Talk:SQUID

Mention to UC Berkeley professor Clarke, in the "Uses for SQUIDs" section is inappropriate. Surely the writer was well-intentioned in writing it. But by citing his name and affiliation, we emphasize the person and not the significance of the work we want to cite. Furthermore, there are many researchers across the world involved with SQUIDs. If we cite one, why should someone else not come around and cite another researcher? Soon we'd have a section on researchers, advertizing their work. Wikipedia is not an advertizement service. I suggest the reference to the person (Dr. Clarke) be removed. It is the work which is significant, and such work is never the product of one single individual. As such, I have edited the original sentence. This paragraph cites my reasoning. —Preceding unsigned comment added by 75.12.148.191 (talk) 01:47, 12 May 2008 (UTC)[reply]

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Is this correct? 3 fT·Hz−½? That reads as "3 femto-tesla per (square root of hertz)", which in turn expands to "3 femto-tesla per (square root of (1/seconds))". Seems like a really odd unit to me. --Carnildo 05:34, 5 August 2005 (UTC)[reply]

Yes, it is correct. Just as electrical voltage noise is specified in units of volts per root Herts (V·Hz−½), magnetic field noise is specified in units of Tesla per root Herts (T·Hz−½).

For example, the root-mean-squared thermal voltage noise in a bandwidth of $\Delta f$ , from a resistor of value R at temperature T is

$V_{n}={\sqrt {4k_{B}TR\Delta f}}$

In order to specify the voltage noise, whether thermal or otherwise, in a measurement-bandwidth-independent-manner, you really specify $V_{n}/{\sqrt {\Delta f}}$ rather than $V_{n}$ , hence the units for voltage noise having units of volts per root Herts (V·Hz−½). An analogous calculation of magnetic noise handles the bandwidth issue the same way, hence resulting in units for magnetic noise of Tesla per root Herts (T·Hz−½). To figure out what the actual magnetic noise observed will be from a SQUID with a noise floor of 3 fT·Hz−½, one has to take the square root of the bandwidth one will be measuring over, and multiply that by 3 fT·Hz−½. This 3 fT·Hz−½ number ignores the fact that at low enough frequency (<1 Hz in a good SQUID), 1/f noise will take over.

-- Former SQUID Guy 01:06, 8 August 2005 (UTC)

High Temperature SQUIDS

Regarding the added info on HT SQUIDS, one of many references would be this [1]

03:29, 4 June 2006 (UTC)~ Changed 'microbiology' to 'biology' under the uses section. I've never heard of squids being used in microbiology. Even if they are, this is not explained in the remainder of the article.

Expanding the Article

Does anyone fancy expanding this article a bit. (At least to give a mention to Clarke, Drung, Ketchen etc.) - I will give it a go if no-one else wants to - if I have enough time/energy! 195.93.21.6 22:12, 22 July 2006 (UTC)[reply]

Take alook at User:Slicky/Microscopy in science, which has a subsection relating to Scanning Magnetic Flux Microscope. DFH (talk) 07:51, 11 April 2008 (UTC)[reply]

SQUID based microscopes

A leading company in the field of Scanning SQUID Microscopes is Neocera, Inc. [2]. DFH (talk) 08:13, 11 April 2008 (UTC)[reply]

Citations

The only citation on this page is broken. Unless the original author can remember where he got what information, it's going to need a complete rewrite with proper inline citations and a reference list. --Dbutler1986 (talk) 07:04, 3 June 2008 (UTC)[reply]

A quick check on the hosting web site of the original citation turned up a PDF version of the same material (verified this at the Internet Archive, http://archive.org). Agree that all the other statements in the article desperately need reliable citations. Tjarrett (talk) 17:55, 6 June 2008 (UTC)[reply]

Missing Figure?

A figure is referred to in the DC SQUID section - where is it? --216.18.1.210 (talk) —Preceding undated comment added 20:22, 13 May 2009 (UTC).[reply]

I AGREE!!!!!

It reads as if the section describing the squid V(phi) function was just lifted from a book. Someone should write a section explaining the maths analogy of the of the SQUID with the optical interference of light. It would also explain why the SQUID is an INTERFERENCE device, something that is not made clear in the article

But what do I know? 217.42.143.111 (talk) 19:47, 3 September 2009 (UTC)[reply]