRF for MYRRHA Project's RFQ prototype” poster.
The regulation loop principle is based on the processing of
the RF cavity pick-up signal which is down-converted to an
10 MHz Intermediate Frequency (IF) signal. This IF signal
is then sampled by an ADC (FMC104-4DSP) to be
processed into the FPGA. The result is two I/Q control
signals which are converted by 2 DACs ( and used to
modulate the RF reference signal feeding the cavity, via a
vector modulator. The MO provides the Phase reference at
176.1MHz and the 10MHz need to produce the Local
oscillator (LO) signal, used by the down converter.
The Master Oscillator is realized using parts with Phase Noise
requirements very hard providing by ar Electronique (OCXO,
PLL) and Wenzel Associates (multipliers). A narrow bandpass
filter allows reducing the PLL noise as it is shown on the plot.
Conclusion
Fault tolerance Interlocks Bus
Auxiliaries ControlSystem
PLC
Master Oscillator
LLRF Feedback Loop System
PRDS
Frequency Tuning System
Fast Interlocks
System
Pf Pr Pt
Co
up
ler
10MHz
Beam axe
Vacuum , T°, cooling,
Cooling, defaults
SSPA
RF authorization
Personnel SafetySystem
RF authorization
MachineProtection
System
Gb-Eth (EPICS)
IOCTimingEVG
TimingEVR
Optical link
tun
er
RFQ
P A
Timing & Master Oscillator
FPGA
Digital board
DAC ADC
DAC
I Q
ADC
•Digital signal processing•Set points•Frequency tuning• Interlocks management• Communication EPICS•Feed Forward
DAC
REF Clock ( ADCs & DACs)Timing( Beam pulses, RF pulses,…)
10MHz
RF
REF RF RF-10MHz
Frequency Tuning System
Fault tolerance Interlocks Bus
Others Data(Forward power, Reflected Power,…)
RF switch
FrequencyDown converter
Personal Protection Safety Diagnostics
signals
Gb-Eth (EPICS)
Vectormodulator
RFQ
Machine Protection System
The LLRF prototype for the RFQ composed of the MO, PRDS and the FB loop will be tested in real condition in 2018 at Louvain-La-Neuve in Belgium where will be installed the injector until 6 MeV. The Master
Oscillator prototype gives very good phase noise results with a jitter inferior to 50fs for all references. The PRDS needs more tests to conclude about the T° regulation. The FB loop hardware and software (VHDL
and EPICS) are close to be operational and in parallel, we are studying a MTCA based version adapted to the MYRRHA reliability requirements. Thank you to the IAP, SCK*CEN and IPNO teams for their support.
ECR LEBT RFQ CH β 0.375
Single Spokeβ 0.705Elliptical
ECR LEBT RFQ CH
β 0.49 Double Spoke
176 MHz 352 MHz 704 MHz
SC sectioninjectors
60 cavities 18 cavities 72 cavities
Beam stop
Spallation target &
sub-critical core
LINAC
600 MeV
32 m 11 m 91 m 35 m 120m
15 cavities
Phase stability versus length for 0.1°C temperature variation using
a LCF38-50J FN( phase vs T° stability coef <6 ppm/°C, velocity :
87%)
10 Tc (K type) per 3 m section
positioned inside and outside
for a profile of temperature.
Insulated duct
heater
Cooling water
Coupler
T° sensors
REF cables
Contact : [email protected]