Alternative production routes and
new separation methods for nocarrier-added 163Ho
Susanta Lahiri, Moumita Maiti
Saha Institute of Nuclear Physics, Kolkata, India
&
Zoltán Szűcs, Sandor Takacs
Institute of Nuclear Research of H.A.S.
Debrecen, Bem tér 18/C
HUNGARY
163Ho:
How to produce?
p+natDy
600
σ ~350 mb at 19 MeV
500
Contributors:
Cross section [mb]
natDy(p,xn) 163Ho
400
Ho-163
Ho-162
300
Ho-161
Ho-160
200
100
163Dy
(24.9%)(p,n)163Ho (σ~0.4 mb)
164Dy (28.2%)(p,2n)163Ho (σ~1254 mb)
0
5
10
15
20
Projectile Energy [MeV]
25
Main reaction: 163Dy(p,n)163Ho
Side reactions: 158Dy)p,2n)157Ho→157Dy→157Tb
160Dy(p,2n)159Ho→159Dy
160Dy(p,2p)159Dy
156Dy(p,3n)154Ho→154Dy
161Dy(p,a)158Tb
163Dy(p,a)160Tb
Radiochemical separation of 163Ho is recommended!
Enriched target material is preferable!
Theoretical cross sections of
163Dy(p,n)163Ho and 163Dy(d,2n)163Ho
Cross section curves of the potential
nuclear reactions
1200
163Dy(p,n)163Ho
1200
163Dy(p,n)163Ho
163Dy(d,2n)163Ho
1000
1000
Cross section (mb)
800
164Dy(p,2n)163Ho
163Dy(d,2n)163H
o
164Dy(p,2n)163H
o
800
Cross section (mb)
600
164Er(p,2n) TENDL-2011
400
164Er(p,x)163Tm exp
600
200
0
0
400
5
10
15
Energy (MeV)
20
25
30
200
0
0
5
10
15
Energy (MeV)
20
25
30
Thick target yields and prices of
target materials
Nuclear reaction
163
Dy(p,n)163Ho
163
Dy(p,n)163Ho
163
Dy(d,2n)163Ho
163
Dy(d,2n)163Ho
164
Dy(p,2n)163Ho
164
Er(p,2n)163Tm
Energy range
[MeV]
6-14
2-20
4-20
4-30
8,5-30
10,7-28,7
*reached by decay chain of 163Tm
Activity
[kBq]
614
875
3600
5000
9800
12000*
163
Er
163
Ho
thickness
[m]
471
1103
661
1350
2000
1620
price of target
[kUSD]
1,2
2,7
1,6
3,3
4,9
61,9
Contaminating isotopes
1.E+02
1.E+01
1.E+00
natDy(p,x)158Tb
1.E+03
1.E-02
-20.0
Energ…
Cr…
Cross section (mb)
1.E+03
natDy(p,x)157Tb cum
natDy(p,x)159Dy
1.E-01
natDy(p,x)163Ho
164Dy(p,g)165Ho
1.E-02
0.0
5.0
10.0
15.0
20.0
Energy (MeV)
25.0
30.0
Irradiation of natDy by proton
Energy
163Ho
range [MeV] [MBq]
157Tb
158Tb
159Dy
[MBq]
[MBq]
[MBq]
5-11
0,20
0,00
0,00
0
5-18
1,74
3,81
0,04
968
5-28.7
2,93
18,27
1,10
20732
1. The highest yield give the (p,2n) reaction
2. Er irradiation is NOT preferred because of the side reactions, producing the stable
165Ho as well as the radioactive 166Ho!!!!
3. The enriched target of 164Dy has to be used. In other case during the irradiation of the
natDy the 157-158Tb and 159Dy will give us extremely high contamination
4. During the irradiation of enriched 164Dy we will get the stable 165Ho too by the 164Dy(p,
γ)165Ho reaction. However this amount is 2 magnitude less, than 163Ho.
5. The calculation of cross section curve of 157Tb contains all possible reaction for 157Ho,
157Dy and 157Tb, as well as for 159Dy also contains all possible reaction for 159Ho and
159Dy.
6. Due to the 10 times higher yield of the (p,2n) reaction than the (p,n) reaction not
necessary 1800 hours irradiation time to get 1 MBq 163Ho, approximately. Looks that
is enough 180 hours, 10 times less, therefore the irradiation cost in cyclotron also can
be 10 times less, it means that is 50kEuro, approximately, which is comparable with
the irradiation on reactor!!!!!
7. The Debrecen cyclotron can't produce the 30MeV proton beam.
Irradiation Parameters:
(i) Projectile – p, (ii) Ep = 19 MeV, (iii) current: 700 nA, (iv) time of irradiation: 10 h
Two targets were irradiated in stack with the following configuration
 There is no way to monitor Ho-163 by
monitoring its nuclear properties.
 Separation of Dy and Ho is difficult.
 Very long time is required to rich the
saturation activity.
natDy(α,
xn) 163Er () 163Ho
Er-165, 10.3h
Er-163, 75m
Er-161, 3.24h
Er-160, 28.6h
Ho-163, 4750y
a+natDy
600
Projectile : α
EP = 40 MeV
first target: 1 µA, 7 h irradiation
second target: 3 µA, 11 h irradiation
500
Cross secion, mb
Irradiation parameters:
400
300
200
100
0
10
15
20
25
30
35
40
Energy, MeV
natDy(α,
xn) 163Er () 163Ho
(σ ~500 mb at 40 MeV)
Exhaustive Chemistry !!
45
50
Technique – Liquid liquid extraction
Reagents: di-(2-ethylhexyl) phosphoric acid (HDEHP) dissolved
in cyclohexane (Organic phase) & HCl (aqueous phase)
161Er
was used as monitor of Er
in the radiochemical separation
&
Dy was measured by ICP-OES
100
Extraction, %
80
60
Dy
40
Er
20
HCl : 0.2 M & HDEHP 1%
Extraction: Dy
48.8%
Er
84%
at 1% HDEHP
0
0.1
0.2
0.3
[HCl], M
0.4
0.5
159Tb(7Li,
3n) 163Er
(σ ~312 mb at 31 MeV)
Cross section [mb]
1200
7Li+159Tb
1000
800
600
163 Er
400
162 Er
200
0
25
30
35
Energy [MeV]
40
Irradiation parameters:
(i) Projectile – 7Li
(ii) EP = 31 MeV
(iii) current: 150 nA
(iv) time of irradiation: 11 h
No successful results have been achieved
using HDEHP
For a sample thickness: 4 mg/cm2
No. of 163Ho (via
atoms/A-h
163Er)
will be = 2.5x1010
For enriched target it will increase by factor
of 2.
For 10 A, 100 h irradiation (one target):
2.5 x 1013 atoms
For a sample thickness: 4 mg/cm2
No. of 163Ho (via 163Er) will be = 2x1010 atoms/A-h
In 6 h, irradiation time = 1.2x1011 atoms
20 A current, 5 targets in a row, 6 h irradiation time
1.2 x 1013 atoms
For a sample thickness: 4 mg/cm2
No. of 163Ho (via 163Er) will be = 4x109 atoms/A-h
In 6 h, irradiation time = 2.4x1010 atoms
20 A current, 5 targets in a row, 6 h irradiation time
2.4 x 1012 atoms
 163Ho
can be produced by charged particle
activation through direct or indirect way

However, separation of Ho from the target
matrix is extremely difficult due to the similar
chemical properties of lanthanides

Therefore, it needs special attention towards
the purification procedure

In order to ensure the production of 163Ho
nuclear properties can not be exploited as it
behaves like stable isotope
ECHo Collaboration
This collaboration has been formed on 29th June, 2012
Participants:
10 Institutes from 5 countries
Thank you….
Future Plan from SINP and ATOMKI Group
1. Will apply for beam time in VECC, Kolkata and in Atomki,
Hungary
2. Verification of theoretical data as much as possible.
3. Storing Ho-163 for future use
4. Development of new separation techniques based on HPLC