In-beam γ ray Experiments

Heiko Scheit紗糸　俳子

September 9-10, 20092009年9月9-10日

1

Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2List of Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

In-Beam γ 2008 4Island of Inversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Exp. Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6DALI2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7PID Before Target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8First γ ray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9PID after target . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10E(2+) vs. N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Next Campaign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

CNS GRAPE 13GRAPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14In-Beam Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Recoil Distance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

SHOGUN 17Next γ spectrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Simulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20SHOGUN 100. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21SHOGUN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Things to Consider 23High Beam Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Atom. BG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25High Beam Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Other Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Other 28RIBF User Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Summary 30Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2

Outline

List of approved in-beam γ ray experiments

Overview of in-beam γ ray results 2008: 8 hours

DALI2 γ ray spectrometer (NaI(Tl) based)

GRAPE γ ray spectrometer (HPGe based)

SHOGUN γ ray spectrometer (LaBr3(Ce) based)

Things to consider

mainly due to high beam energy

RIBF user group meeting in Hawaii

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 2

List of In-Beam γ ray Experiments

prim. beam interest spokesperson days16O, 20Ne, 36Ar ? L. Trache 348Ca B(E2↑): 42Si S. Takeuchi 348Ca B(E2↑): 30Ne, 36Mg,

E(2+): 32Ne,38Mg,...H. Scheit 10

48Ca E(2+): 40Mg P. Fallon 3(+3)48Ca 33Mg D. Bazin 470Zn, 76Ge lifetime near 64Cr E. Ideguchi 486Kr ? Sohler/Elekes ?86Kr B(E2↑): 52,54Ca

E(2+): 54CaS. Takeuchi 2

124Xe B(E2↑): near 100Sn P. Doornenbal 7238U ? Zs. Dombradi 3238U B(E2↑), E(2+) near 132Sn N. Aoi 10238U B(E2↑), E(2+) near 78Ni K. Yoneda 10

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 3

3

In-Beam Gamma Program 2008:8 hours 4

Island of Inversion

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◦

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◦

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◦

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◦

◦

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◦

30Si 31Si 32Si 33Si 34Si 35Si 36Si 37Si 38Si

29Al 30Al 31Al 32Al 33Al 34Al 35Al 36Al 37Al

28Mg 29Mg 30Mg 31Mg 32Mg 33Mg 34Mg 35Mg 36Mg

27Na 28Na 29Na 30Na 31Na 32Na 33Na 34Na 35Na

26Ne 27Ne 28Ne 29Ne 30Ne 31Ne 32Ne 33Ne 34Ne

25F 26F 27F 28F 29F 30F 31F 32F 33F

N = 16 N = 18 N = 20 N = 22 N = 24

Z=

10

Z=

12

Z=

14

228(41)

350(50)

215(10)

270(14)

270(16)

113(33)

?

413(29)

84(33)

?

631(126)

190(60)

?

?

190(70)

2018

1473

2235

1310

1482

1942

791(26)

885

3328

?

670

1399

?

660(6)

1084

?

4020

5280

?

(1789)

(5220)

?

(2322)

?

?

(2120)

?

?

?

?

?

2.7

2.4

?

(1.2)

(2.7)

?

(2.6)

(1.0)

?

(3.2)

?

?

?

?

( 52+

)

52+

52+

1+

( 32+

)

1+

32+

3+

32+

( 52+

)

32+

( 32

,

52)+

??

( 32+

)

2+

12(+)

1+

( 32+

)

( 52+

)

32+

?2?

??

?2?

??

?2?

??

?2?

?2?

?2?

?2?

??

?2?

??

( 72−

)

??

( 72−

)

?2?

?2?

?2?

even-even

B(E2↑)

E(2+1 )

E(4+1 )

E(4+1 )

E(2+1 )

38Mg

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 5

Experimental Setup

2nd BigRIPS stage

0◦ Spectrometer ZeroDegreeparticle ID after secondary target

fragment momentum distribution

various modes of operationmode p/∆p ∆p Ang. Accep.Large Accep. 1240 ±3% ±45 mrad(V) ±30 mrad(H)High res.(achrom) 2120 ±3% ±20 mrad(V) ±30 mrad(H)Dispersive 4130 ±2% ±20 mrad(V) ±30 mrad(H)

secondary target

∼ 3 m between Q-polesDALI2 array (180 NaI(Tl))

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 6

4

DALI2

182 NaI(Tl) detectors

θ coverage: 11◦–165◦

ǫγ ≈ 20%

∆E/E = 6% (1 MeV) 11% (β = 0.6)

target: 2.54 g/cm2 C

S. Takeuchi et al., RIKEN Prog. Rep. 36, 148 (2003)

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 7

PID Before Secondary Target

2.9 3 3.1 3.2 3.3

9

10

11

12

1

10

210

310

2.9 3 3.1 3.2

9

10

11

12

Ratio of Mass to Charge Number A/Z

Cha

rge

Num

ber

Z

1

10

102

103

32Ne

33Na

∆E–Bρ–TOF method

Z ∝ ∆E ∆Z = 0.5 (FWHM)

A/Q ∝ TOF ∆A = 0.06 (FWHM)

32Ne: 5/s E ≈ 230 MeV/u

33Na: 30/s

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 8

5

First New In-Beam γ ray Transition at the RIBF

0

2

4

6

8

10

12

14

0 500 1000 1500 2000 2500 3000 3500 4000

1.147 / 2Constant 1.980 1.140Mean 697.4 30.07Sigma 47.96 48.97

2008/12/17 16.41

0

2

4

0 500 1000 1500

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 9

PID After Target and γ ray SpectraPID after F8

2.9 3 3.1 3.2 3.3

9

10

11

12

1

10

210

310

2.9 3 3.1 3.2

9

10

11

12

Ratio of Mass to Charge Number A/Z

Cha

rge

Num

ber

Z

1

10

102

10333Na

32Ne

C(32Ne,32Ne*), C(33Na,32Ne*)

32Ne: 5 pps, 225 MeV/u

F8 target: nat.C (2.54 g/cm2)

DALI2 array: 182 NaI(Tl) detectors

total data taking: 7 hours

Doppler corrected γ-ray energy

0

5

10

15

20

0 1000 2000 3000 4000

Cou

nts

/ 25

keV

Eγ (keV)

C(32Ne,32Ne*)

Eγ = 722(9) keV

32Ne

0

5

10

15

Cou

nts

/ 25

keV

C(33Na,32Ne*)

32Ne

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 10

6

E(2+) as Function of N

0.5

1

1.5

2

16 18 20 22 24

E(2

1+)

(M

eV)

Neutron Number N

Ne

0.5

1

1.5

2

E(2

1+)

(M

eV)

Mg

Caurier: (N), (I)Utsuno:

Exp.:

P. Doornenbal, H. Scheit et al.Phys. Rev. Lett. 103, 032501 (2009)arXiv:0906.3775

lowest E(2+) of Ne isotopes

very good agreement withUtsuno et al.,PRC 60, 054315 (1999)

very good agreement withIntruder calculation ofCaurier et al.,NPA 693, 374 (2001)

32Ne belongs to the“Island of Inversion”

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 11

Next In-Beam γ Campaign

Nov. 2009: 6 days U (Aoi-san, Yoneda-san)

Dec. 2009: 7 days 48Ca (Scheit-san, Takeuchi-san)

RIBF beam time for in-beam γ ray experiments

year time

2007 02008 8 hours2009 15 days

RIPS still operational

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 12

7

CNS GRAPE 13

CNS GRAPE

Gamma-Ray detector Array with Position and Energy sensitivity

18x2 planar segmented Ge detectors

High Resolution 2.5 keV intrinsic resolution for 1.3 MeV

High Sensitivity ǫΩ ∼ 5 % for 1 MeV

Position Sensitive: Resolution after Doppler Correct. 1 %

Goal: 1 mm position resolution for z-direction

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 14

In-Beam Resolution

4He(12Be,12Be*) β = 0.3 ∆z ≈ 3.4 mm (FWHM)

new digital electronics since 2009

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 15

8

Recoil Distance Setup at F8

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 16

SHOGUN 17

Next Generation Fast Beam γ Spectrometer

need higher precision

better energy resolution than NaI(Tl) DALI2: 10%

higher efficiency than HPGe GRAPE: 5%

better timing than NaI(Tl) or HPGe

new “magic” scintillator material LaBr3(Ce)

high light yield (∼ 60% more than NaI(Tl))

fast decay time constant: 16 ns

time resolution: ∼ 100 ps

high density: 5.1 g/cm3

combines good properties of HPGe, NaI(Tl) and BaF

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 18

9

Simulation: SHOGUN 1000 and DALI2

0 500 1000 1500

Cou

nts

0

20

40

60

80

100

Energy (keV)2000 3000 4000

50×

Mg32

NaI(Tl) DALI2

transition notresolved byNaI(Tl) detector

E/A = 56 MeV/u1H(

32Mg,

32Mg

*)

LH2 tgt 160 mg/cm2

160 pps f. 5 days

103×SHOGUN 1000

Simulation by P. Doornenbalbased on experimental data ofS. Takeuchi et al., PRC 79, 054319 (2009)H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 19

Possible Configurations

8 × 4 × 1.5 cm3

fast beam setup (v = 0.6c)∆EE (%) ǫγ (%) ǫγγ (%)

NaI(Tl) DALI2 10.0 23.5 5.5RISING 1.9 2.8 0.08

SHOGUN 1000 3.2 35.0 12.2

slow/stopped beam setup∆EE (%) ǫγ (%) ǫγγ (%)

RISING 0.2 15.0 2.25SHOGUN 1000 2.4 56.0 31.3

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 20

10

SHOGUN 100 and DALI2

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 21

SHOGUNScintillator based High-resOlutionGamma-ray spectrometer forUnstable Nucleiadvantages: fast beam

high (optimum) resolution

high efficiency

fast timing

easy operation

very low running cost

advantages: slow/stopped beam

high efficiency (esp. γγ)

“prompt flash ” is no problem:high segmentation is not needed

international collaboration (?)

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 22

11

Things to Consider 23

Issues at High Beam Energies

E = 150 . . . 250 MeV/u

Doppler shift and Doppler Broadening

atomic background

back-scattered electrons

Ee−

max =1

500E/A (β → 2β, m →

1

2000m)

isotropic in laboratory system

scales with Z2t

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 24

Atomic Background

Energy [keV]0 500 1000 1500 2000

Cou

nts

/ 10

keV

1

10

210

DALI2 Doppler Corrected

0 500 1000 1500 2000

Cou

nts

/ 10

keV

1

10

210

310DALI2 Energy

All DetectorsForward AnglesBackward Angles

Ne*)30Ne,30Pb(208

Ne @ 250 MeV/u30

Pb20823360 mg/cm

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 25

12

Issues at High Beam Energies

thick targets 1–2 cm (!)

compare: 1 mm position resolution of γ ray detector

additional Doppler broadening:changing beam energy due to energy loss

lifetime of excited state

100 ps = 1–2 cm flight path (!)

unknown decay position

if decay after the target: velocity is exactly known

Doppler correction must take that into account

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 26

Other Issues

charge states: for high-Z beams

measure TKE

for absolute measurements

isomeric ratios can be large

must be measured

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 27

Other 28

RIBF User Group

please join the RIBF user group

RIBF User Guide -> Users Group -> Users Group Registration

http://ribfwww.riken.go.jp/exp/RIBF uec eng/

there will be a RIBF user group meeting during theAPS/JPS meeting in Hawaii

please let me know any wishes

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 29

13

Summary 30

Summary

many in-beam γ ray experiments already approved

main devices for in-beam γ ray spectroscopy at the RIBF

DALI2

GRAPE

NB: both are not user devices; contact owner (!)

RIBF with BigRIPS and ZeroDegree is fully operational

first in-beam γ-ray study in 8 hours32Ne: E(2+) = 722(9) keV (in “Island of Inversion”)

next generation γ ray spectrometer: SHOGUN

H. Scheit, In-Beam γ Experiments JUSEIPEN Workshop, Sep. 9-10, 2009 – 31

14

OutlineList of in-beam gamma experimentsIn-beam gamma program 2008Island of InversionExp. SetupDALI2PID Before Secondary TargetFirst gamma rayPID after targetE(2+) vs. NNext In-Beam Gamma Campaign

CNS GRAPECNS GRAPEIn-Beam ResolutionRecoil Distance Setup at F8

SHOGUNNext gamma spectrometerSimulation: SHOGUN 1000 and DALI2Possible ConfigurationsSHOGUN 100 and DALI2SHOGUN

Things to ConsiderIssues at High Beam EnergiesAtomic BackgroundIssues at High Beam EnergiesOther Issues

OtherRIBF User Group

SummarySummary