MRTOF mass measurements at GARIS-II: Toward SHE identification via - - PowerPoint PPT Presentation

SLIDE 1

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

SLIDE 2

Purpose of SlowSHE

• Already start to see increase in SF
• Eventually longer T1/2 will become bottleneck, too

Rf Db Sg Bh Hs Mt Ds Rg Cn 113 Fl 115 Lv 117 118 175 170 165 160 N= 155 150 Lr No Md 145 Alpha decay Spontaneous Fission Beta Decay / Electron Capture Directly Synthesizable / T <5 ms

1/2

Directly Synthesizable / T >5 ms

1/2

L

• n

g e r h a l f

• l

i v e s 3

• b
• d

y d e c a y m

• r

e l i k e l y L

• w

r a t e s

SLIDE 3

P . Schury

• Nov. 9, 2015

JCNP2015

SlowSHE Facility

SlowSHE

LINAC

Flat Trap Pulsed Drift Tube

SLIDE 4

P . Schury

• Nov. 9, 2015

JCNP2015

Low-energy beam preparation

Very fine wire rf-carpet

SLIDE 5

P . Schury

• Nov. 9, 2015

JCNP2015

Low-energy beam preparation

205Fr

SLIDE 6

P . Schury

• Nov. 9, 2015

JCNP2015

Low-energy beam preparation

ns pulse ns pulse μs pulse Continuous ion beam

Multi-directional flat rf-trap

SLIDE 7

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 8

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 9

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 10

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

• 3. Eject ions from trap

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 11

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

• 3. Eject ions from trap
• 4. Raise voltage on injection

mirror

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 12

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

• 3. Eject ions from trap
• 4. Raise voltage on injection

mirror

• 5. Wait for N reflections

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 13

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

• 3. Eject ions from trap
• 4. Raise voltage on injection

mirror

• 5. Wait for N reflections
• 6. Lower voltage on ejection

mirror

Ion Trap

+

MCP

• Approx. Potential

0V

SLIDE 14

P . Schury

• Nov. 9, 2015

JCNP2015

Simplified MRTOF Methodology

• 1. Accumulate and cool Ions

in trap

• 2. Lower voltage on injection

mirror

• 3. Eject ions from trap
• 4. Raise voltage on injection

mirror

• 5. Wait for N reflections
• 6. Lower voltage on ejection

mirror

• 7. Detect ions at MCP

Ion Trap

+

MCP

• Approx. Potential

0V

m = mref ✓ t − t0 tref − t0 ◆2

SLIDE 15

P . Schury

• Nov. 9, 2015

JCNP2015

Comparison to PTMS

Rm=150,000 N≳150 ⇒δm/m≲5x10-7 N≳10⇒δm/m≲2x10-6

δm m = a Rm √ N

Isochronous!

PTMS ~ 304 T

ttof = L r m 2K ∂ttof ∂K ≈ 0

, , Slow

SLIDE 16

P . Schury

• Nov. 9, 2015

JCNP2015

Simultaneous Measurements

Counts / 6.4 ns Counts / 6.4 ns Counts / 3.2 ns

• 165Ho(40Ar, 4n)201At
• 169Tm(40Ar, 4n)205Fr
• 169Tm(40Ar, 3n)206Fr
• Decays or ypxn-channels?

SLIDE 17

P . Schury

27pSH-6

Results: Weighted average mass deviation

133Cs+ Species Δm [keV] Δm [keV] N [ions]

201At

• 342(45)(3)

522

201gPo

• 16(74)(3)

108

201Bi

• 35(385)(3)

6

205Fr

• 80(36)(60)
• 467

205Rn

212(320) 48

205At

73(420) 11

205Po

• 1059(2050)

2

206mFr

• 98(118)(1)

210

206Rn

551(600)(1) 3

206At

• 69(2150)(1)

3

Reference:

205Fr+

SLIDE 18

P . Schury

• Nov. 9, 2015

JCNP2015

Mass measurements from first run

• 3000
• 2500
• 2000
• 1500
• 1000
• 500

500 1000 1500 2000

201Bi 201gPo 201At 205Fr 205Rn 205At 205Po 206mFr 206Rn 206At

m - mAME’12 [keV]

SLIDE 19

P . Schury

• Nov. 9, 2015

JCNP2015

Next Step: TransFermium nuclei

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”

Fm

252

Rf

261

Rf

259 252 2.3 m 251 4.2 m 250 52 s 256 6 2.9 s 3.5 m 255 0.8 s 1254 keV 2.54 s 252 2 51 s 1295 keV 265 ms 254 4 257 7 24.5 s 1.56 m 253 251 0.8 s 160 keV 1.0 s 254 17.1 s 31 s 40 keV 2.5 s 255 5 22 s 256 6 253 0.6 s 30# keV 1.3 s

Rf

256 6.6 ms

Rf

257 4.8 s 73 keV 4.3 s

Db

258 4.5 s 60# keV 1.9 s

Db

257 2.3 s 140# keV 0.67 s

Sg

260 4.95 ms

Sg

261 183 ms

Cr

54

Ti

50 500 pnA

Ca

48 1 pμA

Ne

22 3 pμA

Projectile Beams

Lr

257 6.0 s

Lr

258 4.1 s

Lr

259 6.2 s

Lr

260 3.0 m

N

15 1 pμA

Ar

40 1 pμA

Fm

244 3.5 ms

Fm

245 4.2 s

Rf

255

Rf

258

Sg

259

Db

259

Db

260

Db

262

Sg

263

Sg

262

Bh

261

Bh

264

Bh

266

Hs

264

Hs

265

Hs

267

Mt

268

Ds

269

Mt

270

Ds

271

Rg

272

Rg

274

Cn

277

Md

253

D

V

R

V

M F

N=152

Md

254

Md

256

Md

255

Md

249

Fm

247

Fm

248

Fm

249

Fm

250

Fm

251

Sg

265

Hs

269

Ds

273

113

278

SLIDE 20

Deeper into the future...

• Already start to see increase in SF
• Eventually longer T1/2 will become bottleneck, too

Rf Db Sg Bh Hs Mt Ds Rg Cn 113 Fl 115 Lv 117 118 175 170 165 160 N= 155 150 Lr No Md 145 Alpha decay Spontaneous Fission Beta Decay / Electron Capture Directly Synthesizable / T <5 ms

1/2

Directly Synthesizable / T >5 ms

1/2

L

• n

g e r h a l f

• l

i v e s 3

• b
• d

y d e c a y m

• r

e l i k e l y L

• w

r a t e s

SLIDE 21

P . Schury

• Nov. 9, 2015

JCNP2015

Conclusion

• Simultaneous mass measurement
• Short-lived nuclei
• Heavy nuclei
• Identify nuclei with few counts

Using MRTOF-MS we can:

SLIDE 22

SlowSHE Facility

• 1. He Gas Cell Stopping
• 2. Ext. via RF-Carpet: 0-5 ms
• 3. OPIG Transport: < 1ms
• 4. Ion Cooling: ≈2 ms
• 5. MRTOF ToF-MS: 2~10 ms

≈60% ≈50% ≈100% >5% ≈100% Process Efficiency

Total ⪆1% ≈5~20 ms

Initial estimates