LENS R&D
Collaboration:
Location of the experiment: LNGS
National Responsible: C. Cattadori
1. Goal of the experiment
LENS is the acronym of Low Energy Neutrino Spectroscopy.
LENS R&D, has the goal to develop and fully characterize organic liquid scintillators (LS) with high scintillation output and attenuation length, and high (~10%) loading in Yb, In and other elements having isotopes with characteristic signature and high cross section for electron neutrino capture.
This development could be of interest also in neutron detection applications, as the cited elements have large cross sections also for neutron capture reactions.
Another aim of LENS R&D is to test O(100 l) modules of the produced liquid scintillator in a shielded environment, to study the intrinsic background of the scintillator.
2.
Activities during 2002
The activity during 2002, can be
summarized as follows
-
Completion of the low level underground test facility: the
shielding (20 cm polyetilene, 23 cm iron and 15 cm ultralow
background copper), offer an internal shielded volume of 2 m3;
the measured (gamma ray spectrometry with Germanium detector)
gamma background reduction factor is 104 í105.
The facility has been equipped with analog and digital electronic
readout for up to 16 channels.
-
Definition and Optimization of an original recipe to produce
liquid scintillator highly doped (up to 10%) with Indium
metallorganic compound having high performances in terms of light
yield and transparency. Characterization of the fluorescents
properties of the produced liquid scintillator, study of the
stability in time of relevant parameters. Study of the properties
of Indium loaded liquid scintillator based on different primary
solvents (mineral oil, pseudocumene, dodecane, mixtures of listed
solvents etc).
-
Simulations of neutrino signal in presence of background for the
full scale detector. In particular the mimics of the pp neutrino
tagging from uncorrelated subsequent 115In beta decay
producing bremssthralung gammas has been investigated. From the
simulations the minimal requirements for the full scale detector
to detect pp neutrinos come out; a segmented detector having
Indium loaded cells (9cm x 9cm) intercalated with no Indium
loaded cells. For this configuration the efficiency for neutrino
detection is 20% with a S/N of 4: for 7Be
neutrinos only, an homogeneous detector would be feasible with a
detection efficiency of 57% (for 10 cm x 10 cm cells) and a S/N
ca. 7.
-
Simulations and tests of the reflectivity of high reflectivity
film (VM2002 produced by 3M) and on flat quartz surfaces in view
of prototype cells production.
-
Commissioning of the inner array of cells (9 cells, quartz HSQ, 5
cm x 5 cm x 80 cm)
- Commissioning of the low level PMs
for the inner array readoutThe following achievements have been obtained:
Milestones 2003:
Synthesys
of O(10 l) InLS with the best available (actual) recipe |
30-02-2003 |
End
of the In bremsstrhalung measurement on 1 kg metallic In
by Ge detector |
30-03-2003 |
Installation
in the Low Level Background Facility (LLBF) of the inner
quartz cells array and of the outer anticoincidence cell
array + low level PM installation |
30-04-2003 |
Measurement
in a shielded environment of O(5 l) InLS |
30-05-2003 |
Final
fixing of the InLS synthesys recipe on the base of the
ongoing stability/ageing studies |
30-06-2003 |
Measurement
of O(50 l) InLS in inner cell array. |
30-12-2003 |
3. INFN contribution to the experiment in term of manpower and financial support
4. Publications in refereed journals (in 2002): 1
5. Conference talks (in 2002): 2
6. Number of undergraduate and doctoral thesis on the experiment:
Undergraduate student: 1 student from
lAquila University is doing her tesi di laurea
on the characterization and development of InLS. She will
graduate on April 2003.
7. Leadership roles and primary responsibilities in the experiment:
MPIK: LLBF, Electronics and DAQ, Inner cells array,
Reflectivity tests, LS development
INFN-LNGS: LS development and characterization, BS measurements
INR: LS development and characterization
DAPNIA-CEA: Montecarlo and Simulations
College de France: Electronics
Los
Alamos:
Envelope array of cells, test cell
Bell Labs: LS development
8. Innovative instruments:
Highly loaded (up to 10%) Indium scintillators, having veru good performances in terms of light yields and transparency. Light yields of the order of 8000 ph/MeV and light attenuation length of order of 1 m @ 430 nm have been obtained
9. Competing experiments:
10. International committee which has reviewed the experiment:
This first phase
of R&D for scintillator development is under examination by
the INFN Committee II. LNGS Scientific commette reviewed the
whole project both in March 2002 and in October 2002.