SIDDHARTA

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SIDDHARTA future precision measurement of
kaonic atoms at DAFNE
LNF SPRING SCHOOL "Bruno Touschek" In Nuclear,
Subnuclear and Astroparticle Physics       Frascat
i (Italy),  May 17th - 21st, 2004
Florin Sirghi
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Silicon Drift Detector for Hadronic Atom
Research by Timing Applications
SIDDHARTA
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The obtained DEAR result represents
indeed the best measurement performed on Kaonic
Hydrogen up to now BUT what we are aiming for is
few eV precision measurement of kaonic
hydrogen 1s level shift first measurement
of kaonic deuterium in order to determine the
isospin dependent KN scattering lengths at
percent level precision
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Kaonic helium measurement towards the study of
deeply bound nuclear kaonic state.Other light
kaonic atoms measurement (Li, Be).Investigate
the possibility of the measurement of other types
of hadronic exotic atoms (sigmonic
atoms).Charged kaon mass precision measurement.
SIDDHARTA Scientific Programme
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SIDDHARTA Collaboration
LNF- INFN, Frascati, Italy IMEP- ÖAW, Vienna,
Austria IFINHH, Bucharest, Romania Politecnico,
Milano, Italy Max-Planck-Institute for
Extraterrestrial Physics, Garching,
Germany PNSensor GmbH, Munich, Germany RIKEN,
Japan
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The choice of the detector

• A good X-ray detector, which preserves
• all good features of the CCD
• large active area
• quantum efficiency
• energy resolution
• linearity and stability
• Trigger capability (fast shaping times 1ms)
• for background rejection

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The classical PIN (Positive-Intrinsic-Negative)
diode detector
Entrance window
ANODE
The anode capacitance is proportional to the
detector active area
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The Semiconductor Drift Detector
Entrance window
ANODE
The electrons are collected by the small
anode, characterized 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
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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

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The integrated JFET
Detector produced at Max-Planck-Institute for
Extraterrestrial Physics, Garching, Germany
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Silicon Drift Detector performances
Quantum efficiency of a 280 mm thick SDD
55Fe spectrum measured with a SDD (5 mm2) at
10C with 0.5 ms shaping time
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Spectroscopic resolution detector comparison
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Timing with the anode signal
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Triggered acquisition
Kaontrigger
Concidencewindows
tdr max
Detectedpulses
Consideredpulses
S/B 5/1
Background reductions
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SIDDHARTA setup version 1
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SIDDHARTA setup version 2
SDDs array
Beam pipe
e-
e
Kaon trigger
Cryogenic target cell
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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
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SIDDHARTA Kaonic hydrogen simulated spectrum
MonteCarlo simulation
Precision on shift 1 eV
integrated luminosity 60 pb-1
S/B 5/1
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SIDDHARTA Kaonic deuterium simulated spectrum
Precision on shift lt 10 eV
S/B 1/4
MonteCarlo simulation
integrated luminosity 100 pb-1
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Test of the 30 mm2 SDD
Detector biasing parameters
electrode Voltage Current
R1 - 10 V 20.8mA
IGR - 18 V 0.5mA
Back - 91 V lt0.1mA
RN - 178 V 20.9mA
IS,OS gnd -
Drain 12 V 400mA
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T - 40C, tsh0.75ms
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Conclusion
Continuing tests of detectors Finalizing the
design of the new experimental setup front-end
electronics, mechanics, cryogenics, vacuum
2006 Assembly of the setup on DAFNE and data
taking