T. Sumiyoshi (TMU) 30, Nov del Carmen 1 Development of HPD （ＨＡＰ Ｄ） Photon-detector for the Aerogel RICH Photon-detector for the Aerogel RICH Development of HPD and HAPD Development of HPD and HAPD  Ｐｒｏｔｏｔｙｐｅ Ｔｅｓｔ Readout Electronics Readout Electronics Ｓｕｍｍａｒｙ Ｓｕｍｍａｒｙ Aerogel Radiator Cherenkov photons Position sensitive Photon Detector Concept of the Aerogel RICH PID upgrade for the forward end-cap region. e-e+e+

T. Sumiyoshi (TMU) 30, Nov del Carmen 2 Photon-detector for the Aerogel RICH Ｒｅｑｕｉｒｅｍｅｎｔｓ Ｒｅｑｕｉｒｅｍｅｎｔｓ  Can detect a single-photon with high efficiency.  Have sensitivity to ～ 400nm photons from aerogel radiators (due to Rayleigh scattering).  Can detect the position of photons with a resolution ～ a few mm. a resolution ～ a few mm.  Immune to the high magnetic field (1.5 Tesla). HPD or HAPD may be the best candidates for the Photon-detector of the Aerogel RICH. HPD or HAPD may be the best candidates for the Photon-detector of the Aerogel RICH. Fine-mesh PMT: Poor resolution for single photons. Fine-mesh PMT: Poor resolution for single photons. MCP-PMT: 60% collection efficiency. MCP-PMT: 60% collection efficiency.

T. Sumiyoshi (TMU) 30, Nov del Carmen 3 Development of HPD and HAPD Develop a multi-anode HPD/HAPD with proximity focus. Develop a multi-anode HPD/HAPD with proximity focus. Make the effective area as large as possible. Make the effective area as large as possible. DEP catalogue Photocathode PD/APD HV e-e- Photons Output 8 kV

T. Sumiyoshi (TMU) 30, Nov del Carmen 4 Development of HPD and HAPD Outer: 72x72 mm 2 Effective : 59x59 mm 2 (65%) Multi-anode:12x12=144 ch. Pixel Size: 4.9x4.9 mm 2 Multi-anode (144ch) HPD/HAPD are under development in the cooperative work between Belle and HPK.

T. Sumiyoshi (TMU) 30, Nov del Carmen 5 Ｐｒｏｔｏｔｙｐｅ Ｔｅｓｔ -Single Channel HPD- Single channel HPD Single channel HPD Leak current ： 4 [nA] Detector capacitance ： 20 [pF] Gain (8kV) ： 1500 [electron/photon] Bias voltage ： 80 [V] Fig.2 ; single photon response & multi photon response 1pe 2pe 3pe 4pe Sensitive area ： φ8[mm]

T. Sumiyoshi (TMU) 30, Nov del Carmen 6 Single-channel HPD Single-channel HPD : □5 [mm/ch] Diode : □5 [mm/ch] Gain : [electron/photon] Gain : [electron/photon] C d : 73 [pF] C d : 73 [pF] I L : 14 [nA] (average/ch) I L : 14 [nA] (average/ch) Condition: V HV =8[KV], V BIAS =320[V] Condition: V HV =8[KV], V BIAS =320[V] 1pe 2pe 3pe 4pe Ｐｒｏｔｏｔｙｐｅ Ｔｅｓｔ - 3×3multi-channel HAPD - Although the gain of the HAPD is higher than the HPD, noise level is also higher due to its large detector capacitance. The HPD shows better single photon resolution. 53 φ １５ｍｍ 1pe 2pe 3pe 4pe

T. Sumiyoshi (TMU) 30, Nov del Carmen 7 Structure of HPD and HAPD Two types of photodiodes are under development for the 4x(6x6) type HPD/HAPD. APD: surface irradiation type. PD ; back irradiation type. Can reduce dead area btw pixels (0.2->0.1mm) p pn n Surface irradiation typeBack irradiation type Photo electron APD PD

T. Sumiyoshi (TMU) 30, Nov del Carmen 8 Total gains of HPD and HAPD Gain vs PC Voltage.

T. Sumiyoshi (TMU) 30, Nov del Carmen 9 Development of HPD and HAPD Leakage current vs Bias voltage.

T. Sumiyoshi (TMU) 30, Nov del Carmen 10 Timing structure of HPD and HAPD Rise time

T. Sumiyoshi (TMU) 30, Nov del Carmen 11 Dead region of HPD and HAPD Dead region between the pads.

T. Sumiyoshi (TMU) 30, Nov del Carmen 12 Development of HPD and HAPD Leakage current before and after activation of PC. HPD HAPD Basic performance has been studied with the 3x3 type HPD /HAPD. 3x3 ch HPD No serious problem Higher EB gain than expected (1500 -> 2100). 3x3 ch HAPD Low yield of good quality APD’s. There is a HV leak from photocathode. High gain but very noisy. Further investigation is underway with a new production batch.

T. Sumiyoshi (TMU) 30, Nov del Carmen 13 Development of a 12x12 HAPD Production of 12x12 multi-anode HAPD. 4x (6x6) APD is assembled in this bulb by a transfer technology. After the activation many APD’s can’t sustain nominal bias voltage 380V. 73mm

T. Sumiyoshi (TMU) 30, Nov del Carmen 14 Response of the 12x12 HAPD Response to a single photoelectron and multi-photoelectrons. Single Photoelectron Multi Photoelectron

T. Sumiyoshi (TMU) 30, Nov del Carmen 15 Uniformity of a 6x6 APD Photocathode EB

T. Sumiyoshi (TMU) 30, Nov del Carmen 16 Uniformity of a 6x6 APD Avalanche gain Total gain

T. Sumiyoshi (TMU) 30, Nov del Carmen 17 Uniformity of a 6x6 APD Over all response QE x gain

T. Sumiyoshi (TMU) 30, Nov del Carmen 18 Readout Electronics Total number of readout channels for the Total number of readout channels for the full detector amounts to 120k. full detector amounts to 120k. Detector characteristics Detector characteristics Leakage current 10 or 25 ［ nA ］ Leakage current 10 or 25 ［ nA ］ Detector capacitance ； 10 or 70 ［ p Ｆ /pixel ］ Detector capacitance ； 10 or 70 ［ p Ｆ /pixel ］ signal ； 2000 or [electron/photon] signal ； 2000 or [electron/photon] Need high density front-end electronics. Need high density front-end electronics. Need high gain with very low noise amplifiers. Need high gain with very low noise amplifiers. Deadtimeless readout scheme-> Pipeline. Deadtimeless readout scheme-> Pipeline. Develop an ASIC for the front-end electronics

T. Sumiyoshi (TMU) 30, Nov del Carmen 19 Rohm CMOS 0.35[μm]) Basic parameters for the ASIC (Rohm CMOS 0.35[μm]) Gain ： 5 [V/pC] Shaping time ： 0.15 [μs] VGA ： 1-16 S/N ： 8 Readout ： pipeline with shift register Package : 18 channels/chip Control : LVDS Power consumption : 5 m W/channel Readout Electronics □ 4.93[mm] Made through VDEC PreampShaper VGA ComparatorShift register

T. Sumiyoshi (TMU) 30, Nov del Carmen 20 Readout Electronics Ｃｕｒｒｅｎｔ n ｏｉｓｅ ｐｅｒｆｏ ｒｍａｎｃｅ ４０００ enc: about twice of SPICE simulation. It could be made half in the next iteration. Threshold behavior. It works as expected.

T. Sumiyoshi (TMU) 30, Nov del Carmen 21 Summary 12x12 HAPD is under development for the photon detectors of the proximity focusing RICH which 12x12 HAPD is under development for the photon detectors of the proximity focusing RICH which is a good candidate of the Belle PID system in future. is a good candidate of the Belle PID system in future. There still remains some problems: There still remains some problems: APD leakage current goes up after the activation of PC. APD leakage current goes up after the activation of PC. Some APD can’t keep nominal bias voltage. Some APD can’t keep nominal bias voltage. For a readout of many anode signals (120k ch.), For a readout of many anode signals (120k ch.), we have been developing an ASIC. we have been developing an ASIC. Basic performance was checked by test pulses. Basic performance was checked by test pulses. Need minor modification for a further improvement of noise Need minor modification for a further improvement of noise level (current S/N 5 → ８）. level (current S/N 5 → ８）.