dearexperiment da ne exotic atoms research lnf spring school bruno touschek in nuclear, subnuclear...
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DEAR DEAR eXperimenteXperiment
DDAANE NE EEXOTIC XOTIC AATOMS TOMS RRESEARCHESEARCH
LNF SPRING SCHOOL “Bruno Touschek”In Nuclear, Subnuclear and Astroparticle Physics
M.Iliescu, May 22, 2003 Frascati (Italy)
M. Augsburgerj, G. Beerb, S.Biancoc, A.M. Bragadireanuc,i,M. Bregantd, W.H. Breunlicha, M. Cargnellia, D. Chatellardj,J.-P. Eggerk, F.L. Fabbric, B. Gartnera, C. Guaraldoc, R.S. Hayanof,M. Iliescuc,i, T. Ishiwatarie, K.Itahashie, T.M. Itol, M. Iwasakie,R. Kinga, P. Knowlesj, T. Koikeh, B. Laussc,a, V. Lucherinic, L. Ludhovaa, J. Martona, E. Milottid, F. Mulhauserj, S.N. Nakamurag,C. Petrascuc,i, T. Pontai, A.C. Sandersonb, L.A. Schallerj, L. Schellenbergj, H. Schneuwlyj, R. Sekil,m, D. Sirghic,i, F. Sirghic,i D. Tomonoe, T. Yoneyamae, E. Zavattinid, J. Zmeskala
a Institute for Medium Energy Physics, Austrian Academy of Sciences, Austria b Univ. of Victoria, Dept. of Physics and Astronomy, Canada c Laboratori Nazionali di Frascati dell'INFN, Italy d Univ. degli Studi di Trieste, Dip. di Fisica and INFN Sezione di Trieste, Italy e Tokyo Institute of Technology, Japan f Univ. of Tokyo, Dept. of. Physics, Japan g Inst. of Physical and Chemical Research (RIKEN), Japan h KEK, High Energy Accelerator Research Organization, Japan i Inst. of Physics and Nuclear Engineering - " Horia Hulubei ", Romania j Univ. de Fribourg, Inst. de Physique, Switzerland k Univ. de Neuchâtel, Inst. de Physique, Switzerland l W.K.Kellogg Radiation Laboratory, California m Department of Physics and Astrophysics, California State University
The DEAR Collaboration The DEAR Collaboration
The determination of the isospin dependent KN scattering lengths through a few percent measurement of the shift and the width of the K line of kaonic hydrogen and the first measurement of kaonic deuterium
dKdKdK
pKpKpK
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)fm eV (60122
)fm eV (41222
1-23
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)(2
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nKpK
kN
kNdK
pK
(Deser - Trueman)
The objective of DEARThe objective of DEAR
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KN
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A measurement of KN scattering lengths at the percent level would enable the determination of the KN sigma terms with a precision
of about 20% or less, to be compared with the 70% uncertainty of the present estimates.
Sigma terms are directly connected with the chiral symmetry breaking part of the strong interaction Hamiltonian.
Also, the fraction of strangeness content in proton
can be derived with better accuracy from KN and N sigma terms (Jaffe ‘87)
The implications of DEAR resultsThe implications of DEAR results
Kaonic Hydrogen cascade
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n
4
3
2
1
s p d f
KkeVK
Strong Interaction causes:
energy shift compared to pure Coulomb
interaction
level width due to the short lifetime caused by Kaon capture
What DEAR measuresWhat DEAR measures
CCD-55 detectors positioning in the cryogenic setup
CCD-55 detectors positioning in the cryogenic setup
e-e+
K+
IPD2
D1
D7
D8
A1
A2
A3
A4
A5
A6
A7
A8
D3
D4
D6
D5
K-
Charge-Coupled Devices are solid state detectors with a pixel structure. They are excellent detectors for soft X rays in the high background environment of a collider, for the powerful rejection capability (given by the topology of X-ray events -single pixels-), together with a very good energy resolution, high efficiency and large active area.
Background suppression by single pixel selection
X-ray
Chargedparticle
Active depletion (30m)Substrate
How DEAR measures KH transitions: X-ray spectroscopic CCDsHow DEAR measures KH transitions: X-ray spectroscopic CCDs
Target and cryogenic
setup layout
Target and cryogenic
setup layout
Operating conditions:
20 K, 3 bar (~40 bar NTP)
Fiber-glass reinforced kapton targetFiber-glass reinforced kapton target
Requirements: high compaction to allow optimal shielding and light materials to reduce Bremsstrahlung
- fiberglass frames- cooling system mounted on the top- thin Al cold finger - reduced diameter of the socket group and, consequently, of the vacuum chamber
CCD mounting,cryogenics andon-cell electronics
CCD mounting,cryogenics andon-cell electronics
Pb walls
Pb platform
Vacuum jacket shielding
Overall shielding factor of the DEAR interaction region ~ 100
Target
e+ e-
Interaction point
Pb collimators
DEAR shieldingDEAR shielding
-Resolution and L.N. characteristics:thermal noise FWHM of about 15 eVenergy resolution at 5.9 keV (Mn K line) 136 eV, charge transport correction not applied
-Linearity: ~ 10-4
-Instability: below 4 eV/month -Charge transport inefficiency: ~10-6
-Synchronous readout of 16 large area detectors (CCD55-30)-Data flow 3264 MB/sec-Dual bus real-time system equipped with N.I. boards-Injection synchronization-Software dual slope integration
CCD55 new DAQ new amp Mn KK136 eV FWHM
0
500
1000
1500
2000
2500
0 200 400 600 800 1000
Channels
Cou
nts
DAQ performanceDAQ performance
-500 50000
200
400
600
800
1000
Shift (eV) [
Wid
th (
eV)
[
Dav
ies
et a
l, 19
79
Izyc
ki e
t al,
1980
Bir
d et
al,
1983
Constant Scattering LengthK-MatrixPotential ModelCloudy Bag ModelConsituent Quark Model
Iwas
aki e
t al,
1997
KpX
DEARpreliminary
result
State of art of
Kaonic Hydrogen
measurement
and
theoretical
predictions