RE: [esa-t474] Re: minutes of the T474 phone conference

[Woods, Michael B.]

Hi Nikolay, the low field magnetometer we have has a full range of 5 Gauss and gives 2V/gauss signal.  I've just placed an order for a second of these to assist our measurements and understand the noise in the devices; this is being purchased from Applied Physics Systems, the Model 535 magnetometer http://www.appliedphysics.com/535_D.html.  Mark Slater reported on some analysis taken during the july run in http://pcfj.hep.phy.cam.ac.uk:8080/slater/7, where the magnetometer is sitting on the SPEAR girder at about the mid-chicane location.  We do see fields at the 1 gauss or larger level due to the rebar in the SPEAR girder.  Beam height will be 17" above this girder and we haven't taken measurements yet at beam height along the girder.  Mark does see variations in the field at the 1-2 mgauss level, though not clear if this is instrumentation noise or real variations.  Some additional studies with the magnetometer were done by students in Summer 2005 and are described at
http://www-project.slac.stanford.edu/ilc/testfac/ESA/meetings/11jul2005/SLAC_ESA_Strayfield.pdf and http://www-project.slac.stanford.edu/ilc/testfac/ESA/meetings/18jul2005/magnetic_map.jpg 
.  mike
-----Original Message-----
From: esa-t474-bounces at hep.ucl.ac.uk [mailto:esa-t474-bounces at hep.ucl.ac.uk] On Behalf Of morozov at nusun.jinr.ru
Sent: Thursday, October 05, 2006 3:53 AM
To: Bino Maiheu
Cc: Â; esa-t474 at hep.ucl.ac.uk
Subject: [esa-t474] Re: minutes of the T474 phone conference

Dear all:
Some remarks about the earth field. The maximal field which can be measured by our fluxgate magnetometer is 1 G and sensitivity is 0.0001 G (I think the SLAC one has approximately the same parameters). It means that there will not be the problems to measure the earth field and its variation in time. The second important point is the background field in the spectrometer region generated by technical equipment. Some questions about it. What is it value and distribution in space? The variation on time and uniformity of the variation?
My best regards, Nikolay.

> Hi All,
>
> I've put up minutes of today's T474 phone conference, with apoplogies 
> for any mistakes or omissions. The internet connection for Skype from 
> Poland was rubbish, so was difficult to follow everything.
>
> http://www.hep.ucl.ac.uk/~bino/T474/20061002.html
>
> Nikolay, I've cc'd you, i didn't know whether you're on the list, so 
> my apologies if you get this mail twice.
>
> Below you can find a forwarded mail from Ray concerning stray field 
> variations, which he asked me to forward.
>
> Cheers,
>      bino
>
>
>
> ---- Mail from Ray :-----------------------
>
> Bino,
>
> Here is the info I have on earth field variations.  Would you send it 
> on to the T474 group.  I don't have such a list that you seem to use.
>
>     Facts:
>
>       Earth's field = 24,000 to 66,000 nT
>
>         1 Gauss = 1 Oersted = 100,000 nT
>         1 gamma = 1 nT
>
> Earths field has much variation mostly from sun activity.  See Figure 
> 1 at  http://www.ips.gov.au/Educational/3/1/2.
>
> There is a peak at frequencies of hundreds of seconds at about 100 
> gamma = 100 nT, which is probably too small for you to see on the flux 
> gate.
> There are also variations of hundreds of nT over larger (minutes to
> hours)
> time scale that you may be able to see.
>
>    Check out:
>
> http://www.ips.gov.au/Educational/3/1
> http://nationalatlas.gov/articles/geology/a_geomag.html
> http://www.geomag.bgs.ac.uk/earthmag.html
> http://www.wdcb.ru/stp/cat1GEO.html
>
>
>     Ray
>
>
> Raymond G. Arnold                        arnold at slac.stanford.edu
> M.S. 42 SLAC                             voice (650) 926-2755
> P.O. Box 4349                            fax   (650) 926-2407
> Stanford, CA 94309
>
>
> ------------------------------------
>
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--
Николай Анатольевич Морозов
Лаборатория ядерных проблем
Объединенный институт ядерных
исследований
141980 Московская обл., г.Дубна
Тел. 496-21-62228
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