Focusing x-rays

jim bell jdb10987 at
Tue Sep 22 19:59:18 PDT 2015

      From: "wirelesswarrior at" <wirelesswarrior at>
 To: jdb10987 at 
Cc: juan.g71 at; cypherpunks at 
 Sent: Tuesday, September 22, 2015 6:56 PM
 Subject: Focusing x-rays
-------- Original Message --------
From: jim bell <jdb10987 at>
Apparently from: cypherpunks-bounces at
To: Juan <juan.g71 at>, "cypherpunks at" <cypherpunks at>
Subject: Re: How much/what hardware does the rowhammer DRAM bug affects?
Date: Fri, 18 Sep 2015 21:30:32 +0000 (UTC)
>Within the last couple of months, I think somebody was arrested for planning some sort of "X-ray death ray".     But only a dweeb doesn't know that X-rays cannot be focussed.  (With one very obscure exception not applicable here.  Find it and get an "attaboy!". )

Its called Grazing Incidence
  >Microwaves, OTOH, can be focussed rather easily.  The frequency is 2.45 Ghz, at about 1 Kilowatt.  (wavelength about 12 centimeters.)  I'd have to consult a Radio Amateur's handbook, but a modern dish (intended or Directv or Dish network) could probably get 15-20 db of gain, compared with isotropic.  An old-style 8-foot dish probably would do 30 db gain.  That would be 100 kilowatts ERP. >Such an unshielded  (open) device would probably impair WiFi at 2.5 Ghz severely, if you're close to it, say a few hundred feet away.  Fortunately, I think microwave ovens have better than 60 db of shielding.  A few 10s of feet, away, hardware damage might occur if that full 1 kw were allowed to leak out.           Jim Bell  

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