Dynamics and Thermodynamics of Exo3c Nuclear Systems OpportuniEes with Reaccelerated Beams at NSCL Alan McIntosh Texas A&M University Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing the neutron star formation and the explosion of a supernova of type II. During these processes,
the prevailing thermodynamic conditions are expected to be similar to those obtained in the
multifragmentation of finite nuclei [Vio98, Bay71, Bet90].
20
Figure 1: Phase diagram of
critica l
point
meta sta ble regions
s
15
ga
uid
liq
Tempera ture (MeV)
Mapping Nuclear Phase Diagram for Systems of different N-­‐Z Asymmetries 10
5
spinoda l region
MULTI−
FRAGMENTATION
0
0.00
sta ble
nucleus
0.25
0.50
0.75
1.00
1.25
ρ/ρ0
nuclear matter. The temperature is plotted as a function of the relative density,
ρ0 is the stable nucleus density. During the collision, the
highly excited compound nucleus is believed to follow the
trajectory indicated by the
dashed arrow, from the liquid
phase to the spinodal region,
where the multifragmentation
occurs. This region is a mixture of liquid and gas phases
and is unstable.
NIMROD 4pi array @ TAMU Zn+Zn, Ni+Ni 5 MeV/u In 1995,
the study
of @
the 3
liquid-gas
phase transition led to the publication of the first caloric
curve, the relation between temperature T and energy E, of nuclear matter by the ALADIN
group [Poc95] shown in the left panel of Fig. 2. This caloric curve, obtained from data for the
Reconstructed hot rimary quasi-­‐
system• Au+Au
at the incidentthe energy
ofp600
AMeV,
presents a plateau-like behaviour from
liquid to gas
phases
in
agreement
with
the
thermodynamical
view of multifragmentation. This
projecEle following the collision plateau may be interpreted as a sign of a liquid-gas phase transition.
•  Extracted thermodynamic quanEEes for shape-­‐equilibrated QPs Caloric curve (T vs E*/A) depends on asymmetry. CriEcal parameters Tc and ρc depend on asymmetry A.B McIntosh et al. PLB 719 337 (2013) A.B. McIntosh et al. EPJA 50 35 (2014) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing Nuclear Thermodynamics (July 2015): Calibra4on underway 78,86Kr+C @ E/A = 15, 25, 35 MeV Fusion reacEons provide systems of well known asymmetry and excitaEon energy Alan McIntosh, Texas A&M University P. Cammarata et al., NIMA 792, 61 (2015) L. Heilborn et al., NIMA arEcle in preparaEon A.B. McIntosh et al., NIMA arEcle in preparaEon Quadrupole Triplet Spectrometer Measure Fusion-­‐EvaporaEon Residues Time-­‐Of-­‐Flight, ΔE, E à Velocity, Energy, Z, A 0.9° ≤ θ ≤ 2.3° FAUST Measure Light Charged ParEcles PosiEon-­‐SensiEve ΔE, E à Z, A, Energy 1.6° ≤ θ ≤ 45° ReA Upgrade Workshop, August 2015, East Lansing Oppo
rtun
ities
at
ReA
Mapping the Nuclear Phase Diagram for Extreme N-­‐Z Asymmetries: •  Fusion with 74,87Kr+C •  @ 4.6 MeV/u (ReA3) à E*/A = 0.6 MeV •  @ 9.2 MeV/u (ReA6) à E*/A = 1.1 MeV •  @ 18.4 MeV/u (ReA12) ! E*/A = 2.2 MeV •  @ 23.0 MeV/u (ReA15) ! E*/A = 2.8 MeV •  Fusion with 74,87Kr+Mg •  @ 4.6 MeV/u (ReA3) à E*/A = 0.8 MeV •  @ 9.2 MeV/u (ReA6) à E*/A = 1.6 MeV •  @ 18.4 MeV/u (ReA12) ! E*/A = 3.3 MeV •  @ 23.0 MeV/u (ReA15) ! E*/A = 4.0 MeV large spr
ead in as
ymmetry
13 neutr
: ons diffe
rence (N-­‐Z)/A =
0.02 to 0
.16 •  Higher beam energy allows more of the phase diagram to be explored •  Measurement of the fusion residue at small angles (Si-­‐CsI or large acceptance spectrometer, e.g. ISLA) •  Measurement of evaporated parEcles 5°-­‐45° (Si-­‐CsI) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing Neutron and proton transport between projec3le and target Earlier work at the SuperHILAC 40,48Ca+U @ 8.5 MeV/u How are nucleons transferred? How are protons transferred differently than protons? Heavy residue yields provide informaEon on the details of the force governing nucleon transport. We’ve learned about the More recently at TAMU’s MARS: potenEal’s 86Kr+64,58Ni @ 15MeV/u Trends in the yield raEos (isoscaling) dependence on demonstrate incomplete equilibraEon asymmetry, density, momentum... G.A. SoulioEs et al, PRC 90 064612 (2014) R.T. de Souza et al, PRC 39 114 (1989) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing Neutron and proton transport between projec3le and target: (N-­‐Z)/A equilibra3on Classical Isoscaling at MSU: Sn+Sn @ 50 MeV/u Isoscaling of intermediate mass fragments Establish degree of N-­‐Z equilibraEon achieved Isotopic yields of all types are sensiEve to the equilibraEon and can provide access to the asymmetry energy This year at TAMU’s NIMROD: 70Zn,64Zn,64Ni + 70Zn,64Zn,64Ni @ 35 MeV/u a)  Isoscaling, b)  isobaric yield raEos, and c)  composiEon of reconstructed quasi-­‐projecEles à provide complementary measures of the N-­‐Z equilibraEon Equilibration Observable
Isoscaling α (Z=4-­‐8)
Isoscaling α (Z=4-­‐14)
3
Theriault et al. PRC 74 051602R (2006) L. May Ph.D. Thesis, Texas A&M Univeristy (2015) M.B. Tsang et al. PRC 92 062701 (2004) Alan McIntosh, Texas A&M University H/3He ratio
QP ms
35 MeV/nucleon 70,64
70,64
Zn+
Zn
35 MeV/nucleon 64
64
64
64
Zn, Ni+ Zn, Ni
50 MeV/nucleon 124,112
Sn+124,112Sn
77%
76%
83%
85%
54%
-­‐
72%
96%
77%
85%
-­‐
-­‐
ReA Upgrade Workshop, August 2015, East Lansing Isospin transport with extreme (N-­‐Z)/A 74,87Kr + 64,70Zn or 74,87Kr + 112,124Sn Oppo
rtun
ities
at
•  @ 4.6 MeV/u (ReA3) •  @ 9.2 MeV/u (ReA6) •  @ 18.4 MeV/u (ReA12) •  @ 23.0 MeV/u (ReA15) Larger range of beam energy: •  varying dynamical character •  varying degree of equilibraEon ! Greater sensi3vity to the poten3al driving equilibra3on ReA
•  Measurement of the projecEle-­‐like fragment at small angles (Si-­‐CsI or large acceptance spectrometer, e.g. ISLA) •  Measurement of charged parEcles in the forward hemisphere (Si-­‐CsI array) •  Measurement of free neutrons (e.g. MoNA-­‐LISA, LENDA, VANDLE) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing Neutron and proton transport to and from the mid-­‐rapidity region Oppo
rtun
ities
at
ReA
Isospin transport including a system with N<Z •  Majority parEcle (the protons!) should be preferred at low density when N<Z •  InteresEng check/constraint on transport models •  Allow for a new type of measurement to constrain the symmetry energy • 
53,64Co + 40,48Ca (N-­‐Z=-­‐1,18) • 
• 
• 
• 
FIRST @ TAMU 64Zn+64Zn @ 35 MeV/u In the nucleon transport process, the excess neutrons are manifest as free neutrons between the target and projecEle Theriault et al. PRC 74 051602R (2006) Alan McIntosh, Texas A&M University @ 4.6 MeV/u (ReA3) @ 9.2 MeV/u (ReA6) @ 18.4 MeV/u (ReA12) @ 23.0 MeV/u (ReA15) •  Higher beam energies produce densi3es farther from satura3on density ! Stronger density-­‐driven transport •  Measurement of projecEle-­‐like fragment small angles (Si-­‐
CsI or large acceptance spectrometer) •  Measurement of charged parEcles, 2°-­‐45° in Si-­‐CsI •  Measurement of neutrons, 2°-­‐45°, M-­‐L, LENDA, VANDLE ReA Upgrade Workshop, August 2015, East Lansing Neutron and proton transport within a deformed PLF* FIRST @ GANIL Xe + Sn @ 50 MeV/u •  Focus on deep inelasEc collisions which oven form a “neck” between the proj and targ. •  The neck region is neutron rich •  Collision dynamics can give rise to deformed PLF* •  The PLF* can iniEally be out of N-­‐Z equilibrium •  The rotaEon angle can be used as a clock to benchmark N-­‐Z equilibraEon •  Isotopic yields varying with decay angle indicate equilibraEon within the PLF* S. Hudan et al. PRC 86 021603 (2012) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing Neutron and proton transport within a deformed PLF* 180-­‐α increasing Eme Watching EquilibraEon As it Occurs The detailed evoluEon of the equilibraEon may contain more informaEon about the equaEon of state than the equilibrium values Currently with NIMROD @ TAMU 70Zn+70Zn @ 35 MeV/u •  Isotopic measurement of both daughters •  Daughters toward each other, and then plateau •  Strongest evidence to date of N-­‐Z equilibraEon within a PLF* •  Technique allows a real-­‐Eme (sub-­‐zeptosecond) measurement showing the smooth evoluEon of asymmetry Alan McIntosh, Texas A&M University M.B. Tsang et al. PRC 92 062701 (2004) A. Jedele et al. Manuscript in preparaEon (2015) S. Hudan et al. PRC 86 021603 (2012) ReA Upgrade Workshop, August 2015, East Lansing Nucleon transport within a deformed PLF* • 
74,87Kr + 64,70Zn and 74,87Kr + 112,124Sn • 
• 
• 
• 
Oppo
rtun
ities
at
ReA
@ 4.6 MeV/u (ReA3) @ 9.2 MeV/u (ReA6) @ 18.4 MeV/u (ReA12) @ 23.0 MeV/u (ReA15) •  Higher beam energies produce larger density gradients and more deformed PLF* ! Stronger larger ini3al asymmetry imbalance within the PLF* •  Measurement of the projecEle-­‐like fragment at small angles (Si-­‐CsI or large acceptance spectrometer) •  Measurement of a broad range of IMFs in the forward hemisphere (Si-­‐CsI array) Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing User needs: Oppo
rtun
ities
at
ReA
Intense, heavy-­‐ion beams spanning a broad asymmetry e.g. 74,87Kr, 53,64Co ... or heavier InteresEng physics in transport and dynamics can be probed at ReA 3 energies. Increased beam energy to ReA12 or even ReA15 greatly enhance the breadth of the science of dynamics and thermodynamics that can be studied. How high should the energy be? ALARA: As Large As Reasonably Achievable Experimental space for moderately compact charged parEcle detector arrays. Coincidence measurements with ancillary detectors such as neutron detectors (e.g. MoNA-­‐LISA, LENDA, VANDLE) and a large acceptance zero-­‐degree spectrometer (e.g. ISLA) can add immense value. Flexibility in terms of configuring the experimental areas is important to maximize the science opportuniEes. Alan McIntosh, Texas A&M University ReA Upgrade Workshop, August 2015, East Lansing