Talk:SQUID

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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)

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 Δf, from a resistor of value R at temperature T is

In order to specify the voltage noise, whether thermal or otherwise, in a measurement-bandwidth-independent-manner, you really specify 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)

[edit] 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.

[edit] 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)