Focal plane detector discussion Kwangbok Lee Low Energy Nuclear Science team Rare Isotope Science Project Institute for Basic Science July 11,

First thought for FPD system IC Si ΔE and E measurement for the recoils, decays at forward Silicon shape can be barrel or can be inserted to Gamma-array IC (MW)PPAC Double side Si for x and y Plastic scintillator x, y positions ( < 1 mm resolution) and incident angle of MWPPAC and Si. ΔE and E with IC and Si, respectively. Timing of 500 ps from MWPPAC. Low energy electron veto with plastic scintillator. For F3 For F5 Recoils Beam 2

Hybrid FPD, NIM A 432 (1999), For Day 1 experiment? 14 N beam(107 MeV) to 24 Mg target 8 silicon detector(80*30mm 2 )s in serial Position resolution; 1 mm 12 C 6+ ; ΔA/A ~ 1/88, E ~ 2.0%, ΔE ~ 8.7%, TOF ~ 6.0 ns angle dependence correction -> E ~ 1.6%, ΔE ~ 7.5%, TOF ~ 3.7 ns W.R.T. RF signals E ~ 1.2% (Si) + 0.7% (gas counter) ΔE ~ 7.2% (ΔE1 counter) TOF ~ acceleration phase of the cyclotron. Position; at A and E ΔE; C and D Residual E; Si or plastic scintillator. No wire in the beam window. -> Minimize the energy loss of pass-through particles. 3

Used at VAMOS as SPIDER. Recoils produces ΔE at first layer(60 μm thick) and E at second layer(1 mm thick). 6.1 AMeV MICRON 4

RIPS, RIKEN Dr. Eunhee Kim(IBS) PPAC detectors - Measure the trajectories of individual projectiles ( 8 B, 9 C) Proton target : cryogenic 5 mm thick gas cell - Hydrogen gas at 27 K (pressure =5 atm) - Target thickness=1.35×10 21 protons/cm 2 ) - 15μm Havar windows RIKEN Telescope of silicon detectors (11°≤Θ≤22°) μm double-sided strip detector (DSSD) - six 750 μm single-sided sectored detectors (SSDs) → measure recoil products (deuterons) Proton target and detectors setup 8 B(p,d) 7 B* : 7 B* → 6 Be(2 + )+p → 4 He+3p 9 C(p,d) 8 C* : 8 C* → 6 Be g.s. (0 + )+2p → 4 He+4p Excitation energy in the residual 7 B* or 8 C* systems PPACsRIKEN telescopeDubna telescope Dubna Telescope (3.0°≤Θ≤7.5°) - 1 mm thick double-sided silicon strip ΔE detector (DSSD) - 16 trapezoid 2cm thick CsI (Tl) crystals with PIN-diod redouts → measure 4 He (α) and p Secondary beam

6 RIPS, RIKEN Dr. Eunhee Kim(IBS) RIKEN telescope Target

Position sensitive Si detector Tested by 63 Cu, 16 O, 4 He ion beams of 7 to 40 MeV/u and 228 Th, 214 Am alpha source(E α = 5.47~ 8.79 MeV) at Texas A&M. Position resolution, < 1 mm (2 mm) with beam measurement (alpha source) and Energy resolution, 2% with alpha source. NIM A, 593: ,

8

α decay measurement for SHE, ,Uus 249 Bk+ 48 Ca (252 MeV. cf. Ec = 239MeV), ER-α 132ms for Eα = MeV, 18ms for MeV. (beam off for 3 min-15min.) 1.1 particle μA, 2.4*10 19 projectiles during 70-day run. 52%(87% with side detectors) efficient for the decays of implanted nuclei. Eα ~ 10 MeV, keV, keV (side) Position resolution ~ mm for ER-α and mm for ER-SF signals. 12 * 4 cm 9

Summary and outlook  PPAC is being developed and first prototype is constructed.  Ionization chamber prototype is constructed and simulation work is being done for the improvement.  It needs to specify FPD for specific physical processes. Consideration for the FPD system; -> Optimization for low energy ions (~0.3 MeV/u of RAON) -> minimize energy threshold, detector windows number/thickness. -> Low energy around Coulomb barrier’ particles has larger angular distribution and low production cross section -> Need large detector window -> Count rate handling -> ex.) VAMOS FPD is limited by the rate of the drift chamber (< 10 kHz). -> Another detector performances of efficiency, handling, building, costs.. and? <- Goal of this year is to have the proper design for the system. -> Your suggestion is quite welcome!! 10

BACK UP 11

Modular design at VAMOS++ Modular mechanical set-upSingle module containing the IC Modular manner has a precise and reproducible geometry. Each detector has its own independent chamber, moves on rail. Minimized electronics cable length and optimized the heat dissipation. It is composed of MWPPAC, DCs with isobutene of 6 mbar and IC with CF 4 of 20 to 40 mbar. (cf. MWPPAC as start detector independent of beam pulse->500 ps->1/220) particles 12

13