Electronic Personal Dosimeter (EPD)( An indicator on the lower right part of the screen that measures how much radiation is a person receiving right now and in total )
![](http://www.xawf.cn/english/image/image014.jpg)
EPD would be and istrument permanently wore by astronaut. It would show how much radiation he receives right now and in total.
EPD in MCO would not need power.
If a player would enter a place that pose radiation-hazard it would start beaping louder and louder.
Player would have the ability to check received radiation by simply looking at the indicator at the lower right of the screen.
It would also indicated how much you have been irradiated totaly. This is reely important becouse if you have radiation poisoning it could turn off reely bad.
Human body can repair some of the damages that radiation hase done, so simply speaking - if you are radiated to much, you need to stay inside the base and let your body recover the received Siverts.
EPD isn't something new - it was used in Apollo missions for instance, and now it's on every EVA-suit.
It's also used very often for scientists and personel that needs to measure radiation exposure.
It's easy to use, it's small, and it doesn't use a lot of power.
EPD measures how much radiation is a person receiving right now, and how much has it received in total.
On Mars colony, radiation exposure is dependant of solar activity and protection.
That means that one day the radiation is small, and on the other one it's big.
By using proper radiation protection you can lower the total radiation received.
Player exposure is dependent mostly from the zone in which he currently is.
NOTE that daily solar radiation activity is not corelated with SPE - Solar Particle Events (Radiation Storm), which are a random quick solar event (like a solar flare) that make's solar radiation increase significantly.
So, if a player is outside without EVA he receives the full dose.
If he has EVA on, he receives less.
If he's inside the ROVER he receives even less.
He receives even less if he's inside the habitat.
The lover he can receive is inside radiation shelter wearing EVA.
There are a couple of methodes to lover radiation poisoning that I won't discuss here: taking anti-rad medicine, polaryzing habitats hull, activating super-magnetic coil. All developed by NASA and ESA.
Radiation units for EPD.It's quite complicated, and I doubt that it would be implemented properly in MCO.
Simply speaking - There are 2 types of radiation units - physical and biological.
Physical units measure how much particle energy gets to the person right now and is measured in
Greys.
We don't use greys but miligreys. One time radiation of 5 Greys means death (usualy up to 14 days).
http://en.wikipedia.org/wiki/Gray_%28unit%291Gy = 1J/kg
1Gy = 100rad
![](http://www.ndt-ed.org/EducationResources/CommunityCollege/RadiationSafety/Graphics/AbsorbedDose.jpg)
Biological units measure how much damage has the radiation done to human body in total by the particles and it's measured in
Sievert's.
We don't use Sivert's - we use milisiverts.
http://en.wikipedia.org/wiki/Sievert 1Sv = 1Gy · Q
[Q is the "Quality factor" that determines what kind of radiation we are dealing with. Photon radiation is "1"]
![](http://www.ndt-ed.org/EducationResources/CommunityCollege/RadiationSafety/Graphics/DoseEquiv.jpg)
So - so to speak, greys measure how much energy has been deposited to human body, and siverts measure how much effect does it have.
If Greys and Siverts ware to be used in MCO they would have to be calibrated properly. Each unit have to be measured in some time (seconds, minutes, hours, days, weeks?).
Greys would show irradiation for 1 hour, and Siverts in total time in MCO.
Showing grays in 1 h exposure is normal - that how they are usualy displayed in EPD.
But why show Siverts in total time in MCO? Becouse - that way we can measure the total player irradiation and his safety.
As I said before - human body has the ability to regenerate if the exposure isn't to big. So practicly speaking - human body "eats" the received Siverts over time.
Let me expaint that on a example.
I just logged on to the MCO with a new character.
My Siverts = 0. My
Greys indicated = something small becouse I'am inside the base with my suit on.
I leave the base. My Siverts are still small. My EPD shows that the radiation in greys is big (let's say 10 mG/h).
Since 1 grey = 1 sivert in MCO after two hours I received 20 siverts. Every hour I would get another 10 mS.
But since my body repairs itself by 4 mS/h After two hours of exposure I end up with beying irradiated with 2 x 10 mG/h - 2 x 4 mS/h = 20 - 8 = 12 mS
My irradiation would rise every time I'am exposed to it and if I'am irradiated to much I will get ill - I could even die!
So how to lower those 12 mS I received?
The simpliest methode is to go back to the base that shield me from the radiation.
The base receives only 2 mG/h.
That means that after an hour I would gain another 2 siverts, but remember...since my body repairs itself by 4 mS/h I would in fact lose 2 siverts from my irradiation!
That means that if I would wish to have zero siverts irradiation again, I would just have to wait 6 hours in the base (but note, that the solar radiation may change during that time, and it might take longer or quicker).
I would like to note that the difference in Siverts and Greys is that, you would die from 5 greys of one time irradiation, but it's possible to not get killed even with something like 40 Greys, becouse it was done overtime, and total damage to the bady in Siverts due to human body reapirs makes it possible, but on the other hand you can die even when ther's few miligreys of radiation, but it was cumulating over time and you have lot's of Siverts in your body.
EXPOSURE:
http://www.wikidoc.org/index.php/Radiation_poisoninghttp://www.youtube.com/watch?v=sW5MF3u1JBA - Siemens EPD Electronic Personal Dosimeter Thermo Radiation
http://www.youtube.com/watch?v=Nj8xYl5AwnQ&feature=player_embedded - M25 Overview
There is a large field for discussion here.
First of all - I could be wrong about something listed here. This is not something easy and as an astrobiologist I use only greys units when needed, but (for instance) workers at nuclear plant use Sivert dosimeters only.
Secondly - do we wish to use Grays and Siverts as I proposed or use only greys, or only siverts (I think that older units like rads are out of the question).
Thirdly - use milisiverts/miligreys or only geys and siverts with lots of zeros after period?
Fourthly - use the units in what power (time)? Greys/sec. or G/h , G/24h or something else?
Fiftly - what is the human body recover ability (and would it depend on some other factor in MCO?). Morover - how would each zone's decrease the radiation.
EDIT: when a solar flare accurs, it's compisitioned mainly from protons and electrons so the "Q" value will be "5" insted of "1".
What that basicly means is that every Grey of radiation that you receive during radiation-storm will couse 5 times more dammage in your body (5 times more Siverts than normally).