CHAPTER 2
2. LITERATURE SURVEY
2.1. Brief History of Germanium (Ge)
2.1.1. Natural Occurrence
Germanium (Ge) is a semiconductor metalloid which belongs to group IV-A of periodic table.
Ge is always found in combination with other elements such as argyrodite (a sulfide of Ge and
Ag), Germanite (containing 8% of element), in Zn ores and other minerals. A significant
concentration (≈ 2-8 ppm) of Ge also occurs in coals worldwide. It is recovered as a byproduct
of production of some metals mainly Zn, Pb and Cu [1-3].
2.1.2. Discovery of Germanium
It was firstly predicted by D. I. Mendeleev in 1871 in his table of elements [4]. This unknown
element was called eka-silicon [5]. In the year 1886, a German chemist Clemens Winkler was
succeeded to produce elemental Ge from isolated argyrodite (Ag8GeS6) by reduction of sulfide
[6]. The physical and chemical properties of the Ge were in very good agreement with the ones
predicted by Mendeleev in 1871 [7].
2.2. Physical and chemical properties of Germanium
Germanium has greyish white appearance with submetallic luster and is very brittle element.
Its atomic number is 32 and relative atomic mass is 72.61. It’s melting and boiling points are
1210.6 K and 3103.2 K respectively [7].
2.3. Importance of Germanium
Germanium has refractive index of 4.0 and a Mohs hardness of 6.0. Any infrared bulk
transmitting material with low dispersion properties and highest refractive index across a wide
range of temperatures keeps off chromatic deviation in many applications. This means, the
imaging using single Ge lens with low f-number can be achievable using the combination of
low dispersion and high refractive index. The mechanical ruggedness and surface hardness of
Ge is also helpful in many applications [8].
A number of applications of Ge can be found in the field of nuclear physics such as highresolution gamma-ray detectors, low temperature thermistors and for IR detectors [4, 9].
Table 2.1 Chemical and physical properties of Ge [10]
Properties
Eka-Silicium [11]
Germanium [6]
Present values
[4]
72
73.32
72.61
Dark grey
Greyish white
Greyish white
5.5
5.47
5.323
High
-
1246.2
13
13.22
13.57
0.306
0.318
0.310
4
4
4&2
Eka-SiO2
GeO2
GeO2
4.7
4.703
4.228
Reacts acidic
Confirmed
Confirmed
Eka-SiCl4
GeCl4
GeCl4
1.9
1.887
1.8443
333-373
359
356.3
Soluble in (NH4)
Confirmed
Confirmed
Eka-SiEt4
GeEt4
GeEt4
Density [gcm-3]
0.96
0.99
0.991
Boiling point [K]
433
436
435.7
Relative atomic maa
Color
Density [gcm-3]
Melting point [K]
Atom volume [cm3]
Specific heat [Jg-1K-1]
Valency
Oxide
Formula
Density [gcm-3]
Properties
Chloride
Formula
Density [gcm-3]
Boiling point [K]
Sulfide
Properties
HS/H2O
Ethyl derivative
Formula
2.4. Isotopes of Germanium
There are nineteen known radioisotopes of Ge. Among these seven radioisotopes (64Ge – 71Ge
with a stable 70Ge) are proton rich and decay with β+ and/or electron capture. Nine isotopes
(75Ge – 84Ge with a stable 76Ge) decay with β- and these are neutron rich. There are only four
metastable isotopes of Germanium (71mGe, 75mGe, 77mGe and 79mGe) which are very lived. The
longest-lived radioisotope is 68Ge with decay characteristics of 270.8 ± 0.3 days [3, 12-15].
2.5. Medical applications and importance of 69Ge
Germanium-69 (t1/2 = 39.05 h) is a PET trace Cyclotron produced radionuclide [3]. It is a
peculiar positron emitting (21% β+, Emax = 1205 keV) radionuclide [16]. In the field of nuclear
medicine, due to its favorable decay characteristics, it is an ideal choice to use
69
Ge-labelled
antibodies for immuno-PET imaging [3]. Also, it is cost effective and has simple and good
production route [16, 17]. However, its full potential is yet to be examined for Positron
Emission Tomography (PET) [16].
The major limitations in the use of
69
Ge are the unavailability of appropriate radiolabeling
techniques and its complex coordination chemistry for the synthesis of
69
Ge-based
radiopharmaceuticals [16].
Using fast and highly particular chelator-free strategy, the above said challenge can be
circumvented by incorporation of
69
69
Ge onto SPION [18, 19] which can be used to establish
Ge-SPION@PEG [16] that may prove a promising agent simultaneous for PET/MR imaging
in future [20]. Furthermore, it can also be beneficial for clinical diagnosing and staging of
cancer disease [16]. The presence of carboxyl group and some other specific ligands (proteins,
antibodies or peptides) [21] at the surface of
69
Ge-SPION@PEG which may make it more
powerful theragnostic agent for cancer.
The chelator-free approach can also be used to prepare multifunctional theragnostic agents both
for therapy and integrated imaging by incorporation of relevant therapeutic isotope such as
77
Ge (t1/2 = 11.3 h, Emax = 2.2 MeV, 100% β-) [3].
Table 2.2 Nuclear data for 69Ge radionuclide
Atomic
number
t1/2
Decay mode
(ratio)
Eβ
MeV
Iβ
%
Ref.
32
39.05 h
β+/EC
1.215
32
[22-25]
(23/77)
0.61
3.6
[26]
0.22
0.7
Figure 2.1 a) After the i. v. injection into mice the serial in vivo images of
69
Ge-SPION@PEG (top) and free 69Ge (bottom) [16].
b) Before and after i. v. of 69Ge-SPION@PEG in vivo MR images of mice. Trans axial
images are presented to show accumulation, contrast enhancement and up taking of
69
Ge-SPION@PEG in the kidneys [16].
69
Figure 2.2 a) In vivo imaging of lymph nodes with PET after hypodermic injection of
Ge-SPION@PEG into the left footpad of the mouse. Lymph nodes and paws are indicated
respectively by green and red arrows [16].
b) Quantification of the 69Ge-SPION@PEG up taken by the paws and nodes of mouse [16].
c) Before and after in vivo lymph node mapping with MRI after injecting of
69
Ge-SPION@PEG into the left footpad of the mouse [16].
Darkening of lymph node is clearly visible (dashed green circles), whereas for the
contralateral lymph node, there is no enrichment has observed (dashed red circles).
2.6. Production routes of 69Ge
There are 19 production routes of 69Ge in EXFOR “retrieve listing only”. Among these routes
only five charged particle induced reactions are chosen for the current study. Those reactions
in which Ge was taken as target are excluded because they may have isotropic impurity.
Moreover, those reactions are also excluded in which heavy projectiles are used.
2.6.1. Production Routes
59
Co (14N, 2n+2p) 69Ge
67
Zn (a, 2n) 69Ge
nat
Cu (p, x) 69Ge
nat
Zn (a, x) 69Ge
68
Zn (a, 3n) 69Ge
68
Zn (He3, 2n) 69Ge
nat
Zn (He3, x) 69Ge
66
Zn (a, n) 69Ge
69
Ga (a, x) 69Ge
nat
Ga (d, x) 69Ge
69
Ga (d, 2n) 69Ge
69
Ga (p, n) 69Ge
nat
Ga (p, x) 69Ge
71
Ga (p, 3n) 69Ge
70
Ge (n, 2n) 69Ge
nat
Ge (d, x) 69Ge
nat
70
Ge (a, x) 69Ge
70
Ge (p, x) 69Ge
Ge (p, n+p) 69Ge
2.6.2. Nuclear Reactions Selected for Evaluation
The nuclear reactions which are evaluated in this work are given below:

66
Zn (a, n) 69Ge

67
Zn (a, 2n) 69Ge

69
Ga (d, 2n) 69Ge

69
Ga (p, n) 69Ge

71
Ga (p, 3n) 69Ge
The experimental detail of these reactions is given by the following tables:
Table 2.3 Experimental details of 66Zn (a, n)69Ge
Author,
Publication
year &
Reference
Details of
Sample
Levkovskij
(1991) [27]
95 – 98%
isotopically natMo (a,
enriched
x)97Ru
target was
used.
-
38
7.8 –
37.7
Abu Issa et
al. (1989)
[28]
66
-
11
14.8 –
24.4
13.0
31
10.7 –
37.9
Nagame et
al. (1989)
[29]
Zn
enriched
was used.
99.8%
isotopically
pure &
enriched
targets
were used.
Monitor
Reactions
Gamma
Intensity
Normalization Cross Energy
Factor
Section Range
points
Author NuDat
(MeV)
2.8
-
-
Table 2.4 Experimental details of
Author,
Publication
year &
Reference
Levkovskij
(1991) [27]
Abu Issa et
al. (1989)
[28]
Details of
Sample
67Zn
Monitor
Reactions
95 – 98%
isotopically natMo (a,
enriched
x)97Ru
targets
were used.
Selfsupporting
67
Zn was
used.
(a, 2n)69Ge
Gamma
Intensity
Normalization Cross Energy
Factor
Section Range
points
Author NuDat
(MeV)
2.8
-
38
15.0 –
46.0
-
11
16.4 24.4
Table 2.5 Experimental details of 68Zn (a, 3n) 69Ge
Author,
Publication
year &
Reference
Details of
Sample
Levkovskij
(1991) [27]
95 – 98%
isotopically
enriched
targets
were used.
Monitor
Reactions
Gamma
Intensity
Normalization Cross Energy
Factor
Section Range
points
Author NuDat
(MeV)
2.8
-
nat
Mo (a,
97
x) Ru
23
28.9 –
46.0
Table 2.6 Experimental details of 69Ga (d, 2n)69Ge
Author,
Publication
year &
Reference
Baron et al.
(1963) [30]
Details of
Sample
Monitor
Reactions
Natural
27
isotopic
Al (d, p +
composition a)24Na
of different 209Bi (d, p)
210
elements
Bi
and
compounds
were used.
Gamma
Intensity
Normalization Cross Energy
Factor
Section Range
points
Author NuDat
(MeV)
2.8
-
1
18.8
Table 2.7 Experimental details of 69Ga (p, n)69Ge
Author,
Publicatio
n year &
Reference
Details of
Sample
Monitor
Reaction
s
Gamma
Intensity
Autho
r
Levkovskij
(1991) [27]
Johnson et
al. (1964)
[31]
Porile et al.
(1963) [32]
Blosser et
al. (1955)
[33]
95 – 98%
isotopically
enriched
targets were
used.
Targets were
electroplated
onto
platinum/gol
d foils.
98.4% 69Ga
deposited on
aluminum.
Finely ground
mixture of
Cu-oxide and
Ga-fluoride.
Normalizatio
n Factor
Cross
Sectio
n
points
NuDa
t 2.8
Energ
y
Range
(MeV)
-
16
7.7 –
21.4
-
-
15
3.0 –
5.48
-
24
12
13.0 –
54.9
Cu (p,
n)63Zn
33
1
12.0
nat
Mo (a,
x)96Tc
63
Table 2.8 Experimental details of 71Ga(p,3n) 69Ge
Author,
Publication
year &
Reference
Levkovskij
(1991) [27]
Porile et al.
(1963) [32]
Details of
Sample
Monitor
Reactions
95 – 98%
isotopically natMo (a,
enriched
x)96Tc
targets
were used.
98.1% 71Ga
deposited
on
aluminum.
Gamma
Intensity
Normalization Cross Energy
Factor
Section Range
points
Author NuDat
(MeV)
2.8
-
8
23.1 –
29.5
24
20
26.6 –
57.5
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
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