Rapid determination of tritium and carbon-14 in urine samples using a combustion technique

Traditionally in bioassay monitoring, ³H determinations in urine have been performed using either direct counting (with or without sample decolourisation) or distillation whilst ¹⁴C has been determined on separate sub-samples following chemical isolation of the carbon from samples. Although these techniques are relatively straightforward they do not permit simultaneous determination of ³H/¹⁴C. For ³H, direct counting can be significantly affected by variations in sample composition/colour resulting in varying degrees of sample quench, does not distinguish between aqueous/organically-bound ³H and is limited to small sample sizes. This study describes the use of purpose built multi-tube combustion furnace for the simultaneous extraction and determination of ³H and ¹⁴C. The technique is insensitive to sample composition and can be adapted to measure Tritiated water (HTO) and organically bound tritium separately. The development of a multi-tube system with integrated cool-down facility permits rapid throughput of high sample numbers and has been proven effective in decommissioning waste characterisation. In addition, the furnace-based technique is capable of processing larger sample sizes, increasing analytical sensitivity and accuracy of dose assessment.     

Proton orbit sizes of the isotopes of tin

Root-mean square radii of the $\text{1}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{, 2}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{and 2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ in the isotopes of tin with A = 112, 116, 118, 120 and 124 have been determined from a DWBA analysis of crosssection data from the sub-Coulomb (t, α) reaction. The differential cross sections for the (t, α) reaction were measured at lab angles in the range from 60° to 160° for triton energies in the range from 4.75 MeV to 5.25 MeV. Spectroscopic factors of the populated states were obtained from a sum rule analysis of published proton stripping and pickup reactions on the isotopes of tin. The measured orbit sizes are compared with the results of Hartree-Fock calculations and the systematic features of the asymptotic proton wave functions are discussed.     

Beta-induced fluorescence as a detection technique for liquid chromatography

The design of a beta-induced fluorescence detector based on a commercially available radioactive source is described. Results obtained with the detector attached to an hplc system operating in both normal and reverse phase modes are presented. The technique of quenched beta-induced fluorescence in normal phase chromatography is also described and some preliminary results presented.     

The determination of minor amounts of tellurium in iron and steel by atomic absorption spectrophotometry

A study was made of the determination of 0.0005–0.030% tellurium in iron and steel by atomic absorption spectrophotometry. Tellurium is separated by precipitation with tin(II) chloride and concentrated by extraction of the diethyldithiocarbamate complex into amyl acetate. The procedure is free from interference by elements which are reduced by tin (II) chloride or from the diethyldithiocarbamates of these elements. The results obtained on standard samples are in agreement with those reported with X-ray spectrometry and cathode-ray polarography.     

The 48Ti(t,d)49Ti reaction: A comparison with magnetic electron scattering

The reaction ⁴⁸Ti(t, d)⁴⁹Ti leading to the ground and first excited states of ⁴⁹Ti has been studied at triton energies of 2.75 and 3.0 MeV. The cross section to the ground state of ⁴⁹Ti has been analysed using the DWBA with a previously determined bound-state well geometry to obtain a value for the (t, d) normalization factor of D² = (3.29 ± 0.40) × 10⁴ MeV² · fm³. This value is in agreement with that obtained from a comparison of the (d, t) reaction with heavy-ion single-neutron transfer reactions. Using this value of the normalization factor the rms radius of the $\text{2}\text{p}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ component in the $\text{3}\text{2}{}^{\mathrm{?}}$ first excited state of ⁴⁹Ti is found to be 4.42 ± 0.07 fm (point neutron), corresponding to the use of a local bound-state potential well.     

Constructions for Circulant and Group‐Developed Generalized Weighing Matrices

An elementary construction yields a new class of circulant (so‐called “Butson‐type”) generalized weighing matrices, which have order and weight n², all of whose entries are nth roots of unity, for all positive integers , where . The idea is extended to a wider class of constructions giving various group‐developed generalized weighing matrices.     

Determination of Cs and Cs in environmental samples: A review

Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products (¹³⁵Cs and ¹³⁷Cs) and activation products (¹³⁴Cs and ¹³⁶Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst ¹³⁷Cs, ¹³⁴Cs and ¹³⁶Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived ¹³⁵Cs by radiometric methods is challenging. This measurement is, however, important given its significance in long-term nuclear waste storage and disposal. Furthermore, the ¹³⁵Cs/¹³⁷Cs ratio varies with reactor, weapon and fuel type, and accurate measurement of this ratio can therefore be used as a forensic tool in identifying the source(s) of nuclear contamination. The shorter-lived activation products ¹³⁴Cs and ¹³⁶Cs have a limited application but provide useful early information on fuel irradiation history and have importance in health physics.