[ RadSafe ] Sickening Solar Flare

Stankewitsch, Brian T. BRIAN.T.STANKEWITSCH at saic.com
Thu Feb 10 18:40:31 CET 2005


Kind of a twisted "LD-50/60 (with attached "Suddenly" modifier) And so much
for "Hormesis".  (The LD-50 value going down and all.)  At this rate, us
hormesis proponents will have nowhere to go!
 
Brian Stankewitsch
SAIC Radiation Safety
16701 West Bernardo Drive
San Diego, Ca 92127
858-826-5734
 
 
-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of Bernard Cohen
Sent: Thursday, February 10, 2005 8:26 AM
To: Maury Siskel
Cc: RadiatSafety
Subject: Re: [ RadSafe ] Sickening Solar Flare
 
Is this piece correct in saying that LD-50 is 300 rem? It used to be 450 
rem.
 
Maury Siskel wrote:
 
> Here is an excerpt from the NASA story about a recent very high energy 
> solar flare. The HPs among you can comment on the accuracy of NASAs 
> account, but this seems a constructive example of  desirable 
> communication with the public which provides meaningful comparisons. 
> Additionally, it is, I think, an intrinsically interesting story 
> containing a couple neat photos.
>
> http://science.nasa.gov/headlines/y2005/27jan_solarflares.htm
>
> And just for the fun of it, here is another site that some of you will 
> enjoy:
>
> http://science.nasa.gov/temp/StationLoc.html
>
> Cheers,
> Maury&Dog        maurysis at ev1.net
>
> =================
> The Jan. 20th proton storm was by some measures the biggest since 
> 1989. It was particularly rich in high-speed protons packing more than 
> 100 million electron volts (100 MeV) of energy. Such protons can 
> burrow through 11 centimeters of water. A thin-skinned spacesuit would 
> have offered little resistance.
>
> "An astronaut caught outside when the storm hit would've gotten sick," 
> says Francis Cucinotta, NASA's radiation health officer at the Johnson 
> Space Center. At first, he'd feel fine, but a few days later symptoms 
> of radiation sickness would appear: vomiting, fatigue, low blood 
> counts. These symptoms might persist for days.
>
> Astronauts on the International Space Station (ISS), by the way, were 
> safe. The ISS is heavily shielded, plus the station orbits Earth 
> inside our planet's protective magnetic field. "The crew probably 
> absorbed no more than 1 rem," says Cucinotta.
>
> One rem, short for Roentgen Equivalent Man, is the radiation dose that 
> causes the same injury to human tissue as 1 roentgen of x-rays. A 
> typical diagnostic CAT scan, the kind you might get to check for 
> tumors, delivers about 1 rem [ref 
> <http://hps.org/publicinformation/ate/q708.html>]. So for the crew of 
> the ISS, the Jan. 20th proton storm was no worse than a trip to the 
> doctor on Earth.
>
> On the Moon, Cucinotta estimates, an astronaut protected by no more 
> than a space suit would have absorbed about 50 rem of ionizing 
> radiation. That's enough to cause radiation sickness. "But it would 
> not have been fatal," he adds.
>
> <>To die, you'd need to absorb, suddenly, 300 rem or more. The key 
> word is suddenly. You can get 300 rem spread out over a number of days 
> or weeks with little effect. Spreading the dose gives the body time to 
> repair and replace its own damaged cells. But if that 300 rem comes 
> all at once ... "we estimate that 50% of people exposed would die 
> within 60 days without medical care," says Cucinotta.
> ===============
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