GOALS of meeting … Discuss status of available detector arrays

1. GOALS of meeting … • Discuss status of available detector arrays • Discuss current developments (both here and elsewhere – DESPEC, …) • Identify technical “know-how” in different labs • Identify and define possible collaborations (FP7 ??) • Define goals, contributions, timelines, … NAO – Réunion 02/07

2. Programme … • Introduction + Goals, ideas, etc for a new array - Nigel Orr • Status of DESPEC neutron detector array work - Daniel Cano Ott • Two-neutron detection with TONNERRE - Miguel Marqués • Simulations using GEANT4 & MENATE - Brian Roeder • Status of the Neutromania project - Franck Delaunay • Digital electronics developments at LPC - David Etasse • Neutron detection at Bruyeres le Chatel - Xavier Ledoux • Discussion of how to go forward, interests and possible contributions from different labs, test experiments, etc NAO – Réunion 02/07

3. A New Low-Energy* Neutron Detector for the GANIL-SPIRAL-2 Community ? • Available detector arrays + status • Current developments • TONNERRE • Future low-energy/b-xn array * b-xn, (d,n), (p,n), - direct reactions not addressed today but requirements very similar NAO – Réunion 02/07

4. Neutron Detector Arrays Available within the French* GANIL-Based Community • DEMON : ~96 liquid scintillator modules (LPC, IRéS, UCL, ULB) • EDEN : ~40 liquid scintillator modules (IPNO) • ToF  En , granularity q, Q n-g discrimination • number of hits x e x ds/dWMn • TONNERRE : ~32 Plastic scintillator bars (LPC, Bucarest) • ToF  En, granularity + Dt q • ORION : large volume Gd-doped liquid scintillator • *see also presentation by Xavier L. later today

5. STATUS of Neutron Detector Arrays Available within the French GANIL-Based Community • DEMON : majority of modules still in reasonable condition • VXI + Daq no longer serviceable •  future unclear • EDEN : majority of modules still in good condition • CAMAC limited lifetime, coupling with new Daq’s • problematic •  future unclear • TONNERRE : upgraded 16 modules/32 PMTs • VXI + GANIL-LPC Daq, VME under implementation • available but not well adapted to future facilities • ORION : “moth balled”

6. Current Developments within the French GANIL-Based Community • New generation (solid) scintillators •  ANR : L. Stuttgé et al. (Strasbourg-Caen) • see contribution by Franck D. • New generation electronics-DAQ •  digital daq : D. Etasse et al. (LPC) • [manpower – BDI requested] • see contribution by David E. • Exploratory studies/simulations & prototype expts (~2007-2008) •  EURISOL + SPIRAL-2 (LPC): breakup arrays + b-n, b-n-n … see contributions by Brian R. & Miguel M.

7. TONNERRE Array TONNERRE scintillators EXOGAM • Up to 32 plasticscintillators [BC400, 160 x 20 x 4 cm, d=1.2 m] • En by TOF : 200 keV < En < ~5 MeV • DW45% of 4p • dE (1 MeV): ~ 80 keV • e (1 MeV) ~50 % A. Buta et al.,NIMA455 (2000) 412

8. TONNERRE : Detection Efficiency A. Buta et al.,NIMA455 (2000) 412

9. TONNERRE @ ISOLDE : State-of-the-Art F Perrot et al., PRC74 (2006)

10. TONNERRE : Limitations … number of counts number of counts 50 100 150 200 250 300 50 100 150 200 250 300 time-of-flight (ns) time-of-flight (ns) • Neutron time-of-flight spectra : b-decay of 45Cl28 and 46Cl29 4000 2000 1500 1000 500 0 2000 1000 800 600 400 200 0 46Cl29 46Cl28 45Cl28 S. Grévy and the TONNERRE collaboration

11. b-Delayed Neutron Detection : “Ground Rules” for a Future Detector • n-g discrimination  reduce backgrounds, enable b-2n,3n ... detection • Liquid scintillators (or new solid scintillators) • improve dEn and eliminate “tails” in TOF spectra •  thin, small volume detectors with increaseddflight • lowest possible threshold in En • thin, small volume detectors + digital electronics • cross-talk rejection  enable b-2n, 3n … detection • modular, highly granular array + variable geometry • high eg  identification of n-decay to excited states • large volume high efficiency Ge det’s (segmented ??) • (conflict with need for high DWn)