[ RadSafe ] ICRP - Assessment of Radiation Exposure of Astronauts in S...
JPreisig at aol.com
JPreisig at aol.com
Thu Jul 5 14:51:57 CDT 2012
Admiral,
You're missing the point, fella, although I do agree that rad
problems are not high on the list of
dangers faced by astronauts (Sounds Dangerous, Count Me in --- supposed
statement in the Right Stuff
by Alan Shepard).
There's a NASA space effects beamline at Brookhaven Lab (associated
with the Alternating
Gradient Synchrotron/Relativistic Heavy Ion Collider) (see BNL's website).
If you write a research
grant to NASA/DOE at the proper time, you can do Space Radiation Effects
Research at BNL.
Think research $$$????
Recent splashdown of the SPACEX International Space Station Supply
Capsule in an
ocean somewhere certainly reminded me of those really dangerous Mercury
rocket launches.
A Shuttle landing seems so much more elegant. Too bad the USA can't
support both
rocket launches and a Space Shuttle Program. Too bad the USA won't
acknowledge their
existing vertical launch (flying saucer???) space program.
Funny, a Chinese flight crew apparently visited their Space Station
the other day. I think there
was a female Chinese astronaut aboard.
I wonder how that Chinese Fast Neutron Reactor is doing. Time for
the USA to catch up,
either with a government or private industry version.
Higgs Boson discovered at CERN. Guess the USA
Texatron/Supercollider was not to be heard
from --- remember when that project was called off.
ITER is the center of global research in Fusion --- in
France????!!!! Well, at least they do
Fusion Work at the Princeton Plasma Physics Lab and elsewhere in the USA.
Thank
goodness. Maybe some kid/adult doing FUSOR research will scoop the
government.
Hope Higgs gets the Nobel Prize in Physics this Fall ---- he's waited
50 years and he deserves
the prize.
You all be good!!!! Regards, Joseph R. (Joe) Preisig, PhD
In a message dated 7/5/2012 2:02:20 P.M. Eastern Daylight Time,
brees at lanl.gov writes:
You forgot "built by the lowest builder"...
-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Brennan, Mike (DOH)
Sent: Thursday, July 05, 2012 1:40 PM
To: The International Radiation Protection (Health Physics) MailingList
Subject: Re: [ RadSafe ] ICRP - Assessment of Radiation Exposure of
Astronauts in Space
The ride up on thousands of tons of barely controlled explosion, spend
months millimeters away from explosive decompression while re-breathing a
limited air supply, contaminated with almost everything, trying to keep their
bones from demineralizing, then return in a craft with the aerodynamics of a
brick. Rad doesn't make it into the top ten things to worry about.
-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Fred Dawson
Sent: Wednesday, July 04, 2012 9:01 AM
To: radsafe at agni.phys.iit.edu
Subject: [ RadSafe ] ICRP - Assessment of Radiation Exposure of
Astronautsin Space
Draft report: Assessment of Radiation Exposure of Astronauts in Space
The draft ICRP report “Assessment of Radiation Exposure of Astronauts in
Space” is now available for public consultation. ICRP welcomes comments from
individuals and groups. The draft document can be downloaded, and comments
submitted, through the ICRP web site.
Comments must be submitted through the ICRP web site no later than August
31, 2012.
Draft Executive Summary
Astronauts are living and working in low Earth orbits for extended periods
of time, especially during the operation and maintenance of the
International Space Station (ISS) and scientific investigations. Furthermore, plans
are already discussed for outer space missions of astronauts.
In ICRP 103 it is stated that “in exceptional cases of cosmic radiation
exposures, such as exposure in space travel, where doses may be significant
and some type of control warranted, should be dealt with separately from the
conventional approach of occupational exposure”. Therefore, although
astronauts are exposed to ionizing radiation during their occupational activities
they are usually not classified as being occupationally exposed in the
sense of the ICRP system for radiation protection.
The report contains 7 Chapters. The first one is an introduction
describing the specific situation of astronauts in space and the differences of the
radiation field in space compared to fields on Earth, thereby showing areas
where approaches applied in radiological protection measures on Earth need
to be modified.
In Chapter 2 the radiation fields in space are described in detail. The
solar system with the Sun at its centre is embedded in a complex mixture of
galactic cosmic radiation (GCR) - protons, alpha particles and heavy ions -
which continuously enters the heliosphere from all directions. Inside the
heliosphere, the GCR fluence rate and particle energy distributions are
modulated by the interplanetary magnetic field produced by the charged
particles continuously emitted by the Sun, the so-called solar wind. In addition to
the solar wind, the Sun occasionally emits unusually large pulses of
energetic particles – mostly protons and electrons – called solar-particle
events (SPEs). Celestial bodies equipped with a magnetic moment like the Earth
are surrounded by toroidal belts of particulate radiation. Such radiation
belts constitute an important third primary exposure source. Fluence rates
of cosmic radiation are not constant; they vary between two extremes which
correspond in time with the maximum and minimum solar activity. Solar
activity and cosmic radiation fluence rates are inversely correlated. In Sections
2.2 to 2.5 the various components of the radiation field in space are
presented and the influence of the Earth´s magnetic field is described.
Chapter 3 is dealing with the quantities used in radiological protection.
In the first part the system of dose quantities as given in Publication 103
(2007) is described and secondly the relative biological effectiveness
(RBE) is discussed especially with respect to the large contribution of heavy
ions and the very high energies. A single wR-value of 20 for all heavy ions
of all energies is not appropriate for space radiation fields. Hence, for
space applications the concept of a quality factor, Q(L), is applied also
to the protection quantities. In Section 3.3 the approach for applications
in space is described in detail.
In Chapter 4 the methods of fluence and dose measurements in space are
described. This includes instrumentation for fluence measurements, radiation
spectrometry, area dosimetry, and individual monitoring. Passive and active
devices are mentioned and also the use of biomarkers for the assessment of
mission doses is described. Some advice for quality control and the
assessment of uncertainties is also given in this Chapter.
In Chapter 5 the methods of determining quantities describing the
radiation fields within a spacecraft are given. Radiation transport calculations
are the most important tool for an assessment of radiation fields inside a
spacecraft starting from the radiation field in free space and considering
the walls and further equipment of the spacecraft. In this chapter some
physical data used in radiation transport codes are presented and the various
codes used for calculations in high-energy radiation fields as in space
described. Results of calculations of radiation fields in spacecrafts are given.
A discussion of shielding possibilities is included in this Chapter, too.
Chapter 6 is dealing with methods of determining mean absorbed doses and
dose equivalent s in organs and tissues of the human body. Calculated
conversion coefficients of fluence to mean absorbed dose in an organ or tissue
are given for heavy ions up to Z=58 for energies from 10 MeV/u to 100 GeV/u.
For the same set of ions and ion energies mean quality factors in organs
and tissues are presented using on the one hand the Q(L) function defined in
Publication 60 of the Commission and on the other hand a Q(Z,E) function
proposed by NASA. In Sections 6.4 assessment of doses in the body by
measurements are described and results are compared with calculations. In Section
6.5 biodosimetric measurements for the assessment of mission doses are
presented.
In Chapter 7 operational measures with regard to the assessment of the
exposure of astronauts during space missions. This includes pre-flight mission
design, area and individual monitoring during flights in space and dose
recording. The importance of considering uncertainties in dose assessment is
also mentioned.
In an Annex numerical data of conversion coefficients and mean quality
factors for protons, neutrons, alpha particles and heavy ions (2 < Z ≤ 28) are
given.
http://www.icrp.org/page.asp?id=163
Fred Dawson
New Malden
England
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