Transcript LHCf CSN1 260110 - Istituto Nazionale di Fisica Nucleare

Torino, 17 Maggio 2010
News da LHCf
Oscar Adriani
Università degli Studi di Firenze
INFN Sezione di Firenze
LHCf: detector overview
Detector I
Tungsten
Scintillator
Scintillating fibers
Detector II
Tungsten
Scintillator
Silicon mstrips
INTERACTION POINT
IP1 (ATLAS)
140 m
140 m
Beam line
44X0,
1.6 lint
Arm#1 Detector
20mmx20mm+40mmx40mm
4 SciFi tracking layers
Arm#2 Detector
25mmx25mm+32mmx32mm
4 Silicon strip tracking layers
Oscar Adriani
Torino, 17/05/10
Calibrate cosmic ray interactions for very
forward energy spectra at LHC energy
Single g
p0
• Discriminate a good model
• Input data for model
building
neutron
Model difference in very forward at 14TeV
Oscar Adriani
Torino, 17/05/10
LHCf 2010 runs
• Successful data taking at 7TeV collisions is ongoing.
– Integrated Luminosity ~ 5.0 nb-1 up to May 16, 2010
– ~60M showers and 200K p0s obtained ( arm1+arm2 ).
• Detector shows good performance with stable
quality.
– Energy scale calibration with the p0 peak.
– Good stability < ±1% level. Yet no radiation problem.
Oscar Adriani
Torino, 17/05/10
Statistic plot up to 16 May 2010
Red = Shower Arm1
Blue = p0 Arm1 (x100)
Light red=Shower Arm2
Light Blue = p0 Arm2 (x100)
Shower Trigger
g-like
p0
Arm1
29,515,720
8.0e6
59,000
Arm2
33,230,720
1.0e7
140,000
Oscar Adriani93%
Torino, 17/05/10
Live time(*)
96%
Arm1
7 TeV collisions
1 TeV gamma-ray shower @ Arm2
Transition curve in towers
Particle Hit
maps
X-view of silicon strip
Arm2
Y-view of silicon strip
Oscar Adriani
Torino, 17/05/10
p0 at 7 TeV
Silicon layers
25 mm
tower
32 mm
tower
 Robust sample
 Good energy calibrator
Tower
32mm 25mm
Scintillator layers
Arm2 event display
Oscar Adriani
Torino, 17/05/10
DM/M=5.0MeV/135MeV=3.7%
Please note the very
high energy!!!!
Oscar Adriani
Torino, 17/05/10
DM/M=3.1MeV/135MeV=2.3%
Oscar Adriani
Torino, 17/05/10
Quick look at 7TeV collisions (Arm2)
Colliding bunch
Non-colliding
bunch
High statistics !!
Only <1% of total
data are used
Very clean data!!
BKG due to beam-gas
collisions is ~ 1%
Oscar Adriani
Torino, 17/05/10
Gamma/Hadron at 7 TeV
Arm1 Data
Small+Large
Small+Large
Gamma+Hadron
Gamma+Hadron
Oscar Adriani
Torino, 17/05/10
Detector gain stability in Apr 2010
7TeV run
±2%
Laser gain calibration
for scintillator layers
15/04
±1% level stability !
±2%
01/04
p0 mass peak
0.045Gy
cumulative
dose
Oscar Adriani
Torino, 17/05/10
FrontCounter as a good luminosity monitor
TAN
BRAN-IC
ZDC
BRAN-Sci
ZDC
ZDC
Stay all the time
LHCfCAL
FC
Beam
pipe
Page1
LHCf page
Neutral
particles
• FC is working very well for
luminosity monitoring
(Very useful monitor for
the machine)
• Continuous monitoring w/
independent DAQ now
available. See Page1
“LHCf experiment”
• Conversion to “luminosity”
from FC rate is now under
study by MC
lumiscan
Arm1
Arm2
Coincidence
Gaussian fit
Oscar Adriani
Torino, 17/05/10
Next Step for the analysis (in progress)
• Understand where LHCf is wrt Beam!!!!
• Crucial for the Pt spectra measurements
• We are using/planning to use:
–
–
–
–
–
Survey measurements
Internal LHCf alignment
Position of the vertical manipulator
Beam spot position from Atlas (Many thanks!!!)
Reconstructed center of the neutral particle flux from
LHCf position sensitive detectors
• Caution: Beam crossing is not stable
– Fill/Fill difference
– Inside-fill difference
Oscar Adriani
Torino, 17/05/10
Reconstruction of the beam center
Make use of the silicon infos
Alghoritm optimized for online monitor
X View
270 mm resolution
Y View
240 mm resolution
Oscar Adriani
Torino, 17/05/10
E-q distribution for g-like shower at 7TeV
Measurement distribution of Arm2
(not corrected by geometrical acceptance)
Geometrical acceptance
• Data : only first collisions (30/03/2010)
38,000 shower trigger
• Assumed the beam center is at (X,Y)=(3.0mm, 0.0mm).
Oscar Adriani
Torino, 17/05/10
p0 PT Distribution at 7 TeV
Data : #fill 1058
(24/04/2010)
Assumed the beam center
is at (X,Y)=(3.0mm, 0.0mm).
Measurement distribution
without correction of
geometrical acceptance
Oscar Adriani
Torino, 17/05/10
Analysis of 900GeV runs in 2009
• Stable beams at 900GeV, 06.Dec. – 15.Dec (27.7 hours)
– 2,800 and 3,700 showers in Arm1 and Arm2, for ~5e5 collisions at IP1
• Progress in Analysis since last LHCC
– Refine analysis tools and fix final data sets for Dec09 run.
– Absolute energy calibration by p0 peak at 7TeV
Expected spectra with each hadron interaction model
Gamma-ray like @ Arm2
Hadron like @ Arm2
with 107 col.
Oscar Adriani
Torino, 17/05/10
Particle Identification
• Clear discrimination between g and hadron showers
based on shower transition curves.
• Basic agreement in the PID parameter (L90)
distribution
• Checking systematics for SPS calibration data (50200GeV for electrons, 150, 350 GeV for protons)
L90% @ 20mm cal.
MC (QGSJET2)
hadron-like
Data
g-like
Oscar Adriani
Torino, 17/05/10
Preliminary spectra from 900GeV runs in 2009
Normalized by gamma-like entry
MC(QGSJET2)
Data
Sys.+Sta.
• Reasonable agreement with MC
• Conservative systematic error for energy scale +10% -4% assigned
• Checking detector response for hadron showers by SPS 350,150GeV p data
Adding May 900GeV runs, 100K showers now (Dec09 x15) !
Oscar Adriani
Torino, 17/05/10
Plan for coming months
• Nominal data taking at 7TeV
Typical unit 10K p0 w/ ~1nb-1
– Vertically shift Arm1&Arm2
– Few runs for checking systematics with a few different
configuration (HV, trig threshold, etc..)
– High statistic with 1 or 2 settings (for h meson, etc. )
• Possible beam crossing angle run (140mrad) at 7
TeV
– Enhance rapidity coverage; h >8.7 g h>8.4
– Important to check flux center moving downward w.r.t.
crossing angle
• Finally, LHCf de-installation
– When luminosity becomes too high ( >1031cm-2s-1, or
2pb-1)
Oscar Adriani
Torino, 17/05/10
Study of h in a high statistics sample
QGSJET2
h
• Next milestone: h meson
– h/p0 ratio or h production spectra vary a lot among
different interaction models. A good handle to probe the
models, though irrelevant to air shower development.
– Another calibration point for more robust energy scale
– Typical h/p0 =10-3~10-4 at 7TeV. Good to collect ~1M p0
(~100nb-1)
• Strangeness production (K0, L) is under study
Oscar Adriani
Torino, 17/05/10
Crossing angle for LHCf 7 TeV run
Shown in 99th LHCC, Sep2009
Aperture of
Beam pipe
a=140mrad
3.5+3.5TeV
All g from IP
2cm
Distance from
neutral center
No crossing
With 140mrad crossing angle,
neutral flux center is lowered by 2cm.  w/o crossing : 30%acc. @Xf = 0.22
 w 140mrad : 50%acc. @Xf = 0.22
Rapidity coverage: >8.7 g >8.4.
If possible, it is nice to have a crossing angle during LHCf run.
LHCf can measure crossing angle by fitting shower center
(DY~ 1mm for 100sec@L=1029gDa~7mrad) to be distributed by DIP.
Oscar Adriani
Torino, 17/05/10
Oscar Adriani
Torino, 17/05/10
LHCf removal and toward the phase-2
• When luminosity become too high (>1031 cm-2s-1, 2 pb-1),
LHCf will go out from the TAN (Radiation damage at
plastc scinitillator ~1kGy@2pb-1 for 20% degradation)
• De-installation work should be quickly done during
monthly Technical Stop.
• Not earlier than the next Technical Stop in June. We’d
like to revisit the scheduling issue when LHC luminosity
profile gets clearer in June.
• After removal, beam calibration again by a SPS test
beam.
• Revisit LHC at the next energy upgrade. R&D and
fabrication of rad-hard GSO scinitillator 1mm
are on-going
thick
for the “phase-2” LHCf detector.
20mm
A new GSO scintillator layer
Oscar Adriani
20mm
Torino,
17/05/10
Summary
• LHCf has started physics program very successfully.
– 100K showers at 900GeV
– 60M showers and 200K p0 at 7TeV
• Detectors work beautifully without any serious trouble.
– Very clean! Negligible beam-gas background
– The p0 peak demonstrates good performance as expected.
• As luminosity is growing up, high stat run and other
optional runs are under discussion
– High stat run for h mesons
– Crossing angle commission f important step to “phase-2”
• Rapid progress in analysis. Almost ready to publish
physics !
– 900GeV results (2009&2010) and 7TeV results
– Finalizing SPS test beam data to confirm energy scale, PID and
hadron shower response at a few 100 GeV.
Oscar Adriani
Torino, 17/05/10
Backup slides
Oscar Adriani
Torino, 17/05/10
Oscar Adriani
Torino, 17/05/10
Comparison between tower calorimeter towers of Arm2
Gamma-rayComparison
like
Hadron like
of spectra
Flat spectra
in h>8.7
at 900GeV
Comparison between two Arms
Both detectors
working
without any
biases
Oscar Adriani
Torino, 17/05/10
-Front Counter• Thin scintillators with 8x8cm2 acceptance,
which have been installed in front of each main
detector.
Schematic view of
Front counter
• To monitor beam condition.
• For background rejection of
beam-residual gas collisions
by coincidence analysis
Oscar Adriani
Torino, 17/05/10
Summary of Expected number of events
QGSJET2
SIBYLL
DPMJET3
Pythia
h
p0
h/ p0
h
p0
h/ p0
h
p0
h/ p0
h
p0
h/ p0
Arm1
(Normal
)
0.08
46.9
0.002
0.01
46.7
0.0002
0.01
75.5
0.0001
Arm1
(-20mm)
7.35
238.4
0.031
0.21
191.9
0.0011
1.05
310.7
0.0034
Arm2
(Normal
)
1.6
123.7
0.012
0.10
110.8
0.0009
0.24
177.5
0.0014
0.15
150
0.0010
Arm2
(-10mm)
3.36
191.3
0.018
0.21
165.1
0.0013
0.47
268.5
0.0016
0.1
169
0.00059
Oscar Adriani
Torino, 17/05/10
LHCf can measure
Energy spectra and
Transverse momentum distribution of
• Gamma-rays (E>100GeV,dE/E<5%)
• Neutral Hadrons (E>a few 100 GeV, dE/E~30%)
• Neutral Pions (E>700GeV, dE/E<3%)
at psudo-rapidity range >8.4
The Aim is to calibrate hadron interaction models
for ultra high energy cosmic ray physics.
Multiplicity@14TeV
Low multiplicity !!
Energy Flux @14TeV
High energy flux !!
simulated
by DPMJET3
Oscar Adriani
Torino,
17/05/10
Radiation Damage Studies
Scintillating fibers and scintillators
•Expected dose: 100 Gy/day at 1030 cm-2s-1
•Fewmonths @ 1030 cm-2s-1: 10 kGy
• 50% light output
•Continous monitor and calibrationwith
Laser system!!!
The LHCf experiment at LHC
ISVHECRI08, Paris 1-6 September
2008
Alessia Tricomi
30Catania
kGy
1 kGyUniversity & INFN
Oscar Adriani
Torino, 17/05/10
Comparing fill# 1031with ATLAS
ATLAS lumi
http://xxxxxxxx
×1026
L*FC
1.7E+27
1.3E+27
L*FC is smaller than by 24%
Difference may come from interaction model
detector MC tuning
Oscar Adriani
Torino, 17/05/10
Oscar Adriani
Torino, 17/05/10