The 13th Symposium on Accelerator Science and Technology, Suita, Osaka, Japan, October 2001

Performance of various Hall generators for 3-axis magnetic field measurements
E. Kusano, K. H. Tanaka, K. Agari, M. Ieiri, Y. Katoh, Y. Sato, Y. Suzuki, M. Takasaki, H. Noumi,
M. Minakawa, and Y. Yamanoi
BH-703's, which is the smallest in F.W.BELL's Hallsensors.
3D-H-30-C made by GMW [5] Co. in U.S. is a novel
single-chip Hall sensor, which can measure 3-axis
The principle ormagnetic field simultaneously.
characteristic is detailed in the reference 5. The 3-D-H30-C Hall sensor is basically a square block of lowdoped silicon fitted with 8 ohmic contacts at the surface.
The current runs in the surface of square block, and eachface generates Hall voltage. The unique vertical Hall
geometry allows the extraction of the information about
the three magnetic field components simultaneously atthe exactly same spot in space within a cube of O.lmm.
Since Electrical connection consists of only two energy
supply contacts and only four sense contacts, it can be
operated remarkably low current, i.e. 3mA, for the 3-axis.

Abstract
Now we are preparing a new 3-axis magnetic fieldmeasurement system based on Hall sensors. In thisreport, we would like to describe the selection of the Hallsensors for the system. Some domestic Hall sensors canbe driven with low control current, high output Hall
voltage, and small temperature dependence. The price ofthem are incredibly low. We studied their performanceby using a dipole magnet whose maximum flux density
is 2.4 Tesla.

1 INTRODUCTION
We have to manage a few hundreds of magnets
equipped in the neutrino beam line and other externalbeam lines of the KEK-PS. Since the construction of the50-GeV Proton Synchrotron at the KEK/JHF andJAERI/NSP joint accelerator project [1] has started, we
will have to manage more and more magnets soon. Then
we need a new 3-axis magnetic field measurement
system, which is sensitive, speedy, and lower cost.
Recently, Hall sensors are used widely, for example,
door switches in refrigerators and washers, rotational
speed sensors of motors of CDs, and so on. Since huge
numbers of Hall sensors are produced and used, theprices of them are going down and their quality is being
improved well. Then we checked their performances up
to high magnetic field.

2CHARACTERISTECSThe number of Hall generators researched in thispaper was 11. Their electrical characteristics are listed inTable 1.
F.W. BELL [2] is a famous company for its Hallsensors for a long time. The BH-703 has been used andmade a good job in the accurate measurements of ourmagnetic field measurement system for more than 10years. However typical output Hall voltage is too low inspite of the relatively large operation current. In addition
it is too expensive for us.
Hall generators of domestic companies of National (3]and ASAHI-Kasei [4] seem better than F.W.BELL's.
Their control current is small, i.e. a few rnA. Output
voltage to the same magnetic field is approximately 10
times higher than F.W.BELL's. Especially, OH023's
operation current is only 1.5 rnA. It can be operated by adry battery. Then we can make a portable fieldmeasurement system without using the specific power
supply. Their temperature dependence also is as small asTemp.
coef. ofHall
voltage[%/"C]-0.04

TypicalOutput
Matevoltage
ModelMaker
rial[mV/O.lT]
10In As
BH-703
BELL
150
OH003
150
OH008
6
Natio-0.06
105
GaAs
OH009
nal
105
OH010
90
1.5
OH023
175
HW105C
-1.8
InSb
175
ASAH HW108C
5170
I-Kasei HG106A
-0.06
GaAs
130
HG106C
X,Y:27.5
3D-H-300.1
3Si
GMWz: 10c
Table 1: Electrical Characteristics of each Hall generator.
OperationCurrent
[rnA]
100

3. MEASUREMENT
The dipole magnet used for this measurement is seenin Fig. 1. The maximum flux density is 2.3 Tesla. The
stability of magnet power supply is better than 10_.. TheHall sensors were mounted in a plastic plate seen in Fig.
2. This plate was inserted into the gap of the magnet andset parallel to the magnet pole face. The Hall sensors
were driven by constant current mode. The stability ofcurrent supply to Hall sensors is within ±0.02%. The
output voltage was read by digital voltmeter. Each Hallsensor was directly connected to the current supply andthe digital voltmeter by twisted cables. The response ofthe each axis of the GMW' s tri-axial Hall sensor wasmeasured independently. In order to set perpendicularly-55-The 13th Symposium on Accelerator Science and Technology, Suita, Osaka, Japan, October 2001

between each axis of the Hall sensor and the direc.tion of
the magnetic field, it was mounted on a plastic cube.
Absolute value of the magnetic field was measured by
NMR at the same time.

Figure. 1 The magnet used for the field measurement.

HG106A and HG106C generate approximately 1.8V at 2Tesla, and linearity is good. HW108C and HW105C
made from InSb reach approximately 2.5V at 2 Tesla.
However their outputs are not linear as clearly seen inFig. 5. Then a simple quadratic function was used forthe fitting and for deducing the non-"linearity". Then thenon-"linearity" for HW108 and for HW105C are plottedin Fig. 6 and are found to be a few percent.
The output voltage of the three independent axis of
GMW's tri-axial Hall sensor is plotted in Fig. 7. The F.W.
BELL's output voltage is showed in Fig. 7, too. It isfound that generated voltages of F.W. BELL and GMW
are very low, e.g. approximately 0.6V at 2 Tesla in the xand y axes of GMW' s and approximately 0.1 V at 2 Teslain the z axis of GMW's and BELL's.
The output non-linearity of BELL's and at each axis ofGMW' s are plotted against the magnetic flux density andshown in Fig. 8. It is found that the linearity at x and yaxes of GMW's is surprisingly good within 0.3% from
0.15 Tesla to 2.3 Tesla. Due to the device geometry, thesensitivity at two in-plane axes, x and y, is different
from that at the other perpendicular axis, z. Then we
fitted the output voltage at z-axis of GMW' s by a simple
quadratic function similar to the InSb devices. Theoutput non-linearity of BELL's and at z axis of GMW's
is approximately 2%.
3···························· ··························································································································Figure. 2 The hall probes mounted on the plastic plate.

4. RESULTS
Measured output Hall voltages of National's Hallsensors are shown in Fig. 3 as a function of magnetic
flux density. It is found that measured output Hall
voltage can be represented by a linear function of themagnetic field.
OH003 and OH023 generate
approximately 2 V at 2 Tesla. OH008, OH009 andOHOlO generate approximately 1.7 Vat 2 Tesla. In Fig.
4 the non-linearity of them are shown as a function of theflux density. Non-linearity[%] is represented by,

Magnetic Reid [Tesla]

I• OH003 II OHOOB .. OH009 1(1! OH01 0 :1: OH023I

Figure 3. The output voltage of each National's Hallsensor plotted as a function of magnetic flux density.
2 ~~r+-.------r-----,.-----,.-----~
1.5 H-il-+--+-'l'-+- -----1--------t- ------11------i~-~

0.5 1-H-+---'1tt--- -+---l-----+--- :c7"''-:=.....-i~ 0 ~~Si~~~~~~~~~~~~~~j'g -o.5 L
H+...,P..--H>...---+-----+:~~'-+------i•

Non-linearity[% ]= (Vobs- vexp) X 100 I vobs"
Here Vobs is the measured Hall voltage and Vexp is theexpected Hall voltage calculated from the fitted function.
OH008, OH009 and OHOlO keep their linearity within
1% between 0.15 Tesla and 2.3 Tesla. OH003 andOH023 is little worse.
Similarly, Fig. 5 and 6 illustrate magnetic fielddependence of measured Hall voltage and the nonlinearity of ASAHI-Kasei's Hall sensors, respectively.

z-56--1-1.5 H-ll--+----- '"c---+--+1 ----+------i-2=----_l_____ j __ _ _ _lMagnetic Field [Tesla]

1-+- OH003 -11- OHOOB -.~r OH009 ·*"- OH01 0 ""*"" OH023IFigure 4. The non-linearity of each National's Hallsensor plotted as a function of the flux density.

The 13th Symposium on Accelerator Science and Technology, Suita, Osaka, Japan, October2001

21.5~-~ 0.5::..

15 1.5 t----+----+af2'---h"""' '-----f------iiii:5>~

0T!5 ~.5z

1-1-1.5
0.5

1.5
Magnetic Field [Tesla]

2-2

2.5

I.

.,;~·

,/~

.

............""'.../''.\ 0 5

I··•···..

""''·::>,. ~--1::.!!.

,, ""''"~·····~·······~·; 5~;__:~

2l5'· l~--'"l"'J.

I

Magnetic Field [Tesla]
1-+-GMW X ...... GMWI• HG106A" HG106C "' HW108C "' HW105CI

Figure 5. The output voltage of each ASAHI-Kasei's
Hall sensor plotted as a function of the flux density.

y ·J>·GMW z ~il- BELLI

Figure. 8 The output non-linearity at each axis of
GMW's Hall sensor, and a F.W.BELL's Hall sensor.

5. CONCLUSION~~ 0.5:~

0 f-+-i---\f-~,'----t'r--""+"\lr-;;;;"'1~.5 ~~-~~--~~-~~?~-~~-~
0z-1-1.5 1-+-l----,c-+---'ll~-h.,_....--+----l-----i-2
Magnetic Field [Tesla]
I-+-HG106A ..... HG106C "'*" HW108C ·t>· HW105CI

Figure. 6. The non-linearity of each ASAHI-Kasei's
Hall sensor plotted as a function of the flux density.

0.8 r - - - - - - + - - - - t - - - - - j - - - - - j - - - - - jo~~~~~L____L____L___~

00.5

1.5
Magnetic Field [Tesla]

2The output Hall voltages of various Hall sensors weremeasured up to high magnetic field of 2.2 Tesla. For allsensors non-linearity of the measurements is only a few
percent in fields as high as 2.2 Tesla. Non-linearity ofOH008, OH009, OHOIOand the direction of x, y of 3DH-30-C was approximately 1 % or less in the flux density
up to 2.2 Tesla. However, due to the geometry, 3D-H30-C has a few percent of cross-sensitivities between thethree axes [5]. So it may not be appropriate for the exact
magnetic field measurement system. Since OH023 or3D-H-30-C has a feature of low power consumption, it isuseful for battery-powered application, e.g. a portable
polarity-checker or a portable field measurement device.
We have made some portable ones, which have alreadybeen used in our beam lines. From this examination ofeach Hall sensor, it can be concluded that theperformance of the new 3-axis magnetic fieldmeasurement system will be improved on better linearity,
higher output voltage, and lower power consumption if
we use either OH008, or OH009, or OHOIO. Our nextstep about the Hall sensor is to assemble 3-axis sensor
complex with the temperature control within 0.1 "C.

2.5

REFERENCES

I• GMW X " GMW y .. GMW z ,,, BELLI

Figure. 7. The output voltage of each axis of
GMW's Hall sensor, and a F.W.BELL's Hall sensor.

[1] The Joint Project team of JAERI and KEK, "TheJoint Project for High-Intensity Proton Accelerators",
KEK Report 99-4, 1999.
[2] http://www.fwbell.com/[3] http://www.panasonic.co.jp/semicon/[4] http://www.asahi-kasei.co.jp/ake/e/index.html[5] http://www.gmw.com[6] Ch. Schott and R. S. Popvic, "Integrated 3-D Hall
Magnetic Field Sensor", http://www.gmw.com-57-