ACTAR TPC a new time projection chamber for

ACTAR TPC: a new time projection chamber for radioactive beam experiments D. Suzuki Institut de Physique Nucléaire d’Orsay On behalf of the ACTAR TPC collaboration suzuki@ipno. in 2 p 3. fr 10 th RD 51 Collaboration Meeting: October 4, 2012 Stony Brook, NY, USA

Outline l Physics l Basic motivation concept: “Active-target” TPC l ACTAR TPC project scope l Micromegas l ACTAR prototype test TPC demonstrator 2

Physics motivation l Structure/ reaction dynamics of unstable nuclei Z • Isospin dependence of nuclear mean field • Weakly-bound many-body systems • Nucleosynthesis N 3

Challenges of RI beam reactions l Light ion (p, d, 3, 4 He…) as hadronic probe l RI beams (heavy) + target (light) l l “Asymmetric” collision l Swiftly moving CM frame l Low-energy probe ion in LAB frame l Energy loss in target deteriorates the resolution Idea of “Active-target” TPC l Track ions “inside” the target 56 Ni(d, d’)56 Ni d CD 2 solid target D 2 gas target 56 Ni http: //pro. ganil-spiral 2. eu/spiral 2/instrumentation/actar-tpc 56 Ni d 4

MAYA @GANIL l Operational since 2003 l Low beam energy (~ 3 Me. V/u) l Low transferred energy C. E. Demonchy et al. , Nucl. Instrum. and Meth. A 583 (2007) 341 56 Ni(d, TRIUMF d’) @50 Me. V/u ISOLDE C. Monrozeau et al. , Phys. Rev. Lett. 100 (2008) 042501 5 http: //pro. ganil-spiral 2. eu/laboratory/detectors/maya

Beyond MAYA l Precise particle identification of stopped particles l Discriminating (p, d, t) or (3 He, 4 He, 6 He) is difficult with MAYA l Using energy deposit profile l MAYA is using wire technology with hexagonal pads ~ 1 cm l MPGD with smaller pixels 2 x 2 mm 2 6 He(α, α) 6 He Taken with Micromegas 2 mm-wide strips α D. Suzuki et al. , Nucl. Instr. and Meth. A 691 (2012) 39. 6

Next Generation: ACTAR TPC l Specifications l l l 2012 - 2013 Research and Development l l l Reactions Microgegas/ GEM (~ 650 cm 2, pad size 2 × 2 mm 2) MMs or GEMs 16, 384 channel GET (General Electronics for TPC’s): l Wave-digitizer using 511 analogue memory cells @ 100 MHz max l Internal trigger/ zero suppression for reducing data traffic l ANR Funded Project (Nov. 2009 − Oct. 2013) l IRFU/CEA-Saclay, CENBG, GANIL, MSU 25. 6 cm Different physical geometries: Reaction and decay Tests of prototype detector (Micromegas & GEM) Building of demonstrator Physics simulations (ACTARsim) Chamber design (geometry, mechanics) GET electronics development 25. 6 cm Decay MMs + GEMs 12. 8 cm 51. 2 cm 7

Micromegas Prototype l ϕ 5. 6 cm, 2 × 2 mm 2 576 channel prototypes l Design @ IPN Orsay l Bulk micromegas @ CEA Saclay (IRFU-SEDI) l Amplification gaps (128 and 256 μm) 5. 6 cm 72 -channel connector 8

Detector tests inside Maya @ GANIL l Determine angular and energy resolution l Gases: C 4 H 10, He: CF 4 98: 2, Ar: CF 4 98: 2 l Pressures: 25 – 1100 mbar l 239 Pu/ 241 Am/ 244 Cm l T 2 K electronics (511 analogue circular memory cells) source T. Lux for the T 2 K TPC groups, J. Phys: Conf. Ser. 65 (2007) 012018 Enclosure Field cage He: CF 4 98: 2 500 mbar Micromegas 256 μm T 2 K electronics Silicon 9

Horizontal Angular Resolution l Slit position reconstruction: He: CF 4 98: 2 l Extrapolation of 4 cm traces on pad plane l Varied pressure, drift and amplification voltages l Angular resolution < 1. 3° (FWHM) 12. 5 mm (4. 1°) α Slit 5 Slit 9 1. 1° FWHM Slit 13 10

Horizontal Angular Resolution l How does resolution evolve with short traces? l Important for low-energy reaction and decay products l MAYA reconstruction not possible below ~ 5 cm 3. 6 cm 2. 4 cm MAYA 1. 2 cm 11

Vertical Angular Resolution l Vertical angles determined from the calibrated drift times l Less sensitive to trace length (gas and pressure dependent) l Angular resolution < 1. 2° (FWHM) l Equivalent to the horizontal resolution 12. 5 mm (4. 1°) 1. 0° FWHM 12

Energy (Range) Resolution l Range of α’s in Ar: CF 4 98: 2 @ 1100 mbar l Range resolution > 0. 8 mm (FWHM) l Energy resolution > 80 ke. V (FWHM) 241 Am 5. 49 Me. V 239 Pu 244 Cm 5. 81 Me. V 1. 2 mm FWHM 5. 16 Me. V 13

ACTAR TPC Demonstrator 12 × 6 cm 2; 2 × 2 mm 2 × 2, 048 pads l Test high-density connection l l l Moveable Source Si Strip Detector High-density connector (IPNO) Direct insertion to Micromegas 24 cm Test GET electronics l Assembled on Sep. 24, 2012 24 cm l 30 cm Enclosure IPNO Field Cage GANIL Beam Entrance Pad Plane 1 IPNO Pad Plane 2 CENBG Electronics 14

Summary l ACTAR-TPC, a new time projection chamber for radioactive beam experiments, is under development in France. l A high-granularity Micromegas was tested with C 4 H 10, He: CF 4, and Ar: CF 4 l l Angular resolution ~ 1° FWHM l Energy resolution ~ 80 ke. V FWHM l Met or exceeded collaboration requirements ACTAR TPC Demonstrator has been assembled l Test starts from October 2012 l Test a complete GET system l Define the final detector design l Budget request for the full detector: Fall 2012 http: //pro. ganil-spiral 2. eu/spiral 2/instrumentation/actar-tpc 15

ACTAR TPC Collaboration l CENBG l l B. Blank, J. Giovinazzo, J. L. Pedroza, J. Pibernat l l l GANIL l l S. Damoy, G. F. Grinyer, J. Pancin, D. Perez-Loureiro, F. Saillant, B. Raine, T. Roger, G. Wittwer l V. Chambert, E. Khan, A. Lermitage, G. Noël, J. Peyre, J. Pouthas, P. Rosier, D. Suzuki, M. Vandebrouck, L. Vatrinet, T. Zerguerras R. Raabe, S. Sambi U de Santiago de Compostela l l F. Druillole, A. Gillibert, E. C. Pollacco K. U. Leuven l IPNO l IRFU Saclay H. Alvarez-Pol, J. Benlliure, M. Caamaño, D. Cortina-Gil, B. Fernandez-Dominguez Funding partners: 16