1. Bordeaux Meeting June 6-7th, 2005 Meeting starts at 2:30 pm, Monday June 6th 1)Summary of EURONS meeting (February 2005, Madeira) 2)Discussion of ACTAR Yellow book 3 key experiments Physics constraints, dynamic range, resolution needed, ancillary detector 3)Discussion on Task 2: development of event generators Choice of geometry (cubic/cylindric) 4)Discussion on Task 3: Test properties of different gases at room temperature (USC) Beam shielding (GANIL) Test of different read-out chambers with existing prototypes Studies of heavy ion interaction with matter at GANIL, Bordeaux, DAPNIA 5)Discussion on Task 4 Evaluation of existing ASICs

2. Summary of EURONS Meeting

6. Task 1-1 : Physics constraints ACTAR Yellow Book 1)Elastic-Inelastic scattering Resolution in energy, in angle Dynamical range (light/heavy partners) 2)Transfer reactions light dripline nuclei (and beyond) 22 Ne( 11 Li, 8 n) 25 Al 22 Ne( 8 He, 8 n) 22 Mg shell structure 78 Ni(d,p) 79 Ni 78 Ni(p,d) 77 Ni 3) New radioactivies 2 proton decay

7. Task 1-1 : Physics constraints ACTAR Yellow Book Summary of our discussion on Yellow Book Modifications to be made to the present document 1)Introduction/Section2: insist on the specificity of ACTAR with respect to EXL or solid state detector arrays (low production rate nuclei, small momentum transfer). Stress that ACTAR will be used at low and high energy. 2)Elastic scattering: add key experiment at high energy p+ 134 Sn for example (Peter) 3)Inelastic scattering (alpha, alpha’) : contact Elias 4)Charge exchange reaction: direct and resonant, take related section in R3B (Wolfi) 5)Transfert: part of the text written by Roy has to be included in the introduction, remove figure on tetraneutron. Give more specific details: kinematics,… (Roy) 6)Resonant cluster break-up: Martin Freer 7)2p radioactivity: Bertram We will try to have the final document ready by end of June. The document can be found via ftp://ftpcenbg.in2p3.fr/pub/nex/ACTAR

8. Reaction Kinematics

9. Task 1-2 : Detailed simulations Development of Event Generators See Lola’s talk

10. Task 2: Test modules Task 2-1: Detection/target gas Task 2-2: Read-out chamber Task 2-3: Magnetic field configuration tests Test properties of different gases at room temperature (USC) Beam shielding (GANIL) Test of different read-out chambers with existing prototypes Studies of heavy ion interaction with matter at GANIL, Bordeaux, DAPNIA

11. Simulations with Garfield of amplification curves Experimental tests with  source H 2,D 2,Ne,CO 2,He, mixtures…. (define the list of useful gases) Temperature and pressure dependence of sparks and drift times Dynamic range (beam shielding) In beam tests Saclay and Bordeaux: direct light ion beams GANIL: elastic scattering on CH 2 or fusion evaporation reactions on a target in SME Task 2-1 and 2-2: Detection gas/ Readout chamber

12. Tests of different readout systems: wires (GANIL), Gems (Bordeaux), Micromegas (Saclay) – for wires: test of different configurations e.g. alternance of amplification wire and mass wire -for Gems: induction/granularity -for Micromegas? Definition of quality criteria -energy resolution (total charge) -range resolution -position resolution (–> angular resolution and vertex)

13. Task 2-2: Readout chamber (N.B. Problems encountered with He in MAYA) -Extend this type of curves down to low pressures (10 mbar), and add other gases -Same for wires -Same for Micromegas

14. Task 2-2: Readout chamber Gases study: Determine  E/  x curve, TRIM calculation : factor 6 between the  E/  x at the Bragg peak and at the low ionization part of the curve (10 MeV proton in 1 atm C 4 H 10 ). MAYA : factor ≈ 2. This is coming from the detector response (induced charge). But for the GEM the response will be different (direct charge collection) and this point is critical for the electronics specification, as the dynamics of the preamplifiers. Localization: GEM readout is mainly based on charge collection Studies done by Carleton University : difficult and not efficient to use the induced signal on the pads in the vicinity). Charge may be collected on a single pad. Same algorithm as for MAYA cannot be used. 3 solutions: - Decrease the size of the pixels - Spread the charge on several pads, ex: Carlton Univ. - Combination of both charge dispersion and small pixels.

15. Task 2-2: Readout chamber

16. 8 Li( ,n) 11 B 7 Be(p,p)

17. TPC De Geronimo IEEE 51 (2004) ≈ 8000 channels Pads= 24 concentric circles 5mm radial pitch, 2mm angular pitch (zigzag) LEGS experiment Detection of pions

18. BoNuS at CEBAF

19. BONUS