Hall Effect Magnetic Flux Sensor in very Strong Magnetic Fields

In summary, the conversation is about finding a good Hall-effect magnetic flux sensor that can handle a very intense magnetic field (16.5 Tesla) and be accurately aligned with the main field. The individual has considered using the Lakeshore Hall device HGT-3030, but it is difficult to find and they are looking for alternative options. They have also mentioned the use of Metglas and have requested suggestions for commercial models with easy application notes. There is also discussion about the physical size of the sensor, the desired measurements (intensity, direction, variations), and the potential impact of the sensor on the local magnetic field. Some resources and suggestions have been provided, but the individual is still looking for more help.
  • #1
_maxim_
105
6
Dear PFs

I am facing a problem with finding a good Hall-effect magnetic flux sensor which should be fixed in the top of a probe working in a very intense magnetic field.

The probe must be aligned to a certain degree with respect to the direction of the main field. The requested alignement accuracy should be on the order of 1/10 of degree (or less even better).

The magnetic field is very strong, of the order of 16.5 Tesla (16.5 x 10^4 Gauss).

I had thought to place the sensor in parallel geometry, with its plane oriented parallel to the magnetic flux lines. Thus I expect to detect a zero voltage when the sensor is perfectly aligned to the main field, and a not-zero voltage which depends strongly on the angle between the direction of the main field and the normal to the sensor surface.
Afterwards I will try to elaborate such voltages (VH) to get a feedback for the correct alignement.

http://img692.imageshack.us/img692/5579/hallfield.png [Broken]

Here's the problem: which kind of sensor can I test?
I've drawn my attention to the Lakeshore Hall device HGT-3030, but it seems to be very difficult to find.

Any experience here?

Can you suggest some commercial models with a easy schematic diagram or application note?

Thanks for your enthusiastic responses!

max
 
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  • #2
might Metglas be of any use?

here's a hobbyist article..see page 2 0f 6.
http://www.tinaja.com/glib/muse104.pdf

and
http://www.metglas.com/faq/?faq_id=24
Question:
What is the permeability of 2714A?
Answer:

Our METGLAS 2714A ribbon can achieve a permeability of 100,000. The ribbon thickness is about 18 micron and we can supply up to 50 mm (2 inch) wide ribbon.
 
  • #3
Thanks Jim.

I think I need a more sophisticated device, as Linear Hall Effect Sensor ICs with a low linearity error and a good magnetic sensitivity.
 
  • #5
HGT-3030 Transverse Hall generator costs $444...

Magnetic sensitivity . . . . . . . . . . 6.0 mV/kG to 10.0 mV/kG
Nominal control current . . . . . . . 100 mA
Maximum linearity error . . . . . . . ±0.30% rdg (-10 to 10 kG) ±1.25% rdg (-30 to 30 kG)
Zero field offset voltage . . . . . . . ±75 µV (max)
Operating temperature range . . . . -40 ºC to +100 ºC
Active area . . . . . . . . . . . . . . . . 1.02 mm diameter



Honestly, I was looking for an equivalent inexpensive device.
 
  • #6
No more ideas? :(
 
  • #7
What physical size must this apparatus be?

What is it about the field that you want to measure? Intensity, direction, variations?

I have only tinkered as a hobbyist with a fluxgate magnetometer measuring Earth's field and i don't have experience with fields as strong as you cited, which sounds like it might be in a speaker voicecoil airgap or something. I also tinkered with some LVDT position sensors (12 feet tall) at work... another story ...

My magnetometer sensed from kitchen table automobiles passing in the street, refrigerator door opening, it had surprising sensitivity. But you are looking for precise measurement of direction? Will your apparatus affect the local field?

Jack M Janicke's Magnetic Measurements Handbook is best "poor man's" introduction to the subject that i ever saw.
Here's Honeywell's introductory appnote.
http://www51.honeywell.com/aero/common/documents/Applications-of-Magnetic-Position-Sensors.pdf

Sorry - i just am not expert in that field, so shotgunned you with what i could find 'cause you asked for help and there didnt seem to be much.
I don't know your degree of familiarity so hope you aren't offended.


old jim
 
  • #8
http://www.diodes.com/datasheets/ZMT32.pdf
 
  • #9
jim hardy said:
What physical size must this apparatus be?

What is it about the field that you want to measure? Intensity, direction, variations?
Hi Jim,

as wrote at the beginning the magnetic field I need to handle is very strong, of the order of 16.5 Tesla (16.5 x 10^4 Gauss)!


I have only tinkered as a hobbyist with a fluxgate magnetometer measuring Earth's field and i don't have experience with fields as strong as you cited, which sounds like it might be in a speaker voicecoil airgap or something. I also tinkered with some LVDT position sensors (12 feet tall) at work... another story ...
Yes, my application is not trivial. I need to measure flux variations of a strong magnetic field over an area of c.a. 1mm2 with high accuracy.

My magnetometer sensed from kitchen table automobiles passing in the street, refrigerator door opening, it had surprising sensitivity. But you are looking for precise measurement of direction? Will your apparatus affect the local field?
The sensor will be placed inside the magnetic field, where a probe for nuclear measurements must be aligned to the lines of force.


Jack M Janicke's Magnetic Measurements Handbook is best "poor man's" introduction to the subject that i ever saw.
Here's Honeywell's introductory appnote.
http://www51.honeywell.com/aero/common/documents/Applications-of-Magnetic-Position-Sensors.pdf
Nice, I will have a look.

Sorry - i just am not expert in that field, so shotgunned you with what i could find 'cause you asked for help and there didnt seem to be much.
I don't know your degree of familiarity so hope you aren't offended.
old jim

Com'on, where is the problem? :biggrin:

Thank you for your help!
 
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  • #10
It sounds fascinating and i wish i had experience to offer you.

But i'd get distracted trying to invent a new sensor out of Flint glass and Faraday effect.:rolleyes:


Best of luck to you, sir, and thanks for your kindness.

old jim
 
  • #11
My advice would be to just buy a proper sensor. The fact that you are working with a 16T magnet means that you are using reasonably sophisticated equipment (you are obiously not doing this in your basement at home), and $400 is not much money under these circumstances.
Also, remember you will -regardless of what you end up using- need some form of reasonbly accurate read-out electronics; and good sensor will probably easier to read out, meaning you won't need a a bunch of extra kit just to compensate for the fact that your sensor is e.g. giving you a very weak signal.
 
  • #12
Hi f95toli

f95toli said:
My advice would be to just buy a proper sensor. The fact that you are working with a 16T magnet means that you are using reasonably sophisticated equipment (you are obiously not doing this in your basement at home), and $400 is not much money under these circumstances.

:smile: In these circumstances $400 is too much when you have to pay from your own pocket...
I guess the driving of such a sensor is not trivial, and I have no experience on that.


Also, remember you will -regardless of what you end up using- need some form of reasonbly accurate read-out electronics; and good sensor will probably easier to read out, meaning you won't need a a bunch of extra kit just to compensate for the fact that your sensor is e.g. giving you a very weak signal.

This I know; infact I was looking for a HGT-3030 Lakeshore sensor.
In the meantime I hoped to find here peple with some experience in projecting of interfaces for Hall sensor, just to avoid lost of time fighting the silliest problems.

Perhaps another thread would be most suitable?


Thanks anyway for your input!

maxim
 
  • #13
Get that Janicke book.

I hope he's still living - we exchanged several emails on my magnetometer.
He is very knowledgeable practical and helpful.
old jim
 
  • #14
Hi Jim,

I've found it on Amazon. I will (re)start from that.
 
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  • #15
How are you making a 165 kilogauss field?
This high a magnetic field requires extremely expensive equipment.
 
  • #16
Carl Pugh said:
How are you making a 165 kilogauss field?
This high a magnetic field requires extremely expensive equipment.

It is a commercial cryomagnet made with superconductive wires working at the liquid Helium temperature (4.2 K). This has not been bought by myself, rather by the lab that asked my expertise. There is no budget saved for the project "Hall-sensor".
That's why I am looking for an unexpensive solution: this should get out of my wallet.
Unfortunately for me it seems that only (expensive) Lakeshore sensors are on the horizon...
 
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  • #18
Hi Jim,

Thanks for the tip.

ZMT32 is in stock but for applications under low field conditions, which is not the case.

I think what I would do in my case, it would be something in the middle between ZMT32 and HGT-3030
 

1. What is a Hall Effect Magnetic Flux Sensor?

A Hall Effect Magnetic Flux Sensor is a type of sensor that is used to measure the strength and direction of magnetic fields. It works by detecting the Hall effect, which is the creation of a voltage difference across a conductor when it is placed in a magnetic field.

2. How does a Hall Effect Magnetic Flux Sensor work?

A Hall Effect Magnetic Flux Sensor works by using a small piece of semiconductor material, typically made of gallium arsenide, placed in a magnetic field. When a current is applied to the sensor, it creates a voltage difference across the material, which is then measured and used to calculate the strength and direction of the magnetic field.

3. What makes a Hall Effect Magnetic Flux Sensor suitable for use in very strong magnetic fields?

A Hall Effect Magnetic Flux Sensor is suitable for use in very strong magnetic fields because it is made of a semiconductor material that is not affected by high magnetic fields. Additionally, the sensor is designed to have a low resistance, which allows it to work in high current situations without overheating.

4. What are some common applications of Hall Effect Magnetic Flux Sensors?

Hall Effect Magnetic Flux Sensors have a wide range of applications, including in automotive systems, industrial motors, and electronic devices. They are also commonly used in scientific research for measuring magnetic fields in experiments and studies.

5. Are there any limitations or disadvantages of using a Hall Effect Magnetic Flux Sensor?

While Hall Effect Magnetic Flux Sensors have many benefits, they do have some limitations. One limitation is that they can be affected by temperature changes, which can impact their accuracy. Additionally, these sensors are sensitive to external magnetic fields and can produce inaccurate readings if not shielded properly.

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