-1-

Safe Handling of Radioisotopes—Chemistry—
Fundamental Radiochemistry
Nuclides，Radioactive decay，Decay series，Natural radionuclides,
Nuclear reactions, Radiation effect

Department of Chemistry
Yasuji Oura
令和2年度放射線業務従事者教育訓練 (2020/5/23)

-21

18

H

2

13

1415

1617

He

Li

Be

B

CN

O

F

NePNa Mg

345689101112AlSi

S

ClAr

KCa

Sc

Ti

V

Cr Mn FeCo

Ni

CuZn

Ga

Ge As Se

BrKr

RbSr

Y

Zr Nb Mo Tc

RuRh

PdAgCdInSn Sb TeI

XeCsBa*Hf TaOsIrPt

Au Hg

TlPbBiPo

AtRnFrRa**

Rf Db Sg

Rg

Cn NhFlMc LvTsOg*LaCePr

Nd Pm Sm Eu Gd Tb

Dy HoEr Tm Yb

Lu**Ac Th

PaUCfEs Fm Md NoLrW

7Re

Bh Hs Mt Ds

Np

Pu Am Cm Bk

Naming Elements 114 and 116 (2016):
Nh (Nihonium)

Mc (Moscovium)

Ts (Tennessine)

Og (Oganesson)

Discovary of element 113 at RIKEN (2004，2012)
209Bi is a radionuclide. [(1.9 0.2) 1019 years] (2003)

-3-Symbol ofelement

mass number = Z + N
atomic number =number of protons

AZENZ: isotope

Nuclidenumber of neutrons

N: isotone

A: isobar

126C6stable

136C7146stableradioactiveC8-4-unstable nuclides= radionuclides

nuclidesstable nuclides

Radionuclide changes to the other nuclide
spontaneously by radioactive decay.

Release energy to transfer to more stable state.
α decay
AZ

44$E→A−E+Z −22 Heα-ray

自発核分裂neutronγ decayβ decay
AZAZ
AZ

E→Z +1AE # +e - + νA+$E→Z −1 E +e + νA
E +e →Z−1E $ + ν
β-ray， γ-ray

AZE * →AZ E + γ

Isomeric Transition
γ-ray
conversion electron

Nuclide Chart
257 stable nuclides
unknownnuclides

核図表2014(JAEA)

-6-

Radioactive decay
decay speed :number of decaying
nuclides per unit time

probabilistic events

dN−= λNdt

N: number of radionuclides， λ: decay constant， t: time−λt

N = N 0e
N0: N at t = 0

-7-−λt

Half LifeN = N 0e

The time required for number of nuclides, N0, to decrease to N0 /2 :T1/2

ln2
T1/ 2 =λ" 1%
N = N 0$ '# 2&t /T1/ 2-0.693 t

N = N0 e

1000

Number of Atoms

1−λT1/ 2
N 0 = N 0e
2800
600
400
20000123Time [h]456-8-Radioactivity
number of nuclides decaying per unit time
Unit: becquerel (Bq)，number of nuclides decaying a second
curie (Ci): radioactivity of 1 g of 226Ra
1 Ci = 3.7×1010 Bq

A = λN = −dN / dt
A: radioactivity [Bq]， λ: decay constant[s-1]，
N: number of nuclides−λt

A = A0 e

-9-• radioactive materials (radionuclides，materials
including radionuclide(s))• radiation• radioactivity (amout of radionuclides．not term
showing materials)
radiation
radiationlightradiation
radioniclide

radioactive
fluorescentmateriallamp

Intensity: radioactivity(amount) illuminance-10-(Ex.) Radioactivity of potassium

A = λN

39K : 93.3 %，40K : 0.012 %，41K : 6.7 %T1/2 : 1.28 109 years
40K in 1 g of K,#& # 1
0.693
23−2 &
× 6.02 ×10 × 0.012 ×10 (%( ×%9$1.28 ×10 × 365 × 24 × 3600 ' $ 39.1'= 32 Bq
K concentration in a body = 0.35 %if weight = 60 ， 6.7 kBq€32 Bq/gK
Specific radioactivity

-11-

Specific radioactivity[ Bq / g ]radioactivity per unit mass of element with its radioisotope
32P :(a) 31P(n, γ)32P， T1/2 = 14 days
If 1 mg of P is irradiated, 60 MBq of 31P is produced.
→ 6 104 MBq/g(b) 32S(n, p)32P， only 32P = without 31P [carrier-free]
60 MBq = 1.0 1014 atoms = 5.2 10-9 g→

1.2 1010 MBq/g

AA
λ × NA
AS ===W (A / λ ) /N A × M
M

constant notdepending on time

-12-Specific radioactivity[ Bq / g ]radioactivity per unit mass of element with its radioisotope

Radioactivity concentration[ Bq / g，Bq / mL ]radioactivity per unit mass of material (sample) including
radionuclide
40K in a human body
137Cs in a food

-13-

Puritychemical purity =radionuclidic
purity =(radiopurity)
32P，33P
radiochemical
purity =PO43-, PO32-

amount of interested chemical
species with radionuclide
total amount of a sample
radioactivity of a interested
radionuclide
total radioactivity in a sample
radioactivity of radionuclide in a
specific chemical formtotal radioactivity of theradionuclide-14-

Puritychemical purity =Content of Target Element
Irrelevant radioactivity

radionuclidic
purity =(radiopurity)
32P，33P
radiochemical
purity =PO43-, PO32-

amount of interested chemical
species with radionuclide
total amount of a sample
Ex. If the weight of Cu in a 1.00 g sample containing a small
amount of Ni and Zn is 0.99 g, the chemical purity is 99%.

radioactivity of a interested
radionuclide
total radioactivity in a sample

radioactivity of radionuclide in a
specific chemical form
total radioactivity of theradionuclide-15-

Puritychemical purity =radionuclidic
purity =(radiopurity)
32P，33P
radiochemical
purity =PO43-, PO32-

amount of interested chemical
species with radionuclide
total amount of a sample
radioactivity of a interested
radionuclide
total radioactivity in a sample
Ex.

60Co: 100 Bq

137Cs: 10 Bq of radionuclide in aradioactivity
Radionuclidic Purity of 60Co
131I:
90 Bq
50%
specificchemical form
Total 200 Bq
total
radioactivity of theradionuclide-16-

Puritychemical purity =amount of interested chemical
species with radionuclide
total amount of a sample

radioactivity of aRadiochemicalinterested
Purityradionuclidic
radionuclideof Benzoic Acid [14C]
purity =100
1414Toluene[ C]×10014
total
in40 +a10sample
Acid[radioactivityC] Toluene[3H]
Xylene[ C] Benzoic+100(radiopurity)
40 Bq
100 Bq
10 Bq= 66.67%
50 Bq
32P，33P
radioactivity of radionuclide in aradiochemical
specific chemical form
purity =total radioactivity of thePO43-, PO32radionuclide
Ex.

-17-

Decay series
When decay products are radionuclides, decay
occurs continuously. The sequence of nuclides
that cause this series of decay is called decay
series.
β-90

Sr →90Y→

28.7 y9990Zr

64.1 hβ-UITβ-

6.0 h

2.1x10 5 yαβ-β-→

4.5x10 9 y

228

Ra →
5.7 ydaughter

228

99→ €Ru

66.0 hparent

Al → 28 Si
2.3 m

Mo → 99m Tc → 99g Tc

238€28β-β-

Ac → ....... →212

6.13 hgranddaughterαPo →208 Pb
0.3 µs-18-

Radioactive Equilibrium
Decay rate of radionuclides in a decay series
APZP

EP →
λpADZD

ED →λDt = 0;

N0PNt;NPND

dN P= −λP N Pdt0DAG DZGDE GD0GD

NNGD

dN D= − λD N D + λP N Pdt

-19-Radioactive
Equilibrium

dN P= −λP N P
dt

dN D= λP N P − λD N Ddt

0 −λP tP

NP = N eλP0−λP t− λD t0 −λD t
ND =N P (e − e ) + N D e
λD − λP
multiply λP or λD on both sides
0 −λP tP

AP = A eλD0−λP t− λD t
0 −λD tAD =AP (e − e ) + ADe
λD − λP

-20-Radioactive
Equilibrium

AP = AP0 e−λP t
λD0−λP t− λD t0 −λD t
AD =AP (e−e+ ADe)λD − λP1) lP < lD

[T1/ 2 > T1/ 2]

2) lP << lD

PDT>>T[ 1/ 2 1/ 2]

3) lP > lD

[T < T ]PP
1/ 2DD1/ 20
Dwhere A = 0-21-1) lP < lD

AP = AP0 e−λP t
λD0−λ t−λ t
AD =AP (e P − e D )λD − λPPDT>
T[ 1/ 2 1/ 2 ]eAfter enough time，−λP t>>e−λD t

λDλD0 − λP tAD ≈AP e=APλD − λP
λD − λP

ADλD=AP λD − λP

Radioactivity ratio of daughter toparent nuclides is equal.

transient equilibriumEx.)

99β-ITβ-

6.0 h→Mo → 99m Tc → 99g Tc
66.0 h2.1x10 5 y99

Ru

-22-

TransientEquilibrium
ADλD=
AP λD − λPIT66.0 h

6.0 h

Mo → 99m Tc → 99g Tc
99Mo+99mTc€In the case of 99Mo → 99mTc,
AD/AP = 1.1

99β-99mTc

99MoAD /AP

-23-2) lP << lD[TP1/ 2AP = AP0 e−λP t
λD0−λ t−λ t
AD =AP (e P − e D )λD − λP>> T1/D2 ]eAfter enough time，−λP t>>e−λD t． And，

λD − λP ≈ λ DλDλDλD0 − λP t
AD ≈AP e=AP ≈AP
λD − λP
λD − λP
λDRadioactivity of parent and daughter
nuclides are equal.

AD = APsecular equilibrium

Ex.)

90

β-Sr →

28.7 y90

β-Y→64.1 h90

Zr

-24-

SecularEquilibrium90

β-Sr →

28.7 y90

β-Y→

90

Zr

64.1 h90Sr+90Y

AD = AP90Sr
90YAD / AP-25-3) lP > lDP
1/ 2β-β-8.7 m

57.2 m

< T1/D2 ]Ca → 49 Sc → 48 Ti

100Activity [Bq]49[TAP = AP0 e−λP t
λD0−λ t−λ t
AD =AP (e P − e D )λD − λP

Radioactive equilibrium is
not established.

49Ca+49Sc
1049Sc
49Ca
1050

100
Time [min]150200-26-Using radioactive equilibrium, daughter
nuclide that is produced from parent
nuclide is extracted repeatedly.

Milking

99Mo(66 h) → 99mTc (6h)10000

Tc generator

Activity [Bq]important innuclear medicine

10000246Time [days]

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-28-

Natural radionuclides
・Secondary radionuclides

・Primordial radionuclides
・Induced radionuclides
118

H

2

13

14

15

16

17

HeLiBeB

CNO

FNePNa Mg

34

5

6

8

910

1112AlSiSClArKCaScTi

VCr Mn FeCoNiCuZnGa

Ge As SeBrKrRbSrY

Zr Nb Mo TcRuRhPdAgCdIn

Sn Sb TeIXeCsBa*Hf TaOsIrPtAu HgTlPbBi

PoAtRnFrRa**Rf Db Sg

Rg

Cn Nh

FlMc LvTsOg*LaCePr

Nd Pm Sm Eu Gd Tb

Dy Ho

Er Tm Yb

Lu**Ac Th

PaUCf

Es Fm Md NoLrW

7Re

Bh Hs Mt Ds

NpPu Am Cm Bk

-29-

Primordial radionuclides
Nuclides that already existed when the solar system wasformed and that still exist due to its long half life.

・Parents of decay series
238U(4.5109 y)，235U(7.0 108 y)，232Th(1.4 1010 y)・Independent
40K (1.3109 y)

50V (1.41017 y)

87Rb (4.81010 y)

115In (4.41014 y)

123Te (1.21013 y)

138La (1.11011 y)

142Ce (>51015 y)

144Nd (2.31015 y)

147Sm (1.11011 y)

148Sm (71015 y)

152Gd (1.11014 y)

176Lu (3.81010 y)

1010 y)，186Os (2.01015 y)

174Hf (2.01015 y)

190Pt (6.51011 y)

187Re (5Isotopic abundance > 10%

-30-Secondary radionuclides
・Short-lived nuclides belonging to decay series originatedin primordial radionuclides.
・Fission products of spontaneous fission

U series: 238U → 206Pb， mass number = 4n + 2
Th series: 232Th → 208Pb， mass number = 4n
Ac series: 235U → 207Pb， mass number = 4n + 3

-31-

1.2m
234

U 

238

24.1d

 2.5x10234y Pa 

 4.5x10 y5230

U series

234

Th

222

210

Po 

21422y 138d 210 Bi 206

Pb

218

At 210Po  2s218

 162µs 214 Bi 26.8mPb

19.8m

214

1.22dTh RaPo Pb 

220

3.05m

10.6h

Bi Pb 207Pb

 2.15m 211 Pb
TlRn 3.9sBi Pa 



231

215

Po

 1.8ms235

U

 7x10 y
8Th

3.3x10 4 yRa 11.4d219

Tl

211

Th 

 18.7d 227 Ac223

 0.15s

212

36.1m

207

Po231

216

208

227

 55.6s212

 60.6m

208

25.6h
22y

Rn

10228

 3.66d 3.05m

 1.41x10 y

Ra

224

PoTh 2325.76y

 1.91y 228Ac  3.8d60.6m

 0.3µs

Rn

Pb

212

Th series

Ra
228

19.8m

Th

4

 1600y

5.0d9

 8x10 y2263.05m

UAc series

-32-Induced radionuclides
Nuclides that are always produced in the upper
atmosphere mainly by nuclear reactions with cosmic rays
in nature.

Nuclear spallation reactions of N and O
3H (12.3 y)，7Be (53.3 d)，10Be (1.5
14C (5.7106 y)，103 y)

Nuclear spallation reactions of Ar
22Na (2.6 y)，32Si (172 y)，32P (14.3 d)，
35S (87.5 d)，36Cl (3.0105 y)

-33-

Induced radionuclides
Nuclides that are always produced in the upper
atmosphere mainly by nuclear reactions with cosmic rays
in nature.
Stratosphere

Cosmic RayNuclear spallation reactions of N and O
3H (12.3 y)，7Be (53.3 d)，10Be (1.514C (5.7103 y)

Altitude: 15Km106 y)，

14N + n → 14C + p

Altitude: 9Km

Nuclear spallation reactions of Ar

22Na (2.6 y)，32Si (172 y)，32P (14.3 d)，
35S (87.5 d)，36Cl (3.0105Tropospherey)

-34-

Artificial radionuclides
produced by nuclear reactions- accelerator
RI,- nuclear reactor(positive ions, electrons)(neutrons)

carrierfree numberproton    fission，spallationradioactivemedicines

18O + p → 18F + n
249Cf + 48Ca → 294118 + 3n

Irradiation energy is important.
yieldssecondary products
neutron number

-35-Radioactivity induced bynuclear reaction

N = nφσ t

N / n = φσ t

A = nφσ (1− e− λt

N : number of reactions
A : induced radioactivity
n : number of target
nuclidesφ : fluence rate
σ : reaction cross)sectionλ : decay constantt : irradiation timesaturation factor(Ex.) 31P(n,γ)32P， T1/2 = 14 days

saturation factor1-λt

0.81-eφ : 1013 cm-2s-1
σ : 0.17 b = 0.17×10-24 cm2
λ : 0.049 d-1 = 5.7×10-7 s-1
t : 14 d = 1.2×106 s

1.2

0.60.4A =1.6×1010 Bq/g
N/n = 2.0 × 10-6

0.200246t / T1/2

81012

-32-Nuclear fission β-131I

235U + n → 236U → 131Sb + 103Nb + 2n + Q

mfmimi > mf
Q = (mi - mf) × c2

asymmetricfission

90137〜200 MeV

1 MeV = 3.8×10-17 kcal
1 g of 235U = 2.5×1021 atoms

symmetricfission

1.9×107 kcal
1 g of coal = 8.1 kcal

Crouch (1977)

-33-Element 113

209Bi + 70Zn → 278Nh + n

Gas-filled
Recoil Ion Separator (GARIS)
K. Morita / Progress in Particle and Nuclear Physics 62 (2009) 325–336

Charge of ionsbecome same bypassing though gas.
variouschargestatesindependent
on initialcharge state

Progress in Particle and Nuclear Physics 62 (2009) 325–336

ew of RIKEN GARIS. The shapes of pole pieces of the dipole magnets are shown in the figure. Envelop of reaction products as well as ofis also shown.
0Contents lists available at ScienceDirect

trajectory in magnetic field: Bρ = 0.0227 A (v/v )/q0227m(v/v0 )(T m).

Progress
q in Particle and Nuclear Physics

radiusmass numbercharge(2)s only on the velocity and atomic number (Z) of the ion, and does not depend on the initial ionic charge stateL ETTERS 113
Element

K. MORITA et al.

-34-

209Bi + 70Zn → 278Nh + n
9 years，net 574 days
1.39 1020 ions wereirradiated at the target.

Known
Known

J. Phys. Soc. Jpn. 81 (2012) 103201

Irradiation Effects of Radiation(1) Radiation trauma
４．具体的データ
lattice defect (metal，semiconductor)
表１

カーネーション「 きらり」の特性（平成(2) Ionization, Excitation, Radical production
切花 切花 分枝品種
茎径 花径数長重・系統(mm) (cm)
(本)
(cm)
(g)
dissociation and formation of chemicalbond
きらり77.9 46.7
10.4
4.6
5.7
oxidation-reduction，cross-link，polymerization

常陸野
82.0 53.7
10.8
5.1
5.6
ひよこ
ﾗｲﾄｸﾘｰﾑ
87.8 50.6
18.1
4.6
5.0
ｷｬﾝﾄﾞﾙ
１）花色は RHS カラーチャートによる。
注）調査 36 株、パイプハウスに定植 6/24、一採花本数データのみ別圃場：調査 18 株、定開花日；「きらり」1/10、「常陸野ひよこ」(3) Killing of organisms，Asexualization
sterilization，pest control，food irradiation，radiotherapy(4) Mutationcereal → (e.g.) Reimei [rice]
fruit → (e.g.) Gold 20 century [pear]
flower → (e.g.) Kirari [carnation]

表https://www.pref.ibaraki.jp/nourinsuisan/seikoken/hinsyu/documents/h27kirari2.pdf
図１

カーネーション 「きらり」Reformulation and processing by radiaiton
monomerpolymerpolymerization
cross-link
disintegration

monomergraft polymerization
curing- producton of fluorine resin(PTFE) particles [radiolysis]- radial tire，heat resistance electric wire，foam plastic [crosslinking]- painting cement tile，laminate steel sheet，paper liner ofadhesive label [radiation curing]
http://www.radia-ind.co.jp/products/service01_05.htm#link

Prevention of melon fly
Kagoshima

maleradiationby γ-rayAmami ilands
bebining
eradication
Okinawa ilands
bebining
eradication
Kume iland
bebining
eradication
Miyako ilands
bebining
eradication
bebining
eradication

Okinawa
normalbarrenmonth[year]

https://www.pref.okinawa.jp/mibae/index.html(沖縄県病害虫防除技術センター)