An instrument for precision magnetic measurements of large magnetic structures

D. Beltrán, J. Campmany, J. Bordas A. Molins, J. Perlas, J. Rosich, M. Traveria

1 st-October-2001

Outline

� Introduction

� Design requirements

� Performance

� System description

� Real examples

� Conclusions

LLS (Spanish synchrotron light source) at Barcelona

Characterize B in Bending, Quadrupolar and higher order magnets

• ∆∆∆∆B < ± 2 Gauss (B < 1.4 T)

• Scan a Volume 500 x 250 x 3000 mm3

• Position confusion < ± 50 µµµµm

• Hall probe motion re-programmable

• Anti-vibration floor (50µµµµm)

• Magnet support (6000 Kg)

• Hall probe bench (500x250x3000 mm3)

X

Y

Z

1. Parallelism magnet-bench 2. Translation vector magnetic struc.-bench

Reference magnet mechanical center to arm coordinate system

• Hall probe

• Hall probe power supply

• Voltmeter

Manufactured by Sentron

450 mV/T ±10%

• Calibration system

• Reference Magnet ∆∆∆∆B/B < 15 ppm

• DC Power converter ∆∆∆∆I/I < 2 ppm

• Magnetometer ∆∆∆∆B < 0.02 G

• Temperature controller

• Magnet power converter

• Cooling system

RS-485

CPUCM-cpu40

SWITCHETHERNET

CPUMVME147

GPIB

PMAC

PS Danfysik Calibration Magnet

Metrolab PT 205 NMR Probe

Motor, drivers,encoders

Mechanical arm

HP3631A

Keithley 2010

Eurotherm 2408

Philips Digital 280

PS Enertrón

Magnetundertest

Hall probe

ETHERNETVMEGPIBRS-232RS-485

Operatorinterface

I/Ocontroller Devices

ETHERNETSWITCH

MedmCA client

Operator Inte rface

GUI

CA Server

CA client

Sequencer C Lib

Registers: ai, ao, strin, strout

Applica tion code

Database

Input/Output Controller

Device DriverGPIB RS-232 RS-485 PMAC

LAN

Alarm Handler

Toolkit EPICS

29/7/9917:45magma990729-1745.binNormalMeasurement2000Magnet #9Hour minute second TH Tin Tout X(mm) Y(mm) Z(mm) Vx(mV) Vy(mV) I(A)16 9 20 0.0 0.0 0.0 200.000 0.000 1000.000 4.567 352.848 0.0016 9 22 0.0 0.0 0.0 200.000 0.000 1010.001 4.581 353.016 0.0016 9 25 0.0 0.0 0.0 200.000 0.000 1020.000 4.234 352.826 0.0016 9 28 0.0 0.0 0.0 200.000 0.000 1030.000 4.590 353.002 0.0016 9 30 24.0 18.0 32.9 200.000 0.000 1040.000 4.621 352.832 849.9616 9 33 0.0 0.0 0.0 200.000 0.000 1049.999 4.432 352.999 0.00...

FINISHED

NEXTPOINT

DAQ

INIT

IDLEIDLE

ERROR

ANYANY

CONTINUE

INIT

NEXTPOINT

FINISHED

DAQ

NEXTPOINT

DAQ CONTINUE

ANY

ERROR

ANY

Labview

Total systematic ± 1.6 Gauss

Total random ± 0.4 Gauss

Error source Rnd/Syst Relation with B Worst case

Magnet power supply (∆I1) Syst ± 0.28 GaussII

BB 1∆=∆

Hall probe power supply (∆V1) Syst ± 0.25 Gauss1VVBB ∆×=∆

Multimeter (∆V2) Syst ± 0.12 Gauss2VGainB ∆×=∆Calibration Error (∆Β1) Syst ± 0.9 Gauss1BB ∆=∆

Temperature (∆T1) Rnd ± 0.15 Gauss14 )105.0( TBB ∆×+=∆ −

Hall probe power supply (∆V3) Rnd ± 0.02 Gauss3VVBB ∆×=∆

Cable noise (∆V6) Rnd ± 0.04 Gauss6VGainB ∆×=∆Hall probe noise (∆V5) Rnd ± 0.4 Gauss5VGainB ∆×=∆Multimeter (∆V4) Rnd ± 0.03 Gauss4VGainB ∆×=∆

� LLS Bending magnet prototype

� ANKA storage ring bending magnets

� CLS combined magnets

• High precision measurement system (±2 Gauss)

• Large volume (250x20x300 mm3) with high precision (±50µµµµm)

• Easily adapted of a wide range of magnets

• In situ data analysis

• Proved: LLS prot., Anka bending, CLS prototype

• Movement + acquisition: 2.5 s per point