Design for Wide FOV Cherenkov telescope upgrading

2011-02-18

THE 2nd WORKSHOP OF LHAASO @ IHEP

Shoushan Zhang Institute of High Energy Physics

Outline

WFCTA telescope prototypes

WFCTA telescope upgrading -- PMT camera

-- PMT candidates

-- ASIC

-- DAQ upgrading program

Summary

Laser calibration

WFCTA telescope prototype ：

Mirror: 4.7 m2

Camera: 16×16 PMT array ， 1o pixel ， FOV 14o×16o

Electronics: 50Hz FADC (20ns/bin)

Elevation: 0-90o

Azimuth: 0-360o

Elevation: 0o-60o

Trigger condition: Npmt>=7Energy threshold: ~40TeV

Trigger condition: Npmt>=3Energy threshold: ~15TeV

WFCTA telescope upgrading : PMT camera

PMT SizePMT array

19 mm32×32

25.4 mm32×32

Size of camera 608×529 mm 832×720 mm

Pixel 0.5 deg. 0.5 deg.

Spot size 19 mm 25.4 mm

FOV 16×14 deg. 16×14 deg.

Active area 92.9% 87.9%

Camera: 1024 PMTs/telescope

Total mirror area: 4.7 m^2

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:

cathode: log10(Npe)

Non

linea

rity

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.

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% @ <126pc3. Nonlinear: < -/+ 1% in the whole range. 4. Pedestal measurement for monitoring sky background5. Time of over threshold in each channel6. 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 pe9. Pulse duration: Cherenkov signal: ~4 ns Fluorescence signal: < 3 us @ 0.50 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 @ 0.50 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.

One Back Scattering Laser Event One Cherenkov Event

20ns/bin

~5 us~120 ns

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

DAQ upgrading program

Sub-clusterserialprotocol

64 ˣ

FPGATCP/IP

SwitchServers

(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)

Summary

Reducing the pixel size to 0.5o 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.

Laser calibration Laser device:

-- The range of elevation: 0o-90o

-- The range of azimuth: 0o-360o

-- Energy: 92 uJ Distance between laser device and WFCTA01 is 176.3 m

Distance between laser device and WFCTA02 is 71. 4 m 。

N2 Laser device

WFCTA01 WFCTA02

Thank You!