J-PARCリニアックでの位相ドリフトモニターのインストールと評価
Installation and Test of the Phase Drift Monitor at J-PARC Linac
WEOB09October 19th
16:30-16:50○チーチェック エルシン ，方 志高，福井 佑治，二ツ川 健太，溝端 仁志（高エネ研），佐藤 福克（NAT）○Ersin Cicek, Zhigao Fang, Yuji Fukui, Kenta Futatsukawa, Satoshi Mizobata (KEK), Yoshikatsu Sato (NAT)
H-CICEK Ersin (チーチェック エルシン )KEK, Accelerator Laboratory
J-PARC Center, Accelerator Division, 7th Section.
On behalf of J-PARC linac RF teamE-mail: ecicek@post.kek.jp
E. Cicek, PASJ22, Online

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Introduction; J-PARC linac
The phase drift monitor-PDM• Introduction: motivation• Hardware & software• Device installation• Long-term RF phase measurements results
Conclusions

E. Cicek, PASJ22, Online

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Introduction: J-PARC linac
J-PARC (Japan Proton Accelerator Research Complex)

Main parameters of the J-PARC linac
Particles→ H- (negative hydrogen)Peak current→ 50 mA
Pulse width→ 500 µs (Beam), 650 µs (RF)
Kinetic energy→ 400 MeV
Repetition→ 25HzAcceleration frequency→ 324 MHz, 972 MHz
Total of 49 RF stations; 24 (324 MHz) + 25 (972 MHz)• SDTL consists of two cavity tanks: “SDTL**A” and “SDTL**B”:• MEBT2B1, MEBT2B2 stations at MEBT2• ACS01 → ACS21• LLRF system with digital feedback (DFB) and feedforward (DFF) at each station.
[3] Z. Fang et al., ”Auto-tuning systems for J-PARC LINAC RF cavities”, Nucl. Instrum.
Methods Phys. Res. A., vol. 767, p.135, 2014. doi.org/10.1016/j.nima.2014.08.014

ISIon source

RFQ

Radio Frequency Quadrupole Linac

DTLDrift Tube Linac

SDTL

Separate-type Drift Tube Linac

ACS

Annual Coupled Structure Linac[1] I. Masanori, “Beam commissioning and operation of the J-PARC linac”, Prog. Theor. Exp. Phys., vol. 2012, p. 02B002, 2012. doi.org/10.1093/ptep/pts019[2] H. Ao et al., “First annular-ring coupled structure cavity for the Japan Proton Accelerator Research Complex linac”, Phys. Rev. ST Accel. Beams, vol. 15,
p. 051005, 2012. doi.org/10.1103/PhysRevSTAB.15.051005
E. Cicek, PASJ22, Online
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Phase drift monitor
Drift compensation systems;

The drift in the momentum of the injection beam must be within ±0.05%;

I) Using cavity phase monitors (CPMs) located at each RF station (extant).

• It is essential to stabilize RF eld in linac cavities✲Two frequencies are individually measured at CPMs.

• Humidity & temperature can cause drift in beam injection momentumII) A phase drift monitor (PDM) installed at MEBT2B1;

constant temperature and humidity

LINAC
LED

REFCLK❁Xilinx Zynq UltraScale+ RFSoC ZCU111 evaluation platform,✭Measure phase relationship between two frequencies simultaneously✭

RFTRIG
PDM @MEBT2B1

aLocal oscillator is not used.

FPGA & CPU
Xilinx ZynQ RF SoC

ADC07

ADC06

ADC05

ADC04

ADC03

ADC02

PLL

ADC01

ADC00

ADCLK

FPGAREF
constant temperature and humidity
RSVD

DFB
DFB
DFB
DFB
DFB
&DFF #1 &DFF #2 &DFF #3 &DFF #4 &DFF #5

to RCS
324MHz

Upstream
cavities&IS

ExtantUpdatedDeviceCavity phase monitor

Phase drift monitor

TechniqueDownconverter + IF sampling

Direct sampling

LO

Used

Not useda

Frequency

324 MHz✲ or 972 MHz✲

324 MHz✭ and 972 MHz✭Key point

Conventional

RFSoC❁

972MHz
L3BT

SDTL
15A

Parameters

SDTL
15B

SDTL
16A

SDTL
16B

MEBT2B1MEBT2
B2

ACS1
Downstream
cavities

Accelerator Tunnel

Installation

Drift compensation scheme:• SDTL16 and MEBT2B1 RF stations placed in a constanttemperature&humidity environment are the references,• Computing the RF phase differences with respect to the reference
phases (SDTL16 and MEBT2B1),• Compensation for possible drift in RF signals within the DFB system.

fi[1] K. Moriya et al., "Energy measurement and correction for stable operation in J-PARC", J. Phys.: Conf. Ser., 2019, 1350, 012140[2] K. Futatsukawa et al., "Performance of Cavity Phase Monitor at J-PARC Linac", IPAC2013, WEPFI017, Shanghai, China
WEOB09E. Cicek, PASJ22, Online

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Hardware & Software
The PDM architecture, by Mitsubishi Electric TOKKI System Co., Ltd (MELOS):• Xilinx UltraScale+ RFSoC ZCU111 evaluation board;❖ XCZU28DR-2FFVG1517 FPGA,❖ Embedded with EPICS IOC runs on the board itself.

• An analog front end; RF differential breakout card (AES-LPA-502-G) and baluns.
[3] ES-LPA-502-G, RF Breakout Card for Zynq UltraScale+ RFSoC[4] ADC wideband balun board (ADC-WB-BB)

Featuring the Zynq UltraScale+ XCZU28DR-2FFVG1517E RFSoC
RF Data Converter# of 12-bit ADCs

8

Max Rate (GSPS) (>1 GHz BW)

4,096# of 14-bit DACs

8

Max Rate (GSPS)

6,554

Communications & Networking

USB 3.0, SFP+, RJ45, USB UART/JTAGFPGA rmware;
Expansion Connectors• Data acquisition, DSP function
RFMC 1.0 → (RFMC (ADC) and RFMC (DAC)• On-board PLL clock generation
Add-on Cards• I/Q calibration (ROT)XM500 RFMC Balun Add-on Card (AES-LPA-502-G)• GUI using CSS software
The development studies;
FPGA & CPU• An individual lter coeff. for each ADC ch.

fifi𝛂fifi𝛂E. Cicek, PASJ22, Online

PLL(Clockgeneration)

1Ethernet

PS

16*2

ROT

16*2

LPF

LS monitor
MS monitor

16DDC

16*2

ROT

16*2

LPF
TBD

ADC(2n+1)

NCO
setting

a,b,cx1=4096

ﬁltercoeff.

PLL x8[PC&CSS]

16*2

VS

New reference clock(324 MHz)REFCLK
324[MHz]+3.8 dBm @50Ω

DDC

16*3

VS combination
ADC00 • ADC01
ADC02 • ADC03
ADC04 • ADC05
ADC06 • ADC071616balun

Differential input board
AES-LPA-502

y(n)=( )*[x(n)-y(n-1)]+y(n-1)

ADC04〜ADC07
972MHz, +0dBm

ADC(2n)2LS monitor
MS monitor

System implementation• Design and implementation ofADC-WB-BB
a cavity-based IIR lter in FPGA:balun
ADC00〜ADC03(simplest LPF, → lter coef)
324MHz, +0dBm

1/4/1/1

16*2

16*2

fadc: 3888 MHz

1.2VLVCMOSFPGAREF (121.5MHz)ADCLK (486MHz)

RFTRIG
5VTTL@50Ω
20•40 msec

levelconv.

PLL
LED

3.3VLVCMOS[1] Zynq UltraScale+ RFSoC ZCU111 Evaluation Kit”, https://www.xilinx.com/products/boards-and-kits/zcu111.html/[2] Mitsubishi Electric TOKKI Systems Corporation, http://www.melos.co.jp/english/products/WEOB09

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Performance analysis completion
The rst results, amplitude and phase stabilities, crosstalk ADC, etc., were reported.
To evaluate the drift in phase differences;• A commercial environmental test chamber (ESPEC PDR-3J),• LTC6954 evaluation board, SMB100A signal generator,• Reference phases

3 (324 MHz),7 (972 MHz).

[2] Espec temperature&humidity chamber

Providing a stable

Programmable temperature&humidity test chamber
Signal generator(SMB100A)

LTC6954

∆𝜙73

∆𝜙30

∆𝜙74

𝜙6fADC∆𝜙75

𝜙7fADC972 [MHz]system in terms of∆𝜙76

temperature&humidity
PDM

Ramping rate

Step

Phase drift [deg]
∆ 324

∆ 972

2℃/3 h( xed 65%RH)

1℃

25%RH/24 h( xed 27℃)

1%RH 1.20E-04 6.63E-04

1.23E-03 6.68E-03

PDM is ideal to be
implemented in the LLRF

ADC07

fADC

the MEBT2B1 LLRF control
rack:

ADC06

fADC

∆𝜙32

∆𝜙31
ZCU111

fADC

𝜙5𝜙4
ADC04

fADC

ADC03

ADC02

fADC

972[MHz]𝜙3𝜙2ADC01

PLL fADC

𝜙1ADC00

𝜙0324 [MHz]ADC05324 [MHz]REFCLK

RFTRG

FG

temperature&humidity insidecharacteristics.
Remarks∆ ref∆ 324 and ∆ 972 average drifts in phase
3.75E-02 differences (pp) of 324 MHz and 972 MHzchannels, respectively.
4.20E-04 ∆ ref:phase drift in relative phase difference
Relative phase difference→∆ 73=∆ 3-(∆ 7/3)

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𝜙

𝜑fi

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𝜑

𝜑fifi

E. Cicek, PASJ22, Online[1] E. Cicek et al., A Recent Upgrade on Phase Drift Compensation System for a Stable Beam Injection at J-PARC
Linac, IPAC2021, Campinas, SP, Brazil

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Installation
Installation at the MEBT2B1 LLRF control rack;
Constant temperature&humidity environment (for SDTL16 andMEBT2B1 RF stations)
3/8" foam dielectric, phase-stabilized Andrew Heliax coax cables,
Front panel mount SMA cables.
f@324 MHzf@972 MHz

Cavity

SDTL
15A

SDTL
15B

SDTL
16A

SDTL
16B

@PDM

0_pdm

1_pdm

2_pdm

3_pdm

VS
phase

01_vs

23_vs

(SDTL15VS)(SDTL16VS)

MEBT2 MEBT2
ACS1
B1
B2
4_pdm

5_pdm

6_pdm

Remarks
and 23_vs are thereference phases, and
VS: vector sum

f@972 MHzf@972 MHzf@324 MHz
Cavity phase diff. MEBT2B2-MEBT2B1 ACS1-MEBT2B1 SDTL16VS-SDTL15VS∆ @PDM∆ 54_pdm

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𝜙

E. Cicek, PASJ22, Online𝜙⭐︎

𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙

𝜙

Installation & Long-term RF phase measurement∆ 64_pdm∆ 2301_pdm

4_pdm

The extant drift compensation system works well…
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Cavityphasediff.
@PDM

f@324 MHzf@972 MHzSDTL15A SDTL15B SDTL16A SDTL16B MEBT2B1 MEBT2B2 ACS10_pdm

1_pdm

2_pdm

@CPM

1_cpm

2_cpm

VS phase

01_vs

3_pdm

f@972 MHzf@324 MHz

Cavity phase diff.

MEBT2B2-MEBT2B1

SDTL16A-SDTL15B

4_pdm

5_pdm

6_pdm

∆ @PDM∆ 54_pdm∆ 21_pdm

4_cpm

5_cpm

6_cpm

∆ @CPM∆ 54_cpm∆ 21_cpm

23_vsPhase differences compared with permanently
installed and successfully operated CPMs:• EPICS archiver appliance for data storage.
Consistency between PDM and CPMs,
No change in the center of phase differences,
Stable temperature and humidity in theMEBT2B1 rack.
MAF → moving average lterfi𝜙𝜙𝜙𝜙𝜙𝜙

E. Cicek, PASJ22, Online
𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙𝜙

𝜙Long-term RF phase measurement cont’d

WEOB098/11

Relative phase difference∆ rel relative phase difference derived from phase differences between two different
frequencies of 324 MHz and 972 MHz;∆ rel = ∆ 23_vs - (∆ 4_pdm/3)
324 MHz(Reference @324 MHz) (Reference @972 MHz)(ADC03 ch.)
(ADC04 ch.)972 MHz∆ 23_vs and ∆ 4_pdm denote phase changes (pp) in the reference channels ofADC03 (SDTL16 VS) and ADC04(MEBT2B1), respectively,
Data was evaluated on the PDM for about 1-week.

Phase difference

SDTL16VS

MEBT2B1∆ rel @PDM

∆ 23_vs∆ 4_pdm

The relative phase difference tends to besimilar to the;• Humidity change in the klystron gallery,• Or, humidity change in the optical duct,
where RF reference signals are distributed.
PDM is a good candidate to compensate forthe drift in the relative phase difference.

𝜙𝜙𝜙

𝜙𝜙

𝜙𝜙𝜙

𝜙

E. Cicek, PASJ22, Online[1] K. Futatsukawa et al., "Upgrade of the RF Reference Distribution System for 400 MeV LINAC at J-PARC", IPAC2012,
WEPPD050, New Orleans, Louisiana, USA
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Conclusions
Phase differences between 324 MHz cavities and their respective reference phase, as well as that of 972 MHz cavities, aremeasured to be stable for the long-term on the CPMs and PDM.
However, we have found that environmental factors, particularly humidity changes, cause long-term phase drift in the relative
phase difference, critical information for stabilizing accelerating RF elds through linac cavities operating at two differentfrequencies.
The source of variation in the relative phase difference is thought to be humidity change in the optical duct or klystron gallery.
➡ The PDM will be employed within the LLRF system to compensate for possible phase and amplitude drifts in cavity RF signals
by eliminating environmental effects, which is crucial for a stable long-term operation.

WEOB09 10/11fiE. Cicek, PASJ22, Online

Special thanks the staff members of Mitsubishi Electric TokkiSystems Co., who implemented a perfect phase drift monitor forthe J-PARC linac.
We also thank the Mitsubishi SC members for their excellent
work during the device installation.

Thank you for your attention.
ご静聴ありがとうございました。

E. Cicek, PASJ22, Online

WEOB09 11/11