MRTOF mass measurements at GARIS-II: Toward SHE identification via mass spectroscopy

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Margaret Morris
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1 MRTOF mass measurements at GARIS-II: Toward SHE identification via mass spectroscopy

2 Purpose of SlowSHE 118 Alpha decay 117 Spontaneous Fission Beta Decay / Electron Capture Directly Synthesizable / T <5 ms 1/2 113 Fl 115 Lv 175 Directly Synthesizable / T >5 ms 1/2 Cn Md No Rf Lr Db Sg Bh Hs Mt Ds Rg Longer half-lives 3-body decay more likely Low rates N= Already start to see increase in SF Eventually longer T1/2 will become bottleneck, too

3 SlowSHE Facility LINAC SlowSHE Flat Trap Pulsed Drift Tube

4 Low-energy beam preparation Very fine wire rf-carpet

5 Low-energy beam preparation 205 Fr

6 Low-energy beam preparation ns pulse Continu ous ion bea m μs pulse ns pulse Multi-directional flat rf-trap

7 Simplified MRTOF Methodology + Ion Trap MCP 0V Approx. Potential

8 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap Ion Trap + MCP 0V Approx. Potential

9 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap 2. Lower voltage on injection Ion Trap + MCP 0V Approx. Potential

10 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap 2. Lower voltage on injection Ion Trap + MCP 3. Eject ions from trap 0V Approx. Potential

11 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap 2. Lower voltage on injection Ion Trap + MCP 3. Eject ions from trap 4. Raise voltage on injection 0V Approx. Potential

12 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap 2. Lower voltage on injection 0V Ion Trap + MCP 3. Eject ions from trap 4. Raise voltage on injection 5. Wait for N reflections Approx. Potential

13 Simplified MRTOF Methodology 1. Accumulate and cool Ions in trap 2. Lower voltage on injection 0V Ion Trap + MCP 3. Eject ions from trap 4. Raise voltage on injection 5. Wait for N reflections 6. Lower voltage on ejection Approx. Potential

14 Simplified MRTOF Methodology t t0 m = m ref t ref t Accumulate and cool Ions in trap 0V Ion Trap + MCP 2. Lower voltage on injection 3. Eject ions from trap 4. Raise voltage on injection 5. Wait for N reflections 6. Lower voltage on ejection Approx. Potential 7. Detect ions at MCP

Comparison to PTMS r m t tof = L 2K @t tof @K 0 Isochronous!

15 Comparison to PTMS r m t tof = L 0 Isochronous! PTMS ~ 304 T m m = Rm=150,000 N 150 δm/m 5x10-7 N 10 δm/m 2x10-6 a R m p N, Slow,

16 Simultaneous Measurements Counts / 6.4 ns Counts / 6.4 ns Counts / 3.2 ns 165 Ho( 40 Ar, 4n) 201 At 169 Tm( 40 Ar, 4n) 205 Fr 169 Tm( 40 Ar, 3n) 206 Fr Decays or ypxn-channels?

17 Results: Weighted average mass deviation Reference: 133 Cs Fr + Species Δm [kev] Δm [kev] N [ions] 201 At -342(45)(3) g Po -16(74)(3) Bi -35(385)(3) Fr -80(36)(60) Rn 212(320) At 73(420) Po -1059(2050) 2 206m Fr -98(118)(1) Rn 551(600)(1) At -69(2150)(1) 3 27pSH-6

18 Mass measurements from first run m - m AME 12 [kev] Bi 201g Po 201 At 205 Fr 205 Rn 205 At 205 Po 206m Fr 206 Rn 206 At

19 Next Step: TransFermium nuclei Cn Projectile Beams 15 N 1 p A 22 Ne 3 p A 40 Ar 1 p A 48 Ca 1 p A 50 Ti 500 pna 54 Cr 272Rg 274Rg 269 Ds 271 Ds 273 Ds 268 Mt 270 Mt 264Hs Hs Hs 269 Hs 261Bh Bh Bh 244 Fm 3.5 ms 245 Fm 4.2 s 249 Md kev 1.0 s s 0.8 s # kev 1.3 s kev 2.54 s m 0.6 s 0.8 s 255Rf 256 Rf 257 Rf 258Rf s m m Fm Fm Fm Fm Fm 257 Db 140# kev 2.3 s 0.67 s 6.6 ms kev 2.5 s 254 N= s 1295 kev 265 ms 51 s 253 Md 252 Fm 259 Sg 258 Db 60# kev 1.9 s 73 kev 4.3 s s 3.5 m 4.5 s 4.8 s 260 Sg 4.95 ms 257 Lr s 2.9 s 261 Sg 183 ms Db Db 262Db 259 Rf 258 Lr s 24.5 s Md Md 255 Md 262 Sg 259 Lr 6.2 s 263 Sg 261 Rf 260 Lr 3.0 m 265 Sg Mass measurements of trans-fermium isotopes will provide important data for nuclear shell models used to predict location and properties of the Island of Stability

20 Deeper into the future Alpha decay 117 Spontaneous Fission Beta Decay / Electron Capture Directly Synthesizable / T <5 ms 1/2 113 Fl 115 Lv 175 Directly Synthesizable / T >5 ms 1/2 Cn Md No Rf Lr Db Sg Bh Hs Mt Ds Rg Longer half-lives 3-body decay more likely Low rates N= Already start to see increase in SF Eventually longer T1/2 will become bottleneck, too

21 Conclusion Using MRTOF-MS we can: Simultaneous mass measurement Short-lived nuclei Heavy nuclei Identify nuclei with few counts

22 SlowSHE Facility Initial estimates Process 1. He Gas Cell Stopping Efficiency 60% 2. Ext. via RF-Carpet: 0-5 ms 3. OPIG Transport: < 1ms 4. Ion Cooling: 2 ms 5. MRTOF ToF-MS: 2~10 ms 50% 100% >5% 100% Total 5~20 ms 1%

Chemistry GARIS

Chemistry GARIS Chemistry planned @ GARIS Cyclotron Center, RIKEN Hiromitsu Haba 1. Introduction 2. Gas-jet chamber coupled to GARIS 3. Search for SHE nuclides for chemical experiments 4. Future plans 1. Introduction