Edit Proposal: Milestone-Proposal:The 20 inch Diameter Photomultiplier Tubes You do not have permission to edit this page, for the following reason: You are not currently logged in. The action you have requested is limited to users in the group: Users. Please log in or create an account. Docket ID: (admins only) Thank you for proposing a technical achievement for possible recognition as an IEEE Milestone in Electrical Engineering and Computing. Your efforts help preserve the heritage of technology. Detailed information on the Milestone application process may be found at: Milestone Guidelines and How to Propose a Milestone. At least one of the proposer(s) must be an IEEE Member (including Student Member) in good standing. To the proposer’s knowledge, is this achievement subject to litigation? If the answer is "yes", the proposal cannot proceed further. None Yes No You must be able to answer "yes" to all of the following questions. 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Yes No Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes No Has the owner of the site given permission to place an IEEE plaque? Yes No Year or range of years in which the achievement occurred: Title of the proposed milestone. (Include date or date range in title. Example: “Alternating Current Electrification, 1886”) Please provide a plaque citation in English summarizing the achievement and its significance. Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons. NOTE: The IEEE History Committee shall have final determination on the wording of the citation. Names of living persons are not normally used in citations. Exceptions to this are cases where the person's name is linked to the achievement itself (e.g. the Lempel-Ziv algorithm, Maxwell's Equations, etc.) or where the person's name is so widely recognizeable to the general public that it makes sense to use it. When used, the names should be the names of the engineers, scientists, or technologists who actually made the achievement, rather than managers or executives. For more information and suggestions about writing milestone citations, please visit Helpful Hints on Citations, Plaque Locations. Hamamatsu Photonics K.K. began developing 20-inch diameter photomultiplier tubes at Toyooka Factory in 1979 for a 3000-ton water-filled Cherenkov particle detector, Kamiokande-II, in response to a request by Professor Masatoshi Koshiba. 1071 PMTs on it collected photons induced in the water by the particles falling on it. Kamiokande-II detected a neutrino burst in the Supernova SN1987A in 1987, earning Professor Koshiba a Nobel Prize in 2002. In what IEEE section(s) will the milestone plaque(s) reside? Please specify the IEEE Organizational Unit(s) which have agreed to sponsor the Milestone, and supply name and contact information for the senior officer from those OU(s). Sponsorship has three aspects: 1) Payment for the cost of the plaque(s), 2) Arranging the dedication ceremony, and 3) agreeing to monitor the plaque and to let IEEE History Center staff know in case the plaque needs to be moved, is no longer secure, etc. Number 3 must be done by the IEEE Section(s) in which the plaque(s) is located, but aspects 1 and 2 can be done by any IEEE Organizational Unit, and they need not be the same one. Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address. 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A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque. Also, please Describe briefly the intended site(s) of the milestone plaque(s). (e.g. Is it corporate buildings? Historic Site? Residential? Are there other historical markers already at the site?) Are the original buildings extant? Please provide the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. How is the intended plaque site protected/secured, and in what ways is it accessible to the public? If visitors to the plaque site will need to go through security, or make an appointment, please give details as well as the contact information visitors will need in order to arrange to visit the plaque. Who is the present owner of the site(s)? In the space below, please describe in detail: the historic significance of the achievement, its importance to the evolution of electrical and computer engineering and science, its importance to regional/national/international development, its benefits to humanity, the ways the achievement was a significant advance rather than an incremental improvement of existing technology. The material submitted here will constitute the main descriptive article on the ETHW website for readers to learn about the milestone. Space is unlimited, and detail is encouraged. Most milestones require 1000 to 1500 words of support, however there is no word limit. The article should be readable by a wide audience that includes practicing engineers, scholars of history, and the general public. Some examples of the text of good milestone articles are First Radio Astronomical Observations Using Very Long Baseline Interferometry] and G3_Facsimile International Standardization of G3 Facsimile (Do not worry about the formatting of the page, IEEE History Center Staff will do that afterwards.) What is the historical significance of the work (its technological, scientific, or social importance)? Technological significance: (1) Successful production of 20 inch diameter photomultiplier tubes, the world largest. [1, 4, 5, 6] (2) High gain, 10⁷, to be able to detect a single-photon event. [4, 5, 6, 7, 8] Scientific significance: Detection of the neutrino burst in the supernova SN1987A, which brought the Nobel Prize in Physics in 2002 to Professor Masatoshi Koshiba. [7, 8, 9] What obstacles (technical, political, geographic) needed to be overcome? Technical obstacle needed to be overcome: (1) Forming the large area uniform-sensitivity photocathode on the inner surface of the view window of the tube. [1, 5] (2) Direct immersion of the large photomultiplier tubes in the water of Cherenkov detector. [1, 5, 9] (3) Glass blowing of the 20 inch diameter tube. [1, 4, 5] What features set this work apart from similar achievements? The following technological features do it: 1. Large diameter Diameter of 20 inch (508 mm) makes it possible to achieve a photosensitive coverage of 20 % of the surface of a cylindrical Cherenkov detector with 15.6 m diameter and 16.1 m height filled with the purified water. [1, 5, 7, 8, 9] 2. Direct immersion of the PMTs in the Water A total of 1071 PMTs are placed around the water tank (15.6 m diameter x 16.1 m height) filled with 3000 metric tons of purified water. The PMTs are immersed directly in the water. The PMTs must withstand the water pressure, must prevent the water from leaking into the tubes, and must maintain the electric insulation to be able to maintain the device voltage across the PMT above 2000 V, for over a period of about 10 years. [1, 6, 8, 9] 3. High gain The gain of the PMT defined by the ratio of the anode output current to the emitted photo current is 10⁷ at 2000 V between the anode and the cathode. The gain of 10⁷ makes it possible to detect single-photon event taking place in the Cherenkov radiation detector. Electron trajectory simulation in a water tank was used, at the early phase of the development in 1979-1980, to find the optimum electrode configuration of the photocathode, focusing electrode, and the first dynode. [4, 10] 4. Quantum efficiency A quantum efficiency of 22 % at the wavelength of 400 nm is obtained with using the photocathode formed by depositing a thin layer of antimony on the inner surface of the tube by vacuum evaporation. The antimony layer is then activated by evaporating the alkali metal in vacuum on to the layer. [4, 5, 6] 5. Uniformity The anode uniformity depends mainly on two factors, i.e., the uniformity of the photocathode quantum efficiency and that of the collection efficiency between the photocathode and the first dynode. The change of anode uniformity over the large view angles is within ±40 %. [4, 5, 6] 6. Mean transit time The mean transit time is found to be 90 ns.  7. Transit time spread The transit time spread (TTS), which is a distribution of transit time for a single PMT, is an important parameter when timing information is required. TTS is found 7 ns at FWHM.  8. Number of the PMTs in a Cherenkov radiation detector A total of 1071 units of the PMTs are employed to construct the Kamiokande II, cylinder-shape Cherenkov radiation detector with a height of 16.1 m filled with the purified water, as mentioned earlier in 9.1. Of the 1071 PMTs, 948 units are viewing the space inside the cylinder with a diameter of 15.6 m (fiducial volume of 2040 tons of the water), while 123 units viewing a thin tubular space just outside the cylinder filled with the purifier water. The outside tubular space gives rise to signals responding to radiations from the rocks in earth surrounding the detector and radiations of stray particles from the space. After appropriate signal processing, the signal-to-noise ratio of the signal from the 948 PMTs for detection of neutrinos hitting the fiducial volume was improved considerably. Tightly controlled TTS (7 ns) permits the use of a large number (1071) of PMTs in a Cherenkov detector. Because the TTS of all the units of PMTs is well controlled, it is possible to calculate the direction of cone axis of Cherenkov radiation from the output signals of 948 PMTs with a high degree of precision. [1, 8, 9, 10] Supporting texts and citations to establish the dates, location, and importance of the achievement. You must supply the texts or excerpts themselves, not just the references. Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. At least one of the references must be from a scholarly book or journal article. 'Scholarly' is defined as peer-reviewed, with references, and published. The full reference, in English, must be uploaded, not just the citation. See below section for details on uploading material to the website. All supporting materials must be in English, or accompanied by an English translation.  Development of 20-inch PMT. http://www.hamamatsu.com/jp/en/technology/projects/20inch_pmt/index.html  T. Hayashi, “RECENT DEVELOPMENTS IN PHOTOMULTIPLIERS FOR NUCLEAR RADIATION DETECTORS,” Nuclear Instruments and Methods 196 (1982), pp.181-186.[[Media:RECENT DEVELOPMENTS IN PHOTOMULTIPLIERS FOR NUCLEAR RADIATION DATECTORS.pdf]]  “Photon is our business,” HAMAMATSU, Corporate Outline.[[Media:Photon is our business.pdf]]  H. Kume, S. Sawaki and M. Ito, K. Arisaka, Hamamatsu TV Co., Ltd., K. Arisaka and T. Kajita, Dept. of Physics, University of Tokyo, A. Nishimura and A. Suzuki, KEK National Laboratory of High Energy Physics, “20 INCH DIAMETER PHTOMULTIPLIER,” Nuclear Instruments and Methods 205 (1983), pp.443-449.[[Media:20 INCH DIAMETER PHOTOMULTIPLIER.pdf]]  Kenji Suzuki, “Developing the 20-inch semispherical photomultiplier tubes,” - The Nobel Prize winning achievement seen from a company R&D perspective”, Spectroscopy Research, Vol.52, No.5, 2003.[[Media:Developing the 20-inch semispherical photomultiplier tubes.pdf]]  HAMAMATSU TECHNICAL DATA SHEET, R1449, PHOTOMULTIPLIER TUBE, 20 INCH HEMISPHERICAL.[[Media:HAMAMATSU TECHNICAL DATA SHEET on R1449.pdf]]  K. Hirata, T. Kajita, M. Koshiba, et al, “Observation of a Neutrino Burst from the Supernova SN1987A,” Physical Review Letters, Vol. 58, No. 14, 6 April 1987, pp.149-1493.[[Media:Observation of a Neutrino Burst from the Supernova SN1987A.pdf]]  Masatoshi Koshiba, “BIRTH OF NEUTRINO ASTROPHYSICS,” Nobel Lecture, December 8, 2002.[[Media:BIRTH OF NEUTRINO ASTROPHYSICS.pdf]]  T. Kajita, M. Koshiba, and A. Suzuki, “On the origin of the Kamiokande experiment and neutrino astrophysics,” The European Physical Journal H, Volume H 37, pp.33-73 (2012).[[Media:On the origin of the Kamiokande experiment and neutrino astrophsics.pdf]]  A. Suzuki and M. Mori, National Lab. High Energy, K. Kaneyuki and T. Tanimori, Dept. of Physics, Tokyo Institute of Technology, J. Takeuchi, H. Kyushima and Y. Ohashi, Hamamatsu Photonics KK., “Improvement of 20 in. diameter photomultiplier tubes,” Nuclea Instruments and Methods in Physics Research A329 (1993), pp.299-313.[[Media:Improvement of 20 in. diameter photomultiplier tubes.pdf]] Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC) which can be made publicly available on the IEEE History Center’s website (i.e. unencumbered by copyright, or with the copyright holder’s permission). All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. Images and photographs are especially appreciated, however, it is necessary that you list the copyright owner for these and obtain the copyright owner’s permission to reuse. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to firstname.lastname@example.org. Please see the Milestone Program Guidelines for more information. To add attachments, first upload the file and add by adding the text: [[Media:(filename)]] For example, if the file you uploaded was named "Milestone Reference.pdf", include the text: [[Media:Milestone Reference.pdf]] in the appropriate field. Please refer to the above. Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to email@example.com with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s). Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished Summary: This is a minor edit Watch this page Cancel Retrieved from "http://ieeemilestones.ethw.org/Milestone-Proposal:The_20_inch_Diameter_Photomultiplier_Tubes"