{"id":2237,"date":"2018-02-06T19:43:36","date_gmt":"2018-02-07T03:43:36","guid":{"rendered":"https:\/\/www.rbdinstruments.com\/blog\/?p=2237"},"modified":"2025-02-20T08:04:21","modified_gmt":"2025-02-20T16:04:21","slug":"how-an-electron-multiplier-works","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/how-an-electron-multiplier-works\/","title":{"rendered":"How an electron multiplier works"},"content":{"rendered":"

This post will explain the basic concept of how an electron multiplier works.<\/p>\n

Electron multipliers are used in surface analysis instruments to boost the detected signal to a level where it can be amplified and processed into data. For Auger Electron spectrometers and X-ray photo electron analyzers the detected signal are electrons. Secondary ion spectrometers detect ions.<\/p>\n

In the 1960s electron multipliers were made out of a series of Oxygen treated copper beryllium (CuBe) plates. \u00a0Copper with 3 to 4% beryllium that is heat treated with oxygen has a secondary electron yield of approximately 3 (varies slightly for kinetic energies between 100 up to 1500V)<\/p>\n

The drawing below shows the basic concept.\u00a0 One electron impacts the first plate and then a few more secondary electrons are generated.\u00a0 A positive voltage is applied across the multiplier array which is divided by a series of vacuum compatible resistors.\u00a0 Each plate is progressively more positive and so emitted electrons are attracted to the next plate. \u00a0The resulting avalanche of electrons is attracted to the final collector plate where the signal is decoupled from the electron multiplier.\u00a0 The total number of plates determines the gain of the multiplier. Most of the CuBe electron multipliers used on Auger spectrometers had a gain of 2 X 10E6\"discrete

\"discrete

When X-ray Electron spectrometers were first developed electron multipliers with higher gains were required in order to achieve better signal to noise.\u00a0 During that time continuous dynode electron multipliers (Channeltrons) were developed.\u00a0 Instead of a series of discrete plates, a Channeltron electron multiplier uses a high resistance semiconductor material that also has high secondary electron emissivity.\u00a0 Gains of a Channeltron are typically 2 X 10E7 to 2 X 10E8. The drawing below shows the gain concept.\u00a0 Many Channeltrons today are spiral instead of horn shaped to provide an even higher gain.\"continuous

\"Channeltron

A third type of electron multiplier, the Micro Channel plate, was developed in order to obtain a larger detector surface area in conjunction with multi-channel detectors. Channel plates are essentially a lot of tiny Channeltron multipliers in parallel. Two plates are stacked on top of each other to increase the gain. \u00a0The drawing below shows the gain concept. Channel plate electron multipliers are commonly used on X-ray Photo electron spectrometers.\"MCD

\"Micro

Electron multipliers typically last for several years with normal usage. With just occasional use they can last for decades.\u00a0 Eventually the high secondary electron emissivity materials in the multiplier are depleted or the multiplier becomes contaminated and then the signal to noise degrades at which time the multiplier needs to be replaced.<\/p>\n

Some additional reference links are listed below.\u00a0\u00a0 Most of these refer to ions and mass spectroscopy but it is the same principle for electron based detectors used in Auger Electron and X-ray photo electron spectrometers.<\/p>\n

cires.colorado.edu\/jimenez\/CHEM-5181\/Lect\/MS_Detectors_AD_SNR.pdf<\/a><\/p>\n

\u00a0<\/p>\n\n\n

Electron Multipliers are available from these companies –<\/p>\n\n\n\n

Photonis<\/a><\/p>\n\n\n\n

Scientific Instrument Services <\/a><\/p>\n\n\n\n

For assistance with installing electron multipliers or channel plates in older Physical Electronics XPS and AES surface analysis instruments contact RBD Instruments, Inc<\/a>.<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n\n\n\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

This post will explain the basic concept of how an electron multiplier works. Electron multipliers are used in surface analysis instruments to boost the detected signal to a level where it can be amplified and processed into data. For Auger … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":2233,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[164,165],"tags":[88,87,253],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2018\/02\/continuous-dynode-electron-multiplier-gain.jpg?fit=719%2C435&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p2DEXo-A5","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":568,"url":"https:\/\/www.rbdinstruments.com\/blog\/electron-multipliers-used-in-phi-aes-and-xps-analyzers\/","url_meta":{"origin":2237,"position":0},"title":"Electron multipliers used in PHI AES and XPS analyzers","author":"Randy","date":"May 17, 2013","format":false,"excerpt":"The Physical Electronics AES cylindrical mirror (CMA), double-pass ESCA (XPS) and single channel SCA hemisphere analyzers use variations of the Channeltron\u00ae (registered trade mark of Photonis \u2013 Burle \u2013 Galileo) type of electron multiplier. The function of the electron multiplier is to increase the number of electrons that the analyzer\u2026","rel":"","context":"In "General Optics and Vacuum"","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2013\/05\/channeltron-electron-multiplier.jpg?fit=203%2C267&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":2747,"url":"https:\/\/www.rbdinstruments.com\/blog\/stability-testing-of-surface-analysis-optics\/","url_meta":{"origin":2237,"position":1},"title":"Stability testing of surface analysis optics","author":"Randy","date":"March 6, 2020","format":false,"excerpt":"There are two easy ways to check the stability of the electron or photon source on an X-ray photoelectron spectrometer, Auger electron spectrometer or Scanning Electron microscope: Measure the target current and plot the results vs. time using a data logging picoammeter such as RBD\u2019s 9103.Acquire a depth profile region\u2026","rel":"","context":"In "General Optics and Vacuum"","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"Electron Current vs time","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2020\/03\/current-vs-time-800px.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2020\/03\/current-vs-time-800px.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2020\/03\/current-vs-time-800px.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":3546,"url":"https:\/\/www.rbdinstruments.com\/blog\/augerscan-electron-multiplier-voltage-logic\/","url_meta":{"origin":2237,"position":2},"title":"AugerScan \u2013 Electron Multiplier Voltage Logic","author":"Randy","date":"April 8, 2022","format":false,"excerpt":"Blog post that explains how the detection mode and electron multiplier voltage are set automatically by AugerScan on older PHI AES and XPS systems.","rel":"","context":"In "General Optics and Vacuum"","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"V\/F setpoint for AES","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2022\/04\/survey-setting-1.jpg?fit=697%2C483&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":3760,"url":"https:\/\/www.rbdinstruments.com\/blog\/electron-multipliers-for-older-phi-aes-and-xps-systems\/","url_meta":{"origin":2237,"position":3},"title":"Electron multipliers for older PHI AES and XPS systems","author":"Randy","date":"June 15, 2023","format":false,"excerpt":"Part numbers for electron multipliers for older Physical Electronics Auger and X-ray photoelectron analyzers.","rel":"","context":"In "General Optics and Vacuum"","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/06\/image.png?fit=775%2C507&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/06\/image.png?fit=775%2C507&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/06\/image.png?fit=775%2C507&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":345,"url":"https:\/\/www.rbdinstruments.com\/blog\/ion-beam-induced-low-energy-electrons\/","url_meta":{"origin":2237,"position":4},"title":"Ion Beam Induced Low Energy Electrons","author":"Randy","date":"February 6, 2013","format":false,"excerpt":"For the purpose of checking the performance of a surface analysis spectrometer such as a cylindrical mirror analyzer (CMA) or spherical capacitive analyzer (SCA), looking at an ion induced low energy electron peak can be extremely helpful. The peak typically occurs at about 20 to 50 eV and the size\u2026","rel":"","context":"In "Operation and Calibration Procedures"","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"ion gun noise","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2013\/02\/Ion-gun-noise.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":1600,"url":"https:\/\/www.rbdinstruments.com\/blog\/measure-electron-current-accurately\/","url_meta":{"origin":2237,"position":5},"title":"Measure electron current accurately","author":"Randy","date":"December 12, 2015","format":false,"excerpt":"To measure electron current accurately (or ion current) you need to take secondary electrons out of the measurement. This is easy to do if you have a Faraday cup. 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