The 2 cents understanding here while having lunch,
Having been involved on surveys using triaxial airborne gradiometer and
3-axis fluxgate vector magnetometers-
Measured gradiometer surveys usually use scalar sensors -alkali vapor- etc.
to measure the difference between cross-axis sensors, cross wing, cross
tail, cross fuselage, say for a fixed wing. The sensors measure the scalar
total field. The gradient across the scalar sensors is then determined.
Fluxgates, the 3-axis type, Bartington is one manufacturer, there are
several even chip scale now, alternatively, measure the three vectors of
the magnetic field and return the three vector readings. The fluxgate can
either be aligned in some way with the 3D earth field, say like might be
seen at an observatory like in Boulder, or not, like out on some sort of
field survey for example, UXO, Archeology, whatever, why limit yourself? As
the fluxgate provides the 3D vectors, a bonus is these can be combined to
get a total field reading too.
Taking this one step further, vector magnetometers can be used instead of
scalars, in 2D or 3D gradient arrays. As might be expected this produces a
wealth of magnetic field data to process and interpret.
Fluxgates can also be used in EM, Smartems been around for a while, MT too?
Cheers,
Ed
Red Rocks Geophysical
Mobile 001 720 300 3641
Sent from my T-Mobile Android device
On Fri, May 3, 2019, 8:44 AM S E Geoscience and Exploration via SEGMIN <
segmin@lists.geosoft.com> wrote:
> Joel,
>
> can you please expand on that ("the gradient of the total field is not the
> same as the gradient of the field")?
>
> A gradient is a spatial derivative, changes of a value in space. So, what
> is the difference between the value "(magnetic) total field" and the value
> "(magnetic) field"?
>
> Thanks
>
>
> On Thu, May 2, 2019 at 10:08 AM Jansen, Joel via SEGMIN <
> segmin@lists.geosoft.com> wrote:
>
>> Peter has brought up a good point: that the gradient of the total field
>> is not the same as the gradient of the field. The former can be collected
>> with proton or Cs/K-vapour magnetometers, while the latter requires
>> fluxgates or SQUIDS.
>>
>>
>>
>> *Joel Jansen *D +1 604 696 3511 M +1 604 218 3887
>>
>>
>>
>> *From:* SEGMIN <segmin-boun...@lists.geosoft.com> *On Behalf Of *Peter
>> Annan via SEGMIN
>> *Sent:* May 1, 2019 7:52 PM
>> *To:* segmin@lists.geosoft.com
>> *Cc:* Peter Annan <a...@sensoft.ca>
>> *Subject:* Re: [SEGMIN] full gradient mag surveys
>>
>>
>>
>> *This message originated outside Anglo American*
>>
>>
>> ------------------------------
>>
>> Hi Richard:
>>
>>
>>
>> From my understanding and talking to many in the archeo field, these are
>> primarily single axis gradiometers or arrays of these devices and not
>> triaxial gradiometers.
>>
>>
>>
>> Someone may have a more advanced version since there are lot of people
>> playing but have not see a triaxial unit. More likely to find the triaxial
>> solution in the UXO area if there is one..
>>
>>
>>
>> Regards
>>
>>
>>
>> Peter
>>
>>
>>
>> *From:* SEGMIN <segmin-boun...@lists.geosoft.com> *On Behalf Of *Richard
>> Smith via SEGMIN
>> *Sent:* Wednesday, May 1, 2019 10:33 PM
>> *To:* segmin@lists.geosoft.com
>> *Cc:* Richard Smith <geofizz...@aol.com>
>> *Subject:* Re: [SEGMIN] full gradient mag surveys
>>
>>
>>
>> There are lots of archeological groups doing multisensory mag for Greek
>> and Roman ruins, Stonehenge etc. There was someone from Flinders
>> University in South Australia written up recently in Preview. These
>> systems are generally towed by a quadbike or similar and are designed for
>> open spaces like fields.
>>
>> Regards
>>
>> Richard Smith
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Roger Henderson via SEGMIN <segmin@lists.geosoft.com>
>> To: segmin <segmin@lists.geosoft.com>
>> Cc: Roger Henderson <ro...@tpg.com.au>
>> Sent: Wed, May 1, 2019 8:07 pm
>> Subject: Re: [SEGMIN] full gradient mag surveys
>>
>> Yes, Sergio did say GROUND and he gets offered helicopter systems.
>>
>> Hasn’t any one watched the British TV show “Time team” using triaxial
>> mags for archaeology? I think they were fluxgates made by Bartington.
>>
>> Anyway plenty of others . Geometrics?
>>
>>
>>
>>
>>
>>
>>
>> *Peter Annan*
>>
>> Chief Executive Officer
>>
>> *Sensors & Software Inc.*
>> 1040 Stacey Court, Mississauga, Ontario, Canada L4W 2X8
>> a...@sensoft.ca | +1 905 624 8909
>>
>> www.sensoft.ca <http://www.sensoft.ca/index.html>
>>
>>
>>
>> This transmission may contain PRIVILEGED OR CONFIDENTIAL INFORMATION.
>> Unauthorized disclosure is strictly prohibited.
>>
>>
>>
>> On 2 May 2019, at 5:17 am, Stephen Reford via SEGMIN <
>> segmin@lists.geosoft.com> wrote:
>>
>>
>>
>> Here is another one:
>>
>> http://www.shageophysics.com/heli-gt.html
>>
>>
>>
>> No doubt there are a few other heliborne triaxial gradiometers out there.
>>
>>
>>
>> However, I see that Sergio is asking for a *ground* triaxial gradiometer.
>>
>>
>>
>> *From:* SEGMIN <segmin-boun...@lists.geosoft.com> *On Behalf Of* Pierre
>> Bérubé via SEGMIN
>> *Sent:* May 1, 2019 3:12 PM
>> *To:* segmin@lists.geosoft.com
>> *Cc:* Pierre Bérubé <pber...@ageophysics.com>
>> *Subject:* Re: [SEGMIN] full gradient mag surveys
>>
>>
>>
>> Never had any problems with these guys, they should be able to deliver
>> what you want.
>>
>>
>>
>>
>> https://www.facebook.com/Airborne-Geophysics-Eagle-K8aranda-Geophysics-133062360111477/about/
>>
>>
>>
>>
>>
>>
>>
>> Pierre
>>
>> <image001.jpg>
>>
>> *Pierre Bérubé, ing**. / Eng.*
>>
>> *Président / President*
>>
>> *_______________________________________________*
>>
>> *tel.: 1.819.874.8800 #201 fax: 1.819.874.8801*
>>
>> *1740 chemin Sullivan suite 1400, Val-d’Or (QC) Canada J9P 7H1*
>>
>> *www.ageophysics.com <http://www.ageophysics.com/>*
>>
>>
>>
>> <image002.jpg>
>>
>>
>>
>> *From:* SEGMIN <segmin-boun...@lists.geosoft.com> *On Behalf Of* S E
>> Geoscience and Exploration via SEGMIN
>> *Sent:* May 1, 2019 9:12 AM
>> *To:* segmin@lists.geosoft.com
>> *Cc:* S E Geoscience and Exploration <
>> se.geoscience.and.explorat...@gmail.com>
>> *Subject:* [SEGMIN] full gradient mag surveys
>>
>>
>>
>> Dear all,
>>
>>
>>
>> is there a ground geophysical contractor offering full gradient mag
>> surveys?
>>
>> (horizontal gradient perpendicular to profile direction + vertical
>> gradient).
>>
>>
>>
>> Thanks
>>
>>
>>
>> --
>>
>> *Sergio Espinosa**, Ph.D., P.Geo*
>>
>> Director, Geophysics
>>
>> *S E G*eoscience & *Ex*ploration
>>
>> -----------------------
>> SEGMIN community mailing list service (segmin@lists.geosoft.com).
>> Change your personal options here:
>> https://lists.geosoft.com/mailman/options/segmin/rogah%40tpg.com.au
>>
>>
>> Colleagues can join here:
>> https://lists.geosoft.com/mailman/listinfo/segmin
>> Archives: https://lists.geosoft.com/mailman/private/segmin/
>> NOTE that <Reply> will reply to all members of the list.
>>
>>
>>
>> -----------------------
>> SEGMIN community mailing list service (segmin@lists.geosoft.com).
>> Change your personal options here:
>> https://lists.geosoft.com/mailman/options/segmin/geofizzics%40aol.com
>> Colleagues can join here:
>> https://lists.geosoft.com/mailman/listinfo/segmin
>> Archives: https://lists.geosoft.com/mailman/private/segmin/
>> NOTE that <Reply> will reply to all members of the list.
>> -----------------------
>> SEGMIN community mailing list service (segmin@lists.geosoft.com).
>> Change your personal options here:
>> https://lists.geosoft.com/mailman/options/segmin/se.geoscience.and.exploration%40gmail.com
>> Colleagues can join here:
>> https://lists.geosoft.com/mailman/listinfo/segmin
>> Archives: https://lists.geosoft.com/mailman/private/segmin/
>> NOTE that <Reply> will reply to all members of the list.
>>
>
>
> --
> *Sergio Espinosa, Ph.D., P.Geo*
> Director, Geophysics
> *S E G*eoscience & *Ex*ploration
> -----------------------
> SEGMIN community mailing list service (segmin@lists.geosoft.com).
> Change your personal options here:
> https://lists.geosoft.com/mailman/options/segmin/ed.cunion%40gmail.com
> Colleagues can join here:
> https://lists.geosoft.com/mailman/listinfo/segmin
> Archives: https://lists.geosoft.com/mailman/private/segmin/
> NOTE that <Reply> will reply to all members of the list.
>
-----------------------
SEGMIN community mailing list service (segmin@lists.geosoft.com).
Change your personal options here:
https://lists.geosoft.com/mailman/options/segmin/archive%40mail-archive.com
Colleagues can join here: https://lists.geosoft.com/mailman/listinfo/segmin
Archives: https://lists.geosoft.com/mailman/private/segmin/
NOTE that <Reply> will reply to all members of the list.
