Performance comparison between signal digitizers and low-cost digital oscilloscopes: spectroscopic, pulse shape discrimination and timing capabilities for nuclear detectors

Signal digitizers revolutionized the approach to the electronics readout of radiation detectors in Nuclear Physics. These highly specialized pieces of equipment are designed to acquire the signals that are characteristic of the detectors in nuclear physics experiments. The functions of the several modules that were once needed for signal acquisition, can now be substituted by a single digitizer. As suggested by the name, with such readout modules, signals are first digitized (i.e. the signal waveform is sampled and converted to a digital representation) and then either stored or analyzed on-the-fly. The performances can be comparable or better than the traditional analog counterparts, in terms of energy, time resolution, and acquisition rate. In this work, we investigate the use of general-purpose digital oscilloscopes as signal digitizers for nuclear detectors. In order to have a proper comparison, we employ a distributed data acquisition system (DAQ), that standardizes the interface between the hardware and the on-line data analysis. The signals, from a set of typical radiation detectors, are digitized and analyzed with the very same algorithms in order to avoid biases due to different software analysis. We compare two traditional signal digitizers (CAEN DT5725 and CAEN DT5751) to two low-cost digital oscilloscopes (Digilent Analog Discovery 2, and Red Pitaya STEMLab 125-14), in terms of their capabilities for spectroscopy (energy resolution), time resolution, pulse shape discrimination, and maximum acquisition rate.Comment: 17 pages, 8 figures, 4 tables, Prepared for submission to JINS

Material recognition with a 252Cf source

Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged 252Cf source. Light elements (C,N,O) are identified by using the measured transmission versus neutron time of flight. The yield of the transmitted gamma ray as a function of energy provides high precision identification of the atomic number of the sample up to Z=83 . A tomography system, currently under construction, is described

a distributed data acquisition system for nuclear detectors

Nowadays, many examples of data acquisition (DAQ) software for experimental nuclear physics are monolithic processes that run on a computer attached to the DAQ hardware. In this article we present a distributed DAQ system developed for the C-BORD project. With our system, we propose a novel approach, in which each task related to the different DAQ parts (acquisition, pre-process, analysis, etc.) runs in a separate process. In particular, the system is composed of a set of servers that exchange information through dedicated communication sockets. Therefore, with this architecture, an important advantage is the possibility to run the processes on different computers to distribute the computational load. The initial tests of the system have been giving excellent results, both in terms of performance (i.e., maximum acquisition rates) and stability. The project entitled "Effective container inspection at BORDer control points" (C-BORD) is funded by the European H2020 programme. Its aim is to develop a comprehensive set of technologies for the generalized non-intrusive inspection (NII) of containers and large-volume freight at the European Union border

The effect of customer perceived value on customer satisfaction: a case study of Malay upscale restaurants

Stiff competition and increasingly high operating costs have driven many international and domestic players to introduce new outlet concepts. Malay fine dining, upscale restaurant segment is gaining popularity among Malaysian, especially in Kuala Lumpur. This study examined the effect of perceived value on customer satisfaction in Malay upscale restaurants in terms of emotional responses, monetary prices, behavioral price and reputation. Primary data were gathered from 170 questionnaires returned by respondents from five Malay upscale restaurants in Kuala Lumpur, and statistically analysed using SPSS version 21. The findings of this study revealed that monetary prices had a high positive relationship with customer satisfaction. In addition, the beta value for emotional responses (β=0.530, p<0.01), behavioral price (β=0.180, p<0.01) and reputation (β=0.168, p<0.01) also indicated the respective contributions made to customer satisfaction

Targeted next-generation sequencing identification of mutations in disease resistance gene analogs (RGAs) in wild and cultivated beets

Resistance gene analogs (RGAs) were searched bioinformatically in the sugar beet (Beta vulgaris L.) genome as potential candidates for improving resistance against different diseases. In the present study, Ion Torrent sequencing technology was used to identify mutations in 21 RGAs. The DNA samples of ninety-six individuals from six sea beets (Beta vulgaris L. subsp. maritima) and six sugar beet pollinators (eight individuals each) were used for the discovery of single-nucleotide polymorphisms (SNPs). Target amplicons of about 200 bp in length were designed with the Ion AmpliSeq Designer system in order to cover the DNA sequences of the RGAs. The number of SNPs ranged from 0 in four individuals to 278 in the pollinator R740 (which is resistant to rhizomania infection). Among different groups of beets, cytoplasmic male sterile lines had the highest number of SNPs (132) whereas the lowest number of SNPs belonged to O-types (95). The principal coordinates analysis (PCoA) showed that the polymorphisms inside the gene Bv8_184910_pkon (including the CCCTCC sequence) can effectively differentiate wild from cultivated beets, pointing at a possible mutation associated to rhizomania resistance that originated directly from cultivated beets. This is unlike other resistance sources that are introgressed from wild beets. This gene belongs to the receptor-like kinase (RLK) class of RGAs, and is associated to a hypothetical protein. In conclusion, this first report of using Ion Torrent sequencing technology in beet germplasm suggests that the identified sequence CCCTCC can be used in marker-assisted programs to differentiate wild from domestic beets and to identify other unknown disease resistance genes in beet

Innovative techniques for non destructive analysis

This work describes the development of a radiometric mobile inspection system called SMANDRA (the Italian acronym stands for Sistema Mobile per Analisi Non Distruttive e RAdiometriche). SMANDRA is part of a large project called SLIMPORT, financed by the Italian Ministry for the Economic Development (MISE), dedicated to the development of an integrated toolbox forming a complete security system to monitor the flow of persons and merchandise in harbors. The system has been conceived as a flexible and transportable tool, to be used in conjunction with fixed installation such as radiation portal monitors, x-ray scanners and large detector arrays. In particular, the aims of SMANDRA are to detect and identify sources of ionizing radiation or identify dangerous and/or illegal materials inside volumes previously tagged as “suspect” by conventional X-ray scanners. The whole detector apparatus was designed minimizing volume and weight to be easily movable, mounted over forklifts or other light vehicles for inspections. In addition, it is possible to operate the entire system with batteries, making it completely independent from external power facilities. The system is made of two pieces having a volume less than 0.1 m3 as follows: 1) A passive unit including two gamma-ray detectors (5”x5” NaI(Tl) and 2”x2” LaBr3(Ce)) and two neutron counters (5”x2” liquid scintillator NE-213 and 3He proportional counter for fast and slow neutrons). The unit hosts batteries, power supplies, front-end electronics and CPU. 2) An active unit including a portable sealed neutron generator based on the Tagged Neutron Inspection System (TNIS) technique. The first unit can be used in standalone mode as a high efficiency spectroscopic radiometer for the detection of ionizing radiation such as gamma-rays, fast and thermal neutrons to search and identify radioactive material as well as Special Nuclear Material (SNM). It can also be used as detector package connected to the second unit for active interrogation of voxels inside a load by tagged neutron inelastic scattering imaging. All detector used in the SMANDRA system have been fully characterized. Initial tests were done with traditional analog NIM electronics followed by the new digital electronics based on fast digitizers. The detection and identification of standard radioactive sources (gamma ray and neutrons) has been tested successfully showing detection probability in order or even better with the requirements of this type of instrumentation. The detection of special nuclear material has been tested using SMANDRA as a high sensitivity passive spectroscopic system or as a complete active inspection system using tagged neutrons. The detection of plutonium samples seems to be possible with passive interrogation even in case of small samples (few grams) due to the yield of gamma ray and neutrons. As it is well known, detection of uranium samples poses more problems because of the low neutron yield that characterizes this material. The gamma ray yield of highly enriched U samples could be easily shielded. In this case active interrogation is needed. Results show that it is possible to provide signature for the discrimination of uranium against heavy metals (as lead) by looking to the absolute gamma and neutron yield in coincidence with tagged neutrons or to correlations between detectors. It is worth mentioning that the SMANDRA system is a mobile multi-purpose spectrometric system not specifically designed to detect SNM. However the results reported might be implemented in future portable systems specifically designed to detect SNM in active mode.Questo lavoro descrive lo sviluppo di un sistema mobile per ispezioni radiometriche, chiamato SMANDRA (Sistema Mobile per Analisi Non Distruttive e Radiometriche). SMANDRA fa parte di un grande progetto chiamato SLIMPORT, finanziato dal Ministero Italiano dello sviluppo Economico (MISE), rivolto allo sviluppo di un sistema di sicurezza integrato per il monitoraggio del flusso di persone e merci nei porti. Il sistema è stato progettato come uno strumento mobile e flessibile, da usare in combinazione con postazioni fisse come portali, scanners x-ray e grandi array di rivelatori. Più in particolare, lo scopo di SMANDRA è quello di identificare sorgenti radioattive e materiali illegali e/o pericolosi nascosti dentro container e bagagli segnalati come “sospetti” dai sistemi di sicurezza tradizionali. L’intero apparato è stato disegnato per minimizzare il volume ed il peso in modo da essere facilmente trasportabile su un muletto o su altri veicoli leggeri per ispezioni mirate. In aggiunta il sistema può essere alimentato a batterie, rendendolo completamente indipendente dall’allacciamento elettrico. Il sistema è composto di due unità che hanno un volume totale minore di 0.1 m3: 1) Un’unità passiva composta da due rivelatori di raggi gamma (5”x5” NaI(Tl) e 2”x2” LaBr3(Ce)) e due rivelatori di neutroni (scintillatore liquido NE-213 da 5”x2” e un contatore proporzionale ad 3He). L’unità contiene le batterie, l’alimentazione, l’elettronica digitale e la CPU per l’acquisizione ed analisi dati. 2) Un’unità passiva che include un generatore portatile di neutroni per l’identificazione dei materiali illeciti e/o pericolosi tramite la tecnica TNIS (Tagged Neutron Inspection System). La prima unità può essere usata da sola come un radiometro spettroscopico ad alta efficienza per la rivelazione di radiazioni ionizzanti come raggi-gamma, neutroni veloci e neutroni termici e per identificare materiale radioattivo come ad esempio il Materiale Speciale Nucleare (SNM). Questa unità è poi usata insieme al generatore di neutroni per interrogazioni attive di specifiche porzioni di volume all’interno di container, grazie alla tecnica TNIS. Tutti i rivelatori di SMANDRA sono stati totalmente caratterizzati: i test iniziali sono stati fatti con elettronica analogica NIM seguiti da quelli effettuati con la nuova elettronica digitale basata su digitizer veloci. E’ stata dimostrata la possibilità di rivelare e identificare le sorgenti radioattive standard (raggi-gamma e neutroni) con un livello di confidenza migliore di quello richiesta dallo standard per questo tipo di strumentazione. La rivelazione di materiale speciale nucleare è stata testata sia in modalità passiva con la prima unità sia in modalità attiva usando il generatore di neutroni. Il riconoscimento di un campione di plutonio è possibile con la sola interrogazione passiva anche in caso di campioni molto piccoli (qualche grammo) grazie all’alta emissione di raggi-gamma e neutroni. Come è noto, invece, la rivelazione di campioni di Uranio è più difficoltosa vista la bassa emissione di neutroni e la possibilità di schermare facilmente i pochi raggi-gamma; in questo caso è necessario intervenire con un’interrogazione attiva. I risultati dimostrano la possibilità di discriminare fra campioni di Uranio rispetto a metalli pesanti (come il piombo) guardando i conteggi assoluti di raggi-gamma e neutroni in coincidenza con l’emissione di un neutrone da parte del generatore o, in alternativa, guardando alla correlazione degli eventi fra due rivelatori (NaI(Tl) e NE-213). E’ importante sottolineare che SMANDRA è un sistema spettrometrico mobile multi-funzione, non disegnato specificamente per la rivelazione di materiale speciale nucleare. Tuttavia i risultati mostrano la possibilità in futuro di poter implementare sistemi portatili disegnati specificatamente per l’identificazione di Materiale Speciale Nucleare con l’ausilio di un generatore di neutroni

Neutron detection in a high gamma-ray background with EJ-301 and EJ-309 liquid scintillators

Using a fast digitizer, the neutron\u2013gamma discrimination capability of the new liquid scintillator EJ-309 is compared with that obtained using standard EJ-301. Moreover the capability of both the scintillation detectors to identify a weak neutron source in a high gamma-ray background is demonstrated. The probability of neutron detection is PD=95% at 95% confidence level for a gamma-ray background corresponding to a dose rate of 100 uSv/h

Neutron detection in a high gamma ray background with liquid scintillators

The capability of liquid scintillator (namely 2\u201d x 2\u201d cells of EJ301 and EJ309) of detecting neutrons in a very high gamma ray background is explored. A weak 252-Cf source has been detected in a high 137-Cs gamma ray background corresponding to a dose rate of 100 uSv/h with probability of detection in compliance with IEC requirements for hand held instruments. Tests were performed with new generation of CAEN digitizers, in particular the V1720 (8 Channel 12bit 250 MS/s) one