Imaging detector of temporally coherent radiation

We present an optical architecture and image processor capable of detecting and locating temporally coherent radiation that may be dominated by incoherent background radiation. The optical architecture makes use of a coherent light modulator that modulates light of sufficient coherence length while it leaves light of short coherence length unmodulated. The design of the coherent light modulator offers a substantially wider field of view than did past designs, permitting its application within an imaging system. The image processor synchronously detects the modulation imposed on coherent light while it rejects incoherent light fluctuations. Results of a laboratory test are presented. The system tested in the laboratory had a 26 degrees field of view and was able to detect and locate coherent radiation >30 dB below the background incoherent light level.     

Evaluation of a digital optical ionizing radiation particle track detector

An outline of an ionizing radiation particle track detector is presented which can in principle, determine the three-dimensional spatial distribution of all the secondary electrons produced by the passage of the ionizing radiation through a low-pressure (0.1–10 kPa) gas. The electrons in the particle track are excited by the presence of a high-frequency ac electric field, and two digital cameras image the optical radiation produced in electronic excitation collisions of the surrounding gas by the electrons. The specific requirements of the detector for neutron dosimetry and microdosimetry are outlined (i.e., operating conditions of the digital cameras, high voltage fields, gas mixtures, etc.) along with an estimate of the resolution and sensitivity achievable with this technique. The proposed detector is shown to compare favorably with other methods for obtaining the details of the track structure, particularly in the quality of the information obtainable about the particle track and the comparative simplicity and adaptability of the detector for measuring the secondary electron track structure for many forms of ionizing radiation over a wide range of energies.     

The fluid-filling system for the Borexino solar neutrino detector

The system for controlled filling of the nested flexible scintillator containment vessels in the Borexino solar neutrino detector is described. The design and operation principles of pressure and shape monitoring systems are presented for gas filling, gas displacement by water, and water displacement by scintillator. System specifications for safety against overstressing the flexible nylon vessels are defined as well as leak-tightness and cleanliness requirements. The fluid-filling system was a major engineering challenge for the Borexino detector.     

A large system of Flash ADCs for a neutrino detector

A large system of 5760 Flash ADCs was used to instrument proportional drift tubes in a neutrino detector. The system uses a common clock source, is data driven, and builds the data stream in hardware. The design, construction, operation, and performance of this system is described.     

A detector system for the study of intermediate energy neutrino interactions

A 15 t fine-grained neutrino detector and high efficiency anticoincidence system are in operation at the LAMPF beam stop, an intense source of neutrinos with a maximum energy of 53 MeV. The primary use of this equipment is in an experiment which is directed towards the observation and cross section measurement of the ν_ee⁻ elastic scattering reaction. The design, operation, and performance of the apparatus is reported.     

The effect of ionizing radiation on metoprolol

The influence of ionising radiation on physico-chemical properties of metoprolol tartrate (MT) in solid phase was studied. The compound was irradiated by radiation produced by a beam of high-energy electrons in an accelerator, in doses from 25 to 400 kGy, and the possible changes in the samples were detected by organoleptic analysis (colour, forms, clarity), chromatographic and spectrometric methods. Already at the standard sterilisation dose of 25 kGy, the presence of free radicals (0.3764 × 10¹⁶ spin/g) and a decrease in the melting point by 1°C were noted. At higher doses of irradiation products of radiolysis appeared (100 kGy) and the colour was changed from white to pale cream (200 kGy). Our observation was that with increasing mass loss of MT after irradiation with 100, 200 and 400 kGy, the concentration of free radicals increased from 1.0330 to 1.6869 × 10¹⁶ spin/g. The radiolytic yield of total radiolysis was 4.54 × 10⁷ mol/J for 100 kGy, 7.42 × 10⁷ mol/J for 200 kGy and 4.74 × 10⁷ mol/J for 400 kGy. No significant changes were observed in the character of FT–IR spectra, but in UV an increase in intensity of the band at the analytical wavelength was noted. As follows from the results MT shows high radiochemical stability for the typical sterilisation doses 25–50 kGy, and will probably be able to be sterilised by radiation in the dose of 25 kGy.     

Integrating encoding systems for recording ionizing radiation

The results are given of a numerical modeling of the instrumental functions of integrating encoding systems with multipinhole encoding collimators for recording ionization radiation. The characteristics of the instrumental functions are investigated using collimators with pseudorandom and self-supporting pinhole locations, making it possible to compare the tomographic properties of the collimators and to make an optimal choice. Translated from Izmeritel'naya Tekhnika, No. 2, pp. 44–50, February, 1997.     

A position-sensitive detector for synchrotron radiation

A two-dimensional detector that gives an electrical signal proportional to the position of a light spot on a 1 × 1 cm² area has been developed. The detector is intended for position measurements of the beam in a synchrotron radiation source.     

CVD金刚石紫外探测器

CVD金刚石紫外探测器有极强的辐射硬度及耐腐蚀性,在宽禁带半导体紫外探测器中占有重要地位.本文主要对金刚石紫外探测器的发展进展、探测机理、电极模式及应用领域做了简要回顾.     

Studies of bis-MSB wavelength shifter for application in a supernova neutrino detector

We have measured the efficiency of a bar of bis-MSB wavelength shifter plastic to capture ultraviolet photons and deliver them as blue photons to a detector at the end of the bar. We find that this process is suitable for application to a supernova neutrino detector consisting of a large number of small heavy water Cherenkov counters.     

Multiplexed systems for the detection of ionizing radiation

Twelve different versions of integrating encoding (multiplexed) measurement systems for recording the spatial and angular characteristics of ionizing radiation are presented. Spatial, temporal, and binary modulation of the valid signal is performed by the multiplexed measurement system, which thereby suppresses the contribution of noise to the test results and, in a number of cases, makes it possible to obtain tomographic information. Different types of periodioc (0, 1), (– 1, 1), and (– 1, 0, 1) codes and tables, methods of constructing encoders based on these codes and tables, and the basic parameters of the encoders are described.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 49–54, November, 1995.     

Integrating enconding systems for recording ionizing radiation. Oblique incidence of radiation

An investigation is made of the influence of the factor of oblique incidence of radiation on the quality of reconstructed images when utilizing integrating encoding systems for measuring ionizing radiation with plane multipinhole encoding collimators. The results are given of a numerical calculation of an instrumental function which takes this factor into account. Four methods for compensating the factor of oblique incidence of radiation are considered. Recommendations are formulated for choosing the type and method of construction of the collimator used. Translated from Izmeritel'naya Tekhnika, No. 5, pp. 48–55, May, 1999.     

Projected performance of a large superfluid helium solar neutrino detector

Based upon experiments carried out using radioactive sources to investigate the particle detection properties of superfluid helium we project a configuration for and the response of a full scale detector for solar neutrinos employing the roton/quantum evaporation technique.