To find a high purity flux for low background experiments is one of the most challenging problems. In this work, we report the production process of a highly purified ammonium acetate flux solution ...for low background experiments. A sub-distilled method has been used to purify initial precursors from contamination for the syntheses of final product. As a result, a high purity ammonium acetate solution was synthesized with a minimum content of elements which collectively represent the main source of background radiation (K < 2.3 × 10
–8
g/g, Th < 2.6 × 10
–11
g/g and U < 1 × 10
–11
g/g). An Estimation of the impurity content of the product has been performed with Instrumental neutron activation analysis, inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry.
The DANSS detector is located directly under the nuclear reactor at the Kalinin nuclear power plant. Such a position ensures about 50 m.w.e. shielding from cosmic rays in the vertical direction; as a ...result, the detector occupies an intermediate position between surface and underground detectors in the shielding from cosmic rays. The sensitive volume of the detector consisting of a 1-m
3
plastic scintillator is surrounded by the multilayer passive shielding and muon veto. The main aim of the DANSS experiment is to measure the antineutrino spectrum at various distances from the source. To this end, the detector is placed on a lifting platform in order to record data at three positions of 10.9, 11.9, and 12.9 m from the reactor core. The detector can reconstruct muon tracks passing through its sensitive volume. The pressure, temperature, and decay coefficients for muons in various regions of the zenith angle
have been determined from the muon data collected during four years using the effective generation level method.
Detection of antineutrino by the reaction of the inverse
β
-decay can be used for an independent monitoring of a nuclear reactor power. DANSS detector is located directly under a commercial WWER-1000 ...reactor and counts up to 5000 antineutrino per day, providing the accuracy of 1.5% in 2 days of the flux measurement. A powerful system of the passive and active shielding in combination with the fine spatial segmentation of the detector allows to diminish the contribution of the background processes to a level, negligible in comparison to the statistical error. The influence of the nuclear fuel composition on the neutrino flux can be accounted for based on the input from the NPP staff.
The 9.2 and 24.3 keV nuclear transitions in
227
Th were studied in the
β
-
decay of
227
Ac employing the internal conversion electron spectroscopy. Values of
(
9244.6
±
0.8
)
and
(
24343.1
±
1.1
)
eV ...were determined for their energies. The 24.3 keV transition was found to be of the mixed (M1
+
E2) multipolarity with the spectroscopic admixture parameter
δ
2
(
E
2
/
M
1
)
=
(
0.0116
±
0.0004
)
. Energies of
(
24342.9
±
1.2
)
,
(
28613.3
±
1.7
)
, and
(
37860.2
±
2.0
)
eV were obtained respectively for the 24.3, 28.6, and 37.8 keV transitions in
227
Th by means of the gamma-ray spectroscopy. Natural atomic-level widths of
(
14.1
±
0.5
)
,
(
11.4
±
0.5
)
,
(
6.9
±
0.4
)
,
(
11.4
±
1.4
)
,
(
8.6
±
1.2
)
, and
(
6.0
±
0.7
)
eV for the M
1
-, M
2
-, M
3
-, N
1
-, N
2
-, and N
3
-subshells of thorium, respectively, were derived from conversion electron lines. The cross checking of the energy values of the 9.2, 15.1, and 24.3 keV nuclear transitions obtained by the ICES method is also given.
The (44)Ti/(44)Sc (T(1/2)(44)Ti=60a) generator provides cyclotron-independent access to positron-emitting (44)Sc (T(1/2)=3.97d) for PET imaging. This work aims to post-elution processing of initial ...(44)Sc generator eluates in order to reduce its volume, HCl concentration and remove the oxalate anions. The on-line adsorption of (44)Sc on cationic resin AG 50W-X8 (200-400 mesh, H(+)-form) is achieved with >98% efficacy. Subsequently, the purified (44)Sc is desorbed by using 3ml of 0.25M ammonium acetate (pH=4.0). The post-processing takes 10min. The overall yield of the post-processing reached 90%, which is referred to the (44)Sc obtained from the (44)Ti/(44)Sc generator. In addition to the chemical purification, the content of (44)Ti breakthrough was further reduced by one order of magnitude. The 185MBq generator finally provides 150MBq of (44)Sc containing <10Bq of (44)Ti ready for labeling.
—
The first results of neutron-flux measurements at the LSM underground laboratory (Modane, France) using a new sensitive method are presented. Neutrons are detected by counting delayed γγ ...coincidences in the
127
I(
n
, γ)
128
I reaction. It is shown that this approach makes it possible to measure thermal-neutron fluxes at a level of 10
–6
neutron cm
–2
s
–1
.
In recent years, radiopharmaceuticals have been increasingly used for diagnostics and treatment of cancer. In addition to a biological vector, a modern radiopharmaceutical includes a chelator that ...binds the radionuclide, as well as a linker for connecting the vector and the chelator. The development of such an approach requires the improvement of methods for obtaining and purifying radionuclides, and the development of methods for the synthesis of radiopharmaceuticals, i.e., preparative direction. It is also necessary to search for new vectors and chelators. This implies the development of methods for analyzing the properties of radiopharmaceuticals in general, as well as their precursors, i.e., analytical direction. In this review, we describe the prerequisites for successfully solving a wide range of challenges in these two areas of nuclear medicine at the Scientific and Experimental Department of Nuclear Spectroscopy and Radiochemistry of the Laboratory of Nuclear Problems of the Joint Institute for Nuclear Research (LNP JINR). These prerequisites are due to rich experience in obtaining the widest range of radionuclides and their application for various spectrometric studies. Both the past and present works on radiopharmaceutical topics carried out in the department are described, and ways of future development are outlined.
.
Using the internal conversion electron spectroscopy, the energy of the 15.1 keV
M
1
+
E
2
nuclear transition in
227
Th populated in the
β
-
decay of
227
Ac was determined to be
15098
.
6
±
1
.
0
...eV. This value is more accurate than the present accepted one by a factor of 200. The present uncertainty in the transition multipolarity was removed and it was found to be
M
1
+
E
2
with the admixture
|
δ
(
E
2
/
M
1
)
|
=
0
.
035
±
0
.
006
.
The distribution coefficients for 60 elements on the anion-exchange resin Dowex 1x8 in ammonium acetate medium (0.1–5.0 M) are determined. The values of
K
d
are presented as a periodic table of the ...elements. A range of possibilities for separating the elements of this system is proposed.
A method for the production of
111
In from an antimony target irradiated with 600 MeV protons has been developed. Here, a three-stage scheme of indium purification using ion-exchange chromatography ...is performed. The radiochemical yield is 85%, with a decontamination factor of the target material of no less than 10
9
. The
111
In preparation produced by the present method was used in studies of perturbed angular correlations. Also, a procedure for the production and separation of
117
m
Sn/
119
m
Te was developed, which is of particular interest for further studies on designing a generator to produce
119
Sb.
