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The HADES Spectrometer Special requirements RICH setup Mirror Window Photon detector Preliminary results from 12 C- 12 C [1.0 AGeV] Outlook. The HADES RICH High Acceptance Di-Electron Spectrometer. For the HADES Collaboration. Motivation. - PowerPoint PPT Presentation
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RICH 2002 @ PylosR. Gernhäuser (TU-München)
The The HADESHADES RICH RICH High High AcceptanceAcceptance Di-Electron Spectrometer Di-Electron Spectrometer
• The HADES Spectrometer• Special requirements • RICH setup
– Mirror– Window– Photon detector
• Preliminary results from 12C-12C [1.0 AGeV]
• Outlook
For the HADES Collaboration
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Motivation
SIS / GSI : heavy ion, proton,pion beams
0 3 0 T 80 MeV
HADES: systematic dilepton spectroscopy• meson prod. in A / pA : T = 0 MeV
• meson prod. in p / pp : 0 , T = 0 MeV
• meson prod. in AA : T = 80MeV
Properties of hadrons in strong int. matter: M, vs , B, T, V
Vector meson , , spectral functions measurements
Hadron’s structure: VDM, Form factors, vector meson-nucleon inter.
Dalitz and two-body decays, pN, N reactions
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Magnet SC. toroid ( 6 coils) in
Lepton Identification RICH C4F10 + gas Phot. Det.
CsI - cathode
META TOF scintillator wall + Pre-Shower detector
p/ identification META and tracking
Tracking p – measurement, vertex
reconstruction
MDC Drift chambers x ~ 80 m ()
High High AcceptanceAcceptance Di-Electron Spectrometer Di-Electron Spectrometer
RICH 2002 @ PylosR. Gernhäuser (TU-München)
experiment hall CsI based MWPC
with gas radiator
Design ConstraintsDesign Constraints
101
20det thr
radlNN
cmlrad 40~;10thr
beam intensity108/s
central collisions105/s
ch. particles < 200/evt
lepton pairs 103/s
Meson Mass (MeV/c2)
(MeV/c2)
dominant decay
e+e-/
769 150 2 4.5 10-5
783 8.5 2 7.1 10-5
1019 4.5 2K 2.9 10-4
N0 ~ 100
fast
high granularity
hadron blind
Trigger device
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Fast Photon DetectorFast Photon Detector
Pad cathode
Anode w ires 20 m
Cathode w ires 50 m
G ate w ires 20 m
2 ,4m m
3,0m m
7,0m m
6,6m m
1,65m m
3,3m m
U =+2,5 kVanod
U =0Vcath
U =500Vgate
U =0Vpcath
e-
UV
Ph
oto
n
PC B
CsI+RSGconnector
CH 4
6 sector shaped MWPCs with 2.4 mm gap 5*104 < gain < 1*105 @ 2450V signal coupling on several pads solid CsI photon converter on special
substrate material (RSG)
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Photon Detector ShapePhoton Detector Shape
– 4712 pads/sector, individually shaped
4.5 mm < y < 7 mm, x = 6.6mm– GASSIPLEX based FE-electronics
– 10s conversion time
rin
g r
adiu
s [p
ads]
polar angle [°]
A trigger device for ~ 1 particles
constant ring radius
RICH 2002 @ PylosR. Gernhäuser (TU-München)
MirrorMirrorØ 150 cm, R = 871 mm, d = 2 mmPoly – Carbon
–rad. length X0 = 28cm
–18 panels polished
Float Glass
–rad. length X0 = 14cm
–6 panels, molded
J. Friese (Saturday afternoon)
RICH 2002 @ PylosR. Gernhäuser (TU-München)
CaFCaF22 - Window - Window
Crystal window Ø = 140cm
64 CaF2 hexagonal crystals
Ø = 20cm,
d = 5mm p < 5mbar
RICH 2002 @ PylosR. Gernhäuser (TU-München)
The Eye of HADESThe Eye of HADES
Commissioning in 2001
Full HADES Setup (! outer tracking)
108 events C – C 1-2 AGeV
400m Carbon fiber
radiator shell
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Typical PatternTypical PatternData Nov. 2001, C - C @ E = 1 AGeV
RICH 2002 @ PylosR. Gernhäuser (TU-München)
RICH online Lepton ID RICH online Lepton ID
• Ring recognition algorithm (fixed radius)– Ring radius (+) inner and outer veto
regions (-)– Threshold on positive and negative
quality parameters
Typical AlgorithmJ. Lehnert (Sunday morning)
Reference of qualitative and quantitative
detector response needed
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Calibration MeasurementCalibration Measurement(OEM online efficiency measurement)(OEM online efficiency measurement)
beam
calibrated light source!Photons produced by 600 AMeV 12C beam particles passing two different solid radiatorspad plane
tank
window
mirror
tank shell
target
radiator gas
detector gas
beam
field plane
photon detector
RICH 2002 @ PylosR. Gernhäuser (TU-München)
OEM resultsOEM results
N0 > 90
Radial distribution of photons represents spectral sensitivity of the detector
L. Fabbietti (Sunday morning)
200 nm
145 nm
200 nm
163 nmsingle 12C hit
beam pipe shadow
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Dominant Dilepton Dominant Dilepton SourceSourcess
e+
e-Conversion
e+
e-
0
Dalitz
7 M events C+C @1.0 AGeV
opening angle [°]
cut on opening angle
combinatory pairs negligible
RICH 2002 @ PylosR. Gernhäuser (TU-München)
The Ring PropertiesThe Ring PropertiesRings from single leptons
e+e- pair with 1 track/ring
Th. Eberl (Sunday afternoon)
momentum [MeV/c]
po
lar
an
gle
[°]
Efficiency of Ring recognition
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Lepton ID with TOF and RICHLepton ID with TOF and RICH
TOF[ns]
preliminary
Data: Nov01C-C 2.0 AGeV
q*m
om
entu
mq
*mo
men
tum
RICH 2002 @ PylosR. Gernhäuser (TU-München)
Lepton ID online -Lepton ID online - offlineoffline
Full HADES simulation
and data analysis
RQMD ev.generator
q* momentum [e*MeV/c]
Ne/N
+pr
elim
inar
y
Correlation of rings found by hardware or software image
processing
A. Toia (Sunday morning)
RICH 2002 @ PylosR. Gernhäuser (TU-München)
OutlookOutlook
•HADES comes into operation
(e/p sep., LVL2 trig., tracking)
•3 MDC layer will be completed this summer (p3% for /)Phase I (2002 – 2003) : (acc. proposals S200 ,S262)
Continuum below M inv < 600 MeV/c2 ; 0 Dalitz in C+C (more statistics)
High statistics e+,e- production in HI reactions C+ C @ 1 – 2 AGeV
(compare to DLS)
e+e- production in - p - p @ 0.8 – 1.3 GeV/c
(below and above threshold for
e+e- pair acceptances pp pp pp e+e-