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T. Lux. 13/12/2012 2 Charged particles X-ray (UV) Photons Cathode Anode Amplification Provides: xy position Energy (z position) e- CsI coating.

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Presentation on theme: "T. Lux. 13/12/2012 2 Charged particles X-ray (UV) Photons Cathode Anode Amplification Provides: xy position Energy (z position) e- CsI coating."— Presentation transcript:

1 T. Lux

2 13/12/ Charged particles X-ray (UV) Photons Cathode Anode Amplification Provides: xy position Energy (z position) e- CsI coating

3 Right gas choice and pressure fundamental! Normally: noble gas + quencher gas Choice depends on: Tracking, photon detection or spectroscopy? Fast gas necessary? (still slower than solid state detectors) Is a high gain required? High rate environment? Is ageing an issue? Safety! Better if not flamable! Sensitive to impurities? Diffusion? -> affects point resolution Complication of the gas system? (open or closed for example) Price! 13/12/2012 3

4 Argon, xenon or …? 13/12/ Stopping power larger in Xenon Better energy resolution in Xenon Argon much cheaper Etc. pressure but … pressure vessel + gas system attachment charge gain voltages …

5 Infinite possibilities: CH4, CO2, C4H10, CF4, DME, … 13/12/2012 5

6 Several advantages about the classical wire readout: Excellent spatial resolution ( amplification structures: ~100 m) Very good energy resolution Low material budget No ExB effects Cheap Can be produced in large quantities 13/12/ GEM

7 1 stage amplification Excellent energy resolution and low threshold (600 eV) Time resolutions below 1 ns possible 13/12/2012 7

8 Amplification within holes of Kapton foil coated with copper Normally operated in cascades -> better stability Can be operated in high rate environments (LHCb: 1 MHz/cm 2 ) 13/12/2012 8

9 2005: Start R&D efforts for a MPGD TPC for T2K European GEM collaboration: UniGe, IFIC, INFN Bari, IFAE 13/12/ Thorsten Lux (IFAE/UAB)9/19 2 GEM tower 3 GEM each ~20x24 cm2 also small setup at IFAE

10 13/12/

11 13/12/ IFAE participated in setting up testbench characterization of ~ 90 MM modules ~12 m2 readout area nowadays focus on analysis

12 13/12/ between two parallel meshes (G1,G2) a voltage is applied operated below the point where charge amplification sets in linear production of light (~172 nm for Xe) -> better energy resolution light is read out by PMT/APD/MPPC/… gain of photons per e- at 10 bar possible G1 G2 Sensors e- Drift region EL gap Cathode

13 13/12/ Started for a DB experiment in 2005 First stage: small HP chamber with 5 APDs Allowed to develop readout electronics Excellent energy resolution achieved Low threshold possible (8.2 ± 0.1)% FWHM xenon 13

14 13/12/ Larger chamber with 25 APDs Pressure up-to 5 bar Focus on tracking

15 2/11/ IEEE 2012 Anaheim Very primitive cluster finder still Using the cosmic ray trigger

16 Optimal imaging: MPGD with Pixel readout New project with CNM will start in January Si-MPGD coupled to MediPix chip 13/12/ MIPs δ-ray! 14 mm

17 Choice of gas and pressure allows wide range of application Energy measurement: 0.6 keV – 100+ keV X-rays (with decreasing detection efficiency for higher energies) Photon counting at lower energies with coating Point resolutions down to m possible Time resolutions below 1 ns possible High radiation hardness Count rates of 1 MHz/cm 2 possible MPGD allow to cover large areas to reasonable costs Gas detector knowledge available at IFAE but a gas detector for a ESRF source would require a dedicated R&D program 13/12/

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19 G.C. Smith, Gas-based detectors for synchrotron radiation, Journal of Synchrotron Radiation, Vol. 13, page , 2006 J.E. Bateman et al., A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments, NIM A, Volume 477, Issues 1–3, 21 January 2002, Pages M. Kocsis et al., A novel gas-filled detector for synchrotron radiation applications, NIM A, Volume 563, Issue 1, 1 July 2006, Pages M. Kocsis, The status of gas-filled detector developments at a third generation synchrotron source (ESRF), NIM A, Volume 471, Issues 1–2, 21 September 2001, Pages /12/

20 The neutrino group at IFAE has built up in the last 7 years a significant amount gas detector knowledge: : MPGD R&D for the T2K TPCs : Electroluminescence detector R&D Future projects at IFAE: : Development of a Si-MPGD with MediPix readout 13/12/


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