From: Jim Choate <ravage@ssz.com>
Date: Mon, 1 Apr 1996 09:53:22 +0800
To: cypherpunks@toad.com
Subject: SQUID's
Message-ID: <199603312132.PAA18565@einstein.ssz.com>
MIME-Version: 1.0
Content-Type: text



Forwarded message:

> 
>  > You wouldn't even have to take it apart. Just subject it to
>  > analysis using SQUID's. Using this technology you would not
>  > even have to physicaly touch the card, let alone remove any
>  > parts of it.
> 
> Excuse me, but April Fool's Day isn't until tomorrow. Besides, all
> you have to do is run the card through a transporter, and then
> dump the pattern buffer to a floppy. :)
> 
> --
>      Mike Duvos         $    PGP 2.6 Public Key available     $
>      mpd@netcom.com     $    via Finger.                      $
> 

Hi Mike,

Apparently you are grossly unfamiliar with the characteristics and
capabilities of SQUID's. To help you catch up...

Conductus
969 West Maude Av.
Sunnyvale, CA  94086
408-737-6700
408-737-6699 Fax

If you happen to be in Austin, TX,

Data Managemenet Associates
3636 Executive Center Dr., #216
Austin, TX  78731
512-338-4701

The product under suggestion is called 'Mr. SQUID' and is a device intended
for educational and introductory appllications. Its specifications are:

SQUID Amplifier:

     Voltage Gain                               x 10,000
     Frequency Responce                         0 - 2.8 kHz
     Voltage Noise Floor                        < 5.0 nV/ sqrt. Hz @ 10 Hz

SQUID Specifications:

      Critical Current (minimum)                5 uAmps @ 77K
      Magnetic Field Modulation (minimum)       1 uVolt @ 77K
      Int. & ext. Coil Mutual Inductance        ~75 pHenries
      Int. & ext. Coil Resistance               ~20 Ohms @ 77K

Mr. SQUID User's Guide Contents:

Typical experiments:

Resistance v Temperature of the YBCO SQUID
Flux-locked Loop
Using a Flux-locked Loop as a sensitive non-contact voltmeter
Microwave induced (Shapiro) steps @ 77K & h/e
Inductive measurement of the Tc of an HTS film
SQUID properties in pumped liquid nitrogen

The following is taken without permission and verbatim from their pamphlet

What's inside the probe?

The heart of Mr. SQUId is a small integrated circuit containing a dc SQUID
and 2 modulation coils. The SQUID itself is a superconducting ring made of
Yttrium Barium Copper oxides (Y1Ba2Cu3O7, sometimes called YBCO or 123) with
two active devices called Josephson Junctions - the basic building block of
all superconducting electronics - made by a process invented at Conductus.
The coils are made of thin film silver deposited on top of an insulating
layer. The chip in Mr. SQUID represents a remarkable level of sophistication
in a materials technology scarecly 5 years old. And, unlike any other SQUID
system currently on the market, Mr. SQUID is designed to operate in a liquid
Nitrogen bath at 77K (-169C).

What does Mr. SQUID do?

Mr. Squid is a sensitive superconducting magnetometer and can therefore be
used to detect small magnetic signals if they are properly introduced to the
SQUID. The limiting performance of Mr. SQUID is set by its economical
electronics package and by its non-superconducting modulation coils. As a
result, Mr. SQUID does not have the sensitivity of high-performance
laboratory SQUIDs and thus cannot be used to detect truly minute signals
such as those generated in the human brain.


Enjoy!