1 / 22

George K. Fanourakis Inst. of Nuclear & Particle Physics – NCSR ‘Demokritos’

Institute of Nuclear & Particle Physics. The Micromegas technique for X-ray and charged particle sensing. George K. Fanourakis Inst. of Nuclear & Particle Physics – NCSR ‘Demokritos’. Micromegas principle of operation. or pads. Microme sh Ga seous S tructure.

reid
Download Presentation

George K. Fanourakis Inst. of Nuclear & Particle Physics – NCSR ‘Demokritos’

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Institute of Nuclear & Particle Physics The Micromegas techniquefor X-ray and charged particle sensing George K. Fanourakis Inst. of Nuclear & Particle Physics – NCSR ‘Demokritos’

  2. Micromegas principle of operation or pads Micromesh Gaseous Structure

  3. Operation as an X-ray detector

  4. The photoelectric effect Ephe=Eγ – Eb (Eγ=hν, Eb=binding energy)

  5. Micromegas layout Micromesh and pillars

  6. Micromegas TPC - principle of operation Ionization electrons particle track E ≈200V/cm pillars mesh PCB strips or pads E≈400V/130μ Time Projection Chamber The arrival time of each signal is also measured

  7. Time Projection Chamber (TPC) Principle B E

  8. Electron transport to the anode pads and ion transport to the mesh e’s Drift (in electric field E) Diffusion mobility μ: thermal u: drift velocity u=velocity, k=Boltzmann constant. T=temperature, electrons~106m/sec, ions~104m/sec for ideal gasses moving charges are in thermal equilibrium and: Einstein relation: N0=initial number of charges created, x=diffusion distance, D=diffusion const. 2d: 1d: mean free path:

  9. Avalanche Multiplication anode If α is the mean free path of the electron for a secondary collision  1/α is probability of an ionization per unit path length. 1/α is known as the ‘first Townsend coefficient’ The multiplication factor M is limited by the Raether limit: M<108 or αx<20. A theoretical model for α (Rose & Korff) gives: minimum at xd=VB/p ~50-150μ

  10. Micromegas performance - uses High radiation resistance : > 30 mC/mm2 > 25 LHC years G. Puill, et al., IEEE Trans. Nucl. Sci. NS-46 (6) (1999)1894. Sub-nanosecond time resolution Time of flight, fast TPC Good energy resolution – 109Cd Signal discrimination NA48-KABES 600 ps A. Delbart, Nucl.Instrum.Meth.A461:84-87,2001 Excellent single electron resolution UV photodetector High accuracy < 12 m Tracker, bio-medical applications  (m) 25/09/2014

  11. CAST: CERN Axion Solar Telescope Mesh Cylindrical Spacers h=50μm Hole diameter=50μm, pitch=100μm, Mesh thickness=5μm, 2-D READ OUT S. Andriamonje et al. Nucl.Instrum.Meth.A518:252-255,2004 Micromegas low-background 384X-Y strips (192 X, 192 Y) 350 m pitch Micromegas in action at CAST

  12. Current technology: Bulk MicromegasI. Giomataris et al., Nucl.Instrum.Meth.A560: 405-408,2006 Bulk Micromegas obtained by lamination of a woven grid on an anode with a photo-imageable film Large area and robustness Easy implementation Low cost Industrial process « Bulk » : construction process Low material budget detectors Goal : 5-10 lower of a standard silicon detector Rui deOliveira – CERN Saclay

  13. Japon T2K TPC Tokai 295 km Kamioka T2K: a long baseline neutrino oscillation experiment Main goal : Direct search for e appearance JPARC facility 280 m near detector ND280 Super-Kamiokande Cerenkov detector • A large TPC : • Measure charge and momentum of charged particles • Particle identification to distinguish e, µ,  and p • Excellent pattern recognition

  14. 24 bulk-micromegas + FEE + mechanics 3 m2 of bulk micromegas 41472 FEE channels Reconstructed cosmics by a readout plane (@ TRIUMF)

  15. A Micromegas hodoscope for sLHC related tests A Demokritos-NTUA project X and Y strips with 250 μm pitch, single plane resolution ~ 50 μm Beam profiles The 3 XY tracker modules as installed at CERN’s H4 beam.

  16. ILC TPC project Large International collaboration ILC TPC with Micromegas, L = 4.6 m, D = 3.4 m No ExB effect ~ 40 m average!! Pad size 2x6 mm Res=5x10-5 ILC TPC prototype with Micromegas Event in DESY test beam I. Giomataris

  17. Micromegas + micro-pixels H. Van der Graaf, J. Timermans et al. P. Colas et al., NIMA535(2004)506 surface: 1.4 x 1.6 cm2 Matrix of 256 x 256 pixel size: 55 x 55 µm2 Medipix2 InGrid technology M. Cambell et al, NIMA540(2005)295 M. Chefdeville et al., NIMA556(2006)490 Gas On Slimmed SIlicon Pixels (GOSSIP) Under study for ATLAS SLHC tracker Great resolution Single electron counting!! 25 septembre 2014 I. Giomataris I. Giomataris

  18. Micromegas inside Novel fabrication technologyMicro-Bulk Type1 Type2 50 m and 25 m gaps fabricated • Very good energy resolution • 11% at 5.9 keV • 5.5% at 22 keV • <1.5% with Am alpha source • Other advantages • Flexible structure (cylinder) • Good uniformity • Low material budget • Low radioactivity • Long term stability ? Xe @ 2 bar Neutrinoless Double Beta (0nbb) using 136Xe target 25 septembre 2014

  19. Micro-bulk in CAST - high performance On low radioactivity support N2 ON N2 ON Benchmark ≈10-7/keV/cm2/s N2 OFF

  20. A TPC for Nuclear Fission and Astrophysics experiments (FIDIAS) A Demokritos-Saclay project Micromegas T2K readout system

  21. Intensive tests at Saclay

  22. Conclusions • Micromegas • A mature technology for various applications: tracking, calorimetry, UV, X-rays, neutron, polarimetry … • Robust, stable operation • Very good energy resolution • Very good linearity • Very good position resolution • Fast signals • High radiation resistance • Widely developed all over the world • Industrial fabrication process • Many application fields (Particle Physics, Nuclear Physics, Medicine, Industry…)

More Related