What is Detectors: Definition and 111 Discussions

In the broadest definition, a sensor is a device, module, machine, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor. A sensor is always used with other electronics.
Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, besides innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure or flow measurement, for example into MARG sensors. Moreover, analog sensors such as potentiometers and force-sensing resistors are still widely used. Applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life. There are a wide range of other sensors, measuring chemical & physical properties of materials. A few examples include optical sensors for Refractive index measurement, vibrational sensors for fluid viscosity measurement and electro-chemical sensor for monitoring pH of fluids.
A sensor's sensitivity indicates how much the sensor's output changes when the input quantity being measured changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C (it is basically the slope dy/dx assuming a linear characteristic). Some sensors can also affect what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors are usually designed to have a small effect on what is measured; making the sensor smaller often improves this and may introduce other advantages.Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a significantly faster measurement time and higher sensitivity compared with macroscopic approaches. Due to the increasing demand for rapid, affordable and reliable information in today's world, disposable sensors—low-cost and easy‐to‐use devices for short‐term monitoring or single‐shot measurements—have recently gained growing importance. Using this class of sensors, critical analytical information can be obtained by anyone, anywhere and at any time, without the need for recalibration and worrying about contamination.

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  1. S

    I Subtractive mode intensity interferometry?

    In the Hanbury-Brown and Twiss (HBT) family of experiments, they multiply the intensity signals from two detectors. Instead, what if we subract the signals? In this case, we should see the RMS type noise addition when the detectors are far apart, decreasing to a null when the detectors are...
  2. murtazashab

    I In the delayed-choice quantum eraser, why is a stepper motor used?

    It appears to misunderstand the notion of the detectors D3, D4 providing path information and affecting the results D0. My question is: When there is no path information being provided, why does the experiment still call for moving D0? I understand that by moving D0 we can modify the arrival...
  3. Simobartz

    Positioning of Capacitance in Ionization Chamber's Equivalent Circuit

    I'm delving into the topic of ionization chambers, but as someone without a background in electrical engineering, I'm finding the equivalent circuits a bit challenging to comprehend. Specifically, I'm puzzled by the placement of the chamber's capacitance and any parallel capacitance in the...
  4. W

    Where Are the Other Detectors for F5 Tally in MCNP?

    The MCNP manual states that you can have multiple detectors for a single F5 tally. Say you have f15:n x1 y1 z1 r x2 y2 z2 r.....Thing is, my output file only lists the tally result for the first f5 detector (x1,y1,z1). Where are other detectors for this tally? Is there a reason code developers...
  5. A

    B How can a superconductor be used to detect monopoles?

    Why does a monopole detector have to be a superconductor? If there were Monopoles. Why couldn't an EEG machine detect them. Remember in monopoles, moving magnetic charges would generate electric fields. If say the monopole is very strong, it should make the EEG detect them by the probe just...
  6. Oldman too

    Dark fiber optic cables as Earthquake detectors

    Hello, Recently while familiarizing myself with the rodent menace affecting Fiber optic networks, I came across this rather novel use for the dark, or unused fibers in buried cables. The method apparently holds a lot of promise as well as significant advantages over many current Seismology...
  7. D

    B Infrared Detectors & The 2nd Law of Thermodynamics

    This started as an astrophotography question and morphed into a thermodynamics question & it was suggested to start a new thread in Thermodynamics. Essentially the question is how do I reconcile the behavior of particular infrared photodetectors with the 2nd Law of Thermodynamics? For example...
  8. L1ght

    I Question about the Which Way experiment & the detectors used

    Hello, I have a question about the Which Way / Quantum Eraser Experiment. I have tried my best to research online before coming to this forum to ask questions, so I apologize in advance if this question is novice but I have researched. I have been looking for a YouTube "video" of a real world...
  9. mesa

    Looking for specs on Failed Fuel Detectors on NPPs in US

    Hello, trying to get some specs on the FFDs typically found on a US reactor. I was told they run NaI scintillation crystals and measure just Bq's (which seems a little odd) with a follow-up with the Hot Lab once a week (at least for the reactors close to my home). Seems a bit simple to me and...
  10. MathematicalPhysicist

    I GW detectors -- How much has their sensitivity improved since 2008?

    According to Schutz's second edition of "A First Course in GR" on page 318: So to my question. The book was written in 2008, since then have the GW detectors become sufficiently sensitive to detect radiation from black holes? What has changed since 2008? Thanks!
  11. C

    Ant chemical trails and detectors Moved to Biology

    1. How do you remove ants chemical trails on the wall? Water and rug not enough? 2. What are the exact details of the ants incredible chemical sensors in their antenna? How can they able to tell the difference between a hydrocarbon with 25 carbon atoms versus 24 atoms? 3. Lastly, is there an...
  12. F

    A Exploring the D0 Experiment: Proportional vs. Mini Drift Tubes

    Hi all, I'm reading an article describing the D0 experiment at Fermilab during Run II. Proportional drift tubes and mini drift tubes were used to detect muons: can someone explain me the difference between these two kinds of drift tubes? Thanks Federica
  13. T

    Wave motion and two detectors to measure that motion

    Solving for t' by substitution I obtained t' = 7/8. Then I substituted x= 10 and t = 7/8 in the given equation. Is that the right way to do it? My answer key says the answer is 100 but I am getting 78.5.
  14. L

    PFAS Detectors and Eliminations

    United States seems to be PFAS free already. How about the rest of us living elsewhere? How do you detect PFAS? What instruments can you possibly use? https://www.epa.gov/pfas/basic-information-pfas "Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes...
  15. J

    RF pulse detection with Power Detectors

    How can I use power detectors for RF pulse detection? RF pulse has a symmetric Gaussian-like shape. Is the output of power detectors continuous line or point?
  16. S

    I How accurate are radon detectors?

    I was looking online at detectors in the $150-$200 range, queried a seller's website, asked how the electrons or helium nuclei (aka alpha particles) from radon could be discriminated from other sources. The reply: "Rn222 is the only thing the monitor measures and it is relatively unaffected by...
  17. T

    I Photon detectors in a double slit experiment

    It is said that if one shoots photons in a double slit experiment, and place a detectors around the slits to find which slit the photon went, one will not see the photon interfere. However, to detect a photon, one must absorb it. So how does the photon detectors work by detecting the photons and...
  18. R

    Can bat detectors disturb bats and cause them to leave their roost?

    This is something that's bothered me for a while and the recent moquito thread reminded me of it. As I understand it, there are various types of bat detectors but the simplest kind works by emitting its own frequency close to that of the bat, then generating sum and difference frequencies - the...
  19. R

    B 2 clocks -- Using orthogonal light path detectors in a space ship

    Hi I can't see the error in this can someone please explain where I went wrong? A man is in a spaceship traveling at a constant velocity He makes 2 identical tubes of length L with a mirror at one end, tube a and tube b He has a single light bulb. Next to the bulb is a detector. He carefully...
  20. f95toli

    Why do e.g. smoke detectors need specific battery models?

    I have once again come across a smoke detector which requires not only a specific type of battery (9V alkaline) but also a specific model (in this case Duracell MN1604) to be used. I had a similar problem with a CO detector about a year ago (which came with a list of about 10 models that should...
  21. sophiecentaur

    I How do PIR detectors react to plants?

    I thought that plants respire so slowly that their surface temperatures must be pretty much the same as ambient. However, on windy nights, I have experienced three different PIR security lights in three different positions that are triggered by nearby leaves when the wind blows them about. None...
  22. S

    I Understanding Scintillation Detectors for Gamma Ray Simulation

    Hello! I am working on the simulation of a detector for gamma rays. I need to simulate the response time of the crystal but I am not sure I understand what is that. Does it means that any crystal has a limit on the number of photons it can see at once?
  23. R

    B Are All Four GW Detectors Currently Operational for Simultaneous Observing?

    The second LIGO observational run started last year and according to Wikipedia the germany and italy based GWs detectors Geo600 and Virgo are already operational, I would like to confirm whether as of now the 4 detectors(2 from LIGO,1 GEO and 1 VIRGO) are simultaneously fully operative. I would...
  24. S

    I Amplitude moving through detectors

    We have two thin parallel detectors, and a ##|1\rangle## photon state passes through them. Each detector has a 10% chance of catching the photon. How can I write the final state? I'm thinking something like ##\sqrt{0.1}|1_A\rangle |0_B\rangle |0\rangle+\sqrt{0.09}e^{-j\theta_1}|0_A\rangle...
  25. V

    Integrated track length in electromagnetic shower

    Homework Statement Show that integrated track length in EM-shower is proportional to ##E_0##. Homework Equations ##E(t)=\frac{E_0}{2^t}##, with radiation length, ##x_0##. Knowledge that shower terminates at ##E_c##. The Attempt at a Solution The total track length is naturally the total...
  26. V

    Electromagnetic shower energy spectrum

    Homework Statement The energy of a daughter particle in electromagnetic shower is approximated by, ##E(t)=\frac{E_0}{2^t}##. Show that the energy falls off like approximately ##E^{-2}##, for small ##E##. Homework Equations Nothing really. Just a matter of knowing how to differentiate. The...
  27. M

    I The manufacture of ionization smoke detectors

    Was reading the ATSDR Public Health Statement for Americium. It mentioned that higher-than-normal levels of americium could be in the soil near plants that manufacture these devices. It also said that if you live near such a facility you should "discourage your children from putting their hands...
  28. C_Pu

    I How Do Silicon Radiation Detectors Work in Detecting Beta and Gamma Radiations?

    So we are doing Radioactivity lab at second year undergraduate. I am confused about the workings of the silicon radiation detects we are using even though the demonstrators tried to explain. We are detecting beta and gamma radiations by placing sources above a silicon detector that have a small...
  29. J

    B Double Slit detectors question

    My question about the double slit experiment is this: why is it that nobody suspects that the detectors used to detect particles as they pass through the slits in the double slit experiment aren't causing some interference with the experiment which makes it seem as though they are acting like...
  30. Avatrin

    What Are the Methods for Detecting Gases in a Room?

    Hi I am not sure if this is the correct forum to post this on, but I guess it can be moved if it is not. I just want to know what methods exists to detect gases in a room. Smoke alarms use ionization or electromagnetic light. What other technologies exist on the market? What technologies are...
  31. N

    What is the reactor power at Source, Intermediate and Power

    hello all, I am trying to determine what the percentage of reactor power will be at each power level range measured by each detector (i.e Source, Intermediate and Power range). All I can seem to find is info in the CPS rate not percent reactor power.
  32. ChrisVer

    A Resolutions of ATLAS Detectors

    Hi, I was looking for ATLAS detector parts resolutions (momentum for Inner Detector and Energy for the CAL systems). Does anyone have a nice reference? So far I found something like this for the ID: \sigma_{1/p_T} = 0.34 \text{TeV}^{-1} \Big(1 \oplus \frac{44 \text{GeV}}{p_T} \Big) With...
  33. P

    Resistance Temperature Detectors

    Can someone explain three wire and four wire RTD circuits in terms of how the lead resistances affect the voltage output ##V_o = \frac{R_3 V_s}{R_2 + R_3} - \frac{R_4 V_s}{R_1 + R_4}## Also, in the case of a three wire, what is the purpose of Lead C?
  34. X

    Ionization & photoelectrons in x-ray solid state detectors

    As far as i understand, this is the principle of solid state x-ray detectors: 1. A photon of energy E enters the detector and goes through photoelectric absorption 2. As a result a photoelectron with energy (E - Φ) is ejected, where Φ is the binding energy required to eject the photoelectron...
  35. F

    A Thought Experiment: Photons Passing through Detectors

    Pretend we have a multi-slitted grating whose slits are infinitesimally small. We On each slit is a detector. If we shine (UPDATE) light monochromatic light through the grating, what distribution pattern occurs on the screen past the grating? I understand the train of thought to a slight...
  36. Tom B

    Two Slit Experiment: Detectors

    I understand the two slit experiment and the outcome, but where I am confused is how the detectors work. It seems to me that a very simple explanation of the result differing due to the presence of the detectors is that somehow the detectors interfere with the path of the electrons. By...
  37. Splizard

    Double slit experiment with 2 detectors

    Can someone please point me to an experiment (photons/electrons/whatever) where detectors were placed on both slits, this seems like a really big hole in the experiment if they stopped at having just the one detector. (Excuse the pun)
  38. ChrisVer

    Exploring the Construction of RICH Detectors

    I have some question about RICH detectors (in particular HERA-B RICH) and why are they constructed in such a way...I think all the RICH detectors though use the same construction that "confuses" me. In their case the particle of some unknown velocity ##\beta## enters the gas of known refractive...
  39. M

    Single photon counting pixel detectors vs CCD

    Hello, I need to learn as much as I can about single photon counting pixel detectors (producing a signal for each photons hitting the detector) e.g. PILATUS. I do not understand how this type of detectors counts single photons as opposed to integrating the energy of multiple photons (CCD, MOS...
  40. ChrisVer

    Neutrino Detectors: Signature of l q & e Interactions

    What would be the signature in a neutrino detector of these interactions? \nu_l q \rightarrow q^\prime X and \bar{\nu}_l e \rightarrow \bar{\nu}_l l^- with q a nucleon's quark and l^- a lepton? In general I would say that the signal would be that of the resulting lepton and maybe hadron jet...
  41. J

    What photon or electron detector is used in double slit experiments?

    What type of photon or electron detector is typically used to observe the slits in double slit experiments?
  42. S

    Calculating moving speaker through two detectors

    Homework Statement A speaker emitting sound at a frequency of 20 Hz is moving in the +x direction between two detectors. The speaker is moving at a speed of 30 m/s and the detectors are wired so that they flash red (λ = 700 nm) when the pressure is a maximum and green (λ = 700 nm) when the...
  43. K

    How to calculate thickness of the wall in a wire chamber

    Homework Statement This is a question on multiple coulomb scattering in a wire chamber momentum p = 500MeV/c wire resolution = 120 microns distance from wall to wire = 0.01m radiation length of wall material X_0 = 2E-3 m mass of charged particle m_{\pi} = 139.6 MeV/c^2 charge z = 1 How thick...
  44. D

    Help Solving Physics Exam Question on Gamma Rays Counting Rate

    Hi, I came across a question in an exam which I couldn't really relate to any topic of physics, that I had studied. It goes like this- A detector is used to count the number of gamma rays emitted by a radioactive source. If the number of counts recorded in exactly 20 seconds is 10000, the...
  45. Phoenix Baldez

    Nuclear Engineer Looking into High Energy Physics Detectors

    So I am a senior nuclear engineer with a good GPA and I've actually taken some extra math (PDEs) and physics (nuclear physics and astrophysics) courses over the years. I am extremely interested in detection in general. I have worked at a national lab designing and building neutron detectors and...
  46. TrickyDicky

    Tracks in particle detectors and quantum paths

    How are the track leftt say by an electron in a cloud chamber and its wave function undefined trajectory related exactly?
  47. S

    Adding SNR from multiple detectors

    I am looking at the same object with two detectors. The SNR on each is 2, which is a low probability of detect given a single sensor. However, if I fuse the two what would be the SNR then? Would it be additive (SNR=4) or rss (SNR=2×sqrt(2)) or something more complicated?
  48. D

    Feynman's detectors at double slit

    As far as I know Feynman was the first who told that if you would put detectors at the double slits the interference pattern would disappear, because of "knowing with path". But I think this specific experiment has never been done because a photon cannot be detected without absorption. So if...
  49. gfxroad

    What is the Best Portable Radiation Detector for Hospital Use?

    Hi I need some helps to find a proper portable instrument/equipment to measurement radiation leakage in a radiological diagnostic facilities of hospitals. Thanks in advance
  50. D

    Delayed Choice Eraser with dispersion pattern controlled detectors

    Sorry if it's a silly question but I was trying to find such an experiment and wasn't successful. What I am thinking is, in the standard delayed choice quantum eraser, the dispersion pattern on the screen correlates to whether or not we can detect which path the electron took. What if the...