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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 - PowerPoint PPT Presentation
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SIDDHARTA: the future of exotic atoms SIDDHARTA: the future of exotic atoms research at DAresearch at DANENE
SiSilicon licon DDrift rift DDetector foretector for H Hadronic adronic
AAtom tom RResearch by esearch by TTiming iming AApplicationspplications
DAFNE-2004: Physics at meson factories
Mihai IliescuMihai IliescuINFN-LNF
10-06-2004
The goal of KH and KD measurementsThe goal of KH and KD measurements
a few eVa few eV determination of both shift and width of the 1s determination of both shift and width of the 1s
level induced by the strong interaction in the Kp and KDlevel induced by the strong interaction in the Kp and KD
atomic systemsatomic systems
The main feature to deal with, in order to obtain the The main feature to deal with, in order to obtain the
desired accuracy, is the desired accuracy, is the S/B ratio.S/B ratio.
This requires to pass from This requires to pass from 1:701:70 (KH today)(KH today)
to at least to at least 1:1 (KH)1:1 (KH) and and 1:5 (KD-first time)1:5 (KD-first time)
Experimental requirements Experimental requirements for the measurementsfor the measurements
a triggerable,a triggerable, large area, high resolution, high efficiency large area, high resolution, high efficiency
in the energy region of interest (1-20 KeV) in the energy region of interest (1-20 KeV)
X-ray detectorX-ray detector
Triggerable SDDsTriggerable SDDs
A large area Silicon Drift Detector (SDD), equipped withA large area Silicon Drift Detector (SDD), equipped with
trigger electronics, presently under developmenttrigger electronics, presently under development
(SIDDHARTA project), satisfies the experimental (SIDDHARTA project), satisfies the experimental
requirementsrequirements
Working principles of the SDDWorking principles of the SDD
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,characterised 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
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
Performances of the SDDsPerformances of the SDDs
Quantum efficiency of a 300 m thick SDD 55Fe spectrum measured with a SDD (5 mm2) at –10°C with 0.5 s shaping time
Silicon Drift Detector QE and resolution
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 - 1
FWHMmeas of monoenergetic emission line 5.9 keV1cm2 detector at 150 K
SDD FWHM=140eV shap =1sSi(Li) FWHM=180eV shap =15s PIN diode FWHM=750eV shap =20sCCD FWHM=140eV frame= ~ s
Spectroscopic resolution: detector comparison - 2
10-2
10-1
100
101
10-8
10-7
10-6
10-5
Area (cm2)
Tdr
ift (
s)
Drift time vs. Active area
A=0.1cm2 Tdrift = 70ns
A=0.5cm2 Tdrift =350ns
A= 1cm2 Tdrift =700ns
With: = 2k/cmH = 450m
Timing resolution with SDD
2
2
HN
A
qTdrift
Dn
s
hIK
IA
h
tIA
tdr max
Timing with the anode signal
Triggered acquisition
Kaontrigger
Concidencewindows
Detectedpulses
Consideredpulses
Kaon trigger X-ray pulseBackground pulse
Tdr max
Background reduction with triggered acquisition
Machine Background
= number of detected kaons per detected K X-ray = 103
Br = background rate = 103 events/s over 200 cm2, full
spectrum (1-20 KeV) -->50 Hz/1KeV
Tw = gate window
Tw = x Tdrift max = 103 x 1 s = 1ms
B = Br x Tw = 50 s-1 x 10-3 s = 5 x 10-2
S/B=20/1 negligibleHadronic background (Kp- interaction, synchronous)
preliminary simulation (typical SDD thickness 300 m)
S/B = 5/1 (KH), 1/4 (KD)
SDD test setup electronics layout
SDD canister
Scintillators
P.S.
Temp.control
7 Shapers, peak stretchers& discriminators
DAQ
Trigger(NIMlogic)
NIM2TTL
AmplifiedSDD output signal
Trigger signal
Stretcher reset
Analog output
Discrim. outputShapers control motherboard
HVcontrol
Test of the 30 mm2 SDD
CurrentVoltageelectrode
400A+12 VDrain
-gndIS,OS
20.9A- 178 VR#N
<0.1A- 91 VBack
0.5A- 18 VIGR
20.8A- 10 VR#1
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
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
SIDDHARTA collaborationSIDDHARTA collaboration
LNF, Frascati (Italy)LNF, Frascati (Italy)
MPE, Garching (Germany)MPE, Garching (Germany)
PNSensor, Munich (Germany)PNSensor, Munich (Germany)
Politecnico, Milan (Italy)Politecnico, Milan (Italy)
IMEP, Vienna (Austria)IMEP, Vienna (Austria)
IFIN-HH, Bucharest (Romania)IFIN-HH, Bucharest (Romania)
Conclusions
Results obtained with DEAR and evaluations done for Results obtained with DEAR and evaluations done for SIDDHARTA show that DASIDDHARTA show that DANE represents an ideal NE represents an ideal machine for hadronic atoms researchmachine for hadronic atoms research
Continuing tests on detectors to obtain best performance Continuing tests on detectors to obtain best performance prototype, compatible with a large area setup.prototype, compatible with a large area setup.
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
20062006Assembly on DAAssembly on DANENE and data takingdata taking
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