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Questions tagged [radiation]

Radiation is a process in which energetic particles or energetic waves travel through a medium or space. The particles or waves radiate (i.e., travel outward in all directions) from a source.

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Difference between mass energy-absorption vs mass attenuation coefficient

I have never fully grasped the difference between the mass energy-absorption vs mass attenuation coefficients, for use in calculating x-ray / gamma radiation absorption in a material. Hopefully ...
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Do air-crafts fall when exposed to nuclear radiation? [on hold]

I don't have a background in physics. However I wanted to ask a question relevant to the Chernobyl disaster. From what I found online the helicopter that tried to release sand to shut down the fire ...
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Question about decay

So, I already asked a question on the topic, that helped me understand some more. Now, here i find myself blocked again. I don't know how to solve the following problem: In a basement, you notice ...
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Activity and radioactive decay

So, I am pretty new to that concept, which i am learning about in the context of physical chemistry. I am a mathematician, so a physicists approach can be confusing at times. I have two questions : ...
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Energy spectrum of photoneutrons

In "Radiation Detection and Measurement" Knoll considers the production of neutrons by a ($\gamma$, n) reaction such as \begin{align} \gamma + \ ^{2}_{1}\text{H} \rightarrow \ ^{1}_{1}\text{H} + n &...
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How is this dose rate equation derived?

I've been trying to determine how the following equation for dose rate from a gamma point source has been derived, I've seen it in numerous books with no clear explanation for its derivation, ...
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Why is net radiation heat loss so impossibly high in this everyday case?

If a hot object (temperature $T_h$) is radiating energy to cooler surroundings (temperature $T_c$) engineers express the radiation heat loss as: $Q = \sigma \varepsilon (T_h^4 - T_c^4) A$ which is ...
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Cooling by radiation in space [on hold]

Let's say that you have a gram of molten gallium in the vacuum of space just floating about. how fast would It cool back to a solid via radiation?
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Fitting Beta Emission spectrum data according to fermi function

I was trying to fit beta emission spectrum data to the equation $$\tau(E_e) \propto (E_e^2 - m_e^2 c^4)(Q-E_e)^2\frac{E/c}{\sqrt{E_e^2 - m_e^2 c^4}}.$$ However, on making a custom equation in Origin,...
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Do γ gamma photons of pair production potential > 1.022MeV accelerate neutron decay? [duplicate]

If there are/have been studies testing this exact or the general version of this hypothesis, a reference link would be the preferred answer. Experimental phy. Leah Broussard describing current ...
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Why do thermal cameras work at infrared radiation and not at visible one?

From the Wien's law I have computed the Spectral Irradiance of a black body at 1000°C. From different thermal cameras manufacturers web sites, a lot of Thermal Cameras work in the range 6-14 $\mu m$....
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Calculation with gamma constant to find dosis in sievert/hour

This is a serious question as it's related to my work and actual handling of flour-18. (Always behind plenty of shielding). But i'm very curios of the danger without any protection. I'm trying to ...
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1answer
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Alpha decay and Fermi-Dirac vs Bose-Einstein statistics

This article on wikipedia on alpha decay states: One curiosity is why alpha particles, helium nuclei, should be preferentially emitted as opposed to other particles like a single proton or neutron ...
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Radioactive Decay ($dN/dt = - \lambda N$)

The formula for radioactive decay, $$N = N_0 \ e^{- \lambda t}$$ is derived from the following assumption: $$\frac{dN}{dt} = - \lambda N.$$ I understand an assumption has been made that no external ...
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Spinthariscope with Uranium pottery / marbles instead of Americium

Usually home made zync sulfide spinthariscopes employ Americium 241 from smoke detectors as an alpha radiation source. Uranium glazed pottery (e g. fiestaware) and uranium 'glow in the dark' marbles ...
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Understanding radiation of objects

I am trying to understand Greenhouse effect. I have heard that during the day the earth absorbs heat from the sun and during the night it looses heat in the form of infrared radiation. Does earth ...
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Would it be possible to create a “Vantablack” to absorb outer space radiation?

Looking at this Business Insider article, one of the biggest hurdles of getting humans to Mars is how to reduce the amount of radiation that they are subjected to. Now we do have the Vantablack paint ...
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Mitigation of dead zones when applying circular polarized antenna in shipping containers

I would like to know if I used a circular polarized (RHCP) antenna inside a metal container as show in the configuration below will it reduce the dead zones, as compared to a linear polarized antenna? ...
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Units of radiation dose

I have been reading a few papers on radiation therapy and have come to something I do not understand. In some of the papers they express the dose rate in the following units $$\frac{MeV}{g\space Bq\...
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Is there any non-experimental way to determine what substances are radioactive? [duplicate]

Is there any way to determine if a substance is radioactive and if so, is there any way to determine in what form the radiation will appear, like β- or α-radiation? For example, if I am making a decay ...
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Anti Zeno Effect producing permanent effects

In the Anti Zeno Effect, in which the system required to provide constant measurements of the material for the purpose of speeding up decay is comprised of a high-frequency laser, could exposing a ...
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1answer
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*Why* were the Chernobyl control rods tipped with graphite?

I understand the graphite tips of the boron control rods displaced water (a moderator) which lead to an increased reaction rate, rise in temperature and steam pressure etc. Question: why were the ...
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What triggers a nuclear decay?

I am not a physicist but I have been wondering about this: I understand that the decay of a nucleus is a random event and one cannot predict exactly when it will happen for a particular nucleus. ...
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How much energy, momentum, and/or angular momentum are lost to radiation in Rutherford scattering?

Inspired by this question: Consider two charged particles, of masses $m_1$ & $m_2$ and charges $q_1$ and $q_2$. They approach each other from a great distance, interact via their electromagnetic ...
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1answer
44 views

Effect of volumetric flow rate on convection and radiation heat fluxes

Say we have two hot objects of the same material but of different width and same thickness. The objects are moving horizontally, have initially the same temperature and are cooled by a gas blown from ...
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1answer
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Radiation levels per hour [closed]

I am trying to understand radiation levels. I have found that where I live the radiation levels go up to 100-120 nsv / hour. Does that mean that to find the daily radiation, I would need to multiply ...
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1answer
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Synchrotron radiation for protons

I know that due to the huge mass difference and dependence of radiated energy on mass, protons lose much less energy in synchrotrons than electrons. Can someone tell me how to calculate the energy ...
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1answer
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When does an oscillating charged particle stop radiating? (classic case)

Although self-force is one of the major problem in physics, I think with a few assumptions it's possible to deal with it, at least in Newtonian mechanics. Let's consider a periodic motion, where we ...
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Working out the radial arc of a magnetic field to get mass of electron

We have an experimental setup as below, the magnetic field strength, Bq/30s, and distances (magnet distance, Geiger counter height, Geiger to magnet centre distance) have all been recorded. The energy ...
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22 views

Shouldn't the remaining photon energy be transferred to both electron and ion in a photoionisation?

I'm studying photoionisation and photodissociation, and I'm having a hard time trying know the microscopic details of such processes. I've read that in a photoionisation the photon is absorbed by a ...
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From where does the radiation come from in an inverse-Bremsstrahlung process?

I'm trying to know more about Bremsstrahlung and inverse-Bremsstrahlung processes. If you know any good references that treat theses topics with a good mathematical and physical basis, please let me ...
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What kind of surfaces can scatter alpha particles? In general, what are the requisites for scattering alpha particle?

What are the properties needed to be possessed by material in order to scatter alpha particles?
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Threshold energy of Ti-48 inverse beta decay

Goal: Use anti neutrinos to convert Ti-48 to Ca-48 using inverse beta decay (IBD). The resulting Ca-48 should have the same half-life as natural Ca-48. Question: What is the threshold energy for the ...
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What are all the types of radiation emitting from the Earth or an arbitrary mass in space?

I'm interested in what forces collectively act upon a body in space (obviously radially, so they usually cancel) due to pressures caused by emitted radiation (of any type, strength, "size"). Can you ...
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Do all (most) frequencies of UV cause sunburn?

I recently read in a book called “The universe in your hand” that the reason you can get hurt by ionizing radiation is that the photons carry enough energy to ionize an atom, which can cause chemical ...
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1answer
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How to express the $Q$-value for alpha decay in terms of binding energy of the relevant species?

I have 2 questions regarding the solution to the following question: The solution states that: Mathematically, I understand how the end result $$Q=BE\left({}^{A-4}_{Z-2}\mathrm{Y}\right)+...
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1answer
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Interstellar medium shock heating

How fast would a hypothetical spacecraft need to get to experience significant heating from interaction with the interstellar medium (ISM)? Significant, in this context, means a steady-state ...
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Why gravitational waves can only be generated by a time-varying quadrupole moment of the mass distribution?

The (rather old) source I dispose of "Sexl, Urbantke : Gravitation and Cosmology" describes the radiation of gravitational waves only rather sketchy. So why gravitational waves are only generated by ...
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1answer
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How to Clearly Define Sample Size in Half-Life Measurements?

I'm curious about how to clearly define the sample size when calculating the half-life of particles. My understanding is that the half life is statistical in nature and that for very small samples, ...
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How do ionizing and non-ionizing radiation interact with each other?

Given an ionizing radiation $ X $ and given non-ionizing radiation $ Y $, how does this radiation 2 interact with each other? For example I have X-rays (ionizing radiations) and Microwaves (non-...
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Is there any published ratio between the photo peak and the compton continuum as seen on NaI(Tl) 3“x3” at 1460 keV?

As I know from Gamma spectroscopy, there should be a photo peak from a given element that emits a gamma ray, with the possibility of single/double escape, back scatter peak if the energy surpasses the ...
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1answer
37 views

Why are helium nuclei, electrons and gamma radiation given special names?

Wikipedia article on alpha radiation says Alpha particles were first described in the investigations of radioactivity by Ernest Rutherford in 1899 I can't access the paper containing this ...
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Is there a radiation equivalent in the strong and weak forces?

I know that light is electromagnetic radiation (sourced by accelerating charge) and gravitational waves are gravitational radiation (sourced by accelerating mass). Is there equivalent radiation for ...
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Can beta rays induce radioactivity

I am aware that alpha particle can induce radioactivity. Is it also true for beta and gamma rays?
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Is Inverse Beta Decay a way to “undo” beta decay?

If we consider the beta-minus decay of a radioisotope, we produce an electron and an antineutrino, and a neutron which is converted to a proton. Say we take this same isotope and shoot an ...
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1answer
124 views

Neutron capture calculation

So, the problem state is: Neutron beam radiates sample A with initial number of atoms $N_0$. With neutron capture nuclei (cores) of A are transitioning to nuclei B (they are just one neutron richer ...
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1answer
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What if there was no baryon-antibaryon asymmetry in our universe?

We know that the universe goes through different evolutionary phases: radiation, matter and later dark energy epoch. What would happen if there was no baryon-antibaryon asymmetry? How would the ...
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How can beta plus decay be possible?

$\beta +$ decay is where a proton gets turned into a neutron and a positron and a neutrino. However, a neutron is heavier than a proton, so obviously this reaction is endothermic. So then, why does ...
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How 'bright' would a lethal dose of radiation be?

I watched the Chernobyl TV series with my family and my mom and brother seemed to have a hard time understanding how radiation works, and thought the show was overstating its effects. It can be hard ...
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Ionizing Radiation Interaction with Air

Asking this question purely out of interest. I have no background in this topic. In modern radiation therapy, there's air in between the treatment machine head and the patient. With the high levels ...