muon flux measurements at the lsc
DESCRIPTION
MUON FLUX MEASUREMENTS AT THE LSC. Héctor Gómez Maluenda, University of Zaragoza. [email protected]. JRA1-N2 Meeting, Zaragoza, Nov 23 rd 2007. Outline. Introduction Detection system features Preliminary tests at sea level Measurements in LSC Outlook Summary and Conclusions. - PowerPoint PPT PresentationTRANSCRIPT
MUON FLUX MEASUREMENTS
AT THE LSC
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Héctor Gómez Maluenda, University of Zaragoza.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Outline
Introduction
Detection system features
Preliminary tests at sea level
Measurements in LSC
Outlook
Summary and Conclusions
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Introduction
LSC Depth: 2450 mwe
Expected Muon Flux: ~3 10-3 m-2 s-1
• Need to check the theoretical value for the muon flux
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Detection system features
• Detectors
2 Plastic scintillators BICRON BC 408 of 80 x 40 x 5 cm3.
2 light guides with PMTs coupled to the scintillators.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Detection system features
• Electronic Chain
NIM Fast – Slow standard coincidence system.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Detection system features
• Readout
C-code based acquisition program using a 32 channel I/O digital card.
Storage of the energy of both detectors and time (up to 100 s accuracy) for each coincidence event allowing energy and time analysis.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Detection system features
Muons produce a coincidence event releasing an energy average of 2 MeV per cm.
<E>T~10 MeV
Most of the gammas coming from natural background (up to ~3 MeV) release all the energy in one detector Rejected event.
Our set up allows to detect muons coming from a solid angle of ~2
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Preliminary tests at sea level
• We made some measurements in Zaragoza (200 m above sea level) in order to adjust the DAQ (gain, thresholds…) and to check the efficiency of the system.
• The total muon flux expected for a 2 solid angle is 125 m-2s-1.PDG. S. Eidelman et al., Physics Letters B 592, 1 (2004)
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Preliminary tests at sea level
• 3 different regions in the spectra
- Background region.
- Intermediate region.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Preliminary tests at sea level
• 3 different regions in the spectra
- Background region.
- Intermediate region.
- Muon region.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Preliminary tests at sea level
• 3 different regions in the spectra
Muon Flux
= 105.64 ± 0.02 (stat.) m-2 s-1
Systematic errors (~10%):
- Not 2 solid angle.
- Unconsidered shielding.
- Efficiency less than 100%.
- Lose of muons:
No coincidence.
Less energy deposit than expected.
COMPATIBLE RESULTS
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Measurements in LSC
• Location
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Measurements in LSC
• Results: 50.8 days of measurement.
= 3.94 ± 0.02 (stat.) ± 0.4 (sys.) 10-3 m-2 s-1
Slightly higher than expected value
WHY?
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Measurements in LSC
• A Possible Explanation: Mountain Profile.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Measurements in LSC
• A Possible Explanation: Mountain Profile.
Hall B 5.04 ± 0.06(stat) ± 0.5(sys) 10-3 m-1s-1 +28%
Hall A 3.94 ± 0.02(stat) ± 0.4(sys) 10-3 m-1s-1
Old Lab 3.59 ± 0.04(stat) ± 0.4(sys) 10-3 m-1s-1 -9%
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Outlook
Complete measurements in the Old Lab and Hall B at LSC trying to corroborate and quantify the influence of the mountain profile in the muon flux.
Make a Monte Carlo study to estimate the muon flux in the different locations (ongoing).
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Summary and Conclusions
We developed and tested successfully an experimental set up to measure the muon flux.
The muon flux measured at the Hall A of the LSC seems to be slightly higher than the expected value regarding the depth of the Lab.
A possible explanation for this difference could be the dependence between the muon flux and the mountain profile.
Preliminary measurements in other locations of the LSC and the Old Lab seem to corroborate this theory.
More accurate measurements and Monte Carlo simulations are ongoing to obtain final conclusions.
MUON FLUX MEASUREMENTS
IN THE LSC
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Héctor Gómez Maluenda, University of Zaragoza.
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Stability of the Rate
Different orientation
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Different Analysis Methods
Method i)
Chu & Chl > 600
Method ii)
Chu & Chl > 170
Method iii)
Chu || Chl >170
JRA1-N2 Meeting, Zaragoza, Nov 23rd 2007
Different Analysis Methods