Overview on Overview on H.E.S.S. camera H.E.S.S. camera

designsdesigns

Overview on Overview on H.E.S.S. camera H.E.S.S. camera

designsdesignsP. Vincent for the HESS collaborationP. Vincent for the HESS collaboration

LPNHE – IN2P3/CNRS – Université Paris VI & LPNHE – IN2P3/CNRS – Université Paris VI & VIIVII

H.E.S.S.-MAGIC-CTA meeting inH.E.S.S.-MAGIC-CTA meeting inBerlin, May 4-5Berlin, May 4-5

P. Vincent - LPNHE 2CTA meeting - Berlin, May 4-5

Requirements• Low threshold (~ 0 GeV)• Large dynamic range and acceptance (∞)• Large FoV (~360o)• High trigger rate for minimal dead time (0%)• Good energy (ΔE/E -> 0) and

angular resolution (ΔΦ -> 0”)

and, all that for free

P. Vincent - LPNHE 3CTA meeting - Berlin, May 4-5

Some basic ideas developed on HESS

cameras• Fine pixelisation ( < PSF) for 5o FoV (extended sources,

survey, energy and angular resolution)• Redundant information for calibration purposes (for data

quality)• Avoid delay line for data storage (also for data quality)• Fast readout with minimum dead time (to go to low

energy).• Fast analogue trigger (to profit from timing information)• Should be easy to install and repair (for human life

quality)• Not totally free but low cost (for our institutions)

P. Vincent - LPNHE 4CTA meeting - Berlin, May 4-5

Fine pixelisation ( < PFS) for 5o FoV

• Advantage :– Energy

reconstruction– Angular

resolution• Disadvantage :

960 pixels/camera have a cost

Image of point source

P. Vincent - LPNHE 5CTA meeting - Berlin, May 4-5

Photo-multipliersStandard PMTs from Photonis

Co:– QE ~ 20-25%– rms ~ 40 %– Time fall ~ 1.8ns– FWHM ~ 3 ns @ 2.105

– Dark current < 1 nA– Unif. 20% for < 2.1 cm– cone eff. ~ 70% DC-DC converters from ISEG Co

:– ΔU/U ~ 1.10-4 (< 0.1V @ 1000 V)– 5V/ms– Imax ≃154 μA– 850 V < U < 1 300V– ΔU/ΔT < 5.10-5 V per C0

– ~250 mW per pixel

About 180 €/channel

P. Vincent - LPNHE 6CTA meeting - Berlin, May 4-5

Photo-detector understanding

• Single photo-electron at nominal HV value– 80 ADC channel @ 2.105 of gain

Dispersion over a camera

Checked every 2 days Stable on a period

Rms ~ 6 ADC count

P. Vincent - LPNHE 7CTA meeting - Berlin, May 4-5

Calibration• Stability thanks to temperature

control and monitoring : – 192 sensors– 92 fans

• NSB monitoring :– HVI vs HV– Scalers– DCI

P. Vincent - LPNHE 8CTA meeting - Berlin, May 4-5

Calibration vs Acquisition

• The single photo-electron @ 2.105 implies 2 gain channels to cover the dynamic range:– 2 data channels – 1 trigger channel

P. Vincent - LPNHE 9CTA meeting - Berlin, May 4-5

Large dynamic rangeTwo gain channels

• HESS I :– HG : from 1 to ~ 200– LG : from 10 to ~ 1 600

From 100 GeV up to few tens of TeV

• HESS II :– HG : from 1 to ~ 150– LG : from 10 to > 5 000

~20 GeV to few tens of TeV

E. Delagnes, Y. Degerli, P. Goret (DAPNIA, CEA/Saclay)P. Nayman, F. Toussenel (IN2P3/LPNHE Paris)

HESS I

HESS II

P. Vincent - LPNHE 10CTA meeting - Berlin, May 4-5

Acquisition speed• HESS I:

– Max speed 2.5 kHz (limited by the front end)– ~15% dead time @ 300 Hz

• HESS II:- Max speed ≥ 3 kHz (limited by the network)- ~ 0.7% dead time @ 3kHz

HESS II

0.7% dead time @ 3 kHz

20082004 20??

P. Vincent - LPNHE 11CTA meeting - Berlin, May 4-5

Acquisition speed enhancement

HESS I• ARS0 : Analogue Memory built

for ANTARES (SEI-Dapnia)5 buffers/chip, 128 cells per

channel.– Sampling @ 1 GHz– Dynamic range 9-10 bits– Linearity (1 – 1,600 γe)– Max readout ~ 15 KHz :

• Sampling (calibration)• integrated charge

(operation)

HESS II• SAM (Swift Analogue

Memory) :2 differential channels x 256 cells– Max sampling freq : 2.5-3 GSps– Analog input bandwidth ≤ 300

MHz– Operate up to 400 kHz – Dynamic range > 11.3 bits– Cross-talk < 0.1%– Linearity (1 – 5,000 γe)– Low power consumption ~ 300

mW.HESS I

P. Vincent - LPNHE 12CTA meeting - Berlin, May 4-5

Use of analogue memories need fast

trigger• Analogue sum of width

of the signal pulse over a programmable threshold + multiplicity in a sector of 64 pixels.

• Answer in 70 ns and ~100 ns for HESS I and II respectively

38 overlapping 38 overlapping sectorssectors

P. Vincent - LPNHE 13CTA meeting - Berlin, May 4-5

Compact & modular• 60 removable drawers

HESS I

HESS IIBy courtesy of P. Manigot - LLR

By courtesy of P. Manigot - LLR

P. Vincent - LPNHE 14CTA meeting - Berlin, May 4-5

Compact & modular• Advantages:

– Integrated electronics and local treatment is faster– Complete monitoring and slow control system– Minimal signal distortion– Compacity allow full construction and test in

laboratory– Only power & network connection– Modularity facilitates the installation and

maintenance

• Constraints:– Weight (~1 ton for HESS I and ~3 for HESS II)– Modularity also has a cost

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 15

HESS I experienceAssembly line : camera build and fully tested at the laboratory

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 16

Ready for usage

Camera # 4November 2003

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 17

Plug & Play• camera

installation

December 2nd

In the morning

At noon

afternoon

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 18

Plug & Play

Very early in the morning

• Fill camera with drawers

December, 3rd

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 19

Plug & PlayDecember 3rd

• Install cone plate

During night

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 20

Plug & PlayConnect to the

power, network and central trigger

look if camera stay in place

December 4th

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 21

Plug & PlayAfter some more

tests and the end of the moon period

First event

December 11th

P. Vincent - LPNHE 22CTA meeting - Berlin, May 4-5

HESS II• Other new features that I will not talk about :

– New photo-tube studies (standard but new processes)– Auto-focus and unloading of the camera – Level 2 trigger (decision ~ 20μs)– ….

see ICRC 2005

SAM FIFOSAM FIFOSAM FIFOSAMAM+ADC FIFO

FPGA

L1 trigger L2 trigger

< 400 kHz < 50 kHzPMs

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 23

CostHESS I

– PMTs (960) 0.15 M€– Mechanics 0.16 M€– Electronics 0.34 M€

• Camera 0.65 M€/unit

HESS II – PMTs (2048) 0.5 M€– Mechanics 0.8 M€– Electronics 1.2 M€ (x4 due to R&D and many test benches)

• Camera 2.5 M€/unit

} Industrialized process

} Industrialized process

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 24

Summary• After 3 years of development 4 cameras were

installed between June 2002 and end of 2003. • Performances reach expectations of five years

ago.• HESS II camera profits from the first phase

experiment with upgrades and additional features …

• HESS cameras have proven their capability under operation … 32 k €/unit/(source/year).

• Large scale production needs complete industrialization. It will induce extra cost but the R&D, already paid, can partially compensate …

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 25

That’s all folks

MPI Kernphysik, HeidelbergHumboldt Univ. Berlin

Ruhr-Univ. BochumUniv. Hamburg

Landessternwarte HeidelbergUniv. Kiel

Univ. Tübingen, GermanyLPNHE - Paris, Univ. Paris VI-VII

LLR, Ecole Polytechnique, PalaiseauAPC - College de France, Univ. Paris VII

CEA - SaclayCESR - ToulouseLAOG - Grenoble

LUTH - Observatoire de ParisLPTA - Montpelier

LAPP - annecyDurham Univ.

Charles Univ., PragDublin Inst. for Adv. Studies

Yerewan Physics Inst.Univ. of Namibia, Windhoek

Univ. Potchefstroom

P. Vincent - LPNHE 26CTA meeting - Berlin, May 4-5

DAS• Linux OS => pseudo-Real time OS

are not quite free but profit from a large community of developers

• cPCI bus. It is fast 64bits @ 33MHz + DMA transfer (HESS ~ 620 Mbits/s)

• Independent remote control via terminal server for security.

• …

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 27

HESS II expected performanceHESS II expected performance

HESS II

StandaloneHESS IIHybrid

~50 GeV

10-20 GeV

~100 GeVHESS I

L1 standard trigger condition only

Stereoscopy H.E.S.S. Phase IHybrid stereoscopy Phase IIMonoscopy Phase II

M. Ouchrif (IN2P3/LPNHE Paris)

Trigger condition : 4 PMs above 5

γe rate 2.5 kHz dead time ~

0.5%

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 28

Level 2 (under study): Binary information at the level of

individual pixel.Decision must be taken in less than 20

s.Algorithm programmed on DSP or FPGA

Reject event without cluster NSB and unclustered gamma

Reject High energy image amplitude Pulsar study

Estimate second moment HillasNeural network …

Trigger

L1 (lower threshold) + L2(clustering)

L1 (standard)

M. Tluczykont (LLR/Ecole polytechnique)M. Tluczykont (LLR/Ecole polytechnique)

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 29

Camera can moves by ~10 cm depending on elevation, to focus on shower image

focusing

W. Hofmann, J.Phys. G27, 933(2001)W. Hofmann, J.Phys. G27, 933(2001)

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 30

Autofocus

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 31

Implantation générale

P. Vincent - LPNHE CTA meeting - Berlin, May 4-5 32

Implantation générale