2. Overview on H.E.S.S. camera designs P. Vincent for the HESS collaboration LPNHE – IN2P3/CNRS – Université Paris VI & VII H.E.S.S.-MAGIC-CTA meeting in Berlin, May 4-5

3. P. Vincent - LPNHE2CTA meeting - Berlin, May 4-5 Requirements Low threshold (~ 0 GeV) Large dynamic range and acceptance (∞) Large FoV (~360 o ) High trigger rate for minimal dead time (0%) Good energy (ΔE/E -> 0) and angular resolution (ΔΦ -> 0”) and, all that for free

4. P. Vincent - LPNHE3CTA meeting - Berlin, May 4-5 Some basic ideas developed on HESS cameras Fine pixelisation ( < PSF) for 5 o 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)

5. P. Vincent - LPNHE4CTA meeting - Berlin, May 4-5 Fine pixelisation ( < PFS) for 5 o FoV Advantage : –Energy reconstruction –Angular resolution Disadvantage : 960 pixels/camera have a cost Image of point source

6. P. Vincent - LPNHE5CTA meeting - Berlin, May 4-5 Photo-multipliers Standard PMTs from Photonis Co: –QE ~ 20-25% –rms ~ 40 % –Time fall ~ 1.8ns –FWHM ~ 3 ns @ 2.10 5 –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 C 0 –~250 mW per pixel About 180 €/channel

7. P. Vincent - LPNHE6CTA meeting - Berlin, May 4-5 Photo-detector understanding Single photo-electron at nominal HV value –80 ADC channel @ 2.10 5 of gain Dispersion over a camera Checked every 2 days Stable on a period Rms ~ 6 ADC count

8. P. Vincent - LPNHE7CTA meeting - Berlin, May 4-5 Calibration Stability thanks to temperature control and monitoring : –192 sensors –92 fans NSB monitoring : –HVI vs HV –Scalers –DCI

9. P. Vincent - LPNHE8CTA meeting - Berlin, May 4-5 Calibration vs Acquisition The single photo-electron @ 2.10 5 implies 2 gain channels to cover the dynamic range: –2 data channels –1 trigger channel

10. P. Vincent - LPNHE9CTA meeting - Berlin, May 4-5 Large dynamic range Two 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

11. P. Vincent - LPNHE10CTA 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 2008 2004 20??

12. P. Vincent - LPNHE11CTA 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

13. P. Vincent - LPNHE12CTA 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 sectors

14. P. Vincent - LPNHE13CTA meeting - Berlin, May 4-5 Compact & modular 60 removable drawers HESS I HESS II By courtesy of P. Manigot - LLR

15. P. Vincent - LPNHE14CTA 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

16. P. Vincent - LPNHECTA meeting - Berlin, May 4-515 HESS I experience Assembly line : camera build and fully tested at the laboratory

17. P. Vincent - LPNHECTA meeting - Berlin, May 4-516 Ready for usage Camera # 4 November 2003

18. P. Vincent - LPNHECTA meeting - Berlin, May 4-517 Plug & Play camera installation December 2nd In the morning At noon afternoon

19. P. Vincent - LPNHECTA meeting - Berlin, May 4-518 Plug & Play Very early in the morning Fill camera with drawers December, 3rd

20. P. Vincent - LPNHECTA meeting - Berlin, May 4-519 Plug & Play December 3rd Install cone plate During night

21. P. Vincent - LPNHECTA meeting - Berlin, May 4-520 Plug & Play Connect to the power, network and central trigger look if camera stay in place December 4th

22. P. Vincent - LPNHECTA meeting - Berlin, May 4-521 Plug & Play After some more tests and the end of the moon period First event December 11th

23. P. Vincent - LPNHE22CTA 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 FIFO SAM FIFO SAM FIFO SAM AM+ADC FIFO FPGA L1 trigger L2 trigger < 400 kHz< 50 kHz PMs

24. P. Vincent - LPNHECTA meeting - Berlin, May 4-523 Cost HESS I –PMTs (960)0.15 M€ –Mechanics0.16 M€ –Electronics0.34 M€ Camera0.65 M€/unit HESS II –PMTs (2048)0.5 M€ –Mechanics0.8 M€ –Electronics1.2 M€ (x4 due to R&D and many test benches) Camera2.5 M€/unit } Industrialized process }

25. P. Vincent - LPNHECTA meeting - Berlin, May 4-524 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 …

26. P. Vincent - LPNHECTA meeting - Berlin, May 4-525 That’s all folks MPI Kernphysik, Heidelberg Humboldt Univ. Berlin Ruhr-Univ. Bochum Univ. Hamburg Landessternwarte Heidelberg Univ. Kiel Univ. Tübingen, Germany LPNHE - Paris, Univ. Paris VI-VII LLR, Ecole Polytechnique, Palaiseau APC - College de France, Univ. Paris VII CEA - Saclay CESR - Toulouse LAOG - Grenoble LUTH - Observatoire de Paris LPTA - Montpelier LAPP - annecy Durham Univ. Charles Univ., Prag Dublin Inst. for Adv. Studies Yerewan Physics Inst. Univ. of Namibia, Windhoek Univ. Potchefstroom

27. P. Vincent - LPNHE26CTA 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. …

28. P. Vincent - LPNHECTA meeting - Berlin, May 4-527 HESS II expected performance HESS II Standalone HESS II Hybrid ~50 GeV 10-20 GeV ~100 GeV HESS I L1 standard trigger condition only Stereoscopy H.E.S.S. Phase I Hybrid stereoscopy Phase II Monoscopy Phase II M. Ouchrif (IN2P3/LPNHE Paris) Trigger condition : 4 PMs above 5 γe rate 2.5 kHz dead time ~ 0.5%

29. P. Vincent - LPNHECTA meeting - Berlin, May 4-528 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 Hillas Neural network … Trigger L1 (lower threshold) + L2(clustering) L1 (standard) M. Tluczykont (LLR/Ecole polytechnique)

30. P. Vincent - LPNHECTA meeting - Berlin, May 4-529 Camera can moves by ~10 cm depending on elevation, to focus on shower image focusin g W. Hofmann, J.Phys. G27, 933(2001)

31. P. Vincent - LPNHECTA meeting - Berlin, May 4-530 Autofocus

32. P. Vincent - LPNHECTA meeting - Berlin, May 4-531 Implantation générale

33. P. Vincent - LPNHECTA meeting - Berlin, May 4-532 Implantation générale