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SIDDHARTA: the future of exotic atoms research at DA F NE

SIDDHARTA: the future of exotic atoms research at DA F NE Si licon D rift D etector for H adronic A tom R esearch by T iming A pplications DAFNE-2004: Physics at meson factories Mihai Iliescu INFN-LNF 10-06-2004. The goal of KH and KD measurements

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SIDDHARTA: the future of exotic atoms research at DA F NE

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  1. SIDDHARTA: the future of exotic atoms research at DAFNE Silicon Drift Detector for Hadronic Atom Research by Timing Applications DAFNE-2004: Physics at meson factories Mihai Iliescu INFN-LNF 10-06-2004

  2. The goal of KH and KD measurements a few eV determination of both shift and width of the 1s level induced by the strong interaction in the Kp and KD atomic systems The main feature to deal with, in order to obtain the desired accuracy, is the S/B ratio. This requires to pass from 1:70(KH today) to at least 1:1 (KH) and 1:5 (KD-first time)

  3. Experimental requirements for the measurements a triggerable, large area, high resolution, high efficiency in the energy region of interest (1-20 KeV) X-ray detector

  4. Triggerable SDDs A large area Silicon Drift Detector (SDD), equipped with trigger electronics, presently under development (SIDDHARTA project), satisfies the experimental requirements

  5. Working principles of the SDD

  6. - V c c p + n n + The classical PIN (Positive-Intrinsic-Negative) diode detector Entrance window ANODE The anode capacitance is proportional to the detector active area

  7. The Semiconductor Drift Detector The electrons are collected by the small anode, characterised by a low output capacitance. Anode Advantages:very high energy resolution at fast shaping times, due to the small anode capacitance, independent of the active area of the detector

  8. The Silicon Drift Detector with on-chip JFET • JFET integrated on the detector • capacitive ‘matching’: Cgate = Cdetector • minimization of the parasitic capacitances • reduction of the microphonic noise • simple solution for the connection detector-electronics in monolithic arrays • of several units

  9. The integrated JFET Detector produced at Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany

  10. Performances of the SDDs

  11. Silicon Drift Detector QE and resolution Quantum efficiency of a 300 mm thick SDD 55Fe spectrum measured with a SDD (5 mm2) at –10°C with 0.5 ms shaping time

  12. SDD PIN Si(Li) 150 K 5.9 keV line 800 700 PIN Tsh=20us 600 500 FWHM (eV) 400 300 Si(Li) Tsh=20us 200 SDD Tsh=1us 100 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 A (cm-2) Spectroscopic resolution: detector comparison - 1

  13. Spectroscopic resolution: detector comparison - 2 FWHMmeas of monoenergetic emission line 5.9 keV 1cm2detector at 150 K SDD FWHM=140eVtshap =1ms Si(Li) FWHM=180eVtshap =15ms PIN diode FWHM=750eVtshap =20ms CCD FWHM=140eVtframe= ~s

  14. Timing resolution with SDD A=0.1cm2 Tdrift = 70ns A=0.5cm2Tdrift =350ns A= 1cm2Tdrift =700ns With: r= 2kW/cm H = 450mm

  15. IK IA hn hn t IA tdr max t Timing with the anode signal

  16. Kaontrigger Concidencewindows Tdr max Detectedpulses Consideredpulses Kaon trigger X-ray pulse Background pulse Triggered acquisition

  17. Background reduction with triggered acquisition Machine Background NK= number of detected kaons per detected Ka X-ray = 103Br = background rate = 103 events/s over 200 cm2, full spectrum (1-20 KeV) -->50 Hz/1KeV Tw = gate window Tw = NKx Tdrift max = 103x 1 ms = 1ms B = Brx Tw = 50 s-1x 10-3 s = 5 x 10-2 S/B=20/1 negligible Hadronic background (Kp-pS interaction, synchronous) preliminary simulation (typical SDD thickness 300 mm) S/B = 5/1 (KH), 1/4 (KD)

  18. SDD test setup electronics layout P.S. Temp. control SDD canister 7 Shapers, peak stretchers & discriminators HV control Amplified SDD output signal Stretcher reset DAQ Analog output Shapers control motherboard Discrim. output Trigger (NIM logic) NIM 2 TTL Trigger signal Scintillators

  19. electrode Voltage Current R#1 - 10 V 20.8mA IGR - 18 V 0.5mA Back - 91 V <0.1mA R#N - 178 V 20.9mA IS,OS gnd - Drain +12 V 400mA Test of the 30 mm2 SDD Detector biasing parameters

  20. T = - 40°C, tsh=0.75ms

  21. target cooling line feed-throughs for SDD electronics port for SDD cooling vacuum chamber SDD pre-amplifier electronics lead table SDD detector chip target cell beam pipe and kaon trigger SIDDHARTA setup version 1

  22. SIDDHARTA setup version 2 SDDs array Beam pipe e- e+ Kaon trigger Cryogenic target cell

  23. Kaon stopping distribution inside hydrogen target for a toroidal setup Signal: ~ 30 times more than in DEAR Kaons stopped inside target ~ 30% (all generated) MonteCarlo simulation

  24. SIDDHARTA Kaonic hydrogen simulated spectrum MonteCarlo simulation Precision on shift ~1 eV integrated luminosity 60 pb-1 S/B = 5/1

  25. SIDDHARTA Kaonic deuterium simulated spectrum Precision on shift < 10 eV S/B = 1/4 MonteCarlo simulation integrated luminosity 100 pb-1

  26. SIDDHARTA collaboration LNF, Frascati (Italy) MPE, Garching (Germany) PNSensor, Munich (Germany) Politecnico, Milan (Italy) IMEP, Vienna (Austria) IFIN-HH, Bucharest (Romania)

  27. Conclusions Results obtained with DEAR and evaluations done for SIDDHARTA show that DAFNE represents an ideal machine for hadronic atoms research Continuing tests on detectors to obtain best performance prototype, compatible with a large area setup. Finalizing the design of the new experimental setup: front-end electronics, mechanics, cryogenics, vacuum 2006 Assembly on DAFNEand data taking

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