Program - Brookhaven National Laboratory

One of the ARRONAX’s objectives is to produce innovative radioisotopes for research in nuclear medicine.
The main applications are the diagnostic imaging (Positron Emission Tomography) and therapeutic (radiotherapy)
in oncology. Another application is medical imaging PET in cardiology. For that purposes,
a particular focus is done on the production of the following radioisotopes: the Sr 82, At 211, Cu 67, Sc
47 and Ga 68. The aim of this work is to study and produce targets for the production of germanium 68.
Germanium 68, mother of gallium 68, will be used to make generators of gallium 68. The manufacturing of
targets should be in accordance with quality criteria. The thickness of the deposit must be uniform to ±5%
over the entire surface and must adhere perfectly to the substrate. Its composition must be accurately
known [1]. The production of Ga68 is in most case made using 69 Ga + p → 68 Ge + 2n. It is obtained from
natural gallium or enriched gallium 69. Gallium has a low melting temperature at 29.7 C [2-4]. During
irradiation, it is in liquid form. This highly corrosive liquid [2,3] is usually encapsulated. However, he attacked
the container whatever materials used sometimes resulting in breaks. To circumvent this problem, a
gallium based alloy can be used whose melting temperature is higher. These alloys are produced by electroplating.
The search for the metal alloyed with gallium is made by studying the phase diagrams of gallium
based alloys. They provide information about existing phases and corresponding melting temperatures.
The electrochemical potentials standards are also taken into account: the ideal is that the potentials of the
two metals are close in order to be simultaneously deposited [5]. One of the chosen metal could be nickel.
According to the phase diagram (Ni/Ga), the maximum atomic proportion of gallium for an homogeneous
compound with a melting temperature above 500 C, is between 60% and 80% gallium. The three possibly
phases are Ga4Ni, Ga3Ni2 and Ga4Ni3. However, the electrochemical standard potentials of gallium (-0.52
V/ENH) and nickel (-0.25 V/ENH) are quite distant. So, nickel reduction is promoted. It is possible to
minimize its amount in the deposit by varying the nickel concentration [6]. The concentrations of nickel and
gallium will have to be maintained at a certain level to succeed in reaching enough thicknesses. The chosen
support, which is the work electrode, is made of gold because it provides a good deposit quality and has a
good thermal conductivity. But the chemical separations risks to be complicated with the presence the big
abundances of 3 metals: gallium, nickel and gold. To avoid this complication, tests were also made with a
nickel support giving good results. A series of experiments have been conducted with different nickel and
gallium ratio varying the speed stirring (from 300 rpm to 1300 rpm), the addition of chloride ions (0.1 M
to 1 M), the voltage and the duration. On both type, the optimized parameters are -1.6 V, 1300 rpm with
concentrations of 0.2 M of Ga2(SO4)3 and 0.2 M of NiCl2. The phase obtained has been characterized by
DRX, ICP-AES and SEM. It corresponds to a homogeneous phase of Ga4Ni3. For the duration of 2 hours,
the thickness reached is 45 µm . Our objectives are now to reach for this phase the thickness between 230
µm and 280 µm which corresponds to the minimal value necessary to implement germanium production
on ARRONAX. This production will be made together with the Strontium 82 production, using the 40
MeV coming out of the Rubidium target.
[1] IAEA, technical reports series no 465, p 135 [2] a new production method for germanium 68, N.R.
Stevenson, M. Cackette and T.J Ruth, The Synthesis and Applications of Isotopes and Isotopically Labelled
Compounds, Strasbourg, France, June 20-24 [3] a new preparation of germanium 68, C. Loch’H,
B. Maziere, D. Comar and Knipper, Int. J. Appl, isto. Vol. 33. pp. 267 to 270, 1982 [4] preparation of
Ge68/Ga68 generator with a binary Ga/Ag electrodepositions as solid target, Wu-Long Cheng, Yun Jao,
Chung-Shin Lee, Ai-Ren Lo, Journal of radioanalytical and Nuclear Chemistry, Vol. 245, No. 1 (2000)
25-30 [5] E. Chassaing, technique de l’ingénieur, alliages électrodéposés, [M 1620] (2006) [6] H. F. Ayedi et
M. Depetris-Wery, technique de l’ingénieur, Electrodéposition de zincs alliés, [M 1602] (2012)
HB 8 5:45 PM
Th-232 (d, 4n) Pa-230 Cross-Section Measurements at ARRONAX Facility
113