gamma spectroscopy in the fermium region at ship · studies at ship since 2010 22. 6. 2013 padova,...

Gamma spectroscopy in the

fermium region at SHIP

Nuclear Structure Physics with Advanced Gamma-

Detector Arrays, Padova June 10-12, 2013

Stanislav Antalic

Comenius University, Bratislava

22. 6. 2013 Padova, 9th - 13th of June 2013 2

Collaboration

University of Jyväskylä

M. Leino

JAEA Tokai

K. Nishio

GSI Darmstadt

F. P. Heßberger

D. Ackermann

S. Hofmann

S. Heinz

B. Kindler

I. Kojouharov

B. Lommel

R. Mann

B. Sulignano

(presently in Saclay)

Comenius University

(Bratislava)

S. Antalic

Š. Šáro

Z. Kalaninová

B. Streicher

(presently in GSI Darmstadt)

Helmholtz Institut

Mainz

L.-L. Andersson


Transuranium nuclei

Desired region of

double magic nuclei

No chance to access it

with present technique

Desired region of

double magic nuclei

No chance to access it

with present technique

Region accesible by present technique

Production rate 1 event / week

Region accesible by present technique

Production rate 1 event / week

Region accessible for nuclear spectroscopy

10 – 1000 nuclei / hour

Rich source for the nuclear structure data

Region accessible for nuclear spectroscopy

10 – 1000 nuclei / hour

Rich source for the nuclear structure data


SHIP separator

Efficiency ~30 %

Flight time ~ 1-2 ms

Bi2O3, PbS target – 400 mg/cm2

Rotating wheel – 31 cm diameter

48Ca ~ 1200 pnA

B. Kindler et al. NIM A561,107 (2006)

Detectors: S. Hofmann and G. Münzenberg, RMP 72, 733 (2000)

Separator: G.,Munzenberg, et al., NIM 161, 65 (1979)

Back detector PSSD Ge-Clover

Esc. a, b Recoils

e a

CE , RTG

ff

+ high intensity beam

+ reliable setup

+ low background

- Low granularity

- Lack of beamtime

+ high intensity beam

+ reliable setup

+ low background

- Low granularity

- Lack of beamtime

Studies at SHIP since 2010


270Ds5.1 m s

10.97 α

180 µ s

10.95α

271Ds56 m s

10.68 α

1.1 m s

10.71α10.74

Ds267Ds

3 µ s

11.60 α

269Ds170 µ s

11.11 α

270Mt819 ms

10.03 α

268Mt70 ms

10.10 α10.24

266Mt1.7 ms

10.46 α

11.74...

265Hs1.7 m s

10.52 α

0.8 ms

10.37α10.3010.34

10.57

266Hs1.9 ms

10.17 α

267Hs59 ms

9.75 α9.839.88

269Hs20.9 s

9.18 α

264Hs0.26 ms

10.4350 α50 sf

Mt

Hs261Bh

11.8 ms

10.03 α10.1010.40

262Bh102 m s

10.24 α

8.0 ms

9.74α10.37

10.08

264Bh440 ms

9.48 α9.62

266Bh1 s ?

9.30 α

267Bh17 s

8.85 α

260Sg3.6 ms

9.72αsf

9.819.76

259Sg0.48 s

9.03 α9.369.62

262Sg6.1 ms

sf

258Sg2.9 ms

sf

261Sg0.23 s

9.47 α9.529.56

263Sg0.9 s

9.25 α

0.3 s

9.06α

265Sg7.4 s

9.69 α8.768.848.94

266Sg21 s

8.52α

? sf

255Db1.6 s

? αsf

256Db3.6 ms

8.89αe

9.079.01

9.12

258Db4.4 s

9.0167 α

33 e

9.179.08

257Db1.5 s

9.16

0.76 s

9.078.97

α?sf

α?sf

259Db0.5 s

9.47 α

260Db1.5 s

9.059.089.13

>90 α<10 sf ?

261Db1.8 s

8.93>50 α<50 sf

262Db34 s

8.4567 α33 sf

8.66

263Db27 s

8.36 57 sf

254Rf23 ms

sf

253Rf48 ms

sf

256Rf62 ms

8.790.6 α98 sf

258Rf13 ms

sf

260Rf20 ms

sf

262Rf2.1 s

sf

257Rf4.0 s

9.16

3.9 s

8.788.74α

α

?sfe

255Rf1.64 s

8.7748 α52 sf

8.72

261Rf78 s

8.28

67 α 33 e

<1 sf ?

259Rf3.1 s

8.77 sf

8.87

261Lr39 m

sf

262Lr3.6 h

e

260Lr3 m

8.03 25 e

259Lr0.36 s

8.45 23 sf

258Lr3.9 s

8.56 α8.598.628.65

257Lr0.65 s

8.80 α8.86

256Lr25.9 s

8.39 α8.438.52

252Lr0.36 s

α9.02

253Lr0.57 s

8.72

1.49 s

8.79αsf

αsf

260No160 ms

sf

262No5 ms

sf

259No58 m

7.52αe

7.587.55

258No1.2 ms

sf

256No2.91 s

8.40 0.53 sf

8.45

257No26 s

8.22 α8.278.32

255No3.1 m

7.9361 α

39 e sf

8.088.12

187...?;e

253No1.7 m

8.01

250No0.25 ms

sf

Sg

Db

Rf

Lr

260Md31.8 d

sf

259Md95 m

sf

258Md51 d57 m

6.72

e

85α

?15e

6.76

488...369

257Md5.52 h

7.01...85 e

?

7.07

371325...

256Md1.30 h

7.15... 91 e 7.22

255Md27 m

7.33... 92 e ?453;405

251Md4.0 m

7.55... 99 e

250Md52 s

7.75 93 e 7.82

252Md2.3 m

<50 αe

252Md2.3 m

<50 αe

249Md24 s

8.03αe

248Md7 s

8.32 20 αe8.36

247Md0.2 s1.12 s

α sfe

8.42

247Md0.2 s0.26 s

α sf8.42

Md0.9 ms0.35 s

α sf8.688.64

254Md28 m10 m

αe

αe

243Fm0.18 s

α

244Fm3 ms

sf

245Fm4.2 s

α

No

246Fm1.1 s

8.25α

6 sf

247Fm35 s

8.86

9.2 s

7.877.93α

αe

248Fm36 s

7.83 sf

7.87

249Fm2.6 m

85 e 7.53

250Fm30 m1.8 s

7.43I?α

sf

251Fm5.30 h

92 e 6.78

252Fm25.4 h

7.00sf7.04

?;e

253Fm3.0 d

6.67 88 e ?272...

6.94

255Fm20.1 h

6.96 sf

7.02

?;e81;58...

254Fm3.24 h

7.15 sf

7.19

?;e99;44...

257Fm100 d

6.52 0.21sf?242;180...

258Fm0.38 ms

sf

259Fm1.5 s

sf

256Fm2.63 s70 ns

488

I?8α

92sf?231

369... sf

6.92369

Fm

Md

Bh

254Lr13 s

8.46

22 e8.4142;209;305 ?

252No2.3 s

911

53 ms

8.37I?

75α25sf886

251No55 s2 sµ

8.58

I?

α

sf714783

8.82

?143...204

253Md6 m

<50 αe

353 ?

254No55 s

53

0.26 s

8.74I?

α

sfe842

943

246Md1.0 s4.4 s

8.56αsf e8.18

α8.74

255Lr25.9 s

8.46 α

2.6 s

8.37α8.31

Published data since 2010

Opened projects

Topic for this talk 253Fm – single particle isomer 253No – K isomer

253Fm – single particle isomer


S. Antalic et al. EPJ A47, 62 (2011)

CE-γ coincidences

γ – before CEs

γ – delayed after CEs

253Fm Produced via 45% beta decay of 253No

and beta decay of 253Md

First beta decay data in region Z>100

Electron - coincidences Electron - coincidences

Applied reaction 48Ca+207Pb → 253No + 2n

(1.8 x 106 nuclei)

Applied reaction 48Ca+207Pb → 253No + 2n

(1.8 x 106 nuclei)

a vs. b decay production of 253Fm



Opened problem:

How to connect upper part populated by beta decay of 253Md, with the lower

part populated by 257No alpha decay [M. Asai et al., PRL 95, 102502 (2005)]?

Opened problem:



How is isomer connected to g.s.? How is isomer connected to g.s.?

M. Asai et al. PRL 95, 102502 (2005)

253Fm produced via a decay of 257No at JAERI

253Fm and N=153 isotones



Opened problem:



Opened problem:



How is isomer connected to g.s.? How is isomer connected to g.s.?


K isomers

Multi-quasiparticle states are located typically above 1 MeV. Very complex decay schemes

Rich source of data on the structure (chance to populate many low lying levels)

K-isomers might have additional hindrance against radioactive decay and might play a important role for enhanced stability of superheavy nuclei. In some cases lifetime of the isomer exceeds the g.s. lifetime. (see e.g. 270Ds or 250No.) [experiment: S. Hofmann et al., Eur. Phys. J. A 10, 5 (2001) and D. Peterson et al., (2006). Phys. Rev. C74 014316]

1 2 3

J

K

22. 6. 2013 Padova, 9th - 13th of June 2013 /18

254No – complex decay scheme

25 50 75 100 125 150 175 200 225 250

0

20

40

60

80

250 275 300 325 350 375 400 425 450 475 500

0

5

10

15

20

25

500 525 550 575 600 625 650 675 700 725 750

0

10

20

30

40

50

60

No254m2_clo_einzel_r229_r2479.5.2007

E / keV

Ere

ign

isse

Ere

ign

isse

179.5

Ere

ign

isse

168.5

156.9

111.4

147.5

143.6

133.3

347.1

325.5

311.9

301.8

605.7

F.P. Hessberger et al., EPJ A43, 55 (2010)

JYFL: R.D. Herzberg et al. Nature 442, 896 (2006)

Argonne: S.K. Tandel et al_PRL97, 082502 (2006)

48Ca+208Pb→254No+2n

~ 270 000 nuclei

~ 6300 in K=16 isomer

48Ca+208Pb→254No+2n

~ 270 000 nuclei

~ 6300 in K=16 isomer

Known isomer since 1973 A. Ghiorso et al. PRC 7, 2032 (1973)

Known isomer since 1973 A. Ghiorso et al. PRC 7, 2032 (1973)


253No –K isomer

F.P. Hessberger , Phys. At. Nucl. 70, 1445 (2007)

Decay spectroscopy


Crucial requirement: We need low

background to see low-energy

electron- coincidences!

Crucial requirement: We need low

background to see low-energy

electron- coincidences!

E / keV

Ee

lectr

on / k

eV

Back to the 48Ca+207Pb → 253No + 2n Back to the 48Ca+207Pb → 253No + 2n


253No Produced in rection 48Ca+207Pb → 253No + 2n (1.8 x 106 nuclei)

Delayed e-- coincidences showed the presence of second isomer with many lines

F.P. Hessberger , Phys. At. Nucl. 70, 1445 (2007)

9/2-[734]: R.D. Herzberg et al., EPJ A42, 333 (2009)

Decay spectroscopy In-beam spectroscopy

7/2+[624]: P. Reiter. et al, PRL 95, 032501 (2005) 032501


Isomer helped to detect rotational band

and provide independent information about its assignment.

Isomer helped to detect rotational band

and provide independent information about its assignment.

Possible decay scheme


A. Lopez-Martens et al. NPA852 15 (2011)

Opened problem:

Despite of high statistics (1.8 x 106

nuclei) very weak - coincidences.

Opened problem:

Despite of high statistics (1.8 x 106

nuclei) very weak - coincidences.

Suggested decay scheme from

VASSILISSA@JINR Dubna

Suggested decay scheme from

VASSILISSA@JINR Dubna

Single-particle isomer Single-particle isomer

Multi-quasi

particle isomer

Multi-quasi

particle isomer

To confirm the decay scheme, more detailed

spectroscopy data are necessary.

To confirm the decay scheme, more detailed

spectroscopy data are necessary.

Geant simulations for present setup


Germanium clover: 60 x 60 x 140 mm Encapsulated in 1 mm Al 802

keV

188 keV

714 keV

209 keV

73 % 27 %

802 keV

89 keV

10% 9%

802 keV

209 keV

26%

140

60

60

142

122

Ge

Al

How important is the detector granularity? How important is the detector granularity?

20 crystals

714 802 keV keV

714 802 keV keV

209 keV 188 keV

209 keV 188 keV

30 counts 3 counts

28 counts

140 counts 140 counts

205 counts

coinc. to 802 keV

coinc. to 714 keV

coinc. to 802 keV

coinc. to 714 keV

single spectrum single spectrum

GEANT simulation (40 000 events)

Increase from one to 5 clovers brought significant

increase for Ga-Ga coincidences (factor of 5 - 6)

Increase from one to 5 clovers brought significant

increase for Ga-Ga coincidences (factor of 5 - 6)

single spectrum

4 crystals


Conclusion • Interesting new data are on the way (see examples 253No

and 253Fm)

• Present limit for spectroscopy is Sg (Z = 106), however

already for Rf (Z = 104) its challenging.

• Requirements for these measurements:

– High intense beam (1 pmA and more)

– low background (low energy electrons and gammas delayed after

ER implantation)

– high-sensitivity detectors (granularity is critical)

• Still lot of work is waiting for us and we need to do many

small steps to understand superheavy elements!


Thank you

gamma spectroscopy in the fermium region at ship · studies at ship since 2010 22. 6. 2013 padova,...

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