MRTOF mass measurements at GARIS-II: Toward SHE identification via mass spectroscopy
Purpose of SlowSHE 118 117 Alpha decay Lv Spontaneous Fission 115 Beta Decay / Electron Capture Fl Directly Synthesizable / T <5 ms 175 1/2 113 Directly Synthesizable / T >5 ms Cn 1/2 y Rg l e 170 k Ds i l e s Mt e r o v i m Hs l - f l y a Bh a h c e r Sg e d g s y n Db e d o t o a 165 L Rf b r - w 3 Lr o L No 160 Md N= 145 150 155 Already start to see increase in SF • Eventually longer T 1/2 will become bottleneck, too •
SlowSHE Facility LINAC SlowSHE Flat Trap Pulsed Drift Tube P . Schury Nov. 9, 2015 JCNP2015
Low-energy beam preparation Very fine wire rf-carpet P . Schury Nov. 9, 2015 JCNP2015
Low-energy beam preparation 205 Fr P . Schury Nov. 9, 2015 JCNP2015
Low-energy beam preparation ns pulse Continuous ion beam μ s pulse ns pulse Multi-directional flat rf-trap P . Schury Nov. 9, 2015 JCNP2015
Nov. 9, 2015 0V Ion Trap + Approx. Potential Simplified MRTOF Methodology MCP JCNP2015 P . Schury
Nov. 9, 2015 0V Ion Trap + Approx. Potential Simplified MRTOF Methodology MCP JCNP2015 1. Accumulate and cool Ions in trap P . Schury
Nov. 9, 2015 0V Ion Trap + Approx. Potential Simplified MRTOF Methodology MCP JCNP2015 2. Lower voltage on injection 1. Accumulate and cool Ions mirror in trap P . Schury
Nov. 9, 2015 0V Ion Trap Approx. Potential Simplified MRTOF Methodology + MCP JCNP2015 3. Eject ions from trap 2. Lower voltage on injection 1. Accumulate and cool Ions mirror in trap P . Schury
Nov. 9, 2015 0V Ion Trap Approx. Potential Simplified MRTOF Methodology + MCP JCNP2015 4. Raise voltage on injection 3. Eject ions from trap 2. Lower voltage on injection 1. Accumulate and cool Ions mirror mirror in trap P . Schury
Nov. 9, 2015 0V Ion Trap + Approx. Potential Simplified MRTOF Methodology MCP JCNP2015 5. Wait for N reflections 4. Raise voltage on injection 3. Eject ions from trap 2. Lower voltage on injection 1. Accumulate and cool Ions mirror mirror in trap P . Schury
Nov. 9, 2015 0V Ion Trap + Approx. Potential Simplified MRTOF Methodology MCP JCNP2015 6. Lower voltage on ejection 5. Wait for N reflections 4. Raise voltage on injection 3. Eject ions from trap 2. Lower voltage on injection 1. Accumulate and cool Ions mirror mirror mirror in trap P . Schury
Nov. 9, 2015 0V Ion Trap m = m ref ✓ t − t 0 Approx. Potential Simplified MRTOF Methodology t ref − t 0 ◆ 2 + MCP JCNP2015 7. Detect ions at MCP 6. Lower voltage on ejection 5. Wait for N reflections 4. Raise voltage on injection 3. Eject ions from trap 2. Lower voltage on injection 1. Accumulate and cool Ions mirror mirror mirror in trap P . Schury
Nov. 9, 2015 PTMS ~ 304 T Comparison to PTMS N ≳ 150 ⇒ δ m/m ≲ 5x10 -7 N ≳ 10 ⇒ δ m/m ≲ 2x10 -6 δ m m = R m =150,000 JCNP2015 R m a √ N t tof = L ∂ t tof ∂ K ≈ 0 Isochronous! r m P 2 K . Schury , , Slow
Simultaneous Measurements Counts / 6.4 ns Counts / 3.2 ns • 165 Ho( 40 Ar, 4n) 201 At • 169 Tm( 40 Ar, 4n) 205 Fr Counts / 6.4 ns • 169 Tm( 40 Ar, 3n) 206 Fr • Decays or y p x n-channels? P . Schury Nov. 9, 2015 JCNP2015
Results: Weighted average mass deviation 133 Cs + 205 Fr + Reference: Species Δ m [keV] Δ m [keV] N [ions] 201 At -342(45)(3) 522 201g Po -16(74)(3) 108 201 Bi -35(385)(3) 6 205 Fr -80(36)(60) -- 467 205 Rn 212(320) 48 205 At 73(420) 11 205 Po -1059(2050) 2 206m Fr -98(118)(1) 210 206 Rn 551(600)(1) 3 206 At -69(2150)(1) 3 P . Schury 27pSH-6
Mass measurements from first run 2000 1500 1000 500 m - m AME’12 [keV] 0 -500 -1000 -1500 -2000 -2500 -3000 201 Bi 201g Po 201 At 205 Fr 205 Rn 205 At 205 Po 206m Fr 206 Rn 206 At P . Schury Nov. 9, 2015 JCNP2015
Next Step: TransFermium nuclei 278 113 277 Cn 272 274 Rg Rg 22 40 48 50 54 15 Ne Ar Ca Ti N Cr Projectile 3 p μ A 1 p μ A 1 p μ A 500 pnA Beams 1 p μ A 269 271 273 Ds Ds Ds 268 270 Mt Mt 269 264 Hs Hs 265 267 Hs Hs 261 264 266 Bh Bh Bh Mass measurements of 259 260 261 262 263 265 Sg Sg Sg Sg Sg Sg N=152 4.95 ms 183 ms trans-Fermium isotopes will 257 258 259 260 262 D Db Db Db Db Db 140# keV V 2.3 s 60# keV 4.5 s 0.67 s 1.9 s provide important data for 256 257 255 Rf Rf R Rf 258 Rf 259 261 Rf Rf 6.6 ms 73 keV 4.8 s 4.3 s nuclear shell models used to 254 253 255 5 256 6 257 258 259 260 Lr Lr Lr Lr 17.1 s 22 s 6.0 s 4.1 s 6.2 s 3.0 m 40 keV 30# keV 2.5 s 31 s 1.3 s 0.6 s predict location and 251 252 2 253 254 4 255 256 6 257 7 1295 keV V 24.5 s 1254 keV 160 keV 1.56 m 265 ms 51 s 3.5 m 2.9 s 0.8 s 0.8 s 2.54 s 1.0 s properties of the “Island of 250 251 252 249 253 254 255 256 Md M Md Md Md Md 52 s 4.2 m 2.3 m Stability” 244 245 247 248 249 250 251 252 Fm Fm Fm Fm Fm Fm Fm F Fm 3.5 ms 4.2 s P . Schury Nov. 9, 2015 JCNP2015
Deeper into the future... 118 117 Alpha decay Lv Spontaneous Fission 115 Beta Decay / Electron Capture Fl Directly Synthesizable / T <5 ms 175 1/2 113 Directly Synthesizable / T >5 ms Cn 1/2 y Rg l e 170 k Ds i l e s Mt e r o v i m Hs l - f l y a Bh a h c e r Sg e d g s y n Db e d o t o a 165 L Rf b r - w 3 Lr o L No 160 Md N= 145 150 155 Already start to see increase in SF • Eventually longer T 1/2 will become bottleneck, too •
Conclusion Using MRTOF-MS we can: • Simultaneous mass measurement • Short-lived nuclei • Heavy nuclei • Identify nuclei with few counts P . Schury Nov. 9, 2015 JCNP2015
SlowSHE Facility Initial estimates Process Efficiency ≈ 60% 1. He Gas Cell Stopping ≈ 50% 2. Ext. via RF-Carpet: 0-5 ms ≈ 100% 3. OPIG Transport: < 1ms >5% 4. Ion Cooling: ≈ 2 ms ≈ 100% 5. MRTOF ToF-MS: 2~10 ms ≈ 5~20 ms ⪆ 1% Total
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