1. H.Ohoka, H.Kubo, M.Aono, Y.Awane, A.Bamba, R.Enomoto, D.Fink, S.Gunji, R.Hagiwara, M.Hayashida, M.Ikeno, S.Kabuki, H.Katagiri, K.Kodani, Y.Konno, S.Koyama, K.Kuroda, J.Kushida, R.Mirzoyan, T.Nakamori, K.Nishijima, A.Okumura, O.Reimann, T.Shcweizer, M.Sasaki, A.Shibuya, R.Sugawara, H.Tajima, M.Tanaka, Y.Terada, M.Teshima, T.Uchida, K.Umehara, T.Yamamoto, M.Yonetani, For the CTA-Consortium Development of PMT Clusters for CTA-LST Camera Reiko Orito (Univ. of Tokushima) ICRC2011, Beijing, China, Aug11 th -18 th,2011

2.  Cherenkov Telescope Array(CTA)  Camera for CTA Large Size Telescope(LST)  Development of PMT Cluster Module  PMT  HV  Preamp  Slow control electronics  Readout electronics  Performance Test  Summary and Future Plan Contents

3. LST (~23m) MST (10~12m) SST (4~6m)  Next Generation IACT  Array from telescopes with three different sizes of mirrors  One order higher sensitivity compared with current IACTs  Gamma-ray energy range : a few 10GeV~100 TeV Cherenkov Telescope Array(CTA) ~23m LST OG2.5 ID726 M.Martinez OG2.5 ID1021 M.Teshima

4. CTA-LST Camera FOV 4.5deg(0.1deg/pixel), Photodetector pixels ~2500 Camera diameter ~2.5m (only for photodetector area) Readout electronics inside Sealed and temperature controlled We have developed first prototype PMT cluster module MAGIC-II(~17m) camera High performance photodetector Fast readout electronics Low power consumption Compact, Light Low cost for mass-production To realize this largest camera and achieve the CTA target sensitivity… Camera Basic Design: ~1.1m

5. PMT Cluster 14 cm Slow- Control Readout electronics 60cm 7 PMTs Preamp 48mm PMT Spacing. Cluster Components High-QE PMTs Cockcroft-Walton HV Preamp Slow Control Electronics Readout Electronics Please check also Poster: OG2.5 ID1119 H.Kubo, Dragon CW-HV

6. PMT Hamamatsu R11920-100 Baseline photodetector for LST: PMT Hamamatsu R11920-100 with 1.5 inch Superbialkali photocathode ~38mm Hamamatsu R11920-100 Typical QE Curve of R11920-100 Promising device for CTA-LST Specifications QE > 35% After pulse rate 4 p.e.) Pulse width 2.5~3ns(FWHM) Frosted Concave-convex Window TTS <1.3ns Life > 10years Operation Gain 4x10 4

7. CW-HV Specifications Consists of 3 PCBs, Made by Hamamatsu Voltage Division 300V(Zener):1:2:1:1:1:1:2:1 +5V Power, Power consumption < 40mW @ dark condition HV Control(Monitor) Line 0 ~ +(-)1.5V (corresponds to 0~-1500V) Cockcroft-Walton(CW) HV PMT Module with CW-HV and Preamplifier ~38mm Cockcroft-Walton High Voltage Preamp Hamamatsu R11920-100 Compact HV with low power consumption CW Power Consumption <25mW@ Gain 5x10 4 ( for most PMTs)

8. Fast Preamplifier Fast and low power preamp board has been developed. Preamp Output ~38mm LEE-39+ (Mini-Circuits co.) amplifier. Bandwidth > 4GHz, Gain 20.8 dB@2GHz Power 180mW for one board Readout line for PMT Anode DC Current is implemented. 0.5mm pitch connector R11920-100 PMT signal After preamp 4ns

9. Slow Control Electronics Control and Monitor PMT HVs Monitor PMT anode current, temperature, humidity Generate fast test-pulse and control its attenuation Consists of two CPLDs, Controlled by FPGA in readout electronics PMT Module Side Readout electronics side ~14cm Power consumption ~17mW(standby)

10. Fast Readout Electronics Using DRS(Domino Ring Sampler)-4, Analog memory chip designed by PSI 1024 x8 capacitors/chip,sample rate 0.7~5GS/s, bandwidth 950MHz We have developed readout electronics board with 8 DRS4 chips with channel cascading(4  s depth @1.0GS/s). Low gain, high gain channels FPGA-based Gbit-Ethernet (SiTCP) Interface The PMT cluster with fast electronics has been developed. 14cm Backplane side SRAM (18Mb) FPGA Virtex-4 ADC Ethernet PHY DAC Analog L0 Trigger Analog L1 Trigger Digital L0 Trigger 41.5cm PMT HV Preamp Slow Control DRS4 Main Amp

11. Performance Test One cluster (7 PMTs): power 14W, weight 1.3kg LED 7-PMTs DRS4 readout board Gbit Ethernet PMT Gain= 5x10 4 [mV x ns] 1 p.e. peak Front View Spectrum was successfully taken at low gain 7 PMT channels are read 900mV ~ 7 p.e. 5ns 2GS/s Waveform was successfully taken with 2GS/s Bandwidth > 400MHz First prototype PMT cluster for CTA-LST camera has been successfully developed !

12. Next Step Cooling plate Water pipe 19 clusters 673.66 mm 610.2 mm Construct mini-camera with 19 PMT clusters Demonstration of the camera cooling Study of mechanical structure Study of the cluster triggering Finalize the cluster design and mass-produce clusters for prototype CTA-LST camera in next 3 years

13. Preparation of next generation Cherenkov telescope CTA is in progress. Now we are actively developing hardware components. We have reported the PMT cluster for CTA-LST. High-QE PMT Cockcroft-Walton HV Preamp Slow control electronics Fast readout electronics This is a first complete prototype photodetector module for CTA-LST. Further study for prototype camera is ongoing. Summary

14. Thank you for your attention!

15. Backup

16. Block Diagram 7-PMT cluster DRS4 DAC Low gain High gain ADC FPGA DRS4 readout board SRAM( 18Mbit) I/O connector Gigabit Ethernet transceiver DAC SiTCP HV voltage set, Test pulse gen. V, I, temp., humidity monitor Trigger ： Analog L0 & L1 or Digital L0 + - diff PMT 1 Preamp Cockcroft- Walton HV DAC PMT 2 PMT 7 Backplane Slow control CPLD ADC Test pulse gen. Temp. &Hum. Sensor Data are transferred via Gigabit-Ethernet.

19. DRS4:150Euro/channle PMT: 150/ch CW+Preamp+Slow control] 130/ch Target price: 400 Main Amp 400mW DRS4 18mW/channel 1 p.e. spectrum @PMT Gain= 9.6x10 4 Readout electronics development in CTA(Poster presentations): ID698 J.Glicenstein, NECTAR ID39 G.Puehlhofer, FlashCam ID1065 J.Vandenbroucke, TARGET ID1119 H.Kubo, DRS4