Status procurement of PMTs Oleg Kalekin KM3NeT WPF/L General Meeting Amsterdam

Photomultipliers for KM3NeT optical modules 3 (2+1) main options for optical modules (OM) in the KM3NeT TDR OM with 1 photomultiplier tube (PMT) 10 or 8 inch diameter OM with two 8-inch PMTs Multi-PMT OM with 31 three-inch PMTs PMTs considered as candidates 10-inch:Hamamatsu R inch: Hamamatsu R5912 ET Enterprises ET inch:Hamamatsu R6233 – prototype R6233MOD ET Enterprises new development MELZ FEUnew development O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

Large PMTs, specification and tests Table from “Synthesis of the large PMT KM3NeT measurements” by P.Keller and S.Henry O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam, Example for R7081 Specification ANTARES R APC CEA Saclay CPPM ECAP INFN (1) Catania INFN Genova Data Hamamatsu QE Gain> x x 10 7 Nominal Gain [V]< Vcc 1 pe for nominal gain [mV] >3042,7 50 Dark count <51,887 Dark Current [nA]50 P/V>32, Rise time [ns]<44, Fall time [ns]12,611 Width FWHM [ns]7.5 TTS FWHM [ns]< TT [ns]63 Prepulses [%]<0.5?0, Delayed pulses [%]<5?3,65.5 After pulse Type 1 [%]<1?1,01.1 After pulse Type 2 [%]<5?2,74.4

10-inch PMTs 8-inch PMTs Prices are net (excluding VAT) Red – from quotations, black – calculated with date exchange rate Hamamatsu has been asked for new quotations – 8 and 10 inch, ba and sba O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam, DatePMTPrice, EURPrice, YenRate ¥/€ R ,760460, R70812,179360, R7081SEL2,644330, Quotation for 10k PMTs, freight 1,000(sea) or 11,000(air) Yen/PMT to be added June 2009R70811,000110, (today) June 2009R7081SEL1,280140, (today) DatePMTPrice, EUR ET93542,009 R5912SEL1,610

Procurement large PMTs 8 and 10 inch PMTs exist KM3NeT have PMTs for tests and for single-PMT OM prototype production Mass production: Hamamatsu – Japan, ET Ent. – Texas, USA Production of 10k PMTs on a time scale 3-4 years feasible ET Ent. needs ~1 year and investment for preparation of mass production But: low energy neutrino experiment will be built parallel with KM3NeT concurrence for large PMTs, possible delays and price increase O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

3-inch PMT specification Proposed form factor to fit a 17-inch spherePin layout suggestion for an optimal PCB layout Diameter of input window can be large Light collectors can be used (KVI) O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

3-inch PMT specification Cathode characteristics Quantum Efficiency at 470 nm > 20% Inhomogeneity of cathode response < 10% Characteristics with voltage divider* Supply voltage < 1400 V Gain 5x10 6 External electro static coating to the cathode Anode characteristics Dark count rate < 3 kHz, determined at 15 °C and for signals above a threshold of 0.3 single-photoelectrons Pulse rise time < 3 ns Duration at half height 5 ns FWHM at single photo-electron (spe) Transit time spread < 2 ns (s) Peak to valley ratio > 3 Environment Storage 0 – 60 °C Operation 10 – 25 °C * Voltage divider (with integer voltage ratios between D1 – D10 and A) K DA G D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 A (total: 13.65) O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

Development and procurement 3-inch PMTs Hamamatsu (ECAP, Nikhef) R6233 – 3-inch prototype, flat photocathode, poor time resolution R6233MOD – intermediate modification: plano-(partly)concave window, 10- stage. Two pieces produced. Satisfactory s.p.e. jitter and TTS along curved part of the photocathode. “Final” modification designed: convex-concave window ET Enterprises (KVI, Nikhef) New 3-inch PMT designed MELZ FEU (ECAP) New 86mm diameter PMT designed Delivery of the test bunches for tests and for production of multi-PMT OMs – Fall 2010 O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

Procurement small PMTs Mass production: Hamamatsu – China; ET Ent. – Texas, USA; MELZ FEU – Russia Production of 200k PMTs (Hamamatsu and ET Ent.), 40k (MELZ FEU) on a time scale 3-4 years feasible All companies need ~1 year and investment for preparation of mass production O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,

Remarks Transportation of PMTs Air – more expensive, sea – cheaper, but maybe not satisfactory because of specified storage temperature -30 – 50°C Unification of electronics? Use of Nikhef bases: modification of large PMTs needed O.Kalekin, KM3NeT WPF/L General Meeting, Amsterdam,