Transcript A1 - Transnational Access to the EU Deep Underground

ILIAS J1 Meeting
WP1 Status Report and discussion
N. Ferrari (LNGS)
J1 general meeting - Zaragoza, 11-12 July 2006
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Summary
 J1-WP1 Review of objectives and general organization
 Status of the activities
- Neutrons
- Gamma background
- Radon
 Summary of next milestones
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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J1-WP1 : Review of objectives and general organization
The main objective of J1-WP1 is to characterize the relevant backgrounds in
the 4 Underground Labs:
- By collecting available existing data
- By performing new, dedicated measurements
The background components under study include:
- Neutrons
- Gamma rays
- Muons
- Radon
The final deliverable will be a database containing information on old and new
measurements of the background components.
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Status of the activities
(from second annual report)
At LNGS, measurements of the gamma background in various locations have been
carried out with a 16 kg NaI detector, and a setup for a high statistics measurement
of the fast neutron flux has been installed in hall A
In the case of Boulby, new gamma and radon measurements have been recorded by
a group from Silesia University in a visit partially funded by a TARI program.
A complete program for the characterization of the new Canfranc Underground
Laboratory has been developed. It started at the beginning of January (after the
completion of the public works) and will continue during 2006.
Radon monitoring continues in all laboratories; in the case of the Modane
Laboratory a new system of radon purification by adsorption in charcoal is
working since 2005
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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A document has been created containing a list of all measurements. The
document will be soon in the form of a real database and it will be
continuously updated so that different users can look into it for information
on new measurements and results on background.
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Neutrons
Location
measurement
Publication
LNGS
3He detectors
E. Bellotti et al., INFN/TC-85/19, October
1985
LNGS
P. Belli, et al., Il Nuovo Cim. 101A (1989)
959
LNGS
integral fast neutron flux with
radiochemical technique
M. Cribier, et al., Astropart. Phys. 4 (1995)
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LNGS
Measurement of fast neutron spectrum
with liquid scintillator
F. Arneodo et al. Nuovo Cim.A112:819831,1999
LNGS
ILIAS: measurement of fast neutron
spectrum with liquid scintillator
LSM
Liquid scintillator doped with 6Li
Chazal et al., Astr. Part. Phys. 3
9(1998)163
Boulby
JIF-Stub 1
Indirect calculation of n fluxes from
gamma lines
Smith et al., Astroparticle Physics 22
(2005), 409
Boulby
ILIAS: measurement of fast neutron
spectrum with Gd-loaded liquid
scintillator
LSC
ILIAS: planned
Pyhasalmi
Measurement of fast neutron spectrum
with liquid scintillator
….
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Neutrons: LNGS new measurement
A setup for a high statistics measurement of the fast neutron flux (energy range
between 0.5 and 20 MeV) has been installed in hall A of the Gran Sasso National. Data
taking started in the beginning of August 2005
•
•
•
New measurement of the spectrum and intensity of the neutron flux
(fast component) in the LNGS underground laboratory.
This activity is mainly focused on the evaluation of possible fluctuations
with time of the neutron intensity.
Identification of the physical correlation with other environmental
parameters.
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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0.3 litre
cells
DAQ
2 litres
cells
n
Qdel
Electronics
Qtot
Qdel
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
Qtot
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Overview
•
February 2005 received first 2 litres BICRON cell
•
June 2005 received second 2 litres BICRON cell
• July 2005 calibration with neutron beams at LNL
• July 2005 installation at LNGS hall A of
electronics
1 litre cell
2 x 0.3 litres cells
• August 2005 installation of the second 2 litres cell
• September 2005 start of the data acquisitionc
• November 2005 installation at LNGS of a dedicated DAQ (0.2 l
cell) for gamma background evaluation
• Marc 2006 installation of a lead shield (8 mm) to reduce the
stochastic contribution induced by gamma background
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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First results
•
The energy distribution of selected data (p recoils) is then obtained using a
detector calibration carried out by means of g-ray sources (eee Electron
Equivalent Energy) and conversion factors (pee Proton Equivalent Energy).
•
The energy distribution of neutrons is computed by means of a deconvolution
program once the response function of the detector are known.
•
With the installation of a lead shield, its sensitivity is now enough to
perform, in few months of data taking, an evaluation of possible fluctuations
with time of the neutron intensity.
•
Preliminary results show the presence of variation of the counting rate
beyond the statistical fluctuation above 3.5 MeV.
•
Identification of the physical correlation with other environmental
parameters, such as the rock moisture, ground water level and pressure, …
is in progress.
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Neutrons: Boulby new measurement
Two neutron background measurement systems have been developed and
commissioned at Boulby: NUTs and DRIFT. Over 3 weeks of unshielded background
data has been acquired and analysis is underway. Further data acquisition and analysis
is planned in the coming months
See presentation by Vitaly
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Gamma rays
Location
measurement
Publication
Boulby
Unshielded 2-kg Ge detector
Astroparticle Physics 22 (2005), 409
LSM
Unshielded NaI detector
NIM A 482 (2002) 832
All labs
ILIAS: measurement of g-rays with
movable Ge detector in all labs
LNGS
ILIAS: measurement of g-rays with NaI
detector at LNGS
LSM
ILIAS: measurement of g-rays with
movable Ge detector
Internal note available
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Gammas : measurements with movable Ge detector in all labs
In August 2005 the IUS/Boulby hosted visitors from the University of Silesia, Poland carrying out a
programme of Ge detector and Radon background measurements at European laboratories. The
results were presented at the JRA1 general meeting in Paris, on February 14th. Furthermore, two
gamma background measurement systems are under development at Boulby: a 2kg Ge and an
encapsulated NaI detectors have been installed and commissioned in the low background laboratory.
Measurements done in LNGS and Boulby, planned in LSC and LSM during 2006
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Gammas : measurements at LNGS with movable NaI detector
LNGS: a total number of 18 measurements of the gamma background in various
locations inside LNGS have been carried out with a 16 kg NaI detector.
15 kg portable NaI detector
(LNGS)
Calculation of absolute fluxes needed
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Muons
Location
measurement
Publication
LNGS
Measurements from MACRO detector
Ap. J. 411 (1993) 301
Phys. Rev. D 52 , 7 (1993)
Phys. Rev. D 56 (1997) 1421
Phys. Rev. D 59 (1998) 012003
LNGS
Measurementsa from LVD detector
Hep-ex-9806001
Hep-ex-9905048
Boulby
flux using ZEPLIN I Compton veto
Robinson et al., NIMA 511 (2003), 347
LSM
?
?
Pyhasalmi
Measurements at different depths
NIM A 554 (2005)
LSC
?
?
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Radon
At LNGS, the Rn in the air of the lab is continuously monitored on-line and integrated on several
months. It varies from approximately 50 Bq/m3 to 150 Bq/m3 in the ventilated areas, but it can reach
800-1000 Bq/m3 in non ventilated corners. The monitoring of the Rn is the water of the Gran Sasso
massive is ongoing since several years. Time dependence of the signal is extremely interesting for
geophysics
At LSC, Rn is being monitored at all the experimental halls. Periodic measurements of radon
concentration has been performed at different points. The results show a mean value of 64 Bq/m3 for
the radon concentration in Hall A and 70 Bq/m3 in Hall B using two AlphaGuard PRO detectors.
At Boulby, Rn measurements are less urgent than in other laboratories due to the low U, Th content.
Typical levels are of the order of 5 Bq/m3. A RAD-7 radon detector is operational inside the low
background laboratory. Other investigations of radon levels, radon-progeny plate-out / deposition and
additional n-flux due to associated (α, n) reactions are planned in the near future.
At LSM a new system of radon purification by adsorption in charcoal is working since 2005, the
volume of clean air for this system is 125 m3/h and the activity of 222Rn is 15 mBq/m3.
Please send some examples of Rn monitoring in the lab if available
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Next milestones
Milestone
Reference people
Deadline
Or
expectation
Include all published data in web-based
database
N. Ferrari, C. Tomei
Next J1
meeting
Neutrons: LNGS liq. Scint. new
measurement first data
G.L. Raselli
Before Apr. 2007
Neutrons: Boulby liq. Scint. new
measurement first data
V. Kudryavtsev
Before Apr. 2007
Gamma rays: completion of new
measurements with portable Ge detectors
In all labs and writing of a report
(publication?)
J. Kisiel
Before Apr. 2007
LNGS: extraction of absolute gamma
fluxes from NaI data
N. Ferrari, C. Tomei
Next J1
meeting
Measurements of backgrounds in the new
LSC
?
?
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
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Milestone
Reference people
Collect Rn monitoring data from all labs
N. Ferrari, .....
N. Ferrari - ILIAS - J1 meeting,
Zaragoza
Deadline
Or expectation
Next J1
meeting
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