A combined 148Gd/244Cm source for energy calibration of alpha-spectrometers.

For high-resolution alpha-particle spectroscopy, detector calibration sources of highest performance are required concerning thickness and homogeneity. In addition, the alpha-emitting radionuclides must have adequate half-lives and alpha-emission energies. This paper describes a new type of alpha-emitting calibration source, represented by a mixture of 148Gd and 244Cm. This system covers an alpha-energy range from 3.18 MeV (148Gd) to 5.76 and 5.80 MeV (244Cm). The source has been prepared by electrolytic deposition and has good performance in terms of thickness and homogeneity.

An experimental comparison of the K- and L-Auger electron spectra generated in the decays of 140Nd and 111In.

The low-energy electron spectra generated in the decay of 140Nd have been measured using a combined electrostatic spectrometer adjusted to the 4, 7, and 35 eV instrumental resolution. In order to estimate the therapeutic potential of low-energy electrons associated with the decay of 140Nd, similar experiments have been performed with 111In. Relative Auger electron intensity ratios per decay are: 111In(K-Auger)/140Nd(K-Auger)=1.47(12), 111In(L-Auger) /140Nd(L-Auger)=1.1(4), and 111In(L-Auger [2.8-7 keV])/140Nd(L-Auger [2.8-7 keV])=0.24(11). The obtained K-Auger group intensity ratios have been compared with results of calculations. The good agreement found for the experimental and estimated values indicates that such information can be also derived using available nuclear and atomic data. The relative intensity of L-Auger electrons emitted within the 2.8-7 keV interval is higher for 140Nd by a factor of about 4 compared to 111In. As the L-Auger emission is dominating relative to that of the K-Auger group, this implicates that any potential endotherapeutic strategy using 140Nd-labelled targeting vectors requires a maximum accumulation of the endoradiotherapeutical close to the cell nucleus or the DNA of the tumour cell.

Development of a gamma-gamma-perturbed angular correlation one-detector method (1-PAC) for investigation of physico-chemical properties of matter.

A new method of the perturbed angular gamma-gamma-correlation (PAC) measurements was developed using one HPGe detector only (1-PAC). For quantifying the perturbation factor, the ratio R gamma 1 + gamma 2 of the summing peak composed of two cascade gamma-rays (the perturbation-affected parameter) to the summing peak composed of one gamma-ray and one X-ray (the perturbation non-affected parameter) was used. This method was demonstrated for the radionuclides 111In and 111mCd, identifying the chemical status of the radionuclides in aqueous solutions.