BoLAS (Flexible 10 B-based converter deposited by the laser ablation) is a technological research experiment based at INFN Lecce aimed at the deposition, by pulsed laser deposition technique (PLD), of 10B enriched films in order to realize flexible thermal neutron converters, alternative to 3He-based ones.

The main advantage of the laser ablation technique is the possibility to deposit thin films on different kind of substrates, including flexible ones at room temperature.
Flexible neutron converter will be deposited on different kind of detectors such as scintillation fibre and solid state detectors. Applications will range from neutron diffraction instruments, to monitor of thermal neutron flux for boron neutron capture therapy, to neutron tomography.

People
National Responsible: Gianluca Quarta

Researchers
L. Calcagnile
A.P. Caricato
D. Manno
A. Lorusso
M. Martino
A. Perrone
A. Serra

Technicians
L. Maruccio
M. Corrado

Work Packages and Time schedule

WP1: Deposition and characterization of 10B enriched film deposited by PLD
The films deposited by PLD will be characterized trough a multi-technique approach by using electron microscopy techniques (TEM/SEM-EDAX), X-Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Ion Beam Analyses (IBA) (CEDAD: Centre for dating and diagnostics).

Aims:

  • Determine the microstructural features
  • Determine the composition (chemical purity)
  • Analyse the crystalline structure
  • Study the surface topography
  • Measure the films’ thickness

Activities:

  • Lecce INFN: Definition of the experimental conditions for the deposition of 10B films (9-12 months)
  • CEDAD: characterization of 10B films (9-12 months)

WP2: Definition of thickness and geometries of 10B thin film

Preliminary evaluations and simulations of the design characteristics (film thickness, geometries, converted-detector configurations) will be performed by taking into account:

  • Energy of the capture products;
  • Ions energy loss;
  • Quenching problems;
  • n/g discrimination;

Deposition of 10B enriched thin films with the above defined characteristics.

Activities:

  1. Lecce INFN, CEDAD, Genoa INFN: Definition of the thickness and geometries of 10B enriched thin films (6-9 months)
  2. Lecce INFN: Deposition of 10B enriched thin films (12-15 months) 

WP3: Deposition and characterization of heterostructures of thin superconductor film and 10B

Superconductors, coupled with a neutron converter, can be used as neutron detectors since the a particle can suppress superconductivity in the superconductor heterostructure. Thermal neutron detection has been shown by this technique by depositing 10B thin films on NbN strips acting as superconductor at T<11 K. We propose the use of thin layers of heterostructures of metal films which can exhibit superconductivity at T> 100K.

Activities:

  1. Lecce INFN: Definition of the experimental conditions for the deposition of the heterostructures of thin superconductors films (15-18 months)
  2. CEDAD, Manchester University: Characterization of the heterostructures of thin superconductor films (15-18 months)
  3. Lecce INFN: Realization of complete heterostructures (heterostructures of thin superconductor +10B films) (18-21 months)

WP4: Test of 10B- based detectors by PLD

Detector test bench using as source of neutrons 241Am-Be radioactive source and near threshold 7Li(p,n)7Be reaction induced at the 3 MV Tandetron accelerator available at CEDAD. Further tests will possible involve the other INFN n-source such as the 241Am/Be source (5 x at INFN- Laboratori Nazionali del Sud.

Activities:

  1. CEDAD: Production of a neutron beam with the accelerator TANDEM (18-21 months)
  2. CEDAD: Test of the 10B-based detectors using a radioactive source and accelerators (21-24 months)