Upload
morna
View
44
Download
0
Embed Size (px)
DESCRIPTION
PNNL Director’s Distinguished Lecture Series Monday, 4 August , 2010. One Atom-at-a-Time Chemistry of the Transactinides (TANs). Darleane C. Hoffman Professor Emerita, Graduate School Department of Chemistry University of California, Berkeley & Faculty Sr. Scientist - PowerPoint PPT Presentation
Citation preview
Darleane C. HoffmanDarleane C. HoffmanProfessor Emerita, Graduate SchoolProfessor Emerita, Graduate School
Department of Chemistry University of California, Berkeley &
Faculty Sr. Scientist Nuclear Science Division
Lawrence Berkeley National Laboratory
PNNL Director’s Distinguished Lecture SeriesMonday, 4 August , 2010
One Atom-at-a-Time Chemistry One Atom-at-a-Time Chemistry of the Transactinides (TANs)of the Transactinides (TANs)
Where are the Transactinides?Where are the Transactinides?Periodic Table of the Elements 2010Periodic Table of the Elements 2010
What are the Transactinides?What are the Transactinides?
OVERVIEWOVERVIEW
I. Introduction to TANs
II. First Atom-at-a-Time Chemistry• Chemical Separation Method
• Positive Identification of Atomic Number
III. Importance, Challenges, Technical Approaches•Suitable chemistry, Isotopes, Production Rates
IV. Studies of TANS • Manual to Sophisticated Computer-Controlled Systems• Aqueous and Gas-Phase Studies• Current Status
V. Relativistic Effects: Theory & Experiment
VI. Prognosis for Future• New Isotopes, New Elements
101 Mendelevium
Md
102 Nobelium
No
103 Lawrencium
Lr
104 Rutherfordium Rf
105# Dubnium (Hahnium)# Db (Ha)#
106 Seaborgium
Sg
107 Bohrium
Bh
108 Hassium
Hs
109 Meitnerium
Mt
110 * Darmstadtium* Ds*
111** Roentgenium** Rg**
112*** Copernicium*** Cn***
IUPAC APPROVED HEAVY ELEMENT NAMESIUPAC APPROVED HEAVY ELEMENT NAMESAugust 30, 1997, Geneva, Switzerland
#Many publications of chemical studies before 1997 use hahnium (Ha) for 105. *Approved by IUPAC, August 2003; **Approved by IUPAC, November 2004.***Approved Spring 2010. (Pure Appl. Chem., DOI: 10.1351/PAD-REC-09-08-20).
Element Name Symbol
Transactinides (TANs)
Chem. & Eng. News 23, 2190-93 (1945)
Timeline of Discovery of Transuranium ElementsTimeline of Discovery of Transuranium Elements
Discovery & Identification of Element 101 (Mendelevium)Discovery & Identification of Element 101 (Mendelevium) A Landmark ExperimentA Landmark Experiment
First Atom-at-a-Time Chemical First Atom-at-a-Time Chemical Identification of a New Element,Identification of a New Element,
Only 17 atoms in 8 experiments.Only 17 atoms in 8 experiments.
Heaviest Element Heaviest Element FirstFirst discovered discovered & identified using direct radio-& identified using direct radio-
chemical separation of the element chemical separation of the element itself. To date, none of the Heavier itself. To date, none of the Heavier Elements have Elements have FirstFirst been Identified been Identified
by Chemical Methods!by Chemical Methods!
All Elements Beyond Md: All Elements Beyond Md: FirstFirst Identified by Nuclear Identified by Nuclear Decay properties/Physical Decay properties/Physical
TechniquesTechniques
Use of 253Es (~20d) target: 109 or 1010 atoms--only a few picograms! Sub-NANO Science (10-9)!
(SF)
Nuclear FissionNuclear FissionEasy to detect but difficult to identify
original fissioning nucleus—Many Controversies!
(n,F)
correlation to correlation to known daughtersknown daughters
Gives positive i.d. of Z & A, but much more complex instrumentation & analysis needed.
Decay Modes and Positive Identification of Element
261Rf75 s
8.28-8.52 MeV
257No26 s
8.22-8.27 MeV
253Fm3 d
Chemistry of TANsChemistry of TANsCHALLENGESCHALLENGES
UNIQUEUNIQUE CAPABILITIES REQUIRED CAPABILITIES REQUIRED Hi-Intensity beams of heavy projectiles: LBNL, Berkeley, CA, USA, 88-Inch Cyclotron; Dubna, Russia U-400 Cyclotron; Darmstadt, Germany GSI, UNILAC; JAERI, Japan; Jyvaskala, Finland; Lanzhou, China. Facilities & expertise: Preparation, handling, & irradiation of radioactive targets; Fast transport of products from accelerator to separation facility; Fast radiochemical separations & detection techniques.
Must be produced & studied at suitable accelerators.Low production rates (few atoms at a time). Very short-lived (minutes to milliseconds). Rates & half-lives decrease as Z (atomic number) increases. Plethora of unwanted elements produced.
• Unique opportunity to extend knowledge of chemistry to uppermost end of periodic table.
• Assess extent & magnitude of relativistic effects predicted to be especially strong in these elements due to their high nuclear charges. • Compare chemical properties with those of lighter homologues & with theoretical predictions.
Elucidation of the chemical properties of the elements & Elucidation of the chemical properties of the elements & their placement in the Periodic Table is one of most their placement in the Periodic Table is one of most
fundamental goals of chemistry—sometimes referred to as fundamental goals of chemistry—sometimes referred to as ““Textbook Chemistry”!Textbook Chemistry”!
* Evaluate validity of extrapolation of periodic table trends. * Search for anomalous trends in oxidation states, ionic radii,
complexing, and chemical bonding. * Establish chemical properties of this new 6d transition series:
Compare with those of 5d(Hf, Ta, W, Re, Os) & 4d(Zr, Nb, Mo,Tc ) elements both across series & down groups 4-8 to evaluate validity of extrapolation of group trends.
Why Study?? IMPORTANCEIMPORTANCE
RELATIVISTIC EFFECTSRELATIVISTIC EFFECTS
Group 6 valence orbital eigenvalues
Primary Relativistic Effects on Atomic Orbitals#• Contraction of radius, energetic stabilization of s & p orbitals.
•Spin-orbit splitting of l>0 orbitals
•Resulting increase in radii, energetic de-stabilization of outer d and all f orbitals.
#P.PyykkÖ, 1988
(Effects Increase as Z2)
IRs of TANs are about 0.05 Å larger than IR of 5d elements due to orbital expansion of the 6p3/2 orbitals, but are
smaller than actinide IRs due to actinide contraction (0.030 Å), mostly relativistic effect. Will influence chemistry.##
##V. Pershina, 2003
Chemistry Valid for One Atom-at-a-Time?Chemistry Valid for One Atom-at-a-Time?
• Must be “FAST” enough to accomplish in times comparable to half-lives of isotopes used.
• Give same results for only a few atoms as for MACRO amounts.
Adloff-Guillaumont thoroughly considered validity of results obtained from very small number of atoms.
Results from chemical procedures with fast kinetics in which single atoms undergo many identical chemical
reactions between 2-phase systems can be combined to give valid results. e.g. Ion-exchange & Gas Chromatography, Solvent Extractions
CONCLUSIONCONCLUSION
Note: Results of Chemical Studies of Md & No originally conducted on one-atom basis were later confirmed with larger quantities .
Production Reactions for TAN ChemistryProduction Reactions for TAN ChemistryHot Fusion—Elements 104 through 108
4,5 n
Fission Products ___________________________________________________________________________
18O + 248Cm 261Rf 78s 5nb
18O + 249Bk 262Db(Ha) 34s 6nb
22Ne + 248Cm 266,265Sg 21s, 7s ~ 0.3nb
22Ne + 249Bk 267,266Bh 17s, ~1s ~ 0.07nb 26Mg + 248Cm 270,269Hs ~4s, 14s ~ 0.005nb______________________________________________________________
**For ~5 nb, ~2 atoms/min produced. After transport efficiency (50%), chemicalyield (80%),detection efficiency(35%), & decay (50%), only detect 0.1/min~144/d.
For Hs, only 0.14/d or ~1/week!
Investigations of chemical and nuclear properties are complementary and should
proceed “Hand-in-Hand”
Nuclear properties, production methods, and detection techniques must be known in order to
study chemical properties on an Atom-at-a-TimeAtom-at-a-Time basis.
Nuclear ChemicalChemicalNuclear
Knowledge of chemical properties permits separation and positive identification of atomic number. Can provide
pure samples for study of nuclear properties and discovery of new isotopes.
2003 Chart of Nuclides2003 Chart of Nuclides
Elements beyond 111 not confirmed.
Ds
No isotopes withN>161 confirmed
Technical ApproachesCHEMICAL SEPARATION
THEN-MANUAL 1987THEN-MANUAL 1987Repeated “SRAFP” collections of recoil products transported via He-jet followed by rapid liquid-liquid extractions or column chromatography.
NOW & FUTURENOW & FUTUREAUTOMATEDAUTOMATEDARCA & SISAK for Solution Chemistry
HEVI & OLGA for Volatility StudiesBGS as Pre-Separator/Recoil Transfer Chamber (RCT)
In-situ Volatilization On-line (IVO) & Cryo-On-Line Detector (COLD)for rapid cyrogenic gas-phase separations.
DETECTIONDETECTION Passivated, ion-implanted planar silicon detectors (PIPS)/ Pin Diodes for alpha & SF detection & kinetic-energy
measurements.Multiple detector systems for aqueous chemistry.Rotating wheel system (MGA) for collection & detection.Flowing Liquid Scintillation Systems.
Record time, energy, position via computer.
First Chemistry on Element 105 (1987-1988)
"Glass chemistry" suggested by Prof. Herrmann (Mainz) based on their experience with homologs Nb & Pa(V) which sorb on glass while actinides and Zr, Hf do not.
•Picked up activity laden aerosol deposited on glass discs on rotating wheel in hood outside radiation area. Washed to remove actinides, and counted. Stopwatch Chem. (50 s)
•Grad students performed 801 such separations. Zr,Hf,actinides didn’t sorb. Showed it was Ha(V) not (III) as some had suggested.
•Produced at LBNL 88-Inch Cyclotron via (249Bk,18O, 5n) reaction.
Positive ID via known decay of 34-s 262Ha to 4.3-s 248Lr.
Manual 50-s “glass chemistry” on 34-s 262Ha.
Ken Gregorich, Darleane Hoffman demonstrate simple setup for first ever studies of 105 solution chemistry using "glass chemistry".
Technical Approaches: Technical Approaches: THEN: 1987—Manual ChemistryTHEN: 1987—Manual Chemistry
First aqueous chemistry of 34-s hahnium shows it sorbs on glass like
group 5 elements not like group 4 elements and trivalent actinides.
“Glass” chemistry: ~50 s from collection to detectors for & SF
Automated Chemistry to Berkeley, 1988
ARCA (Aqueous Chemistry) OLGA (Gas-phase Chemistry)
Participated in Investigations of Chemistry of Element 105 (then Hahnium, now Dubnium)
No Faster than Manual, but More Reproducible, Much Less Tedious, & Saves Grad Students!
GSI/Mainz PSI/Switzerland
Isothermal Gas-Phase Studies of Element 104 (Rf)Isothermal Gas-Phase Studies of Element 104 (Rf)Heavy Element Volatility InstrumentHeavy Element Volatility Instrument Merry-Go-Around (MG)Merry-Go-Around (MG)
261Rf248Cm
18O
1992 1993
(HEVI)(HEVI)
• Comparisons of volatilities of halides of Rf & Db (Ha) with lighter homologs in Groups 4 & 5 showed unexpected differences.
• Indicated gas-phase properties of TANs could not be predicted by simple extrapolation from properties of lighter group 4 & 5 homologs.
• Created much interest in studying heavier TANs.
• Plans initiated to study gas-phase properties of still heavier elements:
Seaborgium (Sg,106)Bohrium (Bh107) Hassium Hs (108)
GAS-PHASE CHEMISTRY BEYOND 104 and 105GAS-PHASE CHEMISTRY BEYOND 104 and 1051988-1996
Volatility of Rf, Hf, Zr chlorides & bromides (1996,2000)
261Rf75 s 8.28-8.52
MeV
257No26 s
8.22-8.27
MeV
253Fm3 d
Br<Cl (predicted)
Hf <HfOCl2?
Confirmation & Naming of Element 1061993: Our group decided it was important to confirm discovery of
element 106 so discoverers# could propose a name. •Used same 249Cf(18O,4n) reaction as discoverers. •Used the 88-Inch Cyclotron rather than the HILAC.
• Different horizontal rotating wheel system in special parent-daughter mode.• Positively identified 263106 via α-decay to its known 3.1-s 259Rf daughter.
• Half-life and cross section consistent with that of 0.9 s and 0.3 nb reported in the original discovery. [Reported by Gregorich for our group at ACS meeting (1993); Phys. Rev. Lett. 72, 1423 (1994). ]
After much deliberation, Albert Ghiorso & Discovery Group proposed Seaborgium to IUPAC. First rejected as Seaborg was still alive—finally found there was no rule against it and was officially approved in 1997!!
#Original discovery published in Phys. Rev. Lett. 33, 1490 (1974) by LBL/LLNL collaboration: LBL: A. Ghiorso, J. M. Nitschke, J. R. Alonso, C. T. Alonso, M. Nurmia, G. T. Seaborg, LLNL: E. K. Hulet and R. W. Lougheed. Same year Yu. Ts. Oganessian et al. published a claim to 106—later retracted by a new group of Soviet scientists.
249Cf + 18O ~0.6 nb 263106 + 4n
9.25, 9.06 MeV
Rf2593 s>97%<3% SF
8.77, 8.86 MeV
8.12, 7.93, 8.08 MeV
1062630.9 s
~50%~50% SF
No2553.1 m62%38% EC
248Cm + 22Ne -4n-5n
265Sg (8 s)8.71-8.91 MeV
266Sg (21 s)8.54-8.74 MeV
261Rf (75 s)
262Rf m (2 s)SF
116 MeV 121 MeV
8.28 MeV
Discovery of longer-lived isotopes of Sg (1996-97), Discovery of longer-lived isotopes of Sg (1996-97), Bh (2000), & Hs (2002) made Chemical Studies possible.Bh (2000), & Hs (2002) made Chemical Studies possible.
100 150 200 250 300 350 400 4500
20
40
60
80
100
120
(300oC - 400oC)
265Sg (13)
Temperature [oC]
WO2Cl
2
MoO2Cl
2
SgO2Cl
2
Rel
ati
ve Y
ield
[%
]
Temperature [oC]
ΔHads = 90 kj/mol (59 s)
ΔHads =96 kj/mol (51 s)
ΔHads =98 kj/mol (8 s)
Volatility: Mo>W>Sg
(as predicted)
Gas-Phase Experiments with Sg (106)Gas-Phase Experiments with Sg (106)International Collaboration at UNILAC at GSI, 1997
-20 0 20 40 60 80 100 120 140 160 180 2000
20
40
60
80
100
180o150o
75o, 267Bh(0)
267Bh (5)
BhO3Cl
TcO3Cl
ReO3Cl
Tisotherm
( oC)
Rel
ativ
e y
ield
(%
)
DiscoveryDiscovery of ~17-s 267Bh LBNL, 2000 Gas-phase studies
at PSI/GSI
First Chemical Studies of Bh (107), 2001-2International Collaboration
Tc>Re>Bh(as predicted)
26Mg5+
PFA Teflon Capillary
Oven (600 °C)
Quartz Wool Plug
Quartz Column
Recoil Chamber
He/O2
Rotating 248Cm-Target
PIN-Diode Detector (12 pairs)
Thermostat (-20 °C)
N2 (l)
Ch.E. Düllmann et al. Nature 418 (2002) 859Ch.E. Düllmann et al. Nature 418 (2002) 859
0
10
20
30
40
50
60
-20 -40 -60 -80 -100 -120 -140 -160
Deposition Temperature [°C]
Rel
ativ
e Y
ield
[%
]
IVOIVO
IIn-situn-situ VVolatilization Chamber olatilization Chamber (IVO) (IVO) && CCryoryo OOn-n-LLineine Detector Detector (COLD)(COLD)
COLDCOLD
OsOOsO44
HsOHsO44
Chemical Studies of Hs (108), 2002International Collaboration: PSI, GSI, LBNL
Hs<Os(Ru)<Os≤Hs (Theory)
BGS as Pre-Separator for Chemical/Nuclear Studies
• Provides decontamination from plethora of unwanted products.
• Uniquely suited for use at high beam intensity accelerators.
• BGS-SISAK studies of Rf show feasibility for studying solution chemistry of other short-lived transactinides.
• Demonstrated with Cyrogenic Thermo-Chromatographic Separator to study volatilities of Group 8 tetroxides, Os, Hs.
Recoil Transfer Chamber Transfer ChamberImportant for pre-separation
prior to other chemical studies
Led by J.P. Omtvedt, U. of Oslo
First successful transactinidechemistry experiment with SISAK.
Detected 24 257Rf (4s half-life)-decays in 17 hours.
Proved flowing liquid scintillatorsystem can be used for TANs.
Demonstrated advantage of using BGS as a pre-separator.
SISAK (SISAK (Short-lived Isotopes Studied by the AKufve technique)
Continuous liquid-liquid extractions & detection
208Pb(50Ti,n)257Rf (T1/2= 4.3 s)
SISAK Collaboration Group, SISAK Collaboration Group, Norway, Sweden, Germany, USANorway, Sweden, Germany, USA
Berkeley, November 2000Berkeley, November 2000
Chemical Periodic Table of the ElementsChemical Periodic Table of the Elements1
H
3
Li
4
2
Be
11 12
Na Mg
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
37
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
He
5
B
6
C
7
N
8
O
9
F
10
Ne
13
Al
14
Si
15
P
16
S
17
Cl
18
Ar
Rb
38
Sr
39
Y
40
Zr
41
Nb
42
Mo
43
Tc
44
Ru
45
Rh
46
Pd
47
Ag
48
Cd
49
In
50
Sn
51
Sb
52
Te
53
I
54
Xe
55
Cs
56
Ba
57
La
58
72
Hf
73 74
W
75
Re Os
77
Ir
78
Pt
79
Au
80
Hg
81
Tl
82
Pb
83
Bi
84
Po
85
At
86
Rn
87
Fr
88
Ra
89
Ac
104
Rf
105 Ha(Db)
107 108 109
Bh Hs Mt
Ce
59
Pr
60
Nd
61
Pm
63
Eu
64
Gd
65
Tb
66
Dy
67
Ho
68
Er
69
Tm
70
Yb
71
Lu
90
Th
91
Pa
92
U
93
Np
95
Am
96
Cm
97
Bk
98
Cf
99
Es
100
Fm
101
Md
102
No
103
Lr
Lanthanides
Actinides
106
Ta
Sg
76
94
Pu
110 111
1
2
3 4 5 6 7 8 9 10 11 12
13 14 15 16 17
18
62
Sm
114 118113115
Ds Rg116116
Rf, Ha, SgSolution & Gas-phase
Bh, Hs Gas-phase
114-112 Cryo
Mt, Ds ? ?
117112112
Cn
Role of Chemical Theory “Atom-at-a-time chemistry” has furnished much new data on
TANs through Hs (108) and some preliminary info on Cn (112), and E-114. Collaboration at TASCA/GSI just reported (June 2010) observation of 13 atoms of E-114 in month-long experiment! Analysis of chemical behavior is in progress. Studies are extremely challenging for theorists as Schrödinger equation is no longer applicable; fully relativistic calculations must be performed. As early as 1975 (Pitzer) reported (based on Hartree-Fock relativistic calculations) that 112, 114, and 118 might be volatile, relatively inert gases due to relativistic effects. These effects
increase as Z2. There has been a recent “new wave” of theoretical relativistic investigations summarized in several reviews by V. Pershina. These results help experimentalists design experiments to answer important theoretical questions. (Predictions for solution chemistry are especially difficult.) Theoretical predictions for elements up to 118 are now available.
In turn, experimental results help improve theoretical models. Such “synergistic” interactions lead to enhanced
understanding of the role & magnitude of relativistic effects.
Global CAST: Heavy Element Nuclear & Radiochemistry Group, U. of Cal. Berkeley/Lawrence Berkeley Natl. Lab. & Groups from around
the world: Mainz U., GSI-Darmstadt, TU Munich, Germany; Bern U., Paul Scherrer Inst., Switzerland; Oslo U., Norway; Chalmers U., Gothenborg, Sweden;
Tokyo Metropolitan U, JAERI, Japan; Dubna, Russia & FSU. (2003)
Chart of TAN Isotopes, July 2010
(Courtesy of C. Duellmann)
108
110
112
114
104
106
2891142.70 s
2881140.80 s
284Cn0.10 s
285Cn33.5 s
277Hs3 ms
281Ds9.6 s
2871140.45 s
2861140.12 s
282Cn1 ms
283Cn3.83 s
271Sg114 s
267Rf77 m
275Hs0.19 s
279Ds0.20 s
2851140.12 s
281Cn97 ms
277Ds5.7 ms
273Hs0.25 s
269Sg130 s
265Rf105 s
• First independent verification of element 114 from 48Ca(242Pu,3-4n)287-286114 using BGS
• Actively participated in further investigations of element 114 from 48Ca(242Pu,3, 4n)287-286114 reactions using new separator TASCA at GSI.
• Production & ID at LBNL with BGS: 6 new isotopes from 48Ca(242Pu,5n)285114
Element 114 Studies Summary
• 17 total element-114 chains observed from Berkeley/GSI
• 43 total element-114 chains observed from DUBNA
H. Nitsche Group, LBNL, UCB
Advantages of Pre-SeparationOpportunities for Chemistry
G R O U P1
2
3 5 4 11 12
13 14 15 16 17
18
1
H
3
L i
4
2
B e
11 12
N a M g
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
37
K C a Sc T i V C r M n Fe C o N i C u Z n G a G e A s Se B r K r
H e
5
B
6
C
7
N
8
O
9
F
10
N e
13
A l
14
S i
15
P
16
S
17
C l
18
A r
R b
38
Sr
39
Y
40
Z r
41
N b
42
M o
43
Tc R u
45
R h
46
Pd
47
A g
48
C d
49
In
50
Sn
51
Sb
52
Te
53
I
54
X e
55
C s
56
B a
58
72
H f
74
W
75
R e
76
O s
77
Ir
78
Pt
79
A u
80
H g
81
T l
82
Pb
83
B i
84
Po
85
A t
86
R n
87
Fr
88
R a
A c
104
R f D b
106
Sg
109
B h H s M t
C e 59
Pr
60
N d
61
Pm
62
Sm
63
E u
64
G d
65
T b
66
D y
67
H o
68
E r
69
T m
70
Y b
71
L u
90
T h
91
Pa 92
U93
N p94
Pu
95
A m
96
C m
97
B k
98
C f
99
E s
100
Fm
101
M d
102
N o
103
L r
Ta
112
L a n th a n id e s
A c t in id e s
44
6 7 8 9 10
73
105 110 111
89
A c
57
L a
89-103
57-71
A n*
L n*
114(115)
116(117) (118)
107 108
D s
40
Zr
104
Rf
Chemistry with pre-separationSystem can favor selectivity between homologues over removal of interfering nuclides. Opens way to classes of chemical systems previously deemed unsuitable.
AcceleratorAccelerator““Cocktail” BeamCocktail” Beam
Target
Producttrajectory
Beam trajectory
Mylar window
RTC
Separation SitesSISAKHEVI/OLGAIVO-COLDCTSL/L extractions
>>
BGS or BGS or
TASCATASCA
Chemistry without pre-separation System needs to separate out all interfering nuclides
Status of "One-Atom-At-A-Time" Chemistry of TANS
• Experimental techniques have evolved from simple "manual" chemistry to sophisticated computer-controlled automated systems.
• The LBNL Gas-filled Separator (BGS) at LBNL has been used successfully as a pre-separator prior to studies of chemical properties which has many advantages. (BGS is also used for many other experimental programs.)
• The TransActinide Separator and Chemistry Apparatus (TASCA), recently completed at the GSI accelerator in Germany, is used to study chemical, atomic, and nuclear properties of the TANs.
• Experimenters must go to one of these large installations (more in the mode of high energy physics programs) to apply for access to the facilities and/or participate in large collaborations. Currently, there are very few such installations with similar facilities.
• Synergistic interactions between experimenters and chemical theorists and experimenters have proven to be extremely fruitful.
FUTURE: "One-Atom-At-A-Time" Chemistry of TANS
• Continue use of BGS and TASCA as pre-separators for chemical studies.
• More detailed studies of solution chemistry of Rf through Sg and study solution chemistry of Bh, Hs, & Mt.
• New chemical investigations with 242Pu and 244Pu targets to produce more neutron-rich, longer-lived TAN isotopes.
• If longer-lived TANs are identified, devise methods for increasing yields, and “stockpiling” them.
• Investigate chemistry of Mt, Ds,Rg,Cn. Produce sufficient quantities for chemical studies using reported longer-lived isotopes such as 9-s Mt, 10-s Ds, 6-s Rg,34-s Cn. Chemistry should be rather interesting & exhibit wide range of oxidation states.
• Attempt to make separators smaller and even portable, e.g., a new super-conducting compact gas-filled separator with near 100% transmission has been proposed.
• Reconsider production of E-119 using 254Es (275 d) microgram targets with 48Ca beams or other suitable projectiles.
4,5 n
18O 249Cf 263SgFission Products
1 n
54Cr 209Bi 262BhFission Products
3,4,5 n?
48Ca 244,242Pu 289-286114Fission Products
TAN PRODUCTION REACTIONSTAN PRODUCTION REACTIONS
Hot Fusion—Elements 104 through 106
Cold Fusion—Elements 107 through 112,113?
Hot (warm) Fusion-reported elements 114,115,116,117,118
<0.1 s (+) 0.1 s to 0.5 min (o) >0.5 min (•)
Contour Plot 2003
(6) 254Es + 48Ca
(6)
CURRENT & FUTURE SHORTAGE OF NUCLEAR SCIENTISTS
Ultrasensitive & radioanalytical analyses. Stockpile stewardship & validation. Surveillance of clandestine nuclear activities (nuclear
forensics). Automated, computer-controlled remote processing systems. Environmental studies: prediction & monitoring of behavior of actinides & other species in the environment. Nuclear medicine, isotope production, radiopharmaceutical
preparation; diagnostics & therapy. Nuclear power: reactor design & performance; mitigation of
“Greenhouse” effects. Treatment, processing, & minimization of nuclear waste. Nuclear waste isolation & site remediation.
Exotic, frontier studies attract many undergraduate & graduate students to nuclear & radiochemistry. Excellent education & training for future careers & contributions to basic research & teaching as well as a variety of applied areas including national security & energy missions.
QUOTESQUOTES
“We cannot very often predict the practical applications of basic science--but we can predict that these applications will occur--to the positive benefit of mankind.”
Glenn T. Seaborg
“There is a beauty in discovery. There is mathematics in music, a kinship of
science and poetry in the description of nature, and
exquisite form in a molecule. Attempts to place different disciplines in
different camps are revealed as artificial in the face of the unity of knowledge.
All literate men are sustained by the philosopher, the historian, the political analyst,
the economist, the scientist, the poet, the artisan and the musician.”
Glenn T. Seaborg, Acceptance Speech Chancellorship at Berkeley, 1958
The The EndEnd