Alessandro Scordo LNF – INFN, Frascati SIDDHARTA Collaboration
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Transcript of Alessandro Scordo LNF – INFN, Frascati SIDDHARTA Collaboration
Alessandro Scordo Alessandro Scordo
LNF – INFN, FrascatiLNF – INFN, FrascatiSIDDHARTA CollaborationSIDDHARTA Collaboration
Frascati – Spring SchoolFrascati – Spring School, 12/05/08, 12/05/08 – 16/05/08 – 16/05/08
SIDDHARTA ExperimentSIDDHARTA Experiment
LNF- INFN, Frascati, ItalyLNF- INFN, Frascati, Italy
IMEP- ÖAW, Vienna, AustriaIMEP- ÖAW, Vienna, Austria
IFIN – HH, Bucharest, RomaniaIFIN – HH, Bucharest, Romania
Politecnico, Milano, ItalyPolitecnico, Milano, Italy
MPE, Garching, GermanyMPE, Garching, Germany
PNSensors, Munich, GermanyPNSensors, Munich, Germany
RIKEN, JapanRIKEN, Japan
Univ. Tokyo, JapanUniv. Tokyo, Japan
Victoria Univ., Canada Victoria Univ., Canada
SISIlicon licon DDrift rift DDetector for etector for HHadronic adronic AAtom tom RResearch by esearch by TTiming iming AApplicationspplications
SIDDHARTA ExperimentSIDDHARTA Experiment((SISIlicon licon DDrift rift DDetector for etector for HHadronic adronic AAtom tom RResearch by esearch by
TTiming iming AApplication)pplication)
1.1. High precision (High precision (~eV) m~eV) measurement of width easurement of width
and shift of Kaonic Hydrogen Kand shift of Kaonic Hydrogen K transition transition
2.2. First measurement of Kaonic DeuteriumFirst measurement of Kaonic Deuterium
Experimental Goals:Experimental Goals:
pp
ee--KK--
KK--
pp
Electronic hydrogenElectronic hydrogen KaonicKaonic hydrogenhydrogen
n=25n=25
n=2n=2
n=1n=1
2p2p-->1s (K>1s (K))X ray of interestX ray of interest
n=1n=1
HydrogenHydrogenatomatom
pp
ee--KK--
KK--
pp
Electronic hydrogenElectronic hydrogen KaonicKaonic hydrogenhydrogen
n=25n=25
n=2n=2
n=1n=1
2p2p-->1s (K>1s (K))X ray of interestX ray of interest
n=1n=1
HydrogenHydrogenatomatom
Kaonic atomsKaonic atoms
s p d fs p d f
KKkeVkeV
= = EE2p2p1s1s
E1s}
E2p
nn
44
33
22
11
KK
Kaonic atomsKaonic atoms
Shift Shift and width and width of 1s state are of 1s state are related to real and imaginary part of s-related to real and imaginary part of s-wave scattering lenght: wave scattering lenght:
Neglecting isospin simmetry breaking Neglecting isospin simmetry breaking corrections, we can write the Deser-corrections, we can write the Deser-Trueman relations [1] for kaonic Trueman relations [1] for kaonic hydrogen and deuterium:hydrogen and deuterium:
pKa
dKfmeV
dK
pKfmeV
pK
aai
aai
60122
41222
23
23
Scattering lenghts can be written in terms of the Scattering lenghts can be written in terms of the
ISOSPIN-DEPENDENT scattering lenghts:ISOSPIN-DEPENDENT scattering lenghts:
Caam
mma
IaIaa
KmN
KNdK
pK
)3(2
12
)1()0(
01
2
10
This term includes contributes due to 3 body problemThis term includes contributes due to 3 body problem
and it can be numerically calculatedand it can be numerically calculated
[1] S.Deser et al., Phys.Rev. 96 (1954) 774;[1] S.Deser et al., Phys.Rev. 96 (1954) 774;
T.L.Truemann, Nucl. Phys. 26 (1961) 57;T.L.Truemann, Nucl. Phys. 26 (1961) 57;
A.Deloff, Phys. Rev. C13 (1976) 730.A.Deloff, Phys. Rev. C13 (1976) 730.
Why SIDDHARTA?Why SIDDHARTA?
Scientific aims: Scientific aims: Scattering lenghts calculations Scattering lenghts calculations
Useful in understanding:Useful in understanding:
Chiral simmetry breaking mechanismChiral simmetry breaking mechanism Strange content of nucleonsStrange content of nucleons
DEAR ResultsDEAR Results
eVsyststat
eVsyststat
.)(39.)(111249
.)(6.)(37193
Results lead to a repulsive character of the interaction.Results lead to a repulsive character of the interaction.
((Phys. Rev. Lett. Phys. Rev. Lett. 9494, 212302 (2005) ), 212302 (2005) )
No deuterium measurement was achived, due to the too highNo deuterium measurement was achived, due to the too high
DAFNE background!!! DAFNE background!!!
Background reduction is needed!Background reduction is needed! SIDDHARTASIDDHARTA
Most precise measurement up to now!Most precise measurement up to now!
Background in DAFNEBackground in DAFNE
SYNCHRONOUS: It’s associated to K production, wich means SYNCHRONOUS: It’s associated to K production, wich means decaysdecays
It can be considered an hadronic backgroundIt can be considered an hadronic background
ASYNCHRONOUS: It’s dued to final products of electromagnatic cascade wich is produced in DAFNEASYNCHRONOUS: It’s dued to final products of electromagnatic cascade wich is produced in DAFNE
and to other materials wich are in the setup and that are activates from particle lost from the beam. and to other materials wich are in the setup and that are activates from particle lost from the beam.
It is also dued to Touschek effect (interaction between particles of the same bunch)It is also dued to Touschek effect (interaction between particles of the same bunch)
The main contribute is the asynchronous one The main contribute is the asynchronous one
wich can be reducted using a trigger.wich can be reducted using a trigger.
DEAR detectors were CCD (Sylicon Pixel Type), DEAR detectors were CCD (Sylicon Pixel Type),
Non triggerable (too slow)Non triggerable (too slow)
In order to measure shift and width of kaonic hydrogen and deuterium KIn order to measure shift and width of kaonic hydrogen and deuterium K line with a fewline with a few eV precision, we need a S/B ratio near unity. DEAR case eV precision, we need a S/B ratio near unity. DEAR case was~ 1/70was~ 1/70
Silicon Drift DetectorsSilicon Drift Detectors : :
-- High efficiency in a wide energy range (from few hundreds eV to 15 KeV)High efficiency in a wide energy range (from few hundreds eV to 15 KeV)
- - Good energy resoultion, (~150 eV at 110 K at 6 keV )Good energy resoultion, (~150 eV at 110 K at 6 keV ) - Big surface (~cm- Big surface (~cm22), wich provide big detected areas with few front end channels), wich provide big detected areas with few front end channels- High rates capability- High rates capability
- - Very fast reading, wich means triggerabilityVery fast reading, wich means triggerability
SIDDHARTASIDDHARTA and SDDs and SDDs
SDDSDDAn electric field leads electrons, generated by particle flow (x-Rays or ionizing) to a small collector anode. At the same time holes are immediately removed from electron’s path by cathode strips.
First time used as spectroscopy (energy) detectors! First time used as spectroscopy (energy) detectors!
Designed for this experimentDesigned for this experiment
DetectorsDetectors
Target cellTarget cell
Cell is made of Kapton, a plastic material with no elements
witch could have transition lines near 6 KeV
Trigger systemTrigger system The trigger system has to The trigger system has to
provide the DAQ start and provide the DAQ start and monitorize Kaon flux wich enter monitorize Kaon flux wich enter the setupthe setup
Kaon produced in back to back Kaon produced in back to back configurationconfiguration
Day-One Setup on DAFNE, 22 Jan. Day-One Setup on DAFNE, 22 Jan. 20082008
SIDDHARTA SetupSIDDHARTA Setup
SIDDHARTA
Kaon monitor
lead shield
DAY1 SetupDAY1 Setup
DAY1 SetupDAY1 Setup
DAY1 SetupDAY1 Setup
Before installing the detector and target system
Installation of SIDDHARTA into final frame
Installing cables and SDD detector
signal and bus cables
HV + LV distribution board
SDDs with pre-amplifierboard
Working group
Day-One setupDay-One setup
Tuning of setup / Tuning of setup / optimisationoptimisation 100 pb100 pb-1-1
Precision measurement of kaonic hydrogenPrecision measurement of kaonic hydrogen 400 pb400 pb-1-1
(at the percent level)(at the percent level)
Measurement of kaonic deuteriumMeasurement of kaonic deuterium 600 pb600 pb-1-1
(first measurement)(first measurement)
Further options:Further options:
Additional kaonic deuterium measurementAdditional kaonic deuterium measurement
Kaonic helium studies (Kaonic helium studies (33He and He and 44He)He)
other light kaonic atoms e.g. Li, Be…other light kaonic atoms e.g. Li, Be…
Beam time requestBeam time request