Electromagnetic radiation with high energies and a typcial wavelength of less than 10 picometers.

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Gamma spectroscopy - Nuclide identification

I have a question about what the usual practice is for nuclide identification in gamma spectroscopy. For example, if I see a line at 477 keV, I would write that the origin of this line is $^7Be$. As ...
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1answer
13 views

Gamma decay multipolar transition rate?

I have been trying to derive the equation for the transition probability per unit time/transition rate for gamma decay of a nucleus, as given by equation (21) of this article. I have also gone through ...
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27 views

Should I see evidence of neutron induced gammas on a background spectrum?

If I am looking at a background gamma spectrum taken from a neutron spallation source whilst the beam was off (IE in a shutdown period), should I expect to see emissions coming from neutron induced ...
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15 views

Finding the geometric efficiency of a cylindrical Marinelli beaker

I want to find the geometric efficiency of a cylindrical marinelli beaker filled with soil to perform gamma spectroscopy, so essentially the ratio of rays that pass through the detector to the overall ...
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1answer
110 views

Why do we need to build photon colliders? Since electron-position colliders are very “clean”

What's the advantage of gamma-gamma colliders? What new physics can be done with it? Reference: http://www.slac.stanford.edu/pubs/beamline/26/1/26-1-kim.pdf
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Puzzled by a new result on neutrino speeds

In a paper appearing today on arXiv, Wie et al. have used the close coincidence of the time of arrival of gamma rays from GRBs and the detection of single 3-30 TeV neutrinos at the IceCube ...
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57 views

What is radiative width?

I am trying to understand gamma radiation and trying to figure out how to calculate radiative width. Is the radiative width how far the atom can be from another one and the probability of it then ...
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37 views

What are the main issues limiting resolution of gamma ray detectors?

Current gamma ray detector resolution is far from diffraction limited. For example, Swift's Burst Alert Telescope has a resolution of 1-4 arcminutes for gamma ray bursts (Wikipedia:Swift). My ...
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74 views

Why does lead have a higher attenuation coefficient for 5.0 MeV than for 10.0 MeV?

I was doing some calculations on radiation, and I noticed that lead has a higher attenuation coefficient for 5.0 MeV than for 10.0 MeV, namely $1.44 \, \mathrm{cm}^{-1}$ for the former and $1.23 \, ...
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1answer
20 views

How to find the error of all the counts within the Full Width Half Maximum (FWHM)?

We've been doing Gamma ray spectroscopy and have peaks from various sources. We'd use Poisson statistics, but obviously the detector doesn't have a resolution of zero, thus we are summing the counts ...
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Formula for scattering and energy change of photons on (naked) nuclei

What is the formula for scattering and energy change of photons on (naked) nuclei? (On wikipedia Compton scattering does only explain scattering of photons by electrons, and I'm not even aware if the ...
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1answer
36 views

What is the likelihood of pair production for a high energy photon?

Wikipedia says that pair production is the dominant form of light-matter interaction for photons with a mass equivalence of at least twice the rest mass of the target particle, implying that not all ...
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68 views

X-ray shielding

X-ray shielding, why is lead used to shield us when taking X-ray images? As far as I remember (but can't find it on wikipedia ... ), the deflection on (high energy) photons increases the more heavier ...
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61 views

Is Electron decay period less than stated?

Phys. Rev. Lett. 115, 231802 – Published 3 December 2015 sets a limit on the stability of the electron for decay into a neutrino and a single monoenergetic photon in $\tau\ge6.6\ 10^{28}\ ...
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1answer
58 views

Temperature from gamma rays?

I was reading about gamma ray bursts and read something along the lines of 1 MeV gamma rays corresponding to a fireball above 2 billion degrees Celsius. How do scientists get temperature from that? ...
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1answer
35 views

Question about the Blandford–Znajek process

I've been trying to understand the Blandford–Znajek process which explains how Gamma Ray Bursts form, but it's still not clear to me how it works. In this article, several theories about the formation ...
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39 views

Why do some stars actually produce “Gamma ray bursts”?

I looked it up but I haven't found any explanation as to why some stars produce them, I understand that collapsing and merging stars produce them, but my question is why is the energy concentrated in ...
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25 views

To which extent is the treatment of nuclear multipole radiation by the means of a classical electromagnetic field valid?

In the treatment of nuclear multipole radiation, for example in the context of nuclear gamma decay, it is standard, at least at the elementary level, to formalize the electromagnetic radiation as a ...
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1answer
30 views

Prompt gamma emission vs gamma decay

I understand prompt gamma emission to mean gamma emission in a time period shorter than a second. I understand gamma decay to be the relaxion of a nucleus into a lower energy level by emission of a ...
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80 views

Could the $\gamma$ ray “weaken law” be used in the air?

I'd better write it down. I do not know if it is called "weaken law" in English. $$N=N_0e^{-\mu d}$$ $N$ is the initial number of photons. $N_0$ is the amount measured after passing through an ...
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Gamma spectroscopy - Extractable information from peak significance changes?

Apologies for the title - I couldn't think of a better way to summarize my question I have a table which contains information on 60 gamma spectra taken over a total period of 20 days, from the hall ...
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1answer
39 views

Direction of Gamma Ray Bursts

After a black hole consumes a star, why do gamma ray bursts only shoot out perpendicular to the spinning accretion disk? Why do they not shoot out parallel to the disk?
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1answer
35 views

Machine readable database of gamma lines

Friends of mine did a lab experiment where they recorded $\gamma$-spectra in the range from 0 to 1500 keV with a soil sample. The data contains some background and a couple sharp peaks at different ...
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38 views

Can alpha, beta or gamma radiations emitted by a radioactive substance be controlled? [duplicate]

Just saw this question in a school class 10 exam. Google search did not yield useful results. Can anyone please explain the answer here?
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94 views

Disintegration of deuteron into n & p by a gamma ray - energy considerations

I was working through a problem that has a Deuteron of mass $M$ and binding energy $B$ disintegrated by a $\gamma$-ray of energy $E_\gamma$ into a neutron and proton. It proceeds to ask to find the ...
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3answers
98 views

FWHM increase with energy (gamma spectra)

Below I have two plots from a gamma spectrum which I've been analyzing. The first plot is between a low energy range, the second between a significantly higher energy range. It is clear that the FWHMs ...
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Is the direction of gamma-ray emission by a nucleus totally random?

Let's consider an excited nucleus emitting one gamma-ray (not cascade etc). Is the direction of gamma-ray emission completely random? In other words, is the probability to detect this gamma equal for ...
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35 views

Gamma spectroscopy - Fitted Singlet

I'm using some gamma acquisition and analysis software. When I ask the software to do some sort of Nuclide Identification, almost every single peak in the generated output is marked with "F". ...
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3answers
482 views

Why we don't use gamma rays, x-rays or ultraviolet to transmit data?

The greater the frequency range of a transmission medium, the greater the number of bits per second it can transmit. In other words, the bigger the bandwidth in hertz available, the bigger the ...
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64 views

why is gamma ray ejected during radioactive decay?

Why are gamma rays are emmited? Why is it not that an x ray or infrared or ultraviolet or cosmic or microwave ray is emmited?
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115 views

Gamma spectroscopy - Do annihilation photons produce a backscatter peak?

Below is a diagram of part of a structure which I find in a gamma spectrum taken from a hall in which a neutron source is undergoing spallation. The structure which I'm interested in can be seen ...
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1answer
84 views

Partial Resonance Widths

Can any one tell me how we calculate the partial width of a resonance reaction? If a proton beam of certain energy is incident on a Carbon nucleus, a 13C(p,gamma)14N reaction takes place and we have a ...
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1answer
497 views

Gamma spectroscopy - Table of radioactive isotopes with gamma energy search

For anyone doing gamma spectroscopy by hand, the task is considerably eased by tables like this: http://nucleardata.nuclear.lu.se/toi/ Where not only can you search for particular nuclides, but you ...
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Gamma spectroscopy – What is this structure?

What is this strange structure in the gamma spectrum between 450 and 550 keV (below) around the peak at 477 keV? The spectrum seems to rise to a plateau (almost like a small Compton plateau) around ...
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53 views

Coincidence summing in gamma spectrum

Question on coincidence summing here. I've been reading about the coincidence summing effect when a radionuclide has two energy levels that decay to another state in rapid succession. There is also ...
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31 views

Gamma spectroscopy - neutron activation of a stable isotope

Question about gamma spectroscopy here. If I suspect that on a gamma spectrum I have a line which is a consequence of the presence of Ge-78 - which is being produced via the neutron activation of a ...
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1answer
56 views

How does scintillation gamma-spectrometers work?

As far as I understand, the incident photon interacts by photoelectric, Compton scattering or pair production with the electrons of the crystal (NaI(Tl) in our case). The electron that emerges from ...
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42 views

Are relativistic spacecraft slowed down by oncoming gamma ray photons?

I recently read that a proton having an energy of ten billion GeV can travel across our galaxy in about 5 minutes from the frame of the proton. From the Earths frame we would see it take roughly ...
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1answer
100 views

What produces this 477 keV spectral line?

Question about a specific line on a gamma spectrum, here. Below is a background gamma spectrum observed by a Ge[li] detector. I've been able to identify all the lines with mostly certainty, apart ...
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1answer
433 views

Should I observe single/double escape peaks for all energies above 1022 keV

I have already asked a question similar to this, but that question was specifically relating to the case of K-40. I'm going to generalize it to any case My question is to do with the field of gamma ...
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1answer
45 views

Why do I not observe single/double escape peaks for K-40

A question on gamma spectrometry here. If I'm looking at a background gamma spectrum with a big peak at 1460KeV (approximately 180 counts) and I attribute this peak to the presence of K-40, should I ...
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1answer
40 views

Gamma Spectroscopy - Why no Intensity level for Neutron Capture?

I'm undertaking a bit of work looking at a Background Gamma Spectrum. On the spectrum, I have a clear, tall line at 834 KeV. I have a PDF file of a table of Gamma Spectra (ordered in energy) from ...
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34 views

Lorentz factor correction for luminosity

I am looking at the physics behind gamma ray bursts, working through a comprehensive review Kumar & Zhang (2014) (arXiv link). On page 92, Eq (111) the luminosity or a relativistically expanding ...
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2answers
188 views

Is there a possibility of anti-dark matter?

Based on Galactic Gamma Ray Emission My question is simply put. Although dark matter itself is almost a complete mystery, has anything been published which postulates the existence of anti-dark ...
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1answer
48 views

Short Gamma Ray Bursts from black hole mergers

I have read in passing that short gamma ray bursts can be caused by the merger of 2 black holes in a binary system. I have Googled but can't seem to find any good sources describing the phenomenon ...
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2answers
84 views

Do gamma ray bursts play a role in cosmic evolution?

If gamma ray bursts were to interact with gas clouds in the early universe, might it be a relevant factor in star production?
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66 views

Can we extract positrons from gamma rays?

If gamma rays undergo pair production is there a way to say, deflect and collect the positrons using magnetic fields?
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192 views

will osmium or lead stop all high-energy photons in a shorter distance?

I remember seeing a similar question to this one on Physics StackExchange once. Most of the answers were to the effect of "I don't like the way this question is phrased, so I will insult your ...
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32 views

Can natural gamma radiation be induced by cosmic rays?

When cosmic-ray particles like muons or neutrons impinge the ground, they get slowed down, thermalized and captured. This process is most effective when water/rain/moisture is present. Furthermore, ...
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453 views

Why did scientists use a zinc-sulfide coated screen to detect the alpha, beta, and gamma radiation?

How does a zinc-sulfide coated screen work, and how does it manage to detect high-frequency radiation, electrons, and helium? Could it be possible that a delta ray managed to somehow slip past ...