TCHoU Workshop
March 29, 2024
University of Tsukuba

Reaction cross sections
for proton-drip line nuclei
Tetsuaki Moriguchi
University of Tsukuba

Collaborators
Univ. of Tsukuba
T. Moriguchi, R. Kagesawa, A. Ozawa, M. Amano, D. Kamioka, A. Yano
Osaka Metropolitan University
W. Horiuchi
RIKEN Nishina Center
Y. Abe, M. Mukai,
National Institutes for Quantum Science and Technology
A. Kitagawa, S. Sato
Tokyo Institute of Technology
D. Nagae
Saitama Universtity
M. Sakaue, T. Suzuki, T. Yamaguchi, K. Yokota
Beihang Universtity
B. H. SunJapan Synchrotron Radiation Research Institute
S. SuzukiStable/ Unstable nuclei• Theoretical prediction : ~10000 nuclei
Stable nuclei︓Exist in nature（~300）
Unstable nuclei︓Decay within their lifetime（all except for stable nuclei）• Even existences of many unstablenuclei are not observed yet.
Pb

Proton-drip line

Nuclear chartSn

ProtonNumber
O
HeNi

Neutron-drip line

Ca

Neutron number

Stable nuclei
Unstable nuclei
Magic number3(2,8,20,28,50,82,126)

Nuclear density distribution
ProtonNeutronStable nuclei
Proton and neutron are mixing uniformly.

Untable nuclei

Halo: Expansion of weakly bound ofvalence nucleon(s)coresurface

Densityr ~ 10-15 m (∝ A1/3)

RadiusDistance fromcore center

1

Skin: Layer of proton or neutron
around nuclear surface

Enhancement

First observation of theenhancement of radii ofneutron-rich nuclei
Neutron halo
11Li14Ben 9Linn 12
BenI. Tanihata et al., PRL55, 2676 (1985). I. Tanihata et al., PLB 88, 592 (1988)- sR measurements are effective methods to extract thenuclear size properties.
- So far, Be, C and Al were mainly used as reaction targets
for sR measurements.
⇨ How about “Nucleon - nucleus” collision?
- Only a few experimental σR for proton-unstable nucleus
collisions.

Proton target for sR measurement- Measurement of total reaction cross section (sR) is aneffective method to investigate nuclear size properties.
- A proton target has several advantages.
Separation of proton and neutron
density distributions (ρp and ρn)

Extraction of the nuclear size ofmedium and heavy nuclei properly

σpn>σpp

Fraction (σcoul./σR)[%]

Fraction of Coulomb breakup to σRW. Horiuchi et al., PRC93,044611(2016)Isospin asymmetry of σNN
Proton target is moresensitive to ρn of projectile.

For proton target, the contributionof the Coulomb breakup is verysmall. (e.g. Carbon ~4% for Z=50)

Only a few experimental σR for unstable nuclei on a
proton target are reported at this time.
It is important to understand the collisions
between unstable nuclei and a proton.

For proton-rich nuclei, investigations are not performed
well yet in both experimental and theoretical sides.

Only a few experimental σR for unstable nuclei on a
proton target are reported at this time.
It is important to understand the collisions
between unstable nuclei and a proton.

For proton-rich nuclei, investigations are not performed
well yet in both experimental and theoretical sides.

Present study
We measured sR for 17F & 17Ne on a p target.
17F•

Proton dripline nuclei

Candidate of a proton skin for 17F (g.s., 5/2+)

17Ne

•

Known as the two-proton halo nucleus⇨ Nuclear size :17F<_17Ne⇨ Neutron number:

17F

>

17Ne

(rm=2.54(8) fm) (rm=2.68(6) fm)
(N=8)

(N=7)

Solid hydrogen target (SHT)
We have developed a thick and large solid hydrogen target (SHT) forsR measurements with RI beams.

Target cell[T. Moriguchi et al., NIMA 624(2010)27]

Appearance of a typical SHT

f50
BeamBeam・[mm]100 (max.)

A thick and large SHT (Maximum volume : f50 x 100 mm3)
without any void or porous region was developed byoptimization of the supply pressure.

Principle of measurement of sR<Transmission method>𝟏𝜞𝐢𝐧
𝝈𝐑 = − 𝐥𝐧,
𝑵𝐭
𝜞𝐨𝐮𝐭

𝑵𝟐
𝜞=𝑵𝟏

𝑁! : The number of incident nuclei
𝑁" : The number of non-interacting nuclei
𝑁# : The number of target nuclei per unit area
𝛤$% : 𝛤 for a target-in measurement
𝛤&'# : 𝛤 for a target-out measurement
Reactiontarget
17F

𝑵𝟏(counts)

17F

𝑵𝐭(counts/cm2)

𝑵𝟐(counts)

For counting 𝑵𝟏 and 𝑵𝟐 , particle
identifications both upstream anddownstream of the reaction target
are needed in the experiment.

Experiment @ HIMAC (Japan)

Fragment separator (SB2 course) [M. Kanazawa et al., NPA 746(2004) 393c]
Vacuumwindow
05

Dipole magnet

F2SiPPAC

F310 mF1
Dipole magnet

Slit

Slit

SHTIC NaI(Tl)

F0Degrader Plastic
scintillation
counter
20Ne 180 ~ 600A MeV²⁰Ne
180, 400, 600 A MeV
Be

Plastic
Vacuumscintillation ChambercounterExperiment @ HIMAC (Japan)

Fragment separator (SB2 course) [M. Kanazawa et al., NPA 746(2004) 393c]
Particle identification
Vacuumwindow

Dipole magnet
05

F3

F2Upstream

10 m

F1
Dipole magnet

ΔEUp
Slit

Slit

Si

PPAC

SHT

Incident 17F
IC NaI(Tl)

F0Degrader Plastic
TOF
scintillation
counter
20Ne 180 ~ 600A MeV²⁰Ne
180, 400, 600 A MeVBe

Plastic
Vacuumscintillation ChambercounterExperiment @ HIMAC (Japan)

Fragment separator (SB2 course) [M. Kanazawa et al., NPA 746(2004) 393c]
Particle identification
Vacuumwindow

Dipole magnet
05F3F2Upstream

10 m

F1Dipole magnet

ΔEUp
Slit

Slit

Si

PPAC

SHT

Incident 17F
IC NaI(Tl)

F0Degrader Plastic
TOF
scintillation
counter
20Ne 180 ~ 600A MeV²⁰Ne
180, 400, 600 A MeVBe

Plastic
Vacuumscintillation ChambercounterExperiment @ HIMAC (Japan)

Fragment separator (SB2 course) [M. Kanazawa et al., NPA 746(2004) 393c]
Particle identification
Vacuumwindow

5Upstream

F2

Dipole magnet
0F310 mF1
Dipole magnet

ΔEDown

ΔEUp
Slit

Slit

Si

PPAC

SHT

Incident 17F

IC NaI(Tl)

F0Degrader Plastic
TOF
scintillation
counter
20Ne 180 ~ 600A MeV²⁰Ne
180, 400, 600 A MeV
Be

Plastic
Vacuumscintillation Chambercounter•

16F is unbound.

⇨ No “17F → 16F“

•SHT is used.

⇨ No “17F → 18F“Downstream-1n(No neutron in the target)+1n

Non-interacting 17F can be identified
by only DE downstream of SHT.

Non-interacting 17F

σR (mb)σR on a carbon target1600
1500
1400
1300
1200
1100
1000
900

Carbon target
Exp.[1,2] Calc. [3,4]17F17Ne

100
Energy (A MeV)

1000Exp.
[1] A. Ozawa et al., NPA693(2001)32.
[2] K. Tanaka et al., PRC82(2010)044309.
Calc. (Glauber model)[3] B. Abu-Ibrahim and Y. Suzuki,
PRC61(2000)051601.
[4] W. Horiuchi et al., PRC75(2007)044607.

σR on a carbon target
R(17Ne)Glauber model calculation
supports the experimental
data for 17F and 17Ne.

σR (mb)σR(17F) < σ17Ne

is known to be a twoproton-halo nucleus, but 17Fin the ground state is not.

1600
1500
1400
1300
1200
1100
1000
900

⇨ Nuclear size : 17F < 17Ne

σR on a carbon target reflects
the spatial spread of a density
distribution of nucleus.

Carbon target
Exp.[1,2] Calc. [3,4]

17F

17Ne

100
Energy (A MeV)

1000

Exp.
[1] A. Ozawa et al., NPA693(2001)32.
[2] K. Tanaka et al., PRC82(2010)044309.
Calc. (Glauber model)[3] B. Abu-Ibrahim and Y. Suzuki,
PRC61(2000)051601.
[4] W. Horiuchi et al., PRC75(2007)044607.

σR (mb)σR on a proton target

380
360340320300
280260240

Proton target

Exp.
[1]
17Ne
[2]
17F

100
Energy (A MeV)
[1] T. Moriguchi et al., submitted to PRC.
[2] T. Moriguchi et al., NPA994(2020)121663.

1000

σR on a proton target
R(17Ne)In contrast to a carbon target

σR(17F) < σR(17Ne)

σR (mb)σR(17F) ≧ σ

380
360
340
320
300
280260240

Proton target
17F

Calc. [3,4,5]

17Ne

Exp.
[1]
17Ne
[2]
17F

100
Energy (A MeV)

1000

[1] T. Moriguchi et al., submitted to PRC.
[2] T. Moriguchi et al., NPA994(2020)121663.
[3] Y. Suzuki et al., Structure and reactions of lightexotic nuclei, Taylor&Francis, London, 2003.
[4] R. J. Glauber, Lectures in Theoretical Physics,Interscience, New York, Vol. 1 (1959).
[5] B. Abu-Ibrahim et al., PRC77(2008)034607.

σR on a proton target
R(17Ne)σR (mb)σR(17F) ≧ σ

In contrast to a carbon target

σR(17F) < σR(17Ne)

380360340
320300280260240

Isospin asymmetry of σNN (σpn>σpp)

Ø Proton target is sensitive toneutrons in a projectile.
Density spread
Contribution of σpnto σR on proton target

17FSmall

17Ne

Large

(w/o halo)(w/ halo)

(N=8)

(N=7)

Large

Small

Proton target
17F

Calc.[3,4,5]

17Ne

Exp.
[1]
17Ne
[2]
17F

100
Energy (A MeV)

1000

[1] T. Moriguchi et al., submitted to PRC.
[2] T. Moriguchi et al., NPA994(2020)121663.
[3] Y. Suzuki et al., Structure and reactions of lightexotic nuclei, Taylor&Francis, London, 2003.
[4] R. J. Glauber, Lectures in Theoretical Physics,
Interscience, New York, Vol. 1 (1959).
[5] B. Abu-Ibrahim et al., PRC77(2008)034607.

σR on a proton target
R(17Ne)σR (mb)σR(17F) ≧ σ

In contrast to a carbon target

σR(17F) < σR(17Ne)

380360340
320300280260240

Isospin asymmetry of σNN (σpn>σpp)

Ø Proton target is sensitive toneutrons in a projectile.
Density spread
Contribution of σpn

to σR on proton target

17F

Small

17Ne

Large

(w/o halo)(w/ halo)

(N=8)

(N=7)

Large

Small

Proton target
17F

Calc.[3,4,5]

17Ne

Exp.
[1]
17Ne
[2]
17F

100
Energy (A MeV)

1000

[1] T. Moriguchi et al., submitted to PRC.
[2] T. Moriguchi et al., NPA994(2020)121663.
[3] Y. Suzuki et al., Structure and reactions of lightexotic nuclei, Taylor&Francis, London, 2003.
[4] R. J. Glauber, Lectures in Theoretical Physics,Interscience, New York, Vol. 1 (1959).
[5] B. Abu-Ibrahim et al., PRC77(2008)034607.

For proton-rich nuclei, theisospin asymmetry of σNN isdominant for σR on a proton
target, not the density
spread.

The decrease of σR on a proton target despite theincrease of matter radii towards the proton dripline
Glauber model calculation[K. Makiguchi, W. Horiuchi, PTEP2022, 073D01.]

This theoretical study supports the present σR for
17F and 17Ne on a proton target.

σR (mb)

Energy dependence of σR on a proton target
380360340
320300280
260
240

17F + p, 17Ne + p
17F

12C + H

Calc. [2,3,4]

17Ne

Exp.
Calc.

[5]
[4]Exp.
17FThis work
17Ne
[1]

100
Energy (A MeV)

1000

[4] B. Abu-Ibrahim et al., PRC77(2008)034607.
[1] T. Moriguchi et al., NPA994(2020)121663.
[3] R. J. Glauber, Lectures in[2] Y. Suzuki et al., Structure and reactions of light
Theoretical Physics, Interscience, [5] R. Carlson, At. Data Nucl. Data Tab. 63(1996) 93.
exotic nuclei, Taylor&Francis, London, 2003.
New York, Vol. 1 (1959).

σR (mb)

Energy dependence of σR on a proton target
380
360
340
320
300
280
260
240

17F + p, 17Ne + p
17F

12C + H

Calc. [2,3,4]

17Ne

Exp.
Calc.

[5]
[4]Exp.
17FThis work
17Ne
[1]

100
Energy (A MeV)

1000

[4] B. Abu-Ibrahim et al., PRC77(2008)034607.
[1] T. Moriguchi et al., NPA994(2020)121663.
[3] R. J. Glauber, Lectures in[2] Y. Suzuki et al., Structure and reactions of light
Theoretical Physics, Interscience, [5] R. Carlson, At. Data Nucl. Data Tab. 63(1996) 93.
exotic nuclei, Taylor&Francis, London, 2003.
New York, Vol. 1 (1959).

Low energies: Exp. < Calc. (Glauber model)Intermediate energies: Exp. > Calc. (Glauber model)

σR (mb)

Energy dependence of σR on a proton target
380
360
340
320
300
280
260
240

17F + p, 17Ne + p
17F

12C + H

Calc. [2,3,4]

17Ne

Exp.
Calc.

[5]
[4]Exp.
17FThis work
17Ne[1]100
Energy (A MeV)

1000

[4] B. Abu-Ibrahim et al., PRC77(2008)034607.
[1] T. Moriguchi et al., NPA994(2020)121663.
[3] R. J. Glauber, Lectures in[2] Y. Suzuki et al., Structure and reactions of light
Theoretical Physics, Interscience, [5] R. Carlson, At. Data Nucl. Data Tab. 63(1996) 93.
exotic nuclei, Taylor&Francis, London, 2003.
New York, Vol. 1 (1959).

Low energies: Exp. < Calc. (Glauber model)Intermediate energies: Exp. > Calc. (Glauber model)
Ø Nuclear medium effects (Fermi motion, Pauli blocking)Low energies: Sensitive
Intermediate energies : Not so sensitive
It seems to be difficult to explain the experimental sR at low andintermediate energies simultaneously with nuclear medium effects.

Summary• We measured σR for 17F & 17Ne on a proton target.
• Solid hydrogen target (SHT) was used as a proton target.
• For proton dripline nuclei 17F and 17Ne,
σR on a carbon target⇨ Contributed by the spread of the density distribution
σR on a proton target⇨ Contributed by an isospin asymmetry of thenucleon-nucleon total cross section (σpn > σpp)
Energy dependence of σR on a proton target⇨ Discrepancy between exp. and calc.

Future plan

• Measurement of σR with the SHT and C for Sn isotopes• Measurement of σR with a solid deuterium target