Detectors are classified by their operating principles, materials, detection methods, performance, and applications. A single type of detector may have multiple names, and conversely, a specific target may be detected by various methods. This section provides a classification of detectors commonly used in analytical instruments that require high-voltage power supplies.
| Detection | Detectors | Abbreviation | Summary | Voltage, etc. |
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| Light | Photomultiplier tube | PMT | Photomultiplier tubes (PMTs) are vacuum-tube detectors capable of detecting faint light (low light) with high sensitivity. Light is converted into electrons at the photocathode of the incident window, and the signal is amplified by an electron multiplier tube. To learn more, please visit Photomultiplier Tube (PMT) | 1000 to 2000V |
| Light | Multi-pixel photon counter | MPPC | MPPC, or Multi-Pixel Photon Counter, is the trade name used by Hamamatsu Photonics K.K. for their Silicon Photomultipliers (SiPMs). It is a type of SiPM detector. For more details, see the Silicon Photomultiplier (Si-PM) entry. | 20 to 100V |
| Light | Silicon photomultiplier | Si-PM | Si-PM is a photodetector that operates based on the avalanche photodiode multiplication principle of semiconductor detectors. They are smaller than conventional photomultiplier tubes, offer sensitivity comparable to PMTs, and operate at lower voltages. | 20 to 100V |
| Light | Photodiode | PD | Photodiodes are the most common light-detecting elements and are sometimes abbreviated as PD. A device that converts light into electrical signals, it is also used in the light-receiving part of optical discs in optical communications. For the difference between a photodiode, a PIN photodiode, and an APD, see the following page. Photodiode |
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| Light and Radiation | PIN photodiode | PIN-PD | A PIN photodiode is a photodiode with an I-layer (intrinsic region) structure between P-type and N-type semiconductors, also abbreviated as PIN-PD. It requires a reverse bias power supply and has excellent high-speed response. It is mainly used as a detector for optical communications. It is also used as a detection element for X-rays. https://www.amptek.com/products/x-ray-detectors/sipin-x-ray-detectors/sipin-x-ray-detectors For the difference between a photodiode, a PIN photodiode, and an APD, see the following page. Photodiode | 100V to 200V |
| Light | Avalanche photodiode | APD | An avalanche photodiode is a photodetector with a signal amplification function. Si-APDs and InGaAs-APDs are available. Due to its amplification function, it is used to measure faint light (low light). A reverse-bias power supply is required, and Si-APD requires a DC power supply of several hundred volts. InGaAs-APDs operate with a low-bias power supply and are used for optical communications. It has a signal amplification function, but is not as sensitive as Si-PM or PMT. For the difference between a photodiode, a PIN photodiode, and an APD, see the following page. Photodiode |
Si-APD: 20 to 200V InGaAs-APD: 5 to 60V |
| Radiation | Survey meter | - | A survey meter is a generic term for radiation measuring instruments. Depending on the detection method, there are ionization chamber survey meters, GM tube survey meters, and scintillation survey meters. | - |
| Radiation | Ionization chamber, ion chamber | - |
An ionization chamber is a type of radiation detection device. Similar detectors include proportional counters and GM tubes, which produce different signals depending on the voltage applied. The voltage applied in the ionization chamber region ranges from +30 to +300 volts. For more information about ionization chambers, please see the following page. Ionization Chamber |
+30 to +300V |
| Radiation | Proportional counter | PC |
A proportional counter is a type of ionizing radiation detector. Like an ionization chamber, it measures ion pairs due to radiation entering the detector. A voltage pulse proportional to the number and energy of the radiation is obtained as a signal. The voltage applied in the proportional counter area is about +500V to +2000V. |
+500 to +2000V |
| Radiation | Geiger muller tube | GM-tube |
GM tubes are a type of detector used in survey meters, also known as Geiger counters. The applied voltage in the GM region varies depending on the structure and type of gas, and ranges from +400V to +1200V are used. For more information, see the Geiger counter page below. Geiger counter (Geiger-Müller tube) |
+400 to +1200V |
| Radiation | Scintillation detector | - | Scintillation detectors are detectors used for radiation measurements, such as survey meters and area monitors. A scintillator converts incident radiation into light (typically visible or UV), which is then converted into an electrical signal by a photomultiplier tube (PMT) or other photosensor for detection. NaI and CsI are the main scintillators used in survey meters. Other scintillators for radiation include inorganic scintillators, plastic scintillators, and liquid scintillators. | 1000 to 2000V |
| Radiation | NaI (Sodium iodide) detector | NaI | The NaI detector is a detector that uses NaI (sodium iodide) for the scintillator portion of the scintillation detector. Detectors using NaI can measure with high sensitivity, but they are deliquescent and sensitive to shock, so care must be taken when handling them. Some detectors have energy resolution and conversion to dose based on spectral characteristics (e.g., line position and intensity). Also called a spectrosurvey meter, a spectral survey meter, or a spectroradiometer. | 1000 to 2000V |
| Radiation | CsI (Cesium iodide) detector | CsI | The CsI detector is a detector that uses CsI (cesium iodide) as the scintillator part of the scintillation detector. It is less sensitive than detectors using NaI, but it is less deliquescent and easier to handle. | 1000 to 2000V |
| Radiation | Solid state detector | SSD | SSDs are radiation detectors used to detect X-rays, gamma rays, and neutrons. Historically, a type of SSD known as the Si(Li) detector (Lithium-drifted Silicon) was common in applications like SEM-EDX. While offering excellent energy resolution, Si(Li) detectors have been largely replaced because they require cryogenic cooling with liquid nitrogen, making them bulky and cumbersome to operate. Modern energy-dispersive X-ray fluorescence (XRF) and SEM-EDX systems predominantly use Silicon Drift Detectors (SDDs). | 300V to 600V |
| Radiation | Silicon drift detector | SDD | The SDD (Silicon Drift Detector) is a radiation detector used for energy-dispersive X-ray fluorescence analysis and SEM-EDX. This detector has replaced the Si(Li) detector because it can detect with high sensitivity even with a larger element area, without reducing the energy (wavelength) resolution. The detector element is characterized by a pattern called a drift ring. | 100V to 300V |
| Radiation | Transition radiation detector | TRD | Transition Radiation Detectors (TRDs) are particle detectors used in high-energy particle collider experiments. Transition radiation, which occurs when charged particles pass through the boundary between a metal foil with a large atomic number and a gas or other substance, is detected with a proportional counter tube or wire chamber. | - |
| Neutron | Neutron detection | - | There are several types of neutron detectors, including scintillation detectors, gas proportional counters, and semiconductor detectors. Since neutron beams have a strong penetrating power and neutrons carry no electric charge, their detection is by measuring reactions due to their interaction with the nuclei of matter. Neutrons play an important role in nuclear reactions such as nuclear power generation. | - |
| Radiation | Si detector, Si(Li) detector | - | Silicon detectors primarily refer to solid-state detectors. Note, however, that in a broad sense, a detector made of silicon semiconductor material may be called a silicon detector. The term silicon detector is also used as a comparison with germanium detectors, mainly in radiation detectors. For solid-state detectors, see the SSD section. | 300V to 600V |
| Gamma ray | Germanium detector | Ge detector | Germanium semiconductor detectors are semiconductor detectors that can analyze radionuclides. It has excellent energy resolution and is useful for high-resolution gamma-ray spectroscopy. Germanium semiconductor detectors are made of high-purity germanium crystals and must be cooled below -200°C with liquid nitrogen. | 2000V to 5000V |
| Gamma ray | cadmium zinc telluride (CZT) detector | CZT | A CZT detector is a type of semiconductor detector that detects radiation. This detector uses CZT crystals, in which CdTe is partially replaced from Cd to Zn. It is used in the same gamma-ray spectroscopy as germanium semiconductor detectors. Unlike germanium semiconductor detectors, CZT detectors can operate at room temperature. | 500V to 2000V |
| Gamma ray | Cadmium telluride (CdTe) detector | CdTe | CdTe detectors are radiation detectors that use cadmium telluride (cadmium telluride). They can efficiently convert radiation such as gamma rays and X-rays into electrons and are used as image sensors for radiation as well as detectors. | 400V to 1000V |
| Charged particle | Charged particle detector | - | Charged particle detector is a generic term for detectors that detect and measure ionized atoms and charged elementary particles. Detects charged particles such as alpha and beta rays. Charged particle detectors include the following detectors: Ionization chambers, proportional counters, Geiger-Muller counters, solid-state detectors, time projection chambers | - |
| Charged particle | Electron multiplier | EM | An electron multiplier tube is a detector that amplifies charged particles such as electrons and ions in a vacuum and measures them as a current at the anode. There are discrete dynode structures and continuous dynode structures. Discrete dynodes are known as Photomultiplier Tubes with a photocathode in the incident window. | 1000V to 3000V |
| Charged particle | Channel electron multiplier | channel tron | A channel electron multiplier (CEM), also called a channeltron, is a type of electron multiplier tube. In a vacuum, signals from electrons, ions, and photons are amplified and detected. | 2000V to 4000V |
| Charged particle | Microchannel plate (MCP) | MCP | A microchannel plate is a disk-shaped plate with numerous holes and a structure that amplifies charged particles and optical signals. MCP does not have a detection function, but it is sometimes referred to as MCP in combination with other detectors. For more information, please see the following microchannel plates. Microchannel Plate (MCP) |
100V to 1000V |
| Charged particle | Time-of-Flight detector | TOF | Time-of-Flight (TOF) is a mass analysis technique, rather than a specific type of detector, commonly used in Mass Spectrometry (MS). In a TOF mass analyzer, ions are accelerated by an electric field and their mass-to-charge ratio (m/z) is determined by measuring the time it takes for them to travel a known distance. Lighter ions travel faster and arrive at the detector first. The detectors used at the end of the flight tube are typically Electron Multipliers (EMs) or Microchannel Plates (MCPs). | Electrostatic deflection: Single, reversible, 2 to 10 kV, etc, Detector: Depends on the detector |
| Charged particle | Flame ionization detector | FID | A hydrogen flame ionization detector (FID) is the standard detector used in gas chromatography. It is very sensitive and has a wide dynamic range. The ionized sample is collected at the anode of the detector and converted into an electrical signal. | - |
| Charged particle | Charged Aerosol Detector | CAD | A charged aerosol detector (CAD), also called a corona-charged particle detector, is a general-purpose detector for liquid chromatography (HPLC). When a sample is sprayed with a nebulizer, the solvent vaporizes and the components become particles. The particle is given a positive charge and measured as a current value. | - |
| Charged particle | Ion trap detector | - | An ion trap detector is a detection method (detector) used in Mass Spectrometry (MS). Supplemental ions generated from the sample are analyzed. Ion trap detectors include quadrupole ion traps, linear ion traps, and pole ion traps. | - |
| Charged particle | Ion detector | - | An ion detector is a device that detects ions in a sample to measure its composition and quantity. Ion detectors are used in chemical, biological, and physical analyzers, as well as in environmental monitoring. There are several types of ion detection with different operating principles. | - |
| Charged particle | Gas ionization detector | - | A gas ionization detector is a type of radiation detector. Detects electrical signals produced by ionization of gases by radiation. It is used in radiation measurements, particle physics, nuclear medicine, X-ray analyzers, and other ionizing radiation measurements. Gas ionization detectors include Geiger-Mueller (GM) counters, proportional counters (proportional counters), ionization chambers | - |
| Charged particle | Barrier discharge Ionization Detector | BID | A barrier discharge ionization detector (BID) is a type of ionization detector used in gas chromatography (GC). Useful for analysis of volatile organic compounds (VOCs) and compounds with low ionization potential. It has the advantage over conventional detectors such as flame ionization detectors (FID) and electron capture detectors (ECD) of being able to detect trace amounts of analytes with high sensitivity. |
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| Charged particle | Sulfur Chemiluminescence Detector | SCD | The Sulfur Chemiluminescence Detector (SCD: Sulfur Chemiluminescence Detector) is a detector specialized for the detection of sulfur-containing compounds in gas chromatography (GC). Chemiluminescent sulfur detectors have the advantage of higher sensitivity and wider dynamic range than other sulfur detection techniques, such as flame photometric detectors (FPD) and flame ionization detectors (FID). |
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| Charged particle | Quadrupole detector | - | A quadrupole is a type of mass filter or mass analyzer used in Mass Spectrometry (MS), not a detector itself. It uses a combination of radio frequency (RF) and DC voltages applied to four parallel rods to selectively stabilize the trajectory of ions with a specific mass-to-charge ratio (m/z). Only ions with a stable path can pass through the filter to reach the detector, which is typically an electron multiplier. By scanning the voltages, a full mass spectrum can be obtained. By varying the RF and DC voltages, it is possible to scan a fixed range of mass-to-charge ratios and obtain mass spectra. | - |
| Charged particle | Flame Photometric Detector | FPD | A Flame Photometric Detector (FPD) is a specialized detector used in gas chromatography (GC) for the detection and quantitation of sulfur (S) and phosphorus (P) compounds. It is very sensitive to these elements and is useful in environmental analysis, petroleum refining, and areas where the presence of sulfur and phosphorus compounds must be monitored. The sample is excited through the process of flame ionization, and the ions emit light of a specific wavelength as they return to their ground state. This light is detected by a Photomultiplier Tube. |
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| Charged particle | Flame Thermionic Detector | FTD | A thermal ion detector (FTD) is a specialized detector used in gas chromatography (GC) that excels in the detection of organic nitrogen and organophosphorus compounds. When a sample containing a carbon-nitrogen bond (CN) passes through the heating coil, it reacts with the rubidium radical produced by the coil, resulting in ionization (CN-). The ion current produced by this process is detected. It is very effective in analyzing certain types of compounds, such as pesticide residues. |
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| Charged particle | Thermal Conductivity Detector | TCD | A thermal conductivity detector (TCD) is one of the most commonly used detectors in gas chromatography (GC). It is based on the principle of detecting changes in the thermal conductivity of a carrier gas caused by the presence of analyte molecules eluting from a chromatographic column. The difference in thermal conductivity between the carrier gas and the carrier gas containing the specimen molecules causes an imbalance in the Wheatstone bridge circuit (measuring the change in filament resistance). This generates an electrical signal proportional to the concentration. |
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| Charged particle | Electron Capture Detector | ECD | An electron capture detector (ECD) is a highly sensitive detector commonly used primarily in gas chromatography (GC). It is especially used to detect compounds containing electronegative functional groups such as halogens (chlorinated pesticides, brominated flame retardants, etc.) and nitro groups. It measures the electrical signal generated by the ion current. |
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| Image | Image sensor | - | An image sensor is a two-dimensional array of sensing elements to obtain an image. Image sensors such as CCD and CMOS are commonly known and used in cameras. | - |
| Image | Flat panel detector | FPD | A flat panel detector (flat panel detector) is a detector used to obtain radiation images. In the past, it was necessary to take images on film and develop them, but now it is possible to take X-rays in real-time, and this technology is becoming popular not only for medical use but also for industrial use. For more information, visit Flat Panel Detector (FPD) | - |
| Image | Photodiode array detector | - | A photodiode array is a detector with a row of photodiodes. Also called a line sensor etc. It is used in in-line inspection equipment, etc. | - |
| Image | Image intensifier | I.I. | An image intensifier is a vacuum detector that amplifies faint light (low light) to produce an image. Image intensifiers, such as night vision, provide vision in the dark. Image intensifiers for X-rays convert X-rays into electrons at the incident plane, amplify the signal, and project the X-ray image on a phosphor. With the widespread use of flat panel detectors, X-ray image intensifiers are rarely used anymore. |
1kV to 30kV |
| Radiation, etc. | Calorimeter, Microcalorimeter | - | Detectors, called calorimeters or microcalorimeters, measure energy from the temperature that rises slightly when light or radiation is absorbed by an object. It has extremely high resolution and is used in particle physics and X-ray spectroscopy. | - |
| Application | Cherenkov detector | - | A Cherenkov detector is a detector for detecting Cherenkov light. As a high-energy charged particle moves through a medium, it emits a cone of Cherenkov light in the direction of travel. Cherenkov detectors are used in the fields of high-energy physics, astronomy, and particle physics. | - |
| Application | Laser range finder | - | Laser rangefinders are so-called rangefinders. Also called laser rangefinders or laser distance meters, they are used to measure the distance to a target. Distance meters mainly for golf are called laser rangefinders. | - |
| Application | Secondary electron detector | SED | A secondary electron detector (SED) is a detector used in Scanning Electron Microscope (SEM). Secondary electrons generated when an electron beam is irradiated (scanned) are detected and captured in an image. It consists of a focusing electrode, a scintillator, and a Photomultiplier Tube, each of which requires a high voltage. |
PMT voltage and collector: +300 V scintillator: +10 kV |
| Application | Backscattered electron detector | BE,BSE | A reflection electron detector is a type of detector used in Scanning Electron Microscope (SEM)s. Reflected electrons generated when a sample is irradiated with an electron beam are detected and captured in an image. The reflected electron detector is located at the end of the object lens. A four-segmented silicon detector is used. | 5V to 20V |
| Detectors | Summary |
|---|---|
| Phosphor | A phosphor is a substance that emits light by converting the wavelength (energy) of incident light into a specific wavelength. It is used in cold cathode tube (CRT) screens and fluorescent lamps. Typical phosphors are called by numbers such as P20, P22, and P43. |
| Fluorescence | Fluorescence and phosphorescence are phenomena in which a substance exposed to light or radiation radiates a specific wavelength. It is used in the authenticity testing of banknotes, X-ray fluorescence analysis, fluorescent labeling of organisms, and mineralogy. It usually emits a wavelength longer than the wavelength of the incident light. For example, a substance fluoresces in the visible spectrum when illuminated by ultraviolet light (from a black light). |
| Luminescence | There are various types of luminescence. Cold light is called luminescence, not incandescent light caused by flames or other heat. The most famous examples are light emission by cathodoluminescence and chemical reactions, light-emitting diodes (LEDs) by electroluminescence, and fluorescence by photoluminescence. |
| Spectroscopy | Spectroscopy is the study of the interaction between matter and electromagnetic radiation. It typically involves separating and analyzing this radiation (often referred to as "light" in a broad sense) according to its wavelength or energy. Historically, spectroscopy involved dispersing light into its constituent wavelengths using a prism or diffraction grating. The resulting band of colors or wavelengths is called a spectrum. Spectroscopy is a method of quantitatively and qualitatively analyzing the components and properties of a substance by finding the wavelengths (spectra) specific to the molecules that make up the substance by spectroscopy of the electromagnetic spectrum, including infrared (IR), visible light, ultraviolet (UV), x-rays, and gamma rays, using a spectroscope. |
| Wavelength | Wavelength is the spatial period of a periodic wave--the distance over which the wave's shape repeats. In the context of light (electromagnetic radiation), it is a fundamental characteristic. The range of wavelengths from 380 nm (violet) to 780 nm (red) is considered visible light. Wavelength can be converted to energy (electron volts, eV). In the wavelength region shorter than vacuum ultraviolet, kiloelectron volts (keV) and MeV are mainly used. Conversely, in the infrared region, frequency is used as the unit of measurement. |
| Photon | A photon is a type of subatomic particle, which is the name given to light (electromagnetic waves) when considered as a particle. |
| Electron | An electron is an elementary particle that carries a negative electric charge. Electrons orbit the nucleus of an atom and are fundamental constituents of matter. |
| Ion | Ion refers to an electrically charged atom or molecule. The state in which electrons and protons are balanced is called neutral; the state with fewer electrons is called cation and the state with more electrons is called anion. |
| Radiation | Radiation is a general term for particles and electromagnetic waves emitted from matter. Alpha, beta, gamma, X-rays, and neutron radiation are included in radiation. |
| Gamma ray | Gamma rays, a type of radiation, are electromagnetic waves emitted from transitions in atomic nuclei. Incidentally, X-rays are electromagnetic waves produced by transitions of orbital electrons in atoms, and are distinguished from gamma rays by their origin (atomic electron shells vs. atomic nuclei), though their energy ranges can overlap. |
| Neutron | Neutrons are uncharged particles that make up the nucleus of an atom. The nucleus is composed of neutrons and protons, which are collectively called nucleons. Free neutrons decay to protons by beta decay with an average lifetime of about 15 minutes. |
| Elementary particle | Elementary particles are the smallest units that make up matter. Matter is composed of subatomic particles smaller than atoms. |