Author Topic: Electronic Personal Dosimeter (EPD)  (Read 3835 times)

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Marco2001

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Electronic Personal Dosimeter (EPD)
« on: November 09, 2010, 12:41:40 AM »
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 )



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%29
1Gy = 1J/kg
1Gy = 100rad




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"]



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_poisoning

http://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).
« Last Edit: November 09, 2010, 12:59:01 AM by Marco2001 »

Poland here. My time: GMT + 1h
Writing a book about Mars. Any ideas? Type to me.
I'am an Astrobiology/Biology student.

profit004

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Re: Electronic Personal Dosimeter (EPD)
« Reply #1 on: November 09, 2010, 02:58:59 PM »
The human body does repair some, but my friend has been repeatedly exposed to nuclear sources that they use to check the welds in steel for critical members and his immune system is completely shot now, his body cannot even fight off simple molds.   Even though he received his doses over the course of years, It still affects his body.

Although admittedly he has probably received several lethal doses worth of radiation if he were to be exposed to it all at once.

*ironically they do not even allow him to wear a EPD.

thedubman

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Re: Electronic Personal Dosimeter (EPD)
« Reply #2 on: November 11, 2010, 12:15:37 PM »
Radioactivity should play a major part in the sim, I see it as the next biggest danger up there (after life support is organised).
Radioactivty and cold weather should dramatically effect players 'surface time' so they need to plan or have a backup plan for there time on the surface.
 We should not forget that the sims main feature is to be able to 'explore mars' in a realistic manner. I for one am allways an advocet for making things 'hard' or 'difficult' to give the sense of 'danger' (thus excitment and challenge).

 I disagree with a 'help the noob' system (ie making it easier). Exploring Mars is and should be difficult and dangerous- and going on the surface in the sim should be challenging, and require thought and planning- so every 'EVA' is an event in itself and clocking up surface time is a side goal of the sim- opposed to 'nipping out to collect toolbox' and not really thinking of what you are simulating..

Radioactivity, should IMHO should effect health, stamina, o2 use etc over exposure time with added danger of solar flares giving a mssive burst (unless bunkered down)- agree, it seems gamey to include a 'medical cure' but for the sake of the sim rules bending 'rule' it could work. Infact 'creating' medical rad 'cures' could be an important part of the sim as important as food making.
Solar flares knocking out systems (electronic) would also add to the element of danger..

It wouldnt be fun if players spent 10mins outside and had to comeback to take there "RadAway" pills but spending a total of an hour or something on the surface could give enougth expose to warrant treatment...
« Last Edit: November 11, 2010, 12:23:23 PM by thedubman »

pad69

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Re: Electronic Personal Dosimeter (EPD)
« Reply #3 on: November 16, 2010, 04:40:43 AM »
nice
Murphy's Law applies "Anything that can possibly go wrong, does." or some say it this way "If anything can go wrong, it will.

Hyper

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Re: Electronic Personal Dosimeter (EPD)
« Reply #4 on: November 19, 2010, 07:59:33 PM »
Yeah that can be added. I will be redoing the environment stuff soon so when I get to that I will drop it in.

profit004

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Re: Electronic Personal Dosimeter (EPD)
« Reply #5 on: November 20, 2010, 06:00:33 AM »
"tick tick tickity means run your ass out of there"-Fallout 3

=)

thedubman

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Re: Electronic Personal Dosimeter (EPD)
« Reply #6 on: November 20, 2010, 05:05:53 PM »
Nice,..

Picture the scene,.. players outside far from base working away- a solar flare alarm goes off. Player have to get back to the base for safety, flare is mins away... gieger counter allready showing in the red...

Mecanico

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Re: Electronic Personal Dosimeter (EPD)
« Reply #7 on: November 21, 2010, 10:00:58 AM »
Well, solar flares and CME's aren't so bad, they need some time to reach Mars (more then 6h), what gives us time to alert everybody and evacuation to safe places. Much more worst are x-ray bursts. Both solar and extra-solar. Even if some solar observatory will register solar x-ray burst, there is too late. Extra-solar bursts are unpredictable, fortunately, mostly to weak to do any harm to Martians.
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pad69

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Re: Electronic Personal Dosimeter (EPD)
« Reply #8 on: November 24, 2010, 11:33:05 AM »
Nice,..

Picture the scene,.. players outside far from base working away- a solar flare alarm goes off. Player have to get back to the base for safety, flare is mins away... gieger counter allready showing in the red...

Well we would have to be prepared for this with emergency safe places built in to the equipment people are using.
Murphy's Law applies "Anything that can possibly go wrong, does." or some say it this way "If anything can go wrong, it will.

thedubman

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Re: Electronic Personal Dosimeter (EPD)
« Reply #9 on: November 26, 2010, 02:09:47 PM »
Exactly..  but it would give an additional atmosphere to the sim if such an emergency took place, I remeber very early versions the suits had no temperature control and when a storm came you had to get back to saftey or die added tension to the sim..

pad69

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Re: Electronic Personal Dosimeter (EPD)
« Reply #10 on: December 02, 2010, 11:40:14 PM »
Exactly..  but it would give an additional atmosphere to the sim if such an emergency took place, I remeber very early versions the suits had no temperature control and when a storm came you had to get back to saftey or die added tension to the sim..

True!
Murphy's Law applies "Anything that can possibly go wrong, does." or some say it this way "If anything can go wrong, it will.