Questions tagged [particle-detectors]

the tools used to detect (and sometimes) characterize ionizing radiation. This tag is appropriate for question about the characteristics and behavior of all such devices from the simplest Geiger-Muller tube, to the compound monsters used by high-energy experiments to the mega-ton instrumented volume of IceCube.

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6
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1answer
672 views

Why are there fixed target experiments?

Collider experiments put all their energy into $ \sqrt{s} = 2E $ while target experiments only provide $ \sqrt{s} = \sqrt{2Em+m^²} $. Yet, there are fixed target experiments. Why?
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1answer
35 views

Determine/measure energy of neutral particles

I wonder that nobody came up with this question in advance - maybe it is too obvious? However.. How can neutral particles be measured (with respect to their energy in a particle detector)? I know ...
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1answer
24 views

Magnetic horn function

I wonder how a magnetic horn works. I can imagine that a magnetic field will distract particles due to their charge but what I don't understand is, how to isolate antiprotons? The charge is probably ...
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1answer
59 views

Momentum of neutral particles in particle colliders

I understand that we can find a momentum (or a charge to momentum ratio anyhow) for a charged particle (charge $q$) in the LHC by using it's radius of curvature $r$ as $$\frac{mv}{q} = Br$$ So that ...
2
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1answer
34 views

What is wrong with my Cloud Chamber? I can't see supersaturated vapor or particles [duplicate]

I'm using black felt at the bottom, a small tin can, and black sponge around the inside of the can. I hot glued them onto the can, and then put 91% isopropyl alcohol in it. Afterwards, I used some ...
2
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1answer
73 views

Which are the highest energy gamma-rays produced by humans?

We can produce energetic gamma-rays on Earth in nuclear reactions but also among the decay products of LHC particle collisions. So I was wandering which are exactly the highest energy man-made gamma-...
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34 views

Do space-borne cosmic ray experiments publish all-particle spectra?

I was trying to gather data to produce my own cosmic ray (CR) spectrum plot. I have relied on this very useful French database collecting past space-based CR measurements. If I try to insert the ...
2
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1answer
35 views

Unknown pulses from SiPM without any source or detector?

I have a SiPM set up with its PCB, no amplification at all, reading out to an oscilloscope. If I supply 29.8 V, which is the maximum power (with overvoltage), I get some random peaks on the ...
3
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1answer
88 views

Cherenkov light and refractive index

LHCb’s Ring Imaging CHerenkov detector (RICH) is aimed at telling different charged particles apart by measuring their velocity, which, together with an independent measurement of their momentum, is ...
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1answer
41 views

Estimating Accidental Coincidence

I am trying to measure muon's mean lifetime using 3 scintillators. The logic of the experiment is shown below: I know that accidental coincidences could happen because of unrelated muons that ...
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0answers
38 views

Can we image the interior of the earth by shooting weakly interacting particles through it?

Could we image the various layers of the earth by shooting weakly interacting particles through it? Let's say we shot a very high amount of neutrinos in one side (say, the north pole) and then ...
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2answers
121 views

What is the Detector in the double slit experiment and how it works?

What about the "DETECTOR". Is it a passive device or is it just a fictional mathematical prob. I think that detector is somehow consuming the energy responsible for the wave nature of the photons, ...
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56 views

What is the formula of operating voltage of GM counter?

In some manuals I found operating voltage formula $$V=V_1+(1/3)(V_2-V_1)$$ and in other manuals $$V=(V_2+V_1)/2.$$ Which formula is correct? If both are correct, then please give the reason.
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1answer
67 views

Muons - how are we even able to detect them? [closed]

muons have a very small half life comparable to 2.5 μs or so. But we know that it has to cover a very large distance from upper atmospheric layers to reach the particle detectors installed at earth's ...
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1answer
195 views

Scintillator decay time=1000 nsec,does that mean dead time is really high?

What I'm really confused about is, say my scintillator is really slow, and has a decay time of about 1000 nsec. Does that mean, if one neutron is being read by the electronics, for that particular ...
2
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1answer
73 views

Are there ways to detect/measure photons that don't involve electrons?

As per question, are there ways to detect photons, and/or to measure their energy, that don't involve any interaction with electrons? And if yes, are there detectors which use photon interactions with ...
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0answers
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What is meant by an “Any Energy” efficiency curve for a particle detector?

So I'm simulating a silicon detector with an electron source incident on it. I need to get 2 efficiency curves, one "photo-peak" and one "any energy". I've got the photo peak one, but I don't ...
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3answers
3k views

In particle colliders, according to QM, how are two particles able to “collide”?

According to QM, we know that The act of measurement forces a particle to acquire a definite (up to experimental errors) position, so in a particle collider, like the one in CERN, by which means ...
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29 views

Notation in a question on probabilities and particle counting

I'm working through Stephen Barnett's book on quantum information and have come across the following question (1.5, for anyone keeping track at home) A particle counter records counts with an ...
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1answer
32 views

Majorana Neutrinos in the KamLAND-Zen

I'm reading the following paper concerning the KamLAND-Zen experiment "Search for Majorana Neutrinos near the Inverted Mass Hierarchy Region with KamLAND-Zen" In the second paragraph of the first ...
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79 views

Micro-channel Plate Detectors - do they or don't they degrade?

Micro-channel plate (MCP) detectors are microscopic holes in a plate. They get put in an electric field and there act like many tiny dynodes, amplifying any electrons that enter. This makes them ...
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1answer
83 views

What is the pulse that is counted in Geiger Muller tube?

I have started reading the theory behind the working of Geiger Muller tube. I dont understand the concept of pulse! According to wikipedia: The ionization is considerably amplified within the ...
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1answer
52 views

In HPGe detector how electron-hole pair remembers energy information of incident gamma?

In the HPGe detector, any gamma energy (> e-h pair production E) shall excite the electron of the valence band and send it to the conduction band. Due to reverse bias, the conduction band e shall be ...
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1answer
28 views

How do scintillation detectors work, for gamma ray spectroscopy

So I understand what happens in the crystal with respect to the interactions and how the electrons in PMT are multiplied by hitting dynodes etc. But what I can't really seem to find any information on ...
3
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1answer
96 views

Matter effects contributing in solar, atmospheric and reactor neutrino oscillations

Neutrino oscillations are affected by the matter effects. For solar neutrinos, which are exclusively neutrinos of $\nu_e$ type, the matter effects can be contributed by (i) the solar plasma, (ii) ...
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1answer
73 views

Width of $\eta$ meson mass peak?

In an experiment an $\eta$ meson is produced with total energy $E _ { 0 } = 2000$ MeV in the laboratory frame. Estimate the width of the $\eta$ mass peasured in a calorimeter that has an energy and ...
3
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1answer
71 views

What formula is used to make exclusion plot in the direct detection of dark matter?

The idea of direct detection of dark matter is that a dark matter particle striking some underground target will cause the target nucleus to recoil. From the recoil, one can determine the scattering ...
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1answer
188 views

What’s wrong with my cloud chamber setup?

For my setup, I am using a fish tank, lined with black felt and with one side open for viewing and a slit on a side for the light. I have a pretty bright multi led flashlight. I am using dry ice ...
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1answer
41 views

Effects of a wire's radius

I have recently read a paper by R. G. Markham titled "High Resolution Position-Sensitive Proportional Counter." In this paper, the author stated that "The guard wires were chosen to have a large ...
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1answer
303 views

Pile-up in particle physics

Regarding pile-up, I came across two definitions. One dealing with electronics of detector where more than one event get recorded at the same time and other regarding all the pp collisions in the ...
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1answer
70 views

Why is it easier to observe B-meson oscillations than D-meson ones?

B-meson oscillations were observed several years ago by the CDF experiment B-oscillations, but D-meson could not be observed until very recently by the LHCb experiment. I'm wondering why is it more ...
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2answers
78 views

Spatial resolution of silicon pixels

There is a variety of silicon pixels being used in very high energy particle applications. I would like to know, if I have a detector with silicon pixels of dimensions N x M, how can I calculate what ...
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0answers
11 views

Impurities in HPGe crystals

Is there any way that one can find the impurities existing in an HPGe crystal? This is required for making an accurate simulation of the material of the crystal including the concentrations of Ge and ...
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1answer
148 views

What is an Anderson-Braun neutron counter?

I found this type of tool reading an article ("A neutron monitor with silver activation") but surfing the internet I can not find an explanation of what it is and how it works. It's probably a basic ...
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1answer
36 views

How do we identify distant radiation sources?

I was reading this question and the answer cites a page which discusses the identification of an x-ray source very far away. I'm a nuclear engineer and based on my understanding of radiation detection,...
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1answer
65 views

Poisson statistics in photo detectors

I was wondering how would Poisson statistics be used in a photodetectors to account for the number of events that I'm missing in my experiment. Say I have a material (scintillator, ...) that emits $n$ ...
3
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3answers
635 views

What is the difference between electrons and holes in silicon?

Electrons and holes behave differently in a silicon semiconductor (e.g. mobility of holes is one order of magnitude smaller than that of electrons, the collection time of holes at the same electric ...
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1answer
44 views

Inverse polarization of semiconductors as detectors

I've been reading the particle detector section of the PDG and in point 33.2.3 they talk about Solid-state photon detectors. They say there that Silicon Photodiodes are simply a "reverse-biased p-n ...
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0answers
37 views

Resolution of a scintillator

I am thinking on buying a scintillator for a particle physics lab lesson. I would like to know what is the best way of measuring its resolution (the photon yield is 4$\times10^4$ photons/MeV and I'm ...
4
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2answers
66 views

Physical processes taking place inside Germanium detectors

Reading about differences between Silicon detectors and Germanium detectors, I decided to learn a bit more about the latter, since I've always used Silicon detectors in all the experiments I worked ...
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0answers
40 views

How do you calibrate a proton-recoil scintillation fast neutron detector?

I have a proton recoil scintillator, but gamma sources like Cs-137, Co-60 don't seem to have linear calibration for the device. Are there other ways of calibrating this device? I'm trying to detect ...
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1answer
39 views

Why are the ionisation tracks not visible when there is turbulence a cloud chamber?

I noticed that if I build a cloud chamber (with 99% isopropyl alcohol), when the mist is falling smoothly, I can see particle tracks passing through the mist. However, if I move the jar at all, ...
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0answers
30 views

Periodic, linear increase in photon counts

Background: In my experimental physics class I had to do an experiment like this one regarding the Bell-Inequality. For the data shown below the photons of blue laser diode in the state $|V\rangle$ ...
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1answer
54 views

How to measure the levels of muonium in the experimental area of a particle accelerator?

I want to know if there is any way of measuring the levels of muonium in the experimental area of a particle accelerator. So, it would start with a beam made up by anti-muons which would collide with ...
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1answer
38 views

Silicon detectors with charge division?

Instead of using double-sided silicon strip detectors to gain a 2D position resolution sometimes a one-sided strip detector is used with resistive charge division, where the signal at one strip is ...
4
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1answer
169 views

Electrons diffusion in gas with present of electric field

For research purposes, I am looking for a way to calculate how far the electrons "spread" perpendicularly to the electric field in a chamber of gas. For example, if a beam of alpha particles ionize ...
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1answer
61 views

What is a non-gaussian tail of momentum resolution?

While reading about the reconstruction of high transverse momentum muons in particle detectors I came across the following statement which I do not understand: Showers and radiative loss account ...
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1answer
71 views

Particle detection at LHC - leptons and jets

Invariably, the events that are triggered on have large transverse momentum, so it seems plausible that a jet and a lepton are often detected in nearly the same point of the detector. In this ...
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3answers
157 views

Is it possible to know the efficiency of a particle detector without assuming the truth of Theory (e.g.,, Quantum Theory)

I reorganized the question to clarify exactly what it is that I'm asking. Suppose an experiment is performed where a particle detector records 50 particles per second, on average. Absent any other ...
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1answer
63 views

How is the energy of a particle measured in a Cherenkov detector [closed]

I don't understand how is the energy measured in a cherenkov detector. How is the number of photons radiated related to the energy of the particle or the measure of energy has nothing to do with the ...