1. Design for Wide FOV Cherenkov telescope upgrading 2011-02-18 THE 2 nd WORKSHOP OF LHAASO @ IHEP Shoushan Zhang Institute of High Energy Physics

2. Outline  WFCTA telescope prototypes  WFCTA telescope upgrading -- PMT camera -- PMT candidates -- ASIC -- DAQ upgrading program  Summary  Laser calibration

3. WFCTA telescope prototype ： Mirror: 4.7 m 2 Camera: 16×16 PMT array ， 1 o pixel ， FOV 14 o ×16 o Electronics: 50Hz FADC (20ns/bin) Elevation: 0-90 o Azimuth: 0-360 o Elevation: 0 o -60 o

4. Trigger condition: Npmt>=7 Energy threshold: ~40TeV Trigger condition: Npmt>=3 Energy threshold: ~15TeV

5. WFCTA telescope upgrading : PMT camera PMT Size PMT array 19 mm 32×32 25.4 mm 32×32 Size of camera608×529 mm832×720 mm Pixel0.5 deg. Spot size19 mm25.4 mm FOV16×14 deg. Active area92.9%87.9%  Camera: 1024 PMTs/telescope Total mirror area: 4.7 m^2

6. Fluorescence Cherenkov QE>25% @ peak QE peak: < 420 nm Spectral range: 300 nm~650 nm Gain: >2.5 * 10^5 HV: <1300 V Size of PMT: 19 mm, 25 mm. Linearity: 2% @ 30 mA Parameters of PMT: Size of PMT = 19 mm -- R4125 (Hamamatsu) -- 9078B (ET) Size of PMT = 25 mm -- R1924A （ Hamamatsu ） -- CR193 （ Beijing Hamamatsu ） is under fabrication in China. PMT candidates:

7. cathode: log10(Npe) Nonlinearity 3.2 orders of dynamic range: Nonlinearity < 5% R1924A （ Hamamatsu ） β=7.88±0.03 Conclusion: R1924A meets our requirements. The other types of PMTs will be test in the near future.

8. Parameters for ASIC 1. Dynamic range: 0.042 pc-126pc @ PMT gain 2.6*10^5 (1pe-3000pe) 2. Resolution: 0.021 pc @ 0.042 pc, <5% @ <126pc 3. Nonlinear: < -/+ 1% in the whole range. 4. Pedestal measurement for monitoring sky background 5. Time of over threshold in each channel 6. Threshold adjustable: 0.084 pc – 4.2 pc (2pe-100pe) 7. Dead time free @ 200 Hz trigger. 8. Single channel trigger rate: <1 kHz @ threshold = 22 pe 9. Pulse duration: Cherenkov signal: ~4 ns Fluorescence signal: < 3 us @ 0.5 0 10. Time interval of fired pmt in one event: Almost at the same time @ Cherenkov mode; <20 us @ Fluorescence mode. 11. Laser calibration. (1) Back scattering mode: Pulse duration < 3 us @ 0.5 0 Time interval of fired pmt in one event: ~20 us. (2) Normal scattering mode: ~210 ns/deg. @ 4 km. Time interval of fired pmt in one event: ~14 us.

9. One Back Scattering Laser EventOne Cherenkov Event 20ns/bin ~5 us ~120 ns

10. ASIC 4. JEM-EUSO: to serve as Cherenkov and Fluorescence telescope. -- EUSO Analog Front End Electronics, D-H. Koang etc. al. 28th ICRC -- I have no details of the ASIC chip at present. 2. IHEP: -- Shaping time: 25 ns, 50 ns, 100 ns -- Dynamic range: 1 – 3000 pe -- Nonlinearity: <1% -- Power Dissipation: ~ 10mW/ch 3. SuperK ： CLC101EF （ TOT ） -- Shaping time: 150 – 1000 ns -- Dynamic range: 0.2 – 2500 pC -- Nonlinearity: < +/- 1% -- Power Dissipation: <100 mW/ch 1. France ： PARISROC -- Shaping time: 25 ns, 50 ns, 100 ns -- Dynamic range: 0 – 3000 pe (two channels/PMT) -- Nonlinearity: <1% -- Power Dissipation: ~10 mW/ch

11. DAQ upgrading program Sub-cluster serial protocol 64 ˣ FPGA TCP/IP Switch Servers (PC) Data cable ： old version 32/sub-cluster new version 3/sub-cluster  TCP/IP : transmission speed > 40 Mbit/s ( 200 Hz @ integral mode ）  Serial protocol ： transmission speed > 10 Mbit/s PC104 (TS7200)

12. Summary  Reducing the pixel size to 0.5 o is necessary for improving the performance of Cherenkov telescope.  New detector simulation will be done in near future to evaluate the performance of Cherenkov telescope.  We have selected four kinds of PMT candidates and one of candidates is measured, which meets our requirement.  May be the ASIC of JEM-EUSO will meets the fluorescence mode requirement. The more details of the ASIC is needed.

13. Laser calibration  Laser device: -- The range of elevation: 0 o -90 o -- The range of azimuth: 0 o -360 o -- Energy: 92 uJ  Distance between laser device and WFCTA01 is 176.3 m Distance between laser device and WFCTA02 is 71. 4 m 。 N 2 Laser device

14. WFCTA01WFCTA02

15. Thank You!