| Summary: | Thesis (PhD)--Stellenbosch University, 2002. === ENGLISH ABSTRACT: Radiochemical separation of 103Pd from natAg, usmg a 66 MeV proton-induced
reaction at iThemba LABS, was studied and a radiochemical method was developed
for the separation. For the separation, which comprises the separation of Pd from a
large amount of target material (16 g Ag), as well as Rh radioisotopes produced from
decay of their Pd parents (mainly 101Rhand IOORh),three ion exchange resins were
tested: a Chelex 100 chelating resin, the AG 1-X8 anion exchange resin and a
AG MP-I anion exchange resin. For the optimum elution ofPd from the latter two
resins, two elution curves using water and 5% ammonia solution, were obtained.
With an average recovery of 97.4% and sharper elution curve from the macroporous
AG MP-I, this resin was finally chosen for routine production. To achieve the
separation, a simple, easily operated radiochemical processing system was designed
and installed in a hot cell.
Radiochemical separation of 103Pd from a Rh target was also studied and several
cation and anion exchange resins were tested. A carrier-free separation of 103Pd was
developed, using an AG 1-X8 anion exchange resin. Bombarded tablets of
RhCh.3H20, as the targets, were used for these separations. The procedure,
originally designed for the separation of Pd from Cu and Rh, was modified using
H202 for the oxidation of Ru prior to the sorption on the resin and successfully used
for the separation of isotopes of Rh from the isotopes of Pd, Ru, Tc, Nb, Mo, Zr
and Y, which were produced by 400 MeV 160_ and 12C-induced RhCb.3H20
targets. To elute the Pd from the resin, 5% ammonia solution was used; the
recovery was about 92%.
To prepare the Rh target for routine production, an electroplating method of Rh on a
Cu substrate was developed. Rh(CI04)3, in 0.5 M perchloric acid, was used as the
electrolyte bath. The electroplated Rh was then dissolved by an alternating current
technique, using 6 M HCI and a current density of 2 Alcm2.
For production of the seeds, I03Pd was sorbed on the weakly basic anion exchange
resin Amberlite IRA-93 (600-700 Il), by recycling a 0.5 M Hel solution of Pd
through a 0.5 cm x 1 cm column for 2 hours. The distribution of I03Pd on the resin
beads was measured and RSD of5.7% was obtained.
A funnel was designed to transfer the I03Pd-loaded resin beads into the Ti tubes to
prepare the seeds (0.7 mm LD., 0.8 mm D.D., and 4.5 mm length). To enclose the
tubes as capsules, the end caps were made from 0.02 mm Ti sheet and several pieces
were designed and machined for the welding of the caps to the tubes. A spotwelding
machine was used for the welding, after small, but vital modifications. === AFRIKAANSE OPSOMMING: Palladium-l03 kan volgens twee produksieroetes by iThemba LABS
vervaardig word, naamlik deur die volgende protongeïnduseerde reaksies:
natAg(p,xn)lo3Cd (ty,=7.3 m) ~ 103Ag (ty,=1.1 h) ~ 103Pden
I03Rh(p,n) ~ 103Pd.
'n Radiochemiese metode om 103Pd van die Ag-skyfmateriaal te skei, is
ontwikkel. Hierdie metode, wat gebaseer is op anioonuitruilerchromatografie
met die makroporeuse hars AG MP-I, behels die skeiding van I03Pd van 'n
groot hoeveelheid skyfmateriaal (16g Ag), sowel as van Rh-radionukliede
(hoofsaaklik looRh en IOlRh), wat geproduseer word deur die verval van hulle
Pd-moederisotope. As die Pd met 5% ammonia oplossing geëlueer word, is 'n
97.4% herwinning moontlik. 'n Radiochemiese paneel is ontwerp, gebou en in
'n warmsel geïnstalleer vir roetine produksie.
'n Metode om Rh op 'n kopersubstraat te elektroplateer is ook ontwikkel om
'n Rh-skyf te verkry vir die protonbombardement. 'n Oplossing van 0.5 M
HCI04 - Rh(HCI04)3 is as die elektrolietbad gebruik. Die geëlektroplateerde
Rh is opgelos in 6 M HCI deur gebruik te maak van 'n wisselstroomtegniek,
met 'n stroomdigtheid van 2A1cm2. 'n Metode om "draervrye" I03Pd vanaf die
Rh-skyfmateriaal te skei, is ook ontwikkel.
Gebombardeerde pille van RhCh.3H20 is as skywe gebruik in die onaktiewe
studies. AGI-X8 anioonuitruilerhars is vir hierdie skeidings gebruik en daar is
gebruik gemaak van 'n metode wat oorspronklik ontwerp is vir die skeiding
van Pd van Cu en Rh. Hierdie prosedure is net effens aangepas deur H202 te
gebruik vir die oksidasie van Ru, alvorens dit op die hars gesorbeer is. Hierdie
metode is ook suksesvol gebruik vir die isolering van Rh van radionukliede
van Pd, Ru, Tc, Nb, Mo, Zr, ens, wat geproduseer is deur 400 MeV 160_ en
12C-geïnduseerde reaksies met Rh in RhCi).3H20 skywe. 5% ammoniakoplossing is gebruik om die Pd uit die hars te elueer, met 'n herwinning van
92%.
Om die saadjies vir implantering te maak, is 103Pd op 'n matige basiese
anioonuitruilerhars Amberlite IRA-93 gesorbeer deur 'n 103pd-oplossing, in
0.5 M Hel, deur 'n 0.5 ' lcm kolom te hersirkuleer vir 2 uur. 'n Tregter is
ontwerp om die I03Pd-gelaaide harskorrels oor te dra na die titaanbuisies (0.7
mm binnedeursnit, 0.8 mm buitedeursnit en 4.5 mm lank). Om die buisies te
verseël, is dekseltjies uit 'n 0.02 mm titaanplaat gesny. Verskeie dekseltjies is
gemasjieneer om op die buisies vas te sweis. 'n Punt-sweismasjien is gebruik
vir die sweiswerk nadat geringe, maar belangrike, aanpassings aan die masjien
gedoen is.
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