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Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 11
STATUS AND CHARACTERIZATION STATUS AND CHARACTERIZATION OF COMPASS RICH-1OF COMPASS RICH-1
on-line image from on-line image from RICH-1 event RICH-1 event displaydisplay
INSTITUTIONS:INSTITUTIONS:Trieste, INFN and University, ICTPTrieste, INFN and University, ICTPTurin, INFNTurin, INFN and Universityand UniversityBielefeld, UniversityBielefeld, UniversityCERN supportCERN support
OUTLINE:OUTLINE:
RICH-1 in COMPASSRICH-1 in COMPASS recall the main characteristiucs recall the main characteristiucs
(4 talks in Pylos !)(4 talks in Pylos !) hardware newshardware news detector performancesdetector performances
S. Dalla TorreS. Dalla TorreINFN – TRIESTEINFN – TRIESTE
on behalf of the COMPASS RICH groupon behalf of the COMPASS RICH group
Playa del Carmen, 30/11-6/12/2004 - 5Playa del Carmen, 30/11-6/12/2004 - 5thth RICH Workshop RICH Workshop
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 22
With the muon beam With the muon beam **
Gluon Polarization Gluon Polarization G/GG/G
transverse spin distribution transverse spin distribution
functions functions TTqq (x) (x)
Flavor dependent polarizedFlavor dependent polarized
quark helicity densities quark helicity densities q(x)q(x)
physicsphysics
Diffractive VM-ProductionDiffractive VM-Production
** Data collected Data collected
COMPASSCOMPASS
With hadron beamsWith hadron beams
Primakoff-Reactions Primakoff-Reactions **- polarizability of and K
glueballs and hybridsglueballs and hybrids
charmed mesons and baryonscharmed mesons and baryons- semi-leptonic decays- double-charmed baryons
understanding theunderstanding the non-perturbative non-perturbative physics physics of the nucleonof the nucleon
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 33
SM1 dipoleSM1 dipole
SM2 dipole
Polarised Target
HCAL1
Muon-filter1,MW1
Micromegas,DC,SciFi
Gems,SciFi,DCs,straws
MWPC Gems Scifi
trigger-hodoscopes
Silicon
COMPASS COMPASS SPECTROMETERSPECTROMETER
RICH_1
BMS
Gem_11
ECAL2,HCAL2
straws,MWPC,Gems,SciFi
straws
Muon-filter2,MW2
DW45
SciFi
Veto
Beam: 160 GeV µ+
2 . 108 µ/spill
(4.8 s/16.2s)
P ~ 80%
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 44
COMPASS RICH-1 - DESIGNCOMPASS RICH-1 - DESIGN
from the experiment design:from the experiment design:
hadron PID up to ~50 GeV/chadron PID up to ~50 GeV/c LARGE acceptance (large LARGE acceptance (large
size): size):
H: 500 mrad H: 500 mrad
V: 400 mrad V: 400 mrad
able to stand trigger rates able to stand trigger rates
up to 100 KHzup to 100 KHz beam rate up to 10beam rate up to 1088 Hz Hz minimize materialminimize material
++ detector designed in 1996 detector designed in 1996
radiator:radiator:
CC44FF1010
5 m
5 m
6 m6 m3 m3 m
photon photon detectors:detectors:CsI MWPCCsI MWPC
mirrormirrorwallwall
vesselvessel
radiator:radiator:
CC44FF1010
detection of detection of VUVVUV photons photons(165-200 nm)(165-200 nm)
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 55
PHOTON DETECTIONPHOTON DETECTIONphoton photon
detectorsdetectors (PD) : (PD) :
5.3 m5.3 m22 MWPCs MWPCs
(8 chambers)(8 chambers)
with with CsI CsI
photocathodephotocathode
read-out:read-out:
84,000 analog84,000 analog
read-out ch.sread-out ch.s
with extended with extended
local intelligencelocal intelligence
MWPCs with MWPCs with
CsI photocathodesCsI photocathodes
2 CsI 2 CsI photocathodes,photocathodes,60 x 60 cm60 x 60 cm2 2 eacheach
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 66
photocathodephotocathodestoringstoring
glove box to glove box to handle handle photocathodesphotocathodes
photocathode photocathode transportation transportation systemsystem
MWPCs WITH LARGE SIZE MWPCs WITH LARGE SIZE PHOTOCATHODES, PHOTOCATHODES, COMPASS EXPERIENCECOMPASS EXPERIENCE
CsI: hygroscopicCsI: hygroscopic,,water degrades QEwater degrades QE never never exposed to airexposed to air(max 50 ppm O(max 50 ppm O2 ,2 ,
routinely: 10 ppm)routinely: 10 ppm)
marble tablemarble table with x,y with x,y movement and microscopemovement and microscopeto solde to solde anode wireanode wire and for and fordimensional checksdimensional checks (gaps, (gaps, planarity within 100 planarity within 100 m)m)
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 77
PHOTON DETECTORs PHOTON DETECTORs behaviour in the behaviour in the
experimentexperiment
wire defect,wire defect,diameter 20 diameter 20 mm
some PDs exhibit some PDs exhibit electrical instabilities electrical instabilities when when exposed to radioactive ratesexposed to radioactive rates (*)(*),,
LONG RECOVERY TIME ! (~ 1 d)LONG RECOVERY TIME ! (~ 1 d)
Instabilities related toInstabilities related to – local tiny defects – local tiny defects
2001 - 2 good PDs / 8 2001 - 2 good PDs / 8 2002 - 5 good PDs / 82002 - 5 good PDs / 82003, 2004 – segmented HV supply: 2003, 2004 – segmented HV supply: 97% MWPC surface good 97% MWPC surface good
(*) with (*) with beams :beams : MIP flux : ~ 5 x 10MIP flux : ~ 5 x 1055 / s / m / s / m2 2 (similar for all PDs)(similar for all PDs) ph. flux : up to 3 x 10ph. flux : up to 3 x 1055 / s / cm / s / cm2 2
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 88
RICH-1 mirror systemRICH-1 mirror system‘‘VUV mirror wallVUV mirror wall’, ’,
21 m21 m22,116 mirrors,116 mirrors
radius: 6.6 mradius: 6.6 m
average on 126 mirror average on 126 mirror units units at productionat production
2000 = @ COATING2000 = @ COATING
refl
ecta
nce
refl
ecta
nce
wave lengthwave length
reflectance stable in timereflectance stable in time
20020022
20020011
20020000
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 99
MIRROR WALL MECHANICS:MIRROR WALL MECHANICS:light, stiff and adjustablelight, stiff and adjustable
mirror wall mechanics, mirror wall mechanics, assembledassembled
the elements of this the elements of this modular structuremodular structure
mirror wall mirror wall mechanics, mechanics, assembling assembling
assembly jigassembly jig
mirror rear sidemirror rear side
individual individual mirror supportmirror support
regulationregulationfor angular for angular alignment,alignment,2 orthog. 2 orthog. movementsmovements
THICKNESSTHICKNESSmechanics: mechanics: 2.5 % X2.5 % X0 0
mirrorsmirrors ~5.5 % X ~5.5 % X0 0
STABILITY:STABILITY:after an initial deformation after an initial deformation ~1 mrad, stable: 0.1 mrad ~1 mrad, stable: 0.1 mrad
over ~ 3.5 yover ~ 3.5 y
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1010
Gas System for:Gas System for:• P constant +/- 0.1 mbar P constant +/- 0.1 mbar to limit to limit P on - P on - vessel windowsvessel windows quartz platesquartz plates He beam pipeHe beam pipe• gas filtering (remove Hgas filtering (remove H22O, OO, O22 ) )• filling with / recovering Cfilling with / recovering C44FF1010
RICH-1 CRICH-1 C44FF1010 GAS GAS SYSTEMSYSTEM
PLC and PLC and electrical electrical installationinstallation compressors compressors
filtersfilters
liquidliquidstoragestoragetanktank
liquifierliquifier
vesselvessel
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1111
PRESENT (>2002) GAS PRESENT (>2002) GAS PERFORMANCESPERFORMANCES
gas (atm. P) gas (atm. P)
leak rate = 90 l/dleak rate = 90 l/d
extremely reduced leak rateextremely reduced leak ratevessel volume ~ 85 mvessel volume ~ 85 m33
total o-rings : ~ 100 mtotal o-rings : ~ 100 m
very good transparency very good transparency (better than design)(better than design)-gas cleaning, see O. Ullaland’s talkgas cleaning, see O. Ullaland’s talk-on-line filters, separate functions:on-line filters, separate functions:
-Cu catalyst, ~ 40Cu catalyst, ~ 4000C for OC for O22
-5A molecular sieve, ~ 105A molecular sieve, ~ 1000C for HC for H22OO
transmission transmission through 1,87 m,through 1,87 m,corresponding to:corresponding to:
HH22O:O: ~1 ppm~1 ppm, ,
OO2: 2: ~3 ppm~3 ppm
typicaltypical
wavelength (nm)wavelength (nm)
tran
smis
sio
ntr
ansm
issi
on
CC44FF1010 : N2 = 95 : 5 : N2 = 95 : 5stabile !stabile !
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1212
PREDICTING ON-LINE (n-1)PREDICTING ON-LINE (n-1)
[(n-1)[(n-1)measmeas – (n-1) – (n-1) calcal] / (n-1)] / (n-1)
(n-1) (n-1) calcal from measured P, T from measured P, Tcontinuous linecontinuous line
(n-1) (n-1) measmeas from off-line data analysis from off-line data analysisredred dots dots
prediction at ‰ level prediction at ‰ level
to allow quasi-online data processing, a must: to allow quasi-online data processing, a must: COMPASS data rate = 3 TB/dayCOMPASS data rate = 3 TB/day
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1313
RICH-1 RAW RICH-1 RAW INFORMATIONINFORMATION
an event, an event, calibration runcalibration run
low intensity: low intensity: 101077/sec/sec
an event, an event, standard run standard run
nominal intensity: nominal intensity: 4 x104 x1077/sec/sec
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1414
RICH-1 CENTRAL REGION RICH-1 CENTRAL REGION
0.4
0.6
0.8
1
102
103
104
screens-pipe-hole
screens-REDpipe-NOhole
NOscreens-pipe-hole
screens-NOpipe-hole
NOscreens-NOpipe-hole
Noscreens-NOpipe-Nohole
solid-mirror-wall
Distance from Beam (mm)Distance from Beam (mm)
Effi
cien
cy M
onit
or
Effi
cien
cy M
onit
or
PID efficiency PID efficiency fromfromMonteCarlo MonteCarlo (beam halo off)(beam halo off)
2 combinated effects: - beam halo2 combinated effects: - beam halo - central dead zones - central dead zones
all dead zonesall dead zones
only photon detector only photon detector dead zones dead zones
photons generatedphotons generated
by the beam haloby the beam halo
overlap of event images overlap of event images
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1515
““SINGLE PHOTON” SINGLE PHOTON” PERFORMANCES PERFORMANCES
hit hit (mrad)(mrad)
ring ring (m
rad)(m
rad)
all particlesall particles
selecting particles according to polar selecting particles according to polar
angle and producing angle and producing ringring slices slices information on:information on:• resolutionresolution• number of detected photons number of detected photons • backgroundbackground
exampleexample
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1616
NUMBER OF PHOTONS NUMBER OF PHOTONS
n. of ph.s n. of ph.s
background background
rings with < 5 ph.s rings with < 5 ph.s not reconstructednot reconstructed
fit above 36 mradfit above 36 mrad
adding up regions 3-6adding up regions 3-6
particleparticle<30 mrad<30 mrad
30-60 mrad30-60 mrad
120-150 mrad120-150 mrad 150-180 mrad150-180 mrad
90-120 mrad90-120 mrad 60-90 mrad60-90 mrad
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1717
IS THE NUMBER OF IS THE NUMBER OF PHOTONS UNDERSTOOD ? PHOTONS UNDERSTOOD ?
Very low beam intensity ~ 4106/spillthreshold at 3 HV = 2000 V eff. Nph ~ 21
expected: 22
<p>=6.3 <p>=6.5
<nPH>=21.3 - 3
<nPH>=20.5 - 3
ring centres ring centres of the selected of the selected particles particles
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1818
RICH-1 RESOLUTIONRICH-1 RESOLUTION
measured from measured from reconstructed ringsreconstructed rings
RIN
GR
ING (
mra
d)
(m
rad
)
COMPARISON OF COMPARISON OF RING RESOLUTIONRING RESOLUTIONDIRECTLY DIRECTLY MEASURED MEASURED (reconstructed (reconstructed rings) AND rings) AND CALCULATEDCALCULATED FROM SINGLE FROM SINGLE PHOTON RESOLUTION:PHOTON RESOLUTION:FULL DETECTOR UNDERSTANDINGFULL DETECTOR UNDERSTANDING
single photon resolutionsingle photon resolution
ph
oto
n
ph
oto
n (
mra
d)
(m
rad
)
p (GeV/c)p (GeV/c)ring resolutionring resolution
calculated from single calculated from single photon resolutionphoton resolution
particleparticle (mrad) (mrad)
2.5 2.5 /K/Ksep. up to 40 GeV/csep. up to 40 GeV/c
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 1919
PID with COMPASS RICH-PID with COMPASS RICH-11
momentum (GeV/c)
C
h (mrad)
0 10 20 30 40 50 60
0
10
20
30
40
50
60
Cherenkov angle vs. momentumfor reconstructed rings (24 runs)
K p
(x30)(x150)
KK
pp
particleparticle> 25 mrad> 25 mrad
p (GeV/c) > pp (GeV/c) > pthrthr(K) + 2 (K) + 2 GeV/cGeV/c
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 2020
PID EFFICIENCYPID EFFICIENCY
±± from from KKss decays decays
p> thr. (= on average p> thr. (= on average 0 0 photons ) photons ) p> thr. + 0.5 GeV/c (=on av. p> thr. + 0.5 GeV/c (=on av. 55 det. ph.s) det. ph.s) p> thr. + 1.2 GeV/c (=on av.p> thr. + 1.2 GeV/c (=on av.88 det. ph.s) det. ph.s) p> thr. + 2 GeV/c (=in m. p> thr. + 2 GeV/c (=in m. 1010 det. ph.s) det. ph.s)
0-30 mrad0-30 mrad
<p> = <p> = 12.4 GeV/c12.4 GeV/c
<p> = <p> = 9.3 GeV/c9.3 GeV/c
<p> = <p> = 7.1GeV/c7.1GeV/c
<p> = <p> = 5.8 GeV/c5.8 GeV/c
<p> = <p> = 4.9 GeV/c4.9 GeV/c
<p> = <p> = 4.3 GeV/c4.3 GeV/c
30-60 mrad30-60 mrad
60-90 mrad60-90 mrad
120-150 mrad120-150 mrad 150-180 mrad150-180 mrad
90-120 mrad90-120 mrad
MOMENTUM SPECTRA IN MOMENTUM SPECTRA IN particleparticle BINS BINS
particleparticle(mrad)(mrad)
E
FF
ICIE
NC
YE
FF
ICIE
NC
Y
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 2121
KK±± from from decaydecay (sample purity: (sample purity: 84%84% ) )
p> thr. + 2. GeV/cp> thr. + 2. GeV/c (= on av. (= on av. 55 det. ph.s) det. ph.s)
EFFICIENCY, learning EFFICIENCY, learning curvecurve
±± da decadimenti da decadimenti KKss
(sample purity: (sample purity: 94%94% ) )
p> thr. + 0.5 GeV/c p> thr. + 0.5 GeV/c (= on av. (= on av. 55 det. ph.s) det. ph.s)
software software upgrade upgrade
particleparticle(mrad)(mrad)
E
FF
ICIE
NC
YE
FF
ICIE
NC
Y
particleparticle(mrad)(mrad)
E
FF
ICIE
NC
YE
FF
ICIE
NC
Y
PD PD stabilitystability
gasgasquality quality
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 2222
2002 : Seff(*)= 151 (8) 2003: Seff = 674 (17)
(*) Seff =S/(1+B/S)
A remarkable example:A remarkable example:G/G open charm-signalG/G open charm-signal D D00 & D & D00 withoutwithout microvertex detector microvertex detector
RICH-1 in COMPASS RICH-1 in COMPASS PHYSICSPHYSICS
20022002 2003 (2004) 2003 (2004)
SSeffeff//dayday * 4.9 * 4.9
Preliminary Preliminary
Silvia DALLA TORRESilvia DALLA TORRE
Playa del Carmen, 30/11-5/12/2004 - 5Playa del Carmen, 30/11-5/12/2004 - 5thth RICH Workshop RICH Workshop 2323
CONCLUSIVE REMARKSCONCLUSIVE REMARKS
COMPASS RICH-1 is fully operativeCOMPASS RICH-1 is fully operative plateau performances since 2003
COMPASS RICH-1COMPASS RICH-1 designed ~ mid 90’s challenging requirements concerning
transversal size and rates (beam, trigger)
large size VUV gas RICH limitationslimitations for the operation of for the operation of large size CsI photocathodeslarge size CsI photocathodes
coupled to gas detectors coupled to gas detectors in radioactive environmentsin radioactive environments have have been encounteredbeen encountered
““single photon” resolution is satisfactory (~ parameter design)single photon” resolution is satisfactory (~ parameter design) ““ring resolution” limited by physical backgroundring resolution” limited by physical background
ring resolution allows 2.5 / K separation up to 40 GeV/c
central for COMPASS physics (demonstrated in polarized DIP)central for COMPASS physics (demonstrated in polarized DIP)