Beam Position Monitoring SQUID array Andrei Matlashov A
Beam Position Monitoring SQUID array Andrei Matlashov, A Selcuk Haciomeroglu, A Yong-Ho Lee, B AIBS/Center for Axion and Precision Physics, BKRISS Daejeon, Korea andrei@ibs. re. kr
IBS/CAPP and KRISS Collaboration
G 1 Beam Position Monitoring SQUID system Magnetically shielded room FLL Electronics - Acquisition/Analysis Dewar DC power/ SQUID control/ SQUID Gradiometers 8 channels
Axial Wire-Wound First-Order Gradiometers SQUID Superconducting wire 50 mm Pickup coil Φ 20 mm d. Bz/dz Pickup coil: Diameter 20 mm, baseline 50 mm
Wire-wound Pick-up Coils Bonding Conventional bonding (Star Croelectronics) KRISS method SQUID chip Nb bonding Nb block Direct bonding Stray pickup area: 0. 3 mm x 2 mm = 0. 6 mm 2 Imbalance = 0. 1 % Better SNR or lighter MSR Diameter 20 mm: A=628 mm 2
3 -Layer Magnetically Shielded Room at CAPP
SQUID Electronics Flux-lock loop circuits DC-power and acquisition High-pass filter: 200 Hz Low-pass filter: 2 k. Hz Sensitivity: 1. 0 n. T/V and 0. 01 n. T/V with Gain = 100 LSB: 15 × 10 -15 T and 0. 15 × 10 -15 T with Gain = 100
G 2 Beam Position Monitoring SQUID system Number of SQUID magnetometers: 2 × 8 Pickup coil: 2 -turn wire-wound magnetometer, Ø 17 mm SQUIDs-in-Vacuum Design Superconductive Shielding Superconducting Imaging Surface the First-Order Gradiometers Horizontal Cylindrical Dewar System Field Resolution: 1. 2 f. T/√Hz @1 k. Hz
G 2 Beam Position Monitoring SQUID system Liquid He Vacuum SQUID magnetometer To p-beam line
Cylindrical Dewar: Schematic OD 230 ID 70 Magnetic Shielding (optional) 250 Mag. shielding ID 344 900 Length 500 Volume 43 L 440 S. C. shielding SQUID OD 650 700
Superconducting Imaging Surface
Cylindrical Dewar: Cross-section
Cylindrical Dewar: Assembly
Cylindrical Cryostat: Re-Liquefier OD 230 ID 70 250 Mag. shielding ID 344 S. C. shielding OD 650 900
16 channel SQUID Magnetometers Array
Magnetometer Design
Magnetometer Parameters Parameter Value Unit Number of pickup-coil turn 2 Turn Nb wire diameter 0. 13 mm Pickup coil diameter 17 mm Pickup coil inductance Lp 213 n. H Input coil inductance Li+Lf 202 n. H Mutual inductance Mi (Ls: Li) 4. 78 n. H Pickup area Ap 454 mm 2 Transfer coefficient (B/Φ) 0. 4 n. T/Φ 0 Flux noise 3. 0 μΦ 0/√Hz Field resolution 1. 2 f. T/√Hz
New Generation SQUID Magnetometers 0. 33 f. T/Hz 1/2 Pick-up Loop: 12 × 12 mm 2 Noise = 0. 33 f. T/Hz 1/2 Pick-up Loop: 24 × 48 mm 2 Noise = 0. 11 f. T/Hz 1/2 IPHT, Jena, Germany (2011) Supercond. Sci. Technol. 24 (2011) 065009(5 pp) doi: 10. 1088/0953 -2048/24/6/065009
SQUIDs Control Electronics and PS
16 channel SQUID Electronics Flux-lock loop circuits DC-power and acquisition Output: Digital, optical High-pass filter: 200 Hz Low-pass filter: 2 k. Hz Optimum signal frequency range: 500 ~ 1, 000 Hz
SQUID Read-out and Control Electronics Flux-Lock-Loop box Control External trigger port Analog-to-digital converter 24 -bit resolution 10 k. Sample/s
Optical Controls and Read-outs Computer (Digital I/O) FLL input (digital/serial) Trigger input (Electrical or optical) 16 bit resolution 10 k. Sample/s per channel FLL output: Optical signal FLL control output
BMP Signals Triggering and Averaging 1 ms 1 s e. g. fm=1 k. Hz Signal Trigger <Measured data> Ch 000 . . . Ch 5 Ch 4 Ch 3 Ch 2 Ch 1 Trigger 1 epoch 1000 epochs/s
SQUIDs Control Software
SQUIDs I-V and V-Ф monitoring and adjustment
Data Acquisition and Averaging Acquisition (Saving) window Real time averaging window During data saving, real time averaging window appears. Data are saved every 20 s (default value).
BMP Systems in the Storage Ring … Optical transmission (signal & control) Storage ring ADC: 16 bit, 10 k. S/s sampling Data (1000 s/epoch) 16 -ch Module <Control/Acquisition> Interference-free control Noise-free acquisition No time-delay bet. modules <Averaging/Analysis>
SUMMARY v The First generation (G 1) of BMP system: tested at KRISS and moved to CAPP for further tests and research. v The Second generation (G 2) of BMP system: designed, all key components manufactured; it will be assembled in May 2018. v Field Resolution: current G 1 system 3. 5 f. T/√Hz @1 k. Hz v Field Resolution: under construction G 2 system 1. 2 f. T/√Hz @1 k. Hz v Field Resolution: new generation SQUIDs 0. 15 f. T/√Hz @1 k. Hz
THANKS FOR YOUR ATTENTION !
DC SQUID Noise In RJ I 0 RJ = Vn Rd ~ 0/4 applied I L n 0 Rd (N+1/2) 0 V 1. Circulating current noise due to 2 RJ: In=(4 k. BT/2 RJ)0. 5 SQUID inductance: L Flux noise=In×L={4 k. BT(L 2/2 RJ)}0. 5 2. Voltage noise due to SQUID dynamic resistance Rd: Vn=(4 k. BTRd)0. 5 Flux-to-voltage transfer: V Flux noise: Vn/V =(4 k. BTRd/V 2)0. 5 Total flux noise (intrinsic): n={4 k. BT(L 2/2 RJ + Rd/V 2)}0. 5 = ~L/Rd 0. 5
Single-chip Magnetometers from IPHT, Jena Sub-micrometer Josephson junctions Intrinsic noise: 0. 33 f. T/√Hz
UC Berkeley Ø 63. 5 mm Gradiometer Single-channel dewar ez-SQUID Sensitivity: 0. 7 f. T/√Hz 63. 5 mm 76 mm
LANL Ø 60 mm Gradiometers 2 nd-order gradiometer 1 d=37 mm, b=60 mm, Noise: 1. 2 -2. 8 f. T/√√Hz at 1 k. Hz 2 nd order gradiometer 2 d = 90 mm, b= 90 mm, Noise < 0. 5 f. T/√Hz
Preamplifier Noise Contribution In direct readout mode Current bias Rw @Tav SQUID Rd Voltage output V n, I n 4. 2 K Preamp. Noise of SQUID system: Φ 2 intrinsic + Φ 2 preamp Preamplifier noise contribution: Φpreamp=Vn, tot/(δV/δΦ) Vn, tot = {Vn 2 + In 2(Rd+Rw)2 + 4 k. BTSQRd + 4 k. BTav. Rw}0. 5
Low-noise Preamplifier Single-ended Lower input noise Higher ground noise Differential Higher input noise Less ground noise
Preamplifier Noise Moderate input voltage noise Moderate input current noise cf) Low input voltage noise High input current noise Large Rd: In. Rd>Vn
KRISS Whole-head MEG System B/Φ: 0. 46 n. T/Φ 0 @ 100 Hz 2. 5 f. T/√Hz
Subjects Category 2014 2015 2016 2017 SQUID magnetometer and control electronics system Low-noise SQUID system for p. EDM Research outcome Pretest SQUID system 8 -ch SQUID system, 3 f. T/Hz 2018 2019 Ultra-low-noise SQUID magnetometer and control electronics system Hollow cylindrical dewar, Superconductive shielding, optimization 16 ch SQUID system, system noise 3 f. T/√Hz System noise (@ 1 k. Hz) 2 f. T/√Hz 1. 5 f. T/√Hz (@ 1 k. Hz)
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