,

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PARTICLE TRMlSFER AND CA$iA RAY

S~IES OF 14{>Pm

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;!.'ARTlCLE TRANSFER AND GAMMA RAY-' - . '.

STUDIES OF 144Pc

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By,

MALCOUI RONALD 'HACPHAlL, B.Se.

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I

~tted to thcSehool of Grnduoti Studies

10 li'ort:L:ll Fulfi1l::cnt of .thc Requir=ntc

for'the· Dogrec

DOctor' of Philosophy

,

, .

lIuu"W'lt 1973

® r'la1colrn, Ror.alii r'l:lcpl".aH 1974

Malcom Ronald 'Macphail. B.Sc •. (Edinburgh),

•reve~ed .a groUJ> lof~elVe levels up

\

DOt:T03.. DF PllILOSOPY (1973) MclfASTER UNIVERSITY(Fnysic:a) H=ilton, OntariV

nTLE: .Particle Transfer and Ga= Ray Studies of l44fu .

AIJTEOR:

SUPERVISQ.'t: Professor R. G. S=rs~ill•

../' ,rroxBER OF PAGES. : D.. ~9\c("SCOPE AND comn.'TS:

"

I . 144'The nuc1~r structure of Pc has been investigated by a

c~inatlon of p~rticle and Y' r~y spectroscopy.

143 144,and rZd(a.t), Pc r=ctions

,to = =cit~ticn of 514 lteV.. and other levels beYQ~,d 840 keV. The

c!cctro-..agnctic de~s of tho 'levels were found froo high resolution~........ .'" . ' .

, - \ . "- 141-· 144s~les =d'~oinCidence studies of' the l;'r(a.ny) Pc and

1~ 144' ', ••d(p.ny) 1'c:re~c~ons.

~ spins. p<:lr~es and spectroscopic fllct;ors of the ,low

lying ~cvef3. det~cd froo the pllrticle transfer and y rllY studies.." .~ .. ' .

c:= be oucccsofully c:p1.:rlJ:cd in teres of the l:l!:l:ed configuratil;lllS

;2dS/2v2f7/2 :md ",lC7/2,,2f7/2 • The observed y rllY branching rlltio?, I

~ro,cl.::;o c:onsistc:1t tdth this '1nterpret~tion. Tentativ'o spin and

p:1r;lty r-si.~nts h;Jvc *0 been =de for lavels beyond 8!+O kcV.

SC~ll ~ec1 cc1cul~ticnb c=ploying a ~urf~ce delta interaction,

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ACKNOHLEDGEDMENTS

I should like to express my ~incere appreciation'to alI those•

who have helped in the' course of t~is work. I would especially like(> ~"

to thank:

Professor R. G. Summers-Gill, my supervisor, for his-many

suggestions and ideas.

The other members of my Supervisory Committee • Drs. J. A.

.'

'Kuehner and C. Calvo for their guidance. '.",

Past arid pr..esent members of the group: Hamish Robertson for -<..,

his ins~gh\:; pon Dohan and Terry 'Taylor for their invaluable Ollsistance/ --.,

with,the long accelerator, experiments ; Sheral1 Hussein, 'Tony Pierce'

-ona'Neil Sanderson for their· friendship; and Konrad Aniol, and ~uil~,IslOtl for their help. free~y given.'

, ,

D.:lveKelly for !!;9~is't=:co with ~y computer programs'.

Brian Cook for many informative discussions.. :t

Phil Ashbaugh and the s~aff of the accelerator.J

'" Finally, Mro. Edna tUlli= for her efforto in tyPing thio

thcoio..

This worlt woo oupporte" by grunt'o to the croup frotl the

National Research Council' of Canada. Financial asoistance frOti

M~ter Univcrolty io gratefully acknowledged •. "

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1.2 Na 83 Odd-odd Nuclei

1.1 The Shell Model

II ,Rr:11:0N TRANSFER STUDIES

; ~2.l Direct Reaction Theory/

I ,NUCLEAR THEORY

Pos,: ---.'

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5

5

7

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. 10

10

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TABLE OF CO~c

,a Stripping Reactions

INTRODUCTION

,CHAPTER '

c Th2 Distorted t~avc Born Appro:W:.:ltion(mmA)

b ~pectroscopic Factors .

2.2 _E::tperii:cntal Outline"

a Tb.2 FN Tand= van de Graaff Accelerator .

,b Tb.2 Enzc Spectro~raph

c R:citation Energies

d TarGet Prepar~on

and Cross ~tions'~

2.3/"0

E::tpcrtccntal.Rcsulto. -143 '3 144 ,,'

'0 The t;d('~Ctd) Pi:;ltlcactlonII •

b '(~td) ·1Ingulllr Distribution:::

143 144c Tae Nd(o.t) Pc Reaction. .d Clac,d)/(ott) Cross~Scetion ~tics

25" '

32 '

34 •..

,c R:trneticn of Spcccroscopic Factors 39

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CHAPTER, Page•

, ,"c '(a,nl) arid (p,ny) Excitation Functions

d ~ Ray Region in the (a,n) Reaction,

b.~ y Ray,Singles Experiments

.3.2 , Electro~etic TransitiC?Us ,in Nuclei

.I~,

3.3' Gamma Ray Sin~les Studies~' ~'f',

, <=> '----a Experimental Outline~, 48

49

56 -

5-9

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69 '\\ 74 ,

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45

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1""a Experimental Outline

b y-y Coincidence'~Results

3.4 y-y Coincidence Studies

'3.1, , Introduction

II~~ GAMMA 'RAY STUDIES

."IV LEVEL SCHEME OF 144Pc

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4.1 Introduction-- .4.2 Energy Leve'ls Below 600 keV

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,11 Const;ruction' of to"", Energy Sch=e,b ) Pari tv AoDig=ento, ,

, ,

c Spin' AllOignccntD ' _

d _ Proton ~rnMfer RcnctioM'/

Io y Ray Intensity Rntioo

,f L:l.fct~D

G Orenching RatioD~ . -

h Ground Stato }wgnotic }~~nt

4.3' EnerilY Lavcle Above ~OO l:cV-

n 'Ccnstruction of High Energy Schct:O '0-

b ~torprctotion'of'Hish Fncrgy Scho~

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80 •811' " ,

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89

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102

102~~

106

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/""'.i?:4 'Shell Model Ca1cu1ati<lns

a "Introduction.

b The Odd-Odd N=R3.Nuc1ei

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,SlJ}!MARY

APPENDIX /~~.~~ "'

""r Al.1 ]Level Scheltes of 143Pm and 145Pm

a 'Introduction

107

107

109

117

119

119

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2

3

4

b . Experimenta~ Stud,ics:,',

c £ Value and ~pin Assigncent~

'145Pm \ ..Q Values

AJ.1 'y Ray Absorption in Targets144 .

A4 .1 Decay of Pm

REFERENCES

,)

for

119

121126

129

136

1)

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vii

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LIST OF FIGURES

FIGURE

i.1 Energy levels of therodd proton N=82 nuclei

~2.1 Il'-JBA IJUgular distributions for th~- (\e.d),. reaction 16

..'

2.3

2.4

2.5

2.~

2.7

2.8

2.9

3.1

"3.2

3.3

3.4

3.5

3.6

FRt=del7, accelerator laboratory

Enge split-pole cagneti,. sllec-irograph

Deuteron spectrum fro~ the {1ae,d)' reactio~r:;'

~ericenta1 angular distributions for the(JRe.d) reactibn , " ~

~tcn and deuteron ~pe~tra fro~ the<xa,t)and~3He,d) reactions '

-(~.d)/(a,t) cross section ratios ,far lOw~lyine levels iIi 144Pc .

Spectroscopic factors =d spina for low lyinglevels in 144Pc

- . . ~

(~.d)f(a:~) cr~ss secti"on rattc:lfor.·~h., q;lCr\zy levels 'in 144Pc .

3Gc(Li) spectra (O. 9 Ctl ) frOt! the. (a ,nl and(p,n)"reactions

. '. .I J . 3'Gc(Li) .spectra (50 Ctl ) frotl the. (e,n) =dJp,n) r=ctionS

y ray =citation .functions for the {a,n)'"'rcnction / •

r ray. e::citation functmnz ror .tho, (p ,n} .rcoction, ,Lo-..1 energyy ray r.f?o.ctnc. fr<r.J the. (apn)'r=ction n

Bleck diaGr~ of y-y coincidence syotco for- . '- ,."

~" detectors

17

20

28.

, 31

33

~38

41

44

53

';'.-54\; ,

57

/50

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70

r

..- '.

,'",,"

j •

. I~ -,

. FIGURE .. 2p~,I'

3;7 diagram of c01nc~de:,ce' ystem forBlock y-y,three deteC,tors 73

3.8

4.1

4.2

4.3

4.4

4.54106

Ge(Li) - Ge(Li) coincidence spectra,. ; .' 144 .

Proposed 1~ve1 scheme of ' Pm'. «600 keV). . . - .

(p'n)/(~,n) y ray intensity ratios

(~,n) y'ray. inteDrlty r'atios

X2 plots' for branching ratios in 144Pm. '. 144

Proposed lever scheme of . Pm (>600 lroV)

140r 142 144 '. Thc~et~ca1 Sllectra of !~, .Pr and( Pm

Root mean square ener\?y deviation for spect'l;a'of l40IA, 142pr ond 144Pm: . .' .

76 .

79 >

."86 "

88 '"96. .

103

111

112~

. A3.1

M.1

-'. . 142' 3 143'~uteron Sllectra from the ~d( He,d) Pc

144 3 145.and Nd( He,~) Pm reactions 120• 3 . .( He,d)/(a,t) crQSS s~tion ratios for levelsin l,,3P!:l and 145Pm .( . " . 124

oy ray attcnuationfu the (a,n)" and (p,n)reactions 131'. "

Decay· of otrongcst lines in (P ,n) target'.' -

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·LIST OF TABLESI \

3.1 y ray energy standards

3.2 y ray energies and intensities fr~ the (~.n) and·(p.n) ,reacttons

Page

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29

35

42

50

60

63

67

77

85/'

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92

93

97

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li4

.composi~ion of t~get =terlals

Results. of y-y coincidence exper1J::onts

Low energy lines fra;:i the (a.n) reaction

Wave vectoro fr~ proton transfer and y roy studies

" . .I'Gyr=enetic ratioa used in branch:ing ratioanalysis

Opti.cal codel par~ters for the 1~~d(3He.d)144Pcreaction '\

Su=med spectroscopic factors ,fr~ pro~on transferreactions to 144Pc .,' ., ,

Level energies and proton transfer cross sectionsfor l44Pc

P~latlve phases for S ~l1tudes

C~arison of calculated end cxper1J::ontal branchingratios

.. 144Proton'transfer spectros.copic factors for Pc

(p.n)/(a.n) y rav intcns1:ty ratios'

,~orl~ntal'and theoretical conf1unuratl~nt:1ng

.......plltuc!es

4.3

2.4

4.7

4.5

4.6

3.4

2.3

4.1

4.2

3.5

2.2

4.4

2.1

,3.3 y ray 'energies and 1ntensities fr~ icpurity

reactions

TABLE-

M..lJ

Level enorgiC!Yend proton tr.~n"forC:ro:l::: cectilr'...:Jfor 143m

and proton transfer cross sections,~ .

I,

I!

A1.2

A2.l

A3.·1

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Level energiesfor l45Pm

3 .( He ,d) Q values

Uhcertainties in y ray att'enuation .

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INTRODUCTIONc /,

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The nuclear force has pro'lred to be so cOtlplex that no~ct·

deocription of it yet exists 'core than 60 years after it<~as first

pr:oposed •. Ourpresent·understan~1.nlt~f nuclear prl.perUes bas.thus

.j~volved from,~tt6n~ts.to ~lass1f17 exper:icental.info~tionin teres'

of a smple. mod~l of the nucle~•. Thesituat;ion. hmreVer. :is chnr- ",...' ., " I

,( .' ",

. octerized bY.:the·exi~teuce of 0c::veral nucleor' moClels. each on'ia being,obleto describe either a certain type of reoction·or.having ito

~- -

appl1cobil1ty to restricted groups of nucJ:eir."~. , L/One of theccst.successful nuclear codels.' tho shell model

(Mayer 1948, 1949; Raxel.Jensen and Suess 1948. 1949).' has cet.with"-. .. , ' " , ,. , .considero1;>lcf oucccoo in- occount:ing for the. properties of .odd c''''0l:l .

-- '"00: - . ~'::"~-'":;;., ~

ophericalnuclei. NuClei :in the regions of singly and doubly closed·····. '. I

ohcl'ls .ore of opedolintereot, oince ~hclr p~perticscan be Under) ... "" . ~ . ' ".,-,,;

l:'otood :in te1"Cll of ° relotivcly ample abell ,model.. Included o~ thb

category ore the' serieo of odd-odd nucle:!. w:1th 83 ncutrono. one. ......

bqyoud o. closed r:hcll of 82.

." .

or",o ~

no 10-" lying l~vel.s of tho09'nucioi ore 'c::j>bctcd to onoe

fra::dho 2dS/ 2 and 187/2 'proton coufigutotioas. and the 2£7/2.i' • / __ . • <>

ncutran'oconfigura~ion only, thus bfiording 1m e:tcellcnt opportunity

to cpply l;h6 techniquea of tb.o~ ohe!:l r::~el. 'Ih:ia region fa probobly

'.~e of tho coot J:lppropdDl;c 0'£ tho .peri.odic tolll~ in t1Mcl~'to :Jyo- .

. t=t~~?l~Y 'otudy rC:Jidtial :ic~tron..protO'::l ~teroctions. Unfo:-t."'otcly, .,)

an oc~o~t of the diff1cultico in otuaying lludc1Uith ¥-eh' level. ., ,

1 ""..."' , ,

2

'.tast decade,. however, the advent of fast computers and sophisticated

experimenta1tech~iquesh~e enabled both theoretical and experimental, . .,

investigations .to extend to a w1de~ range ,of ~uc1ei, including odd~

odd nuclei.

,

."The N=83 0~-oddnuc1e1, which include 134sb , 1361: 138es ,

140La ).42p " 144Pm 146E d 148Tb d ff h . dd, r, , u an I i er by t e successive a i-,,

tion of two protons beyond the Z=50 c10se~ shell.' The ext~eme

members of this ~eries are pe.~ps the most difficult to study since

138 >.

The II and y ray decay of the fission product --Xe has"beenib1e.

. they 'are too far from the region of stability to be reasonably access-..

Inveotig~tio~s of the II decay of 140Bo to 140La , performed

the subject of several investi:gationll. In the most recent',by Nonnand

,eta!. (1972) ;tow- spin states in 138Cs "(ere identified up to an cx-

•

•

The 'spinil, 'patlt!~o ..

studied by !Corn e,t 01.' (1967, .1968)• I

--"'- "

of high resolution ~d.p) and (n.y) reactiono.

citation of 2300,keV.

by oevara,l groupo (Geiger.et a1. 1961, AgDrua~ et al. 1964 and

Burde at 01: 19~~), reoulted ino,n~ber ~f o~ln-pority assi~nts,140 • 142~ .'

as Uell os lifet1J:la determinations. ',. La mid t'r were extenoive1y-,

Iand Jurneyet d., (1970) by ccono

and. decay properties of =y qf thO 10".1 lying levels wore thUs,:

iowd.,

,14~~. ,nent in this'oeries; hos been the subject of very

". .' 144 ' 144 .. 1!-tt:1.c study. InvestiGodolW of tho· Pl::l(c.c,') Ndrcaction

,.' ' 148(nc:::::m 1967. and Al"yaeto!:. 1971). ond the a decoy of Eu

('loth ct ol. '1964):lndicatc 0 5-. spin:.por1~oo::li&!,=cntfor tho

.. ,.

several low spin states.

,3

-- ,;- .oQ

, 144 '. .ground state. The level str}!,cture of Pm was otherwise cCl1:lpletely

142 144 -_ " 'unkno-wn. Neither Pr nor Pilr can be.gtudied by B decay ~ecaUse

"b 1.., 146 'their neigh ouring isobars are stable. Las"",y, Eu was' ifvestigated

,', , 146 ifollowing'the decay Sm by, Antman et al. (1970) who identff1e,,\

I

, Many of these experiments have allowed only spe~if1c .nuclear, ,

properties to be studied. Whi~e this can be an asset in understand-S . . ~

1ng compUcated nuclei, it 'also gives an incomplete picture. The-- ,present. work was undertaken to provide additional expericental

~nformation necessary for the ~valuation of detailed theoreti,al

studies of the odd-odd N~83 nuclei, and has utilized the techniques

of both 'particle an4 yray spectroscopy." '

144 142\ 'Initially the Nd(d,a) Pr reaction loTQO investigated

together with singles and' coincidcnce'yray studies of ~ec ", .

139 142 142 142.' . . 'La(a,ny) Pr and Cc(p,nyl -Pr reactions to locpte certai.n

.?

low ,lying levelo not observed by Kern et al. '(1968). This work.

in'addition to higq resolution (d,p) studies of Hussein (1973).

enabled the J~6 and 7 levels to be identified. This \1llO Ulter

"confirmed by the work of Anl01 (1973). ,Subooquently, a study of

144F1::l \1llO .pe~fo~ed and' is dese~ibed in' ~'etall in this thesis:-144 ' '. '

Since t1lc level s'tructure of )?\:I fu:d llotprcviouoly been

. 143· .3u 144 . 143 . 144 ~in~c:ltigatedJthe Nd(lie,d)' ,.,.FI::l and ~Hd(a. tlPo. proton

trOUDfer reactiono 'wre carried out, as dc:lcdbedinchepter II, •

to eOtahl1sh. the energy levelo. spcctroacopic factorc end.poasible

spins end parit1c:l. Thorosul'ta of 1~4~(a,ny)1441?cend

o.•