LENS R&D

Collaboration:

- Italy: INFN – Laboratori Nazionali del Gran Sasso
- France: College de France – Paris; DAPNIA CEA – Saclay
- Germany: MPIK – Heidelberg
- Japan: RCNP – Osaka (Japan)
- Russia: Institute of Nuclear Research RAS – Moscow; Institute of Physical Chemistry RAS – Moscow
- USA: Bell Laboratories – Murray Hill NJ; B.N.L. – Upton NY; LAL – Los Alamos NM

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 2001

In this year the collaboration has refined the recipe to produce liquid scintillator with the mentioned characteristics. Starting from the industrial procedure to extract rare earth, a procedure to complex the metal in an organic compound (made of carboxylic acid and phosphorganics) soluble in pseudocumene has been defined. The procedure is now reproducible and leads to a stable product (at least on the scale of few months). The obtained light yields are of ~ 40% compared to a commercial standard (BC505, 80% of anthracene) with a ~ 10% Yb and In loading. Attenuation lengths are of order of 1.8 m.

The produced batches of scintillator, volume O(1 l), have been characterized in terms of light yields, light attenuation length, light decay time constant and stability, and have reached the minimal specifications to be produced on a larger scale and tested underground for intrinsic background characterization.

Milestones 2002: to be defined following the possible funding of the activity

3. INFN contribution to the experiment in term of manpower and financial support

INFN actively collaborate at LENS project since second semester of year 2000. In joint work with Bell Laboratories, INR Ras and Institute of Physical Chemistry RAS we have developed and refined the recipe to produce the LS, and we have defined the methodic to fully characterize it. The synthesis activity is still in a development phase, whose main goal is to optimize light yield and attenuation length at 10% metal concentration.

LNGS has also build and equipped with basics services (stabilized electrical power, Ethernet connection and furniture) the underground building devoted to host the specific low activity shielding (responsibility MPIK) to perform test in a protected environment.

- Manpower: 2 physicists and 2 Russian chemists for 8 months each (FAI funds). Support from LNGS Workshop, Chemical, Civil Engineer, Electronic and Special Techniques services.
- Budget for the Year 2002: under examination

4. Publications in refereed journals (in 2001):

5. Conference talks (in 2001): 1

6. Number of undergraduate and doctoral thesis on the experiment: 0

7. Leadership roles and primary responsibilities in the experiment:

8. Innovative instruments:

- LS highly loaded with metals

9. Competing experiments:

- SIREn R&D

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

Status Report on LENS-September 2001, submitted to the Scientific Committee, LNGS, September 12, 2001