16Development in Large Format PMT PMTs for Deep Sea Neutrino Experiment13 inch PMT, 20 inch Short TypePMTs for Megaton Type DetectorFeasibility study for mass-productionLarge Format HPD for T2K ExperimentHigh performance (Good S/N Ratio)Next topic is Development in Large format PMT. Categories of developments are :PMT for Deep Sea Neutrino Experiment, I will show you 13 inch PMT and 20 inch PMT with short length typePMTs for Megaton Type Detector, I will explain you about feasibility study for mass-production, briefly.Large format HPD for T2K Experiment, I will explain you about HPD (Hybrid PhotoDetector) and developmental situation.
17Large Format PMT Lineup 20 inch13 inch PMT is shortercomparing to its diameter.13 inch8 inch10 inchThis picture shows Large Format PMT Lineup from 8 inch to 20 inch.As you see, 20 inch PMT is quite big and long, but 13 inch PMT is relatively shorter comparing to its diameter.
18Large Format PMT Series Part No.DiaEffective AreaTTSP/V(Peak to Valley Ratio)R59128f1902.4ns2.5R708110f2202.9nsR805513f3123.4nsR20f4605.5ns1.7R7250f4303.5ns
19Dimensional Outline of R8055 Electrodes andMetal ShieldThis sketch shows the dimensional outline of R8055, which is 13 inch PMT. Main difference from other PMTs is this metal stem flange. Usually, heating for sealing process damages the dynode surface. It results in low gain. Therefore, some distance between the last dynode and the bottom glass part is necessary to avoid such damage.The metal stem flange can be sealed with Helium Arcing welding. It doesn’t cause much heat. Therefore the metal stem flange can avoid the heating problem, then PMT length can be made shorter.Heating for sealing process damages dynode surface.Metal stem flange can avoid the heating problem.Metal Stem Flange
20This electrode was developed for R7250, which is used for R8055 (13 inch PMT)17“ Glass Spherewith R805517 inchglass sphereThis is a sketch of 17 inch glass sphere with R8055. This PMT can be placed in the 17 inch glass sphere. This electrode was developed for R7250. It’s a fast 20 inch PMT, and is used for KamLand experiment in Japan. As the size of the electrode is larger compared with the tube diameter, CE becomes better. We think that R8055 is the largest PMT, which is suitable for 17 inch glass sphere.This electrode was developedfor R7250, which is used forKamLand experiment in Japan.R8055 is suitable for 17 inch glass sphere !!
21R3600-02 (20 inch) Largest in the world 11,000 tubes for SUPER-K 610 mmThese are a picture and a sketch for 20 inch PMT, R This PMT is the largest one in the world. 11,000 tubes are being used for SUPER-KAMIOKANDE experiment in Japan.11,000 tubes for SUPER-K
22Modification of 20 inch PMT 25 inch Glass Spheretoo long !!Metal StemFlange526 mm610 mm20 inch PMT is the largest one, and its length is 610 mm. Even if a large glass sphere like 25 inch is made, this PMT can’t be placed inside. However, if a metal stem flange is used, its length can be short like 526 mm. Then it’s possible to place it in the 25 inch glass sphere. The matter is whether a 25 inch glass sphere can be made or not.Present 20 inch PMTModified 20 inch PMT
23Feasibility Study for Mass-Production (not official) to Improve Productivity of 20 inch PMT1. Simple Structure for easy production2. Unique Facilities for better efficiencyEarly –Stage Estimation100K tubes in 5 years (20K tubes per year)Number of Employees : 50 peoplesPMT Price : $2,000We have just started feasibility study for mass-production to improve productivity of 20 inch PMT.Hamamatsu is delivering about 500K PMTs per year to customers in all over the world. Compared with it, 10K or 20K is not so big number. However, due to the large size of 20 inch PMT, its productivity is low.To improve it, “Simple structure” is necessary for easy production, and “Unique facilities” is necessary for better production efficiency.This is still early stage, but we got feeling that we can deliver 100K tubes in 5 years (which is 20K tubes per year) with 50 employees (instead of 100). The price could be less than $2,000. We believe that these numbers are acceptable range.Next issue is glass bulbs. We are checking whether glass bulbs can be supplied from glass venders without big problems or not.We are checking whether glass bulbs can be suppliedfrom glass venders without big problems or not.
24Hybrid Photo-detector (HPD) Photocathode(-8kV)APDOutputLightPhotoelectron<Products>R7110U-40 (TO-8 Type)R9503U-04 (Proximity Type)Large Format Type (Development)<Features>Good PHD and CEGood UniformityImmunity to Magnetic FieldThis slide shows HPD, Hybrid Photo Detector. HPD consists of the photocathode, the vacuum envelope and the APD as the target. Its structure is quite simple.(Operation of HPD is following. When photoelectron is emitted from photocathode, it’s accelerated by electric field. It generates electron-hole pairs inside APD. These electrons are sent to avalanche area, then additional avalanche gain is obtained. Total gain is usually 6E+04.)This picture shows TO-8 type HPD, its type number is R7110U. We also have a proximity type, R9503U-04.Large format type is being developed.Features of HPD are good PHD and CE, good uniformity. The proximity type has immunity to magnetic field.8keVElectron BombardmentX1200Avalanche GainX 50Combination of EB and avalanche gain
25Pulse Height Distribution K-APD = 12KV1pe1pe2pe3pe4pe5peThis data shows comparison of PHD between HPD and PMT with pulsed light, which average intensity is few p.e..In case of HPD, its electron bombardment gain is more than 1,000, it can separate number of p.e. like this. When LLD is set here, its detection efficiency is higher that that of PMT.PMTHPD
26Sketch of 5 inch HPD5 inch HPD was made as feasibility study for larger size.Glass bulb of 5 inch hemispherical PMT was used.APD Target(3 mm in dia.)Effective Area(80 mm in dia.)sealing tapefor protectionThis is a sketch of 5 inch HPD. It was made as feasibility study for larger size HPD.Glass bulb of 5 inch hemispherical PMT was used. The size of APD target is 3 mm in diameter, which is used for TO-8 type HPD. This is its picture. As we used existing parts like this bulb and APD, the effective area is limited as 80 mm in diameter.180 mmHPD : Hybrid Photo Detector
27Next Step of Large Format HPD 13 inch HPD is being developed with collaboration of the Univ. of Tokyo and JST(JAPAN SCIENCE AND TECHNOLOGY AGENCY).Working prototype would be made in 2 years (by mar.2007).Development will be finished by Mar.2010.Next step of large format HPD is shown here.1. 13 inch HPD is being developed with collaboration of the Univ. of Tokyo and JST (Japan Science and Technology Agency).2. Working prototype would be made in 2 years (by March 2007).3. Development will be finished by March 2010.