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SIDDHARTA
future precision measurement of kaonic atoms at DANE
Florin Sirghi
LNF SPRING SCHOOL "Bruno Touschek"
In Nuclear, Subnuclear and Astroparticle Physics
Frascati (Italy), May 17th - 21st, 2004
SiSilicon licon
DDrift rift
DDetector foretector for
HHadronic adronic
AAtom tom
RResearch by esearch by
TTiming iming
AApplicationspplications
The obtained DEAR result:
represents indeed the best measurement performed on Kaonic Hydrogen up to now
BUTwhat we are aiming for is
few eV precision measurement of kaonic kaonic hydrogenhydrogen 1s level shift
first measurement of kaonic deuteriumkaonic deuterium
in order to determine the isospin dependent KN in order to determine the isospin dependent KN scattering lengths at percent level precisionscattering lengths at percent level precision
SIDDHARTA Scientific Programme
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 Collaboration
LNF- INFN, Frascati, Italy
IMEP- ÖAW, Vienna, Austria
IFIN–HH, Bucharest, Romania
Politecnico, Milano, Italy
Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany
PNSensor GmbH, Munich, Germany
RIKEN, Japan
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 – 1s) for background rejection
The classical PIN (Positive-Intrinsic-Negative) diode detector
The anode capacitance is proportional to the detector active area
n
n+
p+ -Vcc
ANODE
Entrance window
n
n+
p+ -V cc
p+
The Semiconductor Drift Detector
AnodeThe electrons are collected by the small anode,characterized by a low output capacitance.
Advantages: very high energy resolution at fast shaping times, due to the small anode capacitance, independent of the active area of the detector
Entrance window
ANODE
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
The integrated JFET
Detector produced at Max-Planck-Institute for Extraterrestrial Physics, Garching, Germany
Quantum efficiency of a 280 m thick SDD 55Fe spectrum measured with a SDD (5 mm2) at –10°C with 0.5 s shaping time
Silicon Drift Detector performances
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1100
200
300
400
500
600
700
800
A (cm-2)
FW
HM
(eV
)
SDD PIN Si(Li) 150 K 5.9 keV line
PIN Tsh=20us
Si(Li) Tsh=20us
SDD Tsh=1us
Spectroscopic resolution: detector comparison
hIK
IA
h
tIA
tdr max
Timing with the anode signal
Triggered acquisition
Kaontrigger
Concidencewindows
Detectedpulses
Consideredpulses
Kaon trigger X-ray pulseBackground pulse
dr max
Background reductions S/B = 5/1
beam pipeand kaon trigger
vacuum chamber
feed-throughs forSDD electronics
port forSDD cooling
targetcooling line
SDD pre-amplifierelectronics
SDD detector chip
target cell
lead table
SIDDHARTA setup version 1SIDDHARTA setup version 1
Beam pipe
Cryogenic target cellKaon trigger
SIDDHARTA setup version 2SIDDHARTA setup version 2
e+
e-
SDDs array
Kaon stopping distribution inside hydrogen target for a toroidal setup
Kaons stopped inside target ~ 30% (all generated)
Signal: ~ 30 times more than in DEAR
SIDDHARTA Kaonic hydrogen simulated spectrum
Precision on shift ~1 eV
integrated luminosity60 pb-1
S/B = 5/1
SIDDHARTA Kaonic deuterium simulated spectrum
Precision on shift < 10 eV
integrated luminosity100 pb-1
S/B = 1/4
Test of the 30 mm2 SDD
electrode Voltage Current
R#1 - 10 V 20.8A
IGR - 18 V 0.5A
Back - 91 V <0.1A
R#N - 178 V 20.9A
IS,OS gnd -
Drain +12 V 400A
Detector biasing parameters
5000 5500 6000 6500 7000Energy [keV]
0
1000
2000
3000
4000
Cou
nts
139 eV FW H M T = - 40°C, tsh=0.75s
Conclusion
Continuing tests of detectorsContinuing tests of detectors
Finalizing the design of the new experimental setup:Finalizing the design of the new experimental setup:front-end electronicsfront-end electronics, mechanics, cryogenics, vacuummechanics, cryogenics, vacuum
20062006
Assembly of the setup on DAAssembly of the setup on DANENE and data takingdata taking
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