短寿命核分離加速実験@KEK-JAERI 素核研、物理第4研究系、石山博恒 •Facility Plan • Research Subjects • R&D’s and Schedule

Research Subjects 3. 物質科学 1. 天体核物理 ★天体核反応率の直接測定 1. 天体核物理 　★天体核反応率の直接測定 　★r過程原子核の質量測定 　　⇒宇宙での元素合成の実験的解明 2. 中重中性子過剰核の原子核物理 　★クーロン励起、レーザーによる核分光 　⇒安定核領域から離れた原子核の各構造、核反応機構 3.　物質科学 　★RNBの打ち込みによる材料研究（拡散、電気磁気物性、機械的性質） 　⇒新材料の探索 4.　超アクチノイド元素の核化学と原子核物理 　★超アクチノイド元素の化学的性質の研究 　★超重元素探索とその構造

Facility Proposal KEK-JAERI Joint RNB Facility 1999 - 2000: All the RNB instruments were moved to Tsukuba (no-primary beam accelerator) To rapid resume “Low-Energy RNB Science” including the nuclear physics, nuclear chemistry, nuclear astrophysics, material science, etc. It would be too late to start E-arena in JHF, whose construction will take at least 6-7 years!! KEK-JAERI Joint RNB Facility • 5-9 MeV/u RNB will be available with using the existing S.C. Linac • Neutron-rich medium- and heavy-RNB can be supplied by the help of p-induced U-fission reaction. • Intense stable nuclear beam is also available independent from Tandem • Low Energy RNB center under the collaboration with KEK and JAERI

Time Schedule 2000 2001 2002 2003 2004 2005 (< 1 MeV/u) (5-9 MeV/u) KEK 　Charge Breeder 　Beam line 　Linac 　Measuring device 　Water 　Buncher JAERI 　IH-2、HEBT 　Exp. Room 　Utility house 　Electric power 　Water cooling system (< 1 MeV/u) (5-9 MeV/u)

Charge Breeding(CB-) ECR Accelerator condition: A/q≥30 for SCRFQ, ≥10 for IH1, ≥7 for IH2, SC-linac 1+-I/S ISOL CB-ECRIS MINIMAFIOS (10 GHz) ECRIS 1+ ->n+ breeding efficiency 1+-ion n+-ion to SCRFQ Particle production VCB=2A/q kV DV(~10 eV) Electric potential (V) DC-breeding/Bunching Breeding ECR confinement time: 520 ms for Rb15+ Charge states equibration time: ~20 ms N. Chauvin et al.,Proc. 14th ECRIS99(‘99)151. smooth deceleration sudden deceleration

Layout of the Charge Breeding System at KEK Test Bench

短寿命核ビームによる固体試料中の拡散系数測定 Charge-discharge mechanism in Li Battery 短寿命核ビームによる固体試料中の拡散系数測定 C6Lix(Cathode) Li1-xCoO2(Anode) Li+ 特徴 Li 1.高速短寿命核ビーム 　⇒表面状態によらない拡散条件 2.遅延荷電粒子エネルギー測定 放出エネルギースペクトルの時間変化 　⇒密度分布変化 3.Sensitivity 短寿命核の寿命と遅延荷電粒子の 阻止能 　⇒on-Line測定（大きい拡散系数） s=(2Dt)1/2 8Li density T=t0 t1 t2 position counts Ea

Explosive Nucleosynthesis 17F 18F 19F 20F 21F 22F 23F 24F Explosive Nucleosynthesis 13O 14O 15O 16O 17O 18O 19O 20O 21O 22O T9 = 1 ( 109 K ) 12N 13N 14N 15N 16N 17N 18N 19N 10C 11C 12C 13C 14C 15C 16C 17C STABLE b- DECAY 8B 10B 11B 12B 13B 14B 15B Proton Supernova Explosion 7Be 9Be 10Be 11Be 12Be T9=1 Neutron & Seed 6Li 7Li 8Li 9Li 11Li T9=3 Alpha & Neutron 3He 4He 6He 8He r-process T9=10 Neutron & Proton p D T a-process n Neutron (a,n) reaction Core

Direct-Exclusive Measurement of (α,n) reaction Detector MSTPC & Neutron counter n Veto counter (SSD) RN beam E=1~2 MeV/u I=103～105pps MCP Start counter (PPAC) MSTPC He gas Energy region T9～1 Ecm～0.5MeV Neutron counter