Path: utzoo!utgpu!water!watmath!clyde!att!cuuxb!dlm
From: dlm@cuuxb.ATT.COM (Dennis L. Mumaugh)
Newsgroups: comp.misc
Subject: Re: X-Ray detectors and Tapes
Summary: X-rays don't normally hurt digital tapes
Message-ID: <1925@cuuxb.ATT.COM>
Date: 15 Jul 88 22:27:11 GMT
References: <588@bnlux0.bnl.gov>
Reply-To: dlm@cuuxb.UUCP (Dennis L. Mumaugh)
Distribution: na
Organization: ATT Data Systems Group, Lisle, Ill.
Lines: 36

In article <588@bnlux0.bnl.gov> larese@bnlux0.UUCP (john z larese) writes:
>I have just changed my place of work and I am now working in
>a High security nuclear reactor.  As employees, such as myself
>enter the building, we pass all bags through a X-Ray detector 
>and walk through a metal detector.
>
>My question is, do any magnetic fields exist in either equipment
>that might be high enough to damage Mag tapes?
>

In a time long ago ...  NBS did a  study  and  a  report  on  the
effects  of  magnetic  fields on tapes.  A short summary - locate
the report for more:

1).  Digital tapes are very difficult to erase.  Audio tapes  are
easy as are video tapes.

2).  Airport equipment will not normally erase a digital tape.

3).  The old war story about a person  walking  into  a  computer
room  and  erasing  all  the  tapes  or  the  one about the floor
polished doing so is just that: a story, urban myths.

4).  Their studies  said  that  only  a  LARGE  permanent  magnet
brought  within  2  inches  or  the tape OR a special bulk eraser
designed for digital tapes would erase it.

BUT, it also cautioned about putting tapes near a disk drive with
a  large  solenoid  magnet  or  near the power supply of an X-ray
machine.  It also didn't address floppy disks.

BTW it did discuss temperature and humidity,  etc.  as  well.  So
check NTIS or NBS for the report.
-- 
=Dennis L. Mumaugh
 Lisle, IL       ...!{att,lll-crg}!cuuxb!dlm  OR cuuxb!dlm@arpa.att.com