144Ce - 144Pr spectrum measurement with 4π semiconductor β-spectrometer

Precision β-spectra measurement always had a great importance in some fundamental physics problems including neutrino physics. Magnetic and electrostatic spectrometers have high resolution, but at the same time usage of such kinds of equipment involves the size and cost issues. Since electron mean free path at the energy of 3 MeV (which is basically the maximum energy of a β-transition for the long-lived nuclei) does not exceed 2 g/crn2 , electron registration could be effectively performed with the solid state scintillators and semiconductors. A strong probability of backscattering from detector surface is present in case of semiconductor detectors and is dependent upon the detector material. Such problem can be solved with 4π geometry detector development, which fully covers the radioactive source and is able to register the backscattered electrons. In this work we present the newly developed technology of 4π geometry β-spectrometer based on two semiconductor detectors. This spectrometer was used for measurement of the 144Ce - 144Pr spectrum, that is the perspective anti-neutrino source due to endpoint energy at 3 MeV and can be used for the sterile neutrino search experiments. The form-factor parameters that were obtained are: C(W) = 1 + (-0.02877 ± 0.00028)W + (-0.11722 ± 0.00297)W-1. The measurement accuracy was sufficiently enhanced with respect to the previous results.

Ultra-durable, Multi-template Molecularly Imprinted Polymers for Ultrasensitive Monitoring and Multicomponent Quantification of Trace Sulfa Antibiotics

Traditional analysis methods are susceptible to interference caused by the complexity of sample matrices, and detector surface fouling arising from nonspecific adsorption of microorganisms (in biological samples) which leads in...

A hybrid analytical-numerical method for efficiency calculations of spherical scintillation NaI(Tl) detectors and arbitrarily located point sources

The present work is essentially concerned to introduce a hybrid analytical-numerical method to calculate the geometrical, the total, and the full-energy peak efficiency of the spherical NaI(Tl) detector for using isotropic radiating g-ray point sources. In addition, it calculates the average path lengths travelled by the photon inside the detector active medium, in order to study the characteristics of the source-to-detector configurations. This method was depended mainly on the calculation of the solid angle subtended by the radioactive point sources, which were situated at various locations from the detector surface and the photons path lengths through the detector active medium. Also, taking into account the attenuation coefficients of all the absorbers between the source and the detector material itself. The obtained results were compared against one data set published to show the method's possibility in the calibration process.

Optimized pinhole geometry for small-angle scattering

In order to make the most of the low photon flux in laboratory small-angle X-ray scattering instruments, the experimental geometry has to be chosen carefully, with special stress on the beam-shaping system. The optimum collimation scheme should enable accurate measurements over the desired range of the scattering variable, while yielding the highest flux and the lowest possible instrumental background. In order to identify the best setting, a phase-space optimization of the collimating scheme is carried out in the present work, including constraints on the beam size at the sample position and on the detector surface. The resulting formulae are implemented in a Python script with a graphical user interface, to aid the planning, construction and daily operation of pinhole small-angle scattering cameras.

Corrosion Resistance of Casings for Metal Detectors in Food Industry Made of Cr-Ni Stainless Steel

The paper discusses the problem of recurrent corrosion of casing of metal detectors used in food industry. The detector casing is fabricated by welding sheets of X5CrNi18-10 stainless steel. The detectors in service suffered non-uniform spot corrosion. The likely cause of the corrosion attack was the accumulated contamination of the detector surface with cleaning and disinfecting agents containing chlorine. The sheet surfaces of the original detectors were shot-blasted. After the sheet finishing process was changed to grinding and minor design changes were made, the corrosion resistance of the detector casing improved. The enhanced corrosion resistance of the detectors with ground surfaces was confirmed by salt spray tests. The use of the modified detectors then led to a lower number of complaints about the devices.

Measurement of Uniformity and Multiple Head Registration (MHR)/Centre of Rotation (COR) of a Newly Installed Hybrid SPECT/CT At INMAS, Mymensingh

The main quality controls of hybrid SPECT/CT are Uniformity and Multiple Head Registration (MHR)/Centre of rotation (COR). Uniformity corrects and verifies camera’s response to uniform distribution of radionuclides on the detector surface. MHR/COR not only observes mechanical errors but also quantitatively corrects the errors due to movement of patients and detectors onthe SPECT images. The aim of the study is to establish baseline values thatcan be used as reference for future quality assurance and to verify the manufacturer’s specification. Both intrinsic and extrinsic Uniformity were measured by using 18?Ci 99mTc point source and 35mCi 99mTc flood source respectively. For MHR/COR measurements, MHR Phantom containing five approximately equal strength (1 mCi99mTc of each) point sourceswere used. The values were found to be in correlation with manufacturer’s specification. DOI: http://dx.doi.org/10.3329/bjnm.v17i1.22494 Bangladesh J. Nuclear Med. 17(1): 67-74, January 2014