Portable Multichannel Analyzer Research Articles

Portable multi-channel analyzer for embedded gamma radiation in an ARM Cortex-M7 MCU

The use of digital systems in radiation science has been increased last years in the different knowledge areas, as a detectors, spectrometry, spectroscopy, simulation, etc. This manuscript presents the design and implementation of a low-cost, fully portable multi-channel analyzer for nuclear spectrometry (in situ). The development is based on a 32-bit microcontroller with ARM Cortex-M7, this design is able to digitize and analyze pulses from a radiation detector without the need to transform the input signal with some filter, obtains the maximum height of each of the digitized pulses, segmenting the information into channels to form a histogram and visualizing the LCD screen incorporated in the system. A continuous digitization methodology was used, which is in charge of the DMA and an ADC with a resolution of 12 bits at a speed of 3.6 MSPS. The system has a compact design and can open and save spectra in an SD memory built into the system. The MCA in MCU was tested with a NaI(Tl) Scintillation radiation detector, which allowed us to determine that the spectra obtained are similar compared to commercial MCA's. The results obtained show that the MCA in MCU is efficient for nuclear spectrometry, in addition to being very economical and low power consumption.

Knowledge on radiation emergency preparedness among nuclear medicine technologists

This study aimed to assess the knowledge of nuclear medicine technologists (NMTs) in radiation emergency preparedness and response operations and their willingness to participate in such operations. A survey was developed for this purpose and distributed to NMTs in Saudi Arabia. Sixty participants responded with a response rate of 63.31%. Based on the overall radiation protection knowledge related to emergency response, NMTs can perform radiation detection, population monitoring, patient decontamination, and assist with radiological dose assessments during radiation emergencies. There were no significant differences in the knowledge on the use of scintillation gamma camera (P = 0.314), well counter (P = 0.744), Geiger counter (P = 0.935), thyroid probes (P = 0.980), portable monitor (P = 0.830), or portable multichannel analyzer (P = 0.413) and years of experience. Approximately 44% of the respondents reported receiving emergency preparedness training in the last 5 years. Respondents who reported receiving training were significantly more familiar with the emergency preparedness resources (P = 0.031) and more willing to assist with radiation detection or monitoring in the event of nuclear reactor accident (P = 0.016), nuclear weapon detonation (P = 0.002), and dirty bomb detonation (P = 0.003). These findings indicate the importance of training and continuing education in radiological emergency preparedness and response, which increase the willingness to respond to radiological accidents and fill the gaps in NMTs’ knowledge and familiarity with response resources.

Photon Spectrum behind Biological Shielding of the LVR-15 Research Reactor

Abstract The LVR-15 reactor is a light water research reactor situated at the Research Centre Řež, near Prague. It operates as a multipurpose facility with a maximum thermal power of 10 MW. The reactor core usually contains from 28 to 32 fuel assemblies with a total mass of 235U of about 5 kg. Emitted radiation from the fuel caused by fission is shielded by moderating water, a steel reactor vessel, and heavy concrete. This paper deals with measurement and analysis of the gamma spectrum near the outer surface of the concrete wall, behind biological shielding, mainly in the 3- to 10-MeV energy range. A portable HPGe detector with a portable multichannel analyzer was used to measure gamma spectra. The origin of energy lines in gamma detector spectra was identified.

Focus on software and data acquisition

Focus on software and data acquisition

Monte Carlo simulations of a portable prompt gamma system for nondestructive determination of chloride in reinforced concrete

In this work, the MCNP code was used to perform Monte Carlo simulations of the operation of a portable prompt gamma neutron activation (PGNA) system for chloride detection in reinforced concrete. The system consists of a moderated 252Cf neutron source, a high purity germanium (HPGe) gamma ray detector and a portable multichannel analyzer. The system maximum weight is 23 kg with a largest dimension of 31 cm. The simulations utilized a hybrid approach, which consisted of using MCNP simulations to model neutron transport and ray tracing for gamma ray transport, which considerably reduces computation time in comparison to a fully coupled neutron/photon Monte Carlo simulations. The simulations have shown that the current moderator design effectively thermalizes the neutron energy spectrum. At low to moderate chloride concentrations, the hybrid simulation model of the PGNA chloride detector shows very good agreement with experimental data. The MCNP computations predicted that for a standard error of 10% in counting statistics, the detection of a 2000 ppm chloride concentration (the corrosion threshold) in reinforced concrete can be achieved in a seven minute counting period. This represents a significant improvement over the current standard destructive method of measuring chlorides in concrete. Over the range of water to cement (w/c) ratios normally found in concrete mixes (0.38–0.55), the chloride signal strength shows very little variation especially at the lower chloride concentrations. Thus for all practical purposes the chloride signal remains insensitive to the w/c ratio. Similarly, the chloride signal strength does not vary significantly if limestone coarse or fine aggregate is used in place of quartz.

Comparison of CdTe and CdZnTe detectors for field determination of uranium isotopic enrichments

A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these room temperature semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm3 for the CdZnTe and 25 mm3 for the CdTe detector) and resolution. Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed. There is a need to improve the detection sensitivity during the interdiction of special nuclear materials (SNM) for increased homeland protection. It is essential to provide additional tools to first responders and law enforcement personnel for assessing nuclear and radiological threats.

Federal Radiological Monitoring and Assessment Center: The analytical response

A performance comparison of a CdTe and a CdZnTe detector when exposed to uranium samples of various isotopic enrichments has been performed. These high-resolution detectors can assist in the rapid determination of uranium isotopic content of illicit material. Spectra were recorded from these “room temperature' semiconductor detectors with a portable multi-channel analyzer, both in the laboratory and in a field environment. Both detectors were operated below ambient temperature using the vendor supplied thermoelectric coolers. Both detectors had nominally the same active volume (18 mm 3 for the CdZnTe and 25 mm 3 for the CdTe detector) and resolution (i.e., <1.0 keV resolution FWHM at 59.5 keV). Spectra of samples of known isotopic content were recorded at fixed geometries. An evaluation of potential signature g-rays for the detection of enriched uranium was completed. Operational advantages and disadvantages of each detector are discussed.

Inspector-2000: A DSP-based, portable, multi-purpose MCA

Various in-situ gamma-spectroscopy applications need a versatile, multi-purpose, portable multi-channel analyzer (MCA). Recently, Canberra has introduced the Inspector-2000 for this purpose. It uses digital signal processing (DSP) technology and weighs only about 1.2 kg. It also supports CdTe, NaI and Ge detectors. Due to its use of DSP technology, the Inspector-2000 also provides a longer battery life, a better detector resolution and a better temperature stability than most portable MCAs. This paper includes a short description of the Inspector-2000 MCA and its performance characteristics compared to an analog MCA.

Experimental Evaluation of a Portable Neutron-Based Gamma-Spectroscopy System for Chloride Measurements in Reinforced Concrete

A portable prompt gamma neutron activation (PGNA) spectroscopy system has been developed to analyze the elemental composition (Ca, Si, Al, etc.) of reinforced concrete and to measure chloride contamination. The portable PGNA system consists of a high purity germanium (HPGe) gamma detector with a 70% relative efficiency, a 252Cf neutron source and moderator subsystem, and a portable multichannel analyzer system integrated with a laptop computer. Two types of activation experiments were performed to evaluate the device: first, a detector calibration using a Cl gamma standard provided by a PGNA facility; second, an evaluation of the actual performance of the complete system with the 252Cf source using full scale test slabs containing known amounts of chloride. Both methods indicate that it is feasible to use this device to measure the chloride content of reinforced concrete in the field. The chloride level for the corrosion threshold can be measured with a precision of 10% for a counting time of roughly 6 minutes. This makes the PGNA method competitive with the conventional destructive method.

A portable apparatus for energy-dispersive X-ray fluorescence analysis of sulfur and chlorine in frescoes and stone monuments

A simple and portable equipment was constructed, based on the energy dispersive X-ray fluorescence. It is composed of a small size X-ray tube, a thermoelectrically cooled Si-PIN detector, and a multi channel analyzer. The tube has a Pd anode, and works at 3–30 kV, 0.1 mA. At 3–5 kV, it emits Pd-L lines and bremsstrahlung radiation, and therefore is suited to the analysis of low atomic number elements, such as P, S, Cl. Working at 30 kV the tube emits Pd-K lines and bremsstrahlung radiation, and is able to excite medium atomic number elements up to tin (K-lines) and high atomic number elements (L-lines). The Si-PIN detector has a 25 μm Bc-window and energy resolution of about 190 eV at 5.9 keV. It has a thickness of about 300 μm and thus an efficiency rapidly decreases at energies larger than about 20 keV. The equipment is completed by a portable multi channel analyzer. The described system was first tested in Laboratory and then employed to analyze mainly sulfur and chlorine in the follwoing frescoes and monuments: • frescoes of Piero della Francesca (church of S. Francesco, Arezzo) • frescoes of Domenichino (cathedral of Fano) • Roman frescoes (church of S. Clemente, Rome) • lapideous altars (church of S. Croce, Lecce).

Rapid monitoring of gaseous fission products released from nuclear power stations

Rapid, in situ measurements were used for quantitative monitoring of gaseous fission products around the nuclear power stations in Taiwan. A portable high-resolution germanium detector with portable multichannel analyzer was used in the field monitoring work. The detecting unit was calibrated using activated Ar, Kr, and Xe isotopes dispersed in a large chamber to obtain absolute efficiency curve in terms of γ-counts per m3 versus gamma-ray energy. The calibrated detecting unit was brought to the nuclear power plants for in situ monitoring for both normal operation and nuclear accidental exercise. In a typical four-hour measurement, the detection limits for most Kr and Xe fission product isotopes were 0.0028%≈0.98% of the derived air concentration (DAC) imposed by the local authority. The dose rate caused by gaseous radioisotopes released from nuclear power stations and dispersed to the surroundings can be quantitatively monitored in a short period using this portable unit.

Scout™, a portable MCA system

Quantrad Sensor's hand-held multichannel analyzer (MCA), the ScoutTM, has evolved considerably from the initial licensing from Pacific Northwest Laboratories (operated by Battelle Memorial Institute for the U.S. DOE). The ScoutTM has grown into a flexible MCA system with alpha-, gamma-, X-ray and neutron detection capabilities with wide ranging applications. The development philosophy is discussed along with specific examples of design choices in areas such as manufacturability, upgradability, probe interchangability and software user interface. Recently introduced products include: software enhancements, additional probes, customized software and a second generation instrument, the Scout512TM, that boasts increased capabilities. Future developments are also discussed.

Natural Radiation Background in Metropolitan Taipei.

A high-pressure ionization chamber was used to measure the natural background radiation in metropolitan Taipei, Taiwan, R.O.C. during a period in 1987-1988. The average exposure rate was 27.55 x 10(-10) C kg-1 h-1 including cosmic radiation, but the radon contribution was excluded. Scintillation survey meter, gamma-ray spectroscopy for soil samples, in-situ measurement with a NaI(Tl) detector coupled to a portable multichannel analyzer, instrumental neutron activation analysis of rock samples, and even thermoluminescent dosimeters were used as complementary measuring devices. Areas of higher radiation background were detected. They are the radium-bearing Peitou stones, an unusual occurrence of uraniferous zone at Sanhsia, and uranium precipitation in the glassy olivine basalt in a tea field at Tachi. All these areas are located in suburban sites of Taipei. Three types of building in Taipei City were selected for radon detection. No significantly elevated level of radon was detected, since Taipei is located in a semitropical area where ventilation of buildings is not a problem.

A single chip microcontroller based portable multichannel analyzer

The development of a portable multichannel analyzer for gamma spectroscopy applications is described. The developed unit is based on the Intel 8751 single chip microcontroller and has CRT and liquid crystal displays, preamplifying and amplifying sections, high voltage supply, built-in printer and runs on rechargeable batteries. The design uses standard off the shelf components, minimizes chip count by using all the microcontroller's resources and implementing most functions in software, and this results in a low cost system with good performance. Hardware and software design along with their integration are discussed.

A New Ultra Small Battery Operated Portable Multi-Channel Analyzer

A newly designed portable multi-channel analyzer (MCA) has been developed at Los Alamos that has much improved physical and performance characteristics over previous designs. Namely, the instrument is very compact (25 cm wide × 14 cm deep × 21 cm high) and has a mass of 4.2 Kg (9.2 lb). The device has 1024 channels and is microprocessor controlled. The instrument has most of the standard features of present laboratory-based pulse height analyzers, including CRT display, region of interest integration, etc. Battery life of the MCA is nearly eight hours, with full charging over night. An accessory case carries a small audio cassette recorder for data storage. The case also contains two different NaI (Tl) detectors. Another case contains a 10% efficient hyperpure germanium (HpGe) detector for very high energy resolution gamuna ray spectroscopy. That detector (commercially available) is portable and can carry enough liquid nitrogen for 10 hours of field use. All necessary electronics to acquire data from the various detectors are located on the detectors themselves. No additional power supplies, NIM equipment, etc., are necessary for field operation.