The stochastic risk is the luck (or bad luck) factor of radiation. i.e. even a
very low dose of radiation can cause a DNA mutation and subsequent cancer, if
it hits the right spot! This is completely random but like a bet at the races,
the higher the dose, the better the chance of developing cancer. For example,
for every 2,000,000 chest x-rays (0.02mSv) one will give the patient cancer
that is life threatening.
The risk of death from flying a Lancaster in WW2 was about 60% I seem to
remember. so I wouldn't worry about the cancer risk from the instruments.
Deterministic rates are different, as AJ points out and are known values. e.g.
400mSv to the eye will give you cataracts.
So, both types are accumulative, and are the same sources, best to avoid
radiation. Remember also that all these figures are based on the mutation and
death rates of hiroshima and Nagasaki, both events not easily linked to every
day radiation exposure.
All in all, I think the risk of death from flying a BLANIK IS HIGHER THAN THE
RISK OF CANCER FROM THE INSTRUMENTS, depending on the dose, of course.
JIM
Date: Wed, 30 Jul 2008 21:46:27 +1000From: [EMAIL PROTECTED]: [EMAIL
PROTECTED]: Re: [Aus-soaring] Cockpit warnings
What was interesting about the Taiwan case is that the problem was discovered
by a tenant who brought a Geiger counter home for study purposes...or something
to that effect.
Today's radiation use licenses emphasis disposal as much as acquisition of
radiation sources. Stochastic risk depends is a "linear no threshold"
relationship, and yes this method is chosen as the more conservative measure
over the deterministic risk which has a threshold, ie skin burns, cataract
formation etc., hence why using the Sievert as a dose measurement unit of
deterministic risk is not entirely correct. My understanding is that higher
dose rates are more problematic as, with a low dose rate cell/DNA repair can
take place between radiation interactions. With higher dose rates , this is not
so. Therefore, the concept of DDRF Dose, dose reduction factor for low dose
rates. Except possibly the dials, any other sources of radiation in a Blanik
cockpit? During the WW2 there were ladies that painted radium dials, and licked
the tip of the brush to get the fine tip for detailed work...cheersAJ
On 30/07/2008, Mike Borgelt <[EMAIL PROTECTED]> wrote:
At 01:40 AM 30/07/2008, you wrote:
HA,I was trawling through some aviation museums in Europe and noticed that
there is a health warning on some cockpits. For example, I think the aircraft
preservation people in the UK are only allowed 10 minutes exposure in some
cockpits like Blaniks due to the radiation from the primitive instruments. Same
story in Lancaster bombers.I guess that is probably as long as you would want
to spend in a Blanik cockpit, but it does question the sense in "restoring"
them.D McDAnyone got access to a radiation counter and a Blanik?Might be
interesting.Also interesting is a scientific paper I have about a study on
radiation exposure in Taiwan. Seems someone mixed an old industrial cobalt
radiation source into a bunch of scrap steel which ended up as reinforcing
rods in concrete which went into an apartment building. After some years this
was found out and a study done on the people who lived there. This was a good
study as there were lots of other people in the same situations in other
apartment buildings so there was a good control group. They looked for cancer
rates amongst the exposed - and found that they were 3% of what they
expected.Journal of Amercian Physicians and Surgeons Volume 9 Number 1 Spring
2004Radiation exposure allowances are based on the "Linear No Threshold" theory
on the grounds that this is conservative and safe. There is evidence that it
doesn't work like that for low doses.MikeBorgelt Instruments - manufacturers of
quality soaring instrumentsphone Int'l + 61 746 355784fax Int'l + 61 746
358796cellphone Int'l + 61 428 355784 Int'l + 61 429 355784email:
[EMAIL PROTECTED]:
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