<p>Let's first quickly estimate whether the numbers by <a href="https://en.wikipedia.org/wiki/Chernobyl_(miniseries)" rel="nofollow noreferrer">HBO's TV series</a> make sense:
According to <a href="http://gesundheit.ch/strahlung" rel="nofollow noreferrer">gesundheit.ch/strahlung</a> the <a href="https://en.wikipedia.org/wiki/Chernobyl_liquidators" rel="nofollow noreferrer">liquidiators</a> were exposed to <span class="math-container">$2 \ldots 20 {\rm Sv}$</span> which compares to a life dose of <span class="math-container">$\approx 100 {\rm mSv}$</span> for usual people. I remember from my education that each worker was supposed to spent only <span class="math-container">${\rm 40s}$</span> on the roof of the reactor. Assuming a dose of <span class="math-container">${2 \rm Sv}$</span> in <span class="math-container">${\rm 40s}$</span> corresponds to <span class="math-container">${\rm 180Sv/h}$</span>, so the value of <span class="math-container">${\rm 12\,000R/h=120Sv/h}$</span> makes sense.</p>
<p>On the other hand, you give an <strong>absorbed dose</strong> of <span class="math-container">$20 \cdot 10^6 {\rm rad}=2 \cdot 10^5{\rm Gy}$</span> which is a <em>physical quantity</em>. However, the <strong>dose equivalent</strong> in Sievert quantifies the <em>biological effect</em> (of the deposit of a joule of radiation energy in a kilogram of human tissue), see <a href="https://www.ncbi.nlm.nih.gov/books/NBK230653/" rel="nofollow noreferrer">https://www.ncbi.nlm.nih.gov/books/NBK230653/</a></p>
<blockquote>
<p><span class="math-container">${\rm 1 Sv}$</span> is the amount of radiation necessary to produce the same effect on living tissue as <span class="math-container">${\rm 1Gy}$</span> of high-penetration <span class="math-container">${\rm 200 keV}$</span> x-ray</p>
</blockquote>
<p>Only if we <em>incorrectly</em> assume that the composition of the radiation on the roof Chernobyl in April 1986 and on Juno's flight path are comparable, we could proceed with <a href="https://en.wikipedia.org/wiki/Cross-multiplication" rel="nofollow noreferrer">cross-multiplication</a> by setting <span class="math-container">${\rm 1 Sv= 1 Gy}$</span>.</p>
<p>But this (wrong) assumption is not enough, we also need a time frame for your <a href="https://en.wikipedia.org/wiki/Thought_experiment" rel="nofollow noreferrer">Gedankenexperiment</a>: If we assume that the radiation dose would remain constant (aka reactor core being exposed) at the lower bound of <span class="math-container">${\rm 120 Sv/h}$</span>, the maths gives <span class="math-container">$2 \cdot 10^5 \frac{\rm J}{\rm kg}/ (120 \frac{\rm J}{\rm kg \cdot h}) = 1\,666.7 {\rm h}$</span> which is a bit more than 69 days of survival for the <a href="https://en.wikipedia.org/wiki/Juno_(spacecraft)" rel="nofollow noreferrer">Juno probe</a> on the roof of a burning nuclear reactor. Realistically, I assume the probe would stop working much earlier.</p>
<h3>Further reading</h3>
<p>You might also find the presentation <a href="http://www.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/podzolko_getselev_ELW.pdf" rel="nofollow noreferrer">Charged Particle Fluxes and Radiation Doses in Earth-Jupiter-Europa Spacecraft’s Trajectory</a> by M. V. Podzolko <em>et al.</em> interesting which gives quite a few estimates on radiation dose around Jupiter.</p>

CC BY-SA 4.0
2021-03-10T18:02:26.260Z
Fantastic, thanks for pointing out the incorrect assumptions as well.
Gambhiro
CC BY-SA 4.0
2021-03-10T19:10:38.313Z
Well, the assumptions that all radioactivity is the same is pretty wide-spread, that's why I felt like highlighting it. Obviously, there is $\alpha$, $\beta$, and $\gamma$ radiation, but there is also an energy distribution of the particles, and the effect on the human body is depending on all that. I feel that text books make it sound very complicated, all the Gray vs. Sievert story, that's why my answer got lengthy.
B--rian
CC BY-SA 4.0
2021-03-09T21:46:10.483Z
2021-03-09T22:15:38.773Z
2021-03-09T22:15:38.773Z
B--rian
<p>I suppose the radiation levels are higher at Jupiter, but how much? Would the Juno probe have been able to &quot;operate&quot; on the Chernobyl roof in <span class="math-container">$12\,000\, {\rm Roentgen/hr}$</span>?</p>
<p>After watching the short series Chernobyl, I was curious how the radiation levels compare with that around Jupiter (generally), and what the Juno probe in particular have to withstand, but I couldn't directly compare the numbers I found.</p>
<p>In the Chernobyl accident, the reactor explosion causes pieces of graphite to fall on the roofs of the reactor building, and they describe that they can't push them off with remote-control machines because the radiation damages the circuits.</p>
<p>In the <a href="https://en.wikipedia.org/wiki/Chernobyl_(miniseries)" rel="nofollow noreferrer">series</a>, the <a href="https://youtu.be/Zz1MJq7rW-w?t=63" rel="nofollow noreferrer">value given</a> for the most dangerous roof is <span class="math-container">$12\,000\, {\rm Roentgen/hour}$</span>.</p>
<p>The <a href="https://www.space.com/33331-juno-probe-jupiter-radiation-environment.html" rel="nofollow noreferrer">Juno probe's radiation vault</a> is a titanium box with <span class="math-container">${\rm 1.75cm}$</span> thick walls, and the article says</p>
<blockquote>
<p>But this orbit would still expose an unprotected probe to a radiation
dose of more than <code>20 million rads</code> [...] over the course of its mission.</p>
</blockquote>
<p>The mission was <a href="https://solarsystem.nasa.gov/missions/juno/in-depth/" rel="nofollow noreferrer">planned for 14 Earth months</a> but the probe only spends short periods of time around Jupiter.</p>
<p>Perhaps someone has an idea how to fill in the gaps and help to make a comparison.</p>

<jupiter><radiation>
How much higher is the radiation around Jupiter than at Chernobyl, after the explosion?
Gambhiro
# How much higher is the radiation around Jupiter than at Chernobyl, after the explosion?

(Asked by: username_0 on 2020-01-08)

I suppose the radiation levels are higher at Jupiter, but how much? Would the Juno probe have been able to "operate" on the Chernobyl roof in $12\,000\, {\rm Roentgen/hr}$?

After watching the short series Chernobyl, I was curious how the radiation levels compare with that around Jupiter (generally), and what the Juno probe in particular have to withstand, but I couldn't directly compare the numbers I found.

In the Chernobyl accident, the reactor explosion causes pieces of graphite to fall on the roofs of the reactor building, and they describe that they can't push them off with remote-control machines because the radiation damages the circuits.

In the [series](https://en.wikipedia.org/wiki/Chernobyl_(miniseries)), the [value given](https://youtu.be/Zz1MJq7rW-w?t=63) for the most dangerous roof is $12\,000\, {\rm Roentgen/hour}$.

The [Juno probe's radiation vault](https://www.space.com/33331-juno-probe-jupiter-radiation-environment.html) is a titanium box with ${\rm 1.75cm}$ thick walls, and the article says

> But this orbit would still expose an unprotected probe to a radiation
> dose of more than `20 million rads` [...] over the course of its mission.

The mission was [planned for 14 Earth months](https://solarsystem.nasa.gov/missions/juno/in-depth/) but the probe only spends short periods of time around Jupiter.

Perhaps someone has an idea how to fill in the gaps and help to make a comparison.

**Tags:** jupiter, radiation


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## 1 answers

### Answer by username_1 on 2021-03-09. Score: 4 | Accepted answer

Let's first quickly estimate whether the numbers by [HBO's TV series](https://en.wikipedia.org/wiki/Chernobyl_(miniseries)) make sense:
According to [gesundheit.ch/strahlung](http://gesundheit.ch/strahlung) the [liquidiators](https://en.wikipedia.org/wiki/Chernobyl_liquidators) were exposed to $2 \ldots 20 {\rm Sv}$ which compares to a life dose of $\approx 100 {\rm mSv}$ for usual people. I remember from my education that each worker was supposed to spent only ${\rm 40s}$ on the roof of the reactor. Assuming a dose of ${2 \rm Sv}$ in ${\rm 40s}$ corresponds to ${\rm 180Sv/h}$, so the value of ${\rm 12\,000R/h=120Sv/h}$ makes sense.

On the other hand, you give an **absorbed dose** of $20 \cdot 10^6 {\rm rad}=2 \cdot 10^5{\rm Gy}$ which is a *physical quantity*. However, the **dose equivalent** in Sievert quantifies the *biological effect* (of the deposit of a joule of radiation energy in a kilogram of human tissue), see <https://www.ncbi.nlm.nih.gov/books/NBK230653/>

> ${\rm 1 Sv}$ is the amount of radiation necessary to produce the same effect on living tissue as ${\rm 1Gy}$ of high-penetration ${\rm 200 keV}$ x-ray

Only if we *incorrectly* assume that the composition of the radiation on the roof Chernobyl in April 1986 and on Juno's flight path are comparable, we could proceed with [cross-multiplication](https://en.wikipedia.org/wiki/Cross-multiplication) by setting ${\rm 1 Sv= 1 Gy}$.

But this (wrong) assumption is not enough, we also need a time frame for your [Gedankenexperiment](https://en.wikipedia.org/wiki/Thought_experiment): If we assume that the radiation dose would remain constant (aka reactor core being exposed) at the lower bound of ${\rm 120 Sv/h}$, the maths gives $2 \cdot 10^5 \frac{\rm J}{\rm kg}/ (120 \frac{\rm J}{\rm kg \cdot h}) = 1\,666.7 {\rm h}$ which is a bit more than 69 days of survival for the [Juno probe](https://en.wikipedia.org/wiki/Juno_(spacecraft)) on the roof of a burning nuclear reactor. Realistically, I assume the probe would stop working much earlier.

### Further reading

You might also find the presentation [Charged Particle Fluxes and Radiation Doses in Earth-Jupiter-Europa Spacecraft’s Trajectory](http://www.iki.rssi.ru/conf/2009elw/presentations/presentations_pdf/session2/podzolko_getselev_ELW.pdf) by M. V. Podzolko *et al.* interesting which gives quite a few estimates on radiation dose around Jupiter.

> **Comments:**
> **username_0**: Fantastic, thanks for pointing out the incorrect assumptions as well.  
> **username_1**: Well, the assumptions that all radioactivity is the same is pretty wide-spread, that's why I felt like highlighting it. Obviously, there is $\alpha$, $\beta$, and $\gamma$ radiation, but there is also an energy distribution of the particles, and the effect on the human body is depending on all that. I feel that text books make it sound very complicated, all the Gray vs. Sievert story, that's why my answer got lengthy.  

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