Development of detector pixels based on silicon photomultipliers for the Cherenkov gamma-ray telescope TAIGA-IACT

The design and scheme of signal readout from silicon photomultipliers OnSemi MicroFJ-60035 used as sensitive elements (pixels) of a new detector cluster for the camera of the Cherenkov gamma-ray telescope TAIGA-IACT are developed. The design of the developed pixel follows the shape of the photomultiplier tube XP1911 using in the first generation clusters, and that provides compatibility of the new cluster with the telescope camera. Due to the adjustable gain, the developed scheme allows one to detect and digitize signals in a wide dynamic range from several to 10 000 photons.

Homogeneity of the photocathode in the Hamamatsu Photomultiplier Tube

It is common practice to test the optical properties of photomultiplier tubes (PMTs) by illuminating the entire photocathode region from the front at once and measuring the average performance. However, for optimal utilisation of the PMT performance in experiments, especially in the single-photon region, it is essential to also know the systematic variations across the photocathode, which requires measurements with focused light sources that illuminate only small regions of the PMT. We present a detailed uniformity characterisation of the gain, transit time, transit time spread, and pulse shape of the 80 mm Hamamatsu R15458-02 PMT. We find that the parameters exhibit asymmetry along one axis, likely caused by the position and geometry of the dynode system. For all parameters except the transit time, the observed variations are small given the intrinsic variation of the parameters. For positions with shifted transit time we observe on average underamplified pulses which can potentially be exploited to improve the pulse reconstruction.

Nuclear medicine imaging in oral diseases: A review

Nuclear medicine is the discipline of medicine that deals with the use of radionuclides in research, diagnosis, and treatment. It works on molecular & functional level and uses radiopharmaceuticals in its procedure helping in detection of lesions before morphologic change is evident. Radiopharmaceuticals also known as Radionuclides/ Radioisotopes are unstable atoms of a chemical element, actively emit radiation. These emitted radiations are absorbed by photomultiplier tube and reconstructed by a computer system followed by display of an image. The rationale of writing this article is to understand about Nuclear Medicine and its applications in oral diseases.

A Biochemiluminescent Assay for Rapid Diagnosis of Influenza

Background: A biochemiluminescent assay of influenza diagnosis is presented. The assay diagnoses influenza based on detection of the influenza viral neuraminidase activity. An instrument designed for the assay is also reported. This assay solves the problem that current influenza virus diagnosis assays are susceptible to virus mutation. Methods: A luciferase-based complex is synthesized as biochemiluminescent substrate. The substrate is cleaved to free luciferin with presence of influenza neuraminidase in specimen. Luciferase is oxidized to oxyluciferin with luciferin as catalyzer resulting in luminescence, which is proportional to the neuraminidase activity and measured by instrument. The instrument uses a photomultiplier tube (PMT) as sensor, with 24 test channels. Fine optical arrangements enable the instrument with high sensitive and accuracy. Results: A total of 389 clinical specimens were collected to evaluate the performance of the assay in clinical settings. This assay had a sensitivity and specificity of 95.92% (95% confidence interval: 91.38%-98.12%) and 97.93% (95% confidence interval: 95.26%-99.11%), respectively, compared to the colloidal gold assay. Conclusion: As a biochemiluminscence assay, this assay is advantageous in sensitivity and specificify. It does not require any washing and separation steps, which makes the instrument simple in design and easy to operate or maintenance. The assay is suitable for the rapid diagnosis of influenza virus in POC settings.