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Aims: This study was undertaken to determine the effectiveness of biological indicators currently being employed during formaldehyde decontamination. Data suggest that detectable amounts of formaldehyde are absorbed into the paper strips contained in currently used biological indicators. Absorbed formaldehyde has the potential to inhibit the growth of indicator spores, thus leading to false negative results. Indicators composed of either stainless steel carriers or paper strips were investigated to determine whether stainless steel carriers can be used as an alternative to paper strip indicators. Methods and Results: Biological indicators were exposed to formaldehyde gas and were tested for the presence of formaldehyde and any possible inhibition of spore growth. Absorbed formaldehyde was detected in the paper strip carriers while no formaldehyde was detected from any of the stainless steel carriers. Exposed paper strips were found to inhibit growth of up to 1 × 106 spores while the stainless steel carriers did not inhibit the growth of spores. Conclusions: During decontamination, biological indicators composed of paper spore strips absorb formaldehyde and inhibit growth of any surviving spores. Stainless steel carriers do not absorb formaldehyde and are an ideal alternative substrate for biological indicators. Significance and Impact of the Study: The popular paper strip biological indicator can lead to false negative results during decontamination and is unsuitable for validating formaldehyde decontamination.

238Pu, 239-240Pu, and 241Am were measured, by α-counting after radiochemical separation, in two lake sediment cores. The profiles of these transuranics were compared to those of the fission product 137Cs. Datation of nuclear events and data on behavior of the studied elements were deduced.

A radiochemical separation is presented for americium, plutonium and neptunium from sediment samples by using an unique anionic exchange process. An oxidation-reduction step was introduced in the classical procedure of the radiochemical determination of transuranic elements in order to control the valence of the separated elements.

The transfer of radionuclides such as 137Cs and 90Sr from soil to trees (conifers) was studied in a forest area, the Boreon massif, 30 km north of Nice in South Eastern France. This area has been highly contaminated after the Chernobyl accident. Besides the γ-emitting fission products, the α-emitters 238Pu and 239+240Pu and the pure β-emitter 90Sr were measured in different parts of the studied trees (roots, branches, twigs, etc.). As has already been reported by other authors, the radionuclide activities in the tree rings are not correlated with the fallout deposition. They were found varying according to the sap flux in the tree and higher in sapwood than in heartwood. For cesium the root absorption was found to be lower than the atmospheric deposition. Soil-to-plant concentration factors were calculated for 137Cs, 90Sr and 239+240Pu.

The low-energy photon spectrometry has been applied to measure the activity concentration of radionuclides in sludge samples from the sewage treatment plant in Nice city. Short-lived 201Tl, 99Tcm and 131I isotopes which are currently used in nuclear medicine were detected at levels included between 1 and 250 Bq/kg. 134Cs and 137Cs due to the Chernobyl fallout are also detected.

This study was undertaken to determine the effectiveness of biological indicators currently being employed during formaldehyde decontamination. Data suggest that detectable amounts of formaldehyde are absorbed into the paper strips contained in currently used biological indicators. Absorbed formaldehyde has the potential to inhibit the growth of indicator spores, thus leading to false negative results. Indicators composed of either stainless steel carriers or paper strips were investigated to determine whether stainless steel carriers can be used as an alternative to paper strip indicators.Biological indicators were exposed to formaldehyde gas and were tested for the presence of formaldehyde and any possible inhibition of spore growth. Absorbed formaldehyde was detected in the paper strip carriers while no formaldehyde was detected from any of the stainless steel carriers. Exposed paper strips were found to inhibit growth of up to 1 × 10(6) spores while the stainless steel carriers did not inhibit the growth of spores.During decontamination, biological indicators composed of paper spore strips absorb formaldehyde and inhibit growth of any surviving spores. Stainless steel carriers do not absorb formaldehyde and are an ideal alternative substrate for biological indicators.The popular paper strip biological indicator can lead to false negative results during decontamination and is unsuitable for validating formaldehyde decontamination.

The radioactive decays of166Ho isomers (Iπ=7− and 0−) have been reinvestigated using high-resolution γ-ray detectors in single and coincidence measurements. Nine γ-lines are new, among the fifty-three γ-lines accurately measured belonging to166Hom decay (Iπ=7−); sixteen γ-lines were measured in166Hog decay (Iπ=0−) out of which 3 are new; moreover, γ-γ coincidence experiments using two germanium detectors were performed. A166Er level scheme was built which interprets all γ-lines measured: two new levels are proposed to be fed in the166Hom decay, namely theKIπ=22+ at 785.8 keV and aIπ=4− state at 1572.1 keV; in166Hog decay, theKIπ=022+ state in166Er is confirmed, and a new level is found at 1812.8 keV (Iπ=1+). Spin, parity and Nilsson orbitals assignments of the intrinsic166Er states are discussed.

After the reactor accident at Chernobyl, samples of soil, moss, lichen and fern were collected in the forest around the Vesubie valley in the South East of France and analyzed by low energy photon and gamma spectrometry. Activity concentrations as high as 42.8, 9.4 and 3.8 kBq.m−2 were measured for137Cs,134Cs and106Ru, respectively, in soil, in October 1988.125Sb and110mAg were also detected. The contamination was found to be the most important between 1400 and 1700 m altitude.

Actinides activity levels deposited after the Chernobyl accident on the coastal Mediterranean area at Monaco have been recently measured (1). The values obtained are low. However, our γ-measurements on humic soils from the southern Alps revealed high137Cs level contamination areas and urged us to evaluate241Pu activity levels. The indirect determination of241Pu was based on the γ-activity measurement of the241Am in situ ingrown.

The decay of the naturally occuring 176Lu nucleus has been reinvestigated using coaxial and planar HPGe detectors. Energy and intensity values of the three main γ rays are given with an improved precision. The 401.04-keV γ-ray was measured in single γ-spectra and its intensity I = 0.48% was deduced. The 176Lu half life was measured using a 133Ba standard γ-activity source mixed with the Lu2O3 sample, found to be T 1 2 = (3.73 ± 0.05)×10 10 years. A revised 176Lu decay scheme has been derived.

A method based on the measurement of γ-ray and x-ray low-energy spectra was applied to the analysis of a sediment sample. The activities of fission products and transuranium elements were measured by this non-destructive method and the results for the transuranics were then compared with the results obtained after radiochemical separation.

The {sup 14}C decay of {sup 222}Ra has been reinvestigated, using an 85 MBq activity {sup 230}U source radiochemically separated, a Si barrier detector, and a superconducting magnetic spectrometer. In a 16 days counting run, 210 {sup 14}C events were recorded. The {sup 14}C particles energy value 30.930{plus minus}0.090 MeV was found and an upper limit {ital b}{le}2{times}10{sup {minus}12} was estimated for the {sup 14}C branching ratio to the {sup 208}Pb first excited state; the branching-ratio value to the {sup 208}Pb ground state, thus equal to the total branching ratio, was found to be {ital b}={lambda}{sub {ital c}}/{lambda}{sub {alpha}}=(2.31{plus minus}0.31){times}10{sup {minus}10}.

The α-decay of225Ac to221Fr excited states has been reinvestigated using high-resolution γ-spectroscopy for single and γ-γ coincidence measurements. Twenty nine221Fr nuclear excited states were proposed; ten of which are newly observed.

The decay of a225Ac source in equilibrium mixture with its decay products was investigated using high-resolution HP/Ge/ detectors. Energies and intensities of more than 78 γ-photons were measured with an improved accuracy; 44 of them are reported for the first time. A tentative221Fr level scheme was built on the basis of good energy sum relationships; seven new221Fr excited levels are proposed at 496.9, 570.9, 603.5, 630.7, 637.7, 649.0 and 758.9 keV.

The objective of this paper is to report on the results of a study of 238 Pu, 239+240 Pu and 241 Am inventories onto Blelham Tarn in Cumbria (UK). The atmospheric fallout inventory was obtained by analysing soil cores and the results are in good agreement with the literature: 101 Bq m −2 for 239+240 Pu; 4.5 Bq m −2 for 238 Pu and 37 Bq m −2 for 241 Am. The sediment core inventory for the whole lake is compared to the atmospheric fallout inventory. The sediment activity is 60–80% higher than the estimated fallout activity, showing a catchment area contribution and in particular the stream input.

Alpha emitting actinides such as plutonium, americium or curium were measured by alpha-spectrometry after radiochemical separation. The short range of alpha-particles within matter requires, after a pre-concentration process, a succession of isolation and purification steps based on the valence states modification of the researched elements. For counting, actinides were electrodeposited in view to obtain the mass-less source necessary to avoid self-absorption of the emitted radiations. Activity concentrations of gamma-emitting fission products were calculated after measurement with high purity germanium detectors (HPGe). These different methods were used to analyse soils sampled in the Republic of Belarus, not far from the Chernobyl nuclear plant.

The 14C‐decay of 222Ra has been reinvestigated using a strong 230U source and the magnetic superconducting spectrometer SOLENO in view of looking for a possible feeding of the first 208Pb excited state. 210 14C‐events were recorded in a single peak of (30.930±0.090) MeV energy; the 14C branching ratio values b=(2.31±0.31)×10−10 and

The decay of radiochemically-separated /sup 228/Ac sources has been reinvestigated using high-resolution coaxial HPGe detectors and ..gamma..-..gamma.. coincidence measurements. Energies and intensities of more than 240 photons were accurately measured, 80 of them for the first time. A /sup 228/Th level scheme, built on the bases of good energy fits and on ..gamma..-..gamma.. coincidence data, involves 58 excited states, of which 17 are new, up to 2159 keV with spin 0less than or equal toIless than or equal to6. Collective properties of low-energy states belonging to K/sup ..pi../ = 0/sup -/,2/sup +/,2/sup -/ bands are discussed in the framework of the Bohr-Mottelson model. Decay modes of a K/sup ..pi../ = 0/sup +/ excited band at 831.82 keV favor strong two octupole phonon K/sup ..pi../ = 0/sup -/ components. The K/sup ..pi../ = 1/sup -/ band is expected to have I = 2 and 3 members at 938.5 and 968.4 keV. Coriolis coupling calculations involving the four K/sup ..pi../ = 0/sup -/, 1/sup -/, 2/sup -/, and 3/sup -/ bands were carried out. Tentative K/sup ..pi../ = 2/sup +/ two-quasiparticle bands at 1638.23 and 1899.99 keV are discussed in terms of Nilsson orbitals.

The decay of radiochemically separated $^{234}\mathrm{Pa}$ (UZ) sources has been reinvestigated by means of single and \ensuremath{\gamma}-\ensuremath{\gamma} coincidence spectrometry using planar and high efficiency coaxial HPGe detectors. Of the 330 \ensuremath{\gamma} rays observed in the 40--2100 keV energy range, of which 140 are new, more than 310 \ensuremath{\gamma} rays are accommodated in an improved $^{234}\mathrm{U}$ level scheme, accounting for 98% of the $^{234}\mathrm{Pa}$ \ensuremath{\beta} decay; of the 77 excited states observed here, 37 had not been previously found in this decay. Within the framework of the collective model of strongly deformed nuclei, couplings between the collective positive parity ${K}^{\ensuremath{\pi}}$${=0}_{1}^{+}$ (g.s. band), ${0}_{2}^{+}$, ${2}_{1}^{+}$, ${0}_{3}^{+}$, and ${2}_{2}^{+}$ bands are estimated from the perturbed transition probabilities and the distortions to the adiabatic energy systematics. The Coriolis interaction weakly coupling the ${K}^{\ensuremath{\pi}}$${=0}^{\mathrm{\ensuremath{-}}}$, ${1}^{\mathrm{\ensuremath{-}}}$, and ${2}^{\mathrm{\ensuremath{-}}}$ octupole bands was evaluated consistently by a fit to the experimental energy levels. Several new levels and a tentative ${K}^{\ensuremath{\pi}}$${=3}^{+}$ band (at 1770 keV) are discussed in terms of Nilsson orbitals assignments.

The radioactive decay of 110Agm+g has been studied extensively using gamma-gamma coincidence and sum-coincidence spectrometers. Levels at 2078.8, 2250.7, 2287.7, 2433.1, 2539.6, 2659.9, 2706, 2793.4, 2842.5 and 2876.8 keV previously proposed on energy sum considerations are proved by these techniques. For the first time the gamma rays of 120.3, 133.4, 341.4 and 356.4 keV are interpreted. The existence of a new level at 2356.2 keV is proposed. An interpretation is suggested for known gamma rays of 120.3, 133.4, 341.4 and 356.4 keV as well as for new transitions of about 648, 714.9, 1465.6 and 1698.5 keV. The spins of a few levels of 110Cd are discussed on the basis of present models.

The decay of228Ac has been reinvestigated by means of high resolution HPGe detectors. Accurate energies and intensities of 242 γ photons were measured, of which 80 were found for the first time.

The 233Pa β decay has been reinvestigated using high resolution HPGe detectors. The energy and intensity of 25 γ lines have been carefully remeasured; 8 of them are new. The 233U level scheme is completed including twelve excited levels among which three are newly observed in 233Pa β decay.

Le spectre xL du Np accompagnant la desintegration de 241Am a ete soigneusement examine avec des detecteurs HPGe. Les valeurs des energies des raies principales sont en bon accord avec les resultats deduits du travail de Bearden, sauf pour les raies Lα1 et Lβ2,15 qui depassent les valeurs theoriques de 8 et 22 eV respectivement. Les intensites des differentes raies s'accordent bien avec les resultats anterieurs; les raies β9, β10, γ11, γ13, t et s sont caracterisees pour la premiere fois dans le Np (Z = 93). Les rapports de probabilite dans les sous-couches L sont coherents avec les calculs Hartree–Fock–Slater de Scofield. The L x-ray spectrum of Np following α-decay of 241Am was carefully reinvestigated by using HPGe detectors. Energy values of major lines are in good agreement with data deduced from Bearden's work, except for Lα1 and Lβ2,15 which exceed theoretical values by 8 and 22 eV, respectively. Intensities of different components agree well with previous experimental work, and β9, β10, γ11, γ13, t and s lines were found for the first time for Np (Z = 93). L subshell probability ratios are consistent with the Hartree-Fock-Slater calculations of Scofield.

The decay of234Pa(UZ) was reinvestigated using high-resolution coaxial and planar HPGe detectors. Accurate energy and intensity values of 327 γ photons are given, of which 144 previously unobserved.

The decay of radiochemically separated /sup 144/Ce source in equilibrium with /sup 144/Pr isomers has been reinvestigated with HPGe detectors. The energies and intensities of 19 ..gamma.. rays were measured, of which three are new. A /sup 144/Nd level scheme allows the incorporation of most of the transitions between 13 excited states. Levels at 2072.8 (2/sup +/), 2368.3 (2/sup +/), 2581.8 (3/sup +/), and 2742.8 (0/sup +/) keV, observed earlier in nuclear reactions, are found to be fed in these decays. A 2675.3 keV (J/sup ..pi../ = 0/sup +/) level seems to be a component of the 2.663 MeV multiplet observed in the (p,t) reaction.

The radioactivity of various terrestrial vegetation leaves characteristic of Mediterranean countries has been measured after the Chernobyl accident. In addition, we paid particular attention to lichens and seaweed which are considered as bioindicators of radioactive contamination. Most measurements were performed non-destructively using both coaxial and planar HPGe detectors. For odd mass radionuclides having low energy lines, such as 125Sb or 141Ce the sensitivity of the planar HPGe detector is better than the coaxial detector. The concentration of long-lived fission nuclides remaining three months after the accident were found to be enhanced in needle form leaves and in lichens. The seaweed Sphaerococcus exhibits a strong specific activity for iodine and ruthenium elements and poor concentration for caesium nuclides. The activity ratios of different isotopes of the same element measured in vegetation samples agree well with values found in airborne aerosols by other authors. The activation nuclide 110mAg is found in all samples with the same ratio 110mAg/137Cs = (1.0 +/- 0.2).10(-2) as in the soil deposition.

L'etude du rayonnement gamma de l'arsenic 77 a l'aide d'un spectrometre a semiconducteur a permis d'observer des gammas de 87,7 keV (16,1), 162,0 keV (19,1), 238,8 keV (100), 249,5 keV (22,5), 271,1 keV (0,5), 281,9 keV (3,5) et 520,74 keV (24,9). La desintegration de l'arsenic 77 se fait partiellement par l'intermediaire de deux niveaux tres voisins du selenium 77 situes a 238,8 et 249,5 keV.

The energy of the E1 γ-ray following the isomeric transition of 108Agm was carefully measured with a high resolution HPGe detector. A mean value of (79.131±0.003) keV was found at the 2σ confidence level, which could be used for energy calibration.

The decay of radiochemically separated 144Ce source has been reinvestigated with a high resolution HPGe detector. Accurate energy values of three γ lines at 53.395 ± 5, 80.120 ±5 and 131.515 ± 4 keV (eV) can be used for calibrating Ge detectors.