Detection of anti-aquaporin-4 autoantibodies in the sera of Chinese neuromyelitis optica patients★

Science.gov (United States)

Li, Miao; Su, Weiheng; Wang, Jie; Pisani, Francesco; Frigeri, Antonio; Ma, Tonghui

2013-01-01

In this study, we recruited 10 neuromyelitis optica patients, two multiple sclerosis patients and two myelitis patients. Chinese hamster lung fibroblast (V79) cells transfected with a human aquaporin-4-mCherry fusion protein gene were used to detect anti-aquaporin-4 antibody in neuromyelitis optica patient sera by immunofluorescence. Anti-aquaporin-4 autoantibody was stably detected by immunofluorescence in neuromyelitis optica patient sera exclusively. The sensitivity of the assay for neuromyelitis optica was 90% and the specificity for neuromyelitis optica was 100%. The anti-aquaporin-4 antibody titers in sera were tested with serial dilutions until the signal disappeared. A positive correlation was detected between Expanded Disability Status Scale scores and serum anti-aquaporin-4 antibody titers. The anti-aquaporin-4 antibody assay is highly sensitive and specific in the sera of Chinese neuromyelitis optica patients. Detection of aquaporin-4 autoantibody is important for the diagnosis and treatment of neuromyelitis optica. PMID:25206717

Imaging Surrogates of Disease Activity in Neuromyelitis Optica Allow Distinction from Multiple Sclerosis.

Science.gov (United States)

Matthews, Lucy; Kolind, Shannon; Brazier, Alix; Leite, Maria Isabel; Brooks, Jonathan; Traboulsee, Anthony; Jenkinson, Mark; Johansen-Berg, Heidi; Palace, Jacqueline

2015-01-01

Inflammatory demyelinating lesions of the central nervous system are a common feature of both neuromyelitis optica and multiple sclerosis. Despite this similarity, it is evident clinically that the accumulation of disability in patients with neuromyelitis optica is relapse related and that a progressive phase is very uncommon. This poses the question whether there is any pathological evidence of disease activity or neurodegeneration in neuromyelitis optica between relapses. To investigate this we conducted a longitudinal advanced MRI study of the brain and spinal cord in neuromyelitis optica patients, comparing to patients with multiple sclerosis and controls. We found both cross-sectional and longitudinal evidence of diffusely distributed neurodegenerative surrogates in the multiple sclerosis group (including thalamic atrophy, cervical cord atrophy and progressive widespread diffusion and myelin water imaging abnormalities in the normal appearing white matter) but not in those with neuromyelitis optica, where localised abnormalities in the optic radiations of those with severe visual impairment were noted. In addition, between relapses, there were no new silent brain lesions in the neuromyelitis optica group. These findings indicate that global central nervous system neurodegeneration is not a feature of neuromyelitis optica. The work also questions the theory that neurodegeneration in multiple sclerosis is a chronic sequela to prior inflammatory and demyelinating pathology, as this has not been found to be the case in neuromyelitis optica where the lesions are often more destructive.

Brain MRI lesions in neuromyelitis optica: clinical case

International Nuclear Information System (INIS)

Rosales Bravo, Luis Guillermo; Heyden Cordero, Marvin; Chinchilla Weinstok, Dennis; Mendelewicz Goldwaig, Isaias

2011-01-01

Many cases of patients with neuromyelitis optica have submitted without demyelinating lesions in the cerebral white matter, it has documented that this entity can cause from the onset of illness or through its natural evolution. Diagnostic methods currently as Magnetic Resonance Imaging (MRI) and specific antibodies in plasma (such as antiaquaporin-4) have been diagnosed of neuromyelitis optica cases that were initially confused with multiple sclerosis. Disease in Costa Rica has been little prevalent and is not exactly known what the prevalence and incidence. The degree of disorder is illustrated through a case study, both in the cerebral white matter as spinal cord, in a patient with neuromyelitis optica during a follow-up period of 4 years. This is the first case that has been reported in the scientific literature of Costa Rica. (author) [es

Imaging Surrogates of Disease Activity in Neuromyelitis Optica Allow Distinction from Multiple Sclerosis.

Directory of Open Access Journals (Sweden)

Lucy Matthews

Full Text Available Inflammatory demyelinating lesions of the central nervous system are a common feature of both neuromyelitis optica and multiple sclerosis. Despite this similarity, it is evident clinically that the accumulation of disability in patients with neuromyelitis optica is relapse related and that a progressive phase is very uncommon. This poses the question whether there is any pathological evidence of disease activity or neurodegeneration in neuromyelitis optica between relapses. To investigate this we conducted a longitudinal advanced MRI study of the brain and spinal cord in neuromyelitis optica patients, comparing to patients with multiple sclerosis and controls. We found both cross-sectional and longitudinal evidence of diffusely distributed neurodegenerative surrogates in the multiple sclerosis group (including thalamic atrophy, cervical cord atrophy and progressive widespread diffusion and myelin water imaging abnormalities in the normal appearing white matter but not in those with neuromyelitis optica, where localised abnormalities in the optic radiations of those with severe visual impairment were noted. In addition, between relapses, there were no new silent brain lesions in the neuromyelitis optica group. These findings indicate that global central nervous system neurodegeneration is not a feature of neuromyelitis optica. The work also questions the theory that neurodegeneration in multiple sclerosis is a chronic sequela to prior inflammatory and demyelinating pathology, as this has not been found to be the case in neuromyelitis optica where the lesions are often more destructive.

A population-based study of neuromyelitis optica in Caucasians

DEFF Research Database (Denmark)

Asgari, N; Lillevang, S T; Skejoe, H P B

2011-01-01

Epidemiologic studies have suggested different prevalence of neuromyelitis optica (NMO) in different ethnic groups. However, data on the incidence and prevalence of NMO in Caucasians are scarce.......Epidemiologic studies have suggested different prevalence of neuromyelitis optica (NMO) in different ethnic groups. However, data on the incidence and prevalence of NMO in Caucasians are scarce....

[A treatment of neuromyelitis optica (Devic's disease) during pregnancy].

Science.gov (United States)

Daouda, Moussa Toudou; Obenda, Norlin Samuel; Assadeck, Hamid; Camara, Diankanagbe; Djibo, Fatimata Hassane

2016-01-01

Neuromyelitis optica (Devic's disease) is an inflammatory demyelinating disease of the central nervous system that mainly affects spinal cord, optic nerve and brain regions with high aquaporin 4 antigen expression. This is a severe autoimmune disease caused by autoantibodies directed against aquaporin 4 and associated with high morbidity and mortality. Unlike other inflammatory conditions such as multiple sclerosis or rheumatoid polyarthritis, pregnancy does not seem to influence the activity of neuromyelitis optica, hence the need for a thorough treatment during pregnancy. Corticosteroid therapy is the treatment of choice for neuromyelitis optica during pregnancy. Other treatments may also be used including rituximab, some immunosuppressive agents and immunoglobulins. Immunosuppressive treatment or rituximab is recommended when the long-term corticosteroid treatment is contraindicated, in case of inefficiency or if side effects are intolerable. Immunoglobulins are administered to patients with serious outbreaks of neuromyelitis optica which do not respond to bolus methylprednisolone. Immunoglobulins alone can also be continued at a dose of 0.4 g/kg/day for 6-8 weeks until delivery. Plasmapheresis is also a good alternative to bolus methylprednisolone when outbreaks are extremely severe.

Clinical evaluation of rituximab treatment for neuromyelitis optica.

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Fernández-Megía, M J; Casanova-Estruch, B; Pérez-Miralles, F; Ruiz-Ramos, J; Alcalá-Vicente, C; Poveda-Andrés, J L

2015-10-01

Neuromyelitis optica is an inflammatory and usually relapsing demyelinating autoimmune disease of the central nervous system that targets the optic nerves and spinal cord. Rituximab has been used for different neurological diseases that are probably immune-mediated or involving humoural immunity. The objective of this study is to evaluate the efficacy and safety of rituximab as treatment for neuromyelitis optica in a tertiary hospital. Retrospective study of patients with neuromyelitis optica treated with rituximab 1000mg on days 1 and 15, repeated every 6 to 8 months. We recorded EDSS score, relapse rate, overall condition, CD19+ count, presence of anti-NMO antibodies, and possible adverse reactions. Six patients were treated; all were women with a median age of 46 years (range, 38-58). Anti-NMO antibodies were detected in 3 patients (50%). Baseline EDSS was 4 (range 2.0-5.5). Two patients had previously been treated with an immunomodulatory drug. Median time from the first rituximab infusion to first relapse was 3.7 years (range 1.7-6.9). Two patients had infusion reactions after the first dose of rituximab. Four patients remained relapse-free and their EDSS score did not progress during rituximab treatment, one patient showed no clinical improvement, and one patient could not be evaluated. Rituximab can be considered an attractive therapeutic alternative for patients with neuromyelitis optica as there are no approved treatments for this disease. Further studies with rituximab are needed to establish the role of this drug in treating neuromyelitis optica. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.

Neuromyelitis Optica and Neuromyelitis Optica Spectrum Disorder Patients in Turkish Cohort: Demographic, Clinical, and Laboratory Features.

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Altintas, Ayse; Karabudak, Rana; Balci, Belgin P; Terzi, Murat; Soysal, Aysun; Saip, Sabahattin; Tuncer Kurne, Asli; Uygunoglu, Ugur; Nalbantoglu, Mecbure; Gozubatik Celik, Gokcen; Isik, Nihal; Celik, Yahya; Gokcay, Figen; Duman, Taskin; Boz, Cavit; Yucesan, Canan; Mangan, Mehmet Serhat; Celebisoy, Nese; Diker, Sevda; Colpak Isikay, Ilksen; Kansu, Tulay; Siva, Aksel

2015-10-01

Neuromyelitis optica (NMO) is an immune-mediated, chronic relapsing, inflammatory disease characterized by severe attacks of optic neuritis and myelitis. To determine the demographic, clinical, and laboratory features; antibody status; and treatment modalities of patients with NMO and neuromyelitis optica spectrum disorders in a Turkish cohort from 11 centers. A total of 182 patients were included in this study. Data on age at disease onset, sex, type of attacks, clinical presentation, analysis of cerebrospinal fluid, serum antiaquaporin-4 antibody status, annual progression index, and medical and family histories were collected. Mean age was 38.43±12.40 years (range, 13 to 75 y), and mean age at disease onset was 31.29±12.40 years (median, 29 y; range, 10 to 74 y). In NMO group, the rate of NMO immunoglobulin (Ig)G positivity was 62.5%. The annual progression index was significantly higher in the longitudinally extending spinal cord lesion. The mean Expanded Disability Status Scale score was higher in the late than early-onset NMO group. Our results revealed a lower rate of NMO IgG positivity, more severe disability in patients with NMO/neuromyelitis optica spectrum disorders presenting with either transverse myelitis or late-onset NMO, and no correlation between disability and NMO IgG status.

Imaging Differences between Neuromyelitis Optica Spectrum Disorders and Multiple Sclerosis: A Multi-Institutional Study in Japan.

Science.gov (United States)

Tatekawa, H; Sakamoto, S; Hori, M; Kaichi, Y; Kunimatsu, A; Akazawa, K; Miyasaka, T; Oba, H; Okubo, T; Hasuo, K; Yamada, K; Taoka, T; Doishita, S; Shimono, T; Miki, Y

2018-05-03

Both clinical and imaging criteria must be met to diagnose neuromyelitis optica spectrum disorders and multiple sclerosis. However, neuromyelitis optica spectrum disorders are often misdiagnosed as MS because of an overlap in MR imaging features. The purpose of this study was to confirm imaging differences between neuromyelitis optica spectrum disorders and MS with visually detailed quantitative analyses of large-sample data. We retrospectively examined 89 consecutive patients with neuromyelitis optica spectrum disorders (median age, 51 years; range, 16-85 years; females, 77; aquaporin 4 immunoglobulin G-positive, 93%) and 89 with MS (median age, 36 years; range, 18-67 years; females, 68; relapsing-remitting MS, 89%; primary-progressive MS, 7%; secondary-progressive MS, 2%) from 9 institutions across Japan (April 2008 to December 2012). Two neuroradiologists visually evaluated the number, location, and size of all lesions using the Mann-Whitney U test or the Fisher exact test. We enrolled 79 patients with neuromyelitis optica spectrum disorders and 87 with MS for brain analysis, 57 with neuromyelitis optica spectrum disorders and 55 with MS for spinal cord analysis, and 42 with neuromyelitis optica spectrum disorders and 14 with MS for optic nerve analysis. We identified 911 brain lesions in neuromyelitis optica spectrum disorders, 1659 brain lesions in MS, 86 spinal cord lesions in neuromyelitis optica spectrum disorders, and 102 spinal cord lesions in MS. The frequencies of periventricular white matter and deep white matter lesions were 17% and 68% in neuromyelitis optica spectrum disorders versus 41% and 42% in MS, respectively (location of brain lesions, P optica spectrum disorders (cervical versus thoracic, 29% versus 71%), whereas they were equally distributed in MS (46% versus 54%). Furthermore, thoracic lesions were significantly longer than cervical lesions in neuromyelitis optica spectrum disorders ( P = .001), but not in MS ( P = .80). Visually detailed

Neuromyelitis optica-like pathology is dependent on type I interferon response

DEFF Research Database (Denmark)

Khorooshi, Reza; Wlodarczyk, Agnieszka; Asgari, Nasrin

2013-01-01

Neuromyelitis optica is an antibody-mediated autoimmune inflammatory disease of the central nervous system. Reports have suggested that interferon beta which is beneficial for multiple sclerosis, exacerbates neuromyelitis optica. Our aim was to determine whether type I interferon plays a role in ...

Pediatric familial neuromyelitis optica in two sisters with long term follow-up.

Science.gov (United States)

Chuquilin, Miguel; Mullaguri, Naresh; Weinshenker, Brian

2016-07-01

Neuromyelitis optica causes bilateral optic neuritis and longitudinal extensive transverse myelitis. Although usually sporadic, 3% of cases of neuromyelitis optica are familial. The interval over which attacks continue and the long term prognosis for pediatric-onset neuromyelitis optica are not well defined. We describe two patients with pediatric familial neuromyelitis optica with the longest clinical follow-up of a pediatric case reported in the literature to our knowledge. One woman developed blindness with bilateral eye involvement within a few weeks at age 3. This was followed by transverse myelitis with paraparesis at age 19 leading to diagnosis of neuromyelitis optica. Her serum anti-aquaporin 4 antibody was later found to be positive. She continued with sporadic myelitis-related relapses but remained ambulant until age 40 when she had a more severe relapse. There was evidence of longitudinal extensive T2 hyperintensity in the thoracic spinal cord. Her sister also developed blindness at age 3.5 followed by myelitis 1year later with multiple relapses of gait impairment until her death from pneumonia at age 21. These patients represent the rare occurrence of neuromyelitis optica in children within the same family and show that this disease can have prolonged periods of remission but a continued tendency to relapse, supporting the need for lifelong immunosuppression. Copyright © 2016 Elsevier Ltd. All rights reserved.

Individualized rituximab treatment for relapsing neuromyelitis optica: a pediatric case report.

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He, Dian; Yu, YunLi; Yan, WeiBo; Dai, QingQing; Xu, Zhu; Chu, Lan

2014-08-01

Neuromyelitis optica is an autoimmune inflammatory disorder of the central nervous system. Current therapeutic approaches are based on small uncontrolled trials, case series, or case reports. There are only a few case reports describing rituximab for pediatric neuromyelitis optica. A 7-year-old girl with neuromyelitis optica had high disease activity with recurrent myelitis and steroid dependence. A remarkable increase of CD19(+) B-cell count in the peripheral blood mononuclear cells and seropositivity for anti-aquaporin 4 antibody were detected at each attack. After induction therapy with rituximab, the CD19(+) B-cell number was significantly reduced and sustained at low levels. The level of serum anti-aquaporin 4 antibody normalized. She was relapse-free over 1-year follow-up period. An individualized maintenance therapy scheme is underway. Treatment with rituximab for relapsing neuromyelitis optica requires an individualized regimen to optimize the frequency and dosage of administration to maximize efficacy yet minimize overtreatment and cost. Personal levels of CD19(+) B cells in peripheral blood mononuclear cells at previous attacks and responsiveness to rituximab in induction therapy may be two useful indicators in establishing individualized maintenance therapy schemes for relapsing neuromyelitis optica. Copyright © 2014 Elsevier Inc. All rights reserved.

Paucity of natural killer and cytotoxic T cells in human neuromyelitis optica lesions

Science.gov (United States)

Saadoun, Samira; Bridges, Leslie R.; Verkman, A. S.; Papadopoulos, Marios C.

2013-01-01

Neuromyelitis optica is a severe inflammatory demyelinating disease of the central nervous system. Most patients with neuromyelitis optica have circulating immunoglobulin G (IgG) antibodies against the astrocytic water channel protein aquaporin-4 (AQP4), which are pathogenic. Anti-AQP4 IgG-mediated complement-dependent astrocyte toxicity is a key mechanism of central nervous system damage in neuromyelitis optica, but the role of natural killer and cytotoxic T cells is unknown. Our objective was to determine whether natural killer and cytotoxic T cells play a role in human neuromyelitis optica lesions. We immunostained four actively demyelinating lesions, obtained from patients with anti-AQP4 IgG positive neuromyelitis optica, for Granzyme B and Perforin. The inflammatory cells were perivascular neutrophils, eosinophils and macrophages, with only occasional Granzyme B+ or Perforin + cells. Greater than 95% of inflamed vessels in each lesion had no surrounding Granzyme B+ or Perforin + cells. Granzyme B+ or Perforin+ cells were abundant in human spleen (positive control). Although natural killer cells produce central nervous system damage in mice injected with anti-AQP4 IgG, our findings here indicate that natural killer-mediated and T cell-mediated cytotoxicity are probably not involved in central nervous system damage in human neuromyelitis optica. PMID:23108041

Neuromyelitis optica and multiple sclerosis

DEFF Research Database (Denmark)

Bennett, J. L.; de Seze, J.; Lana-Peixoto, M.

2015-01-01

Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel...

Neuromyelitis optica in an adolescent after bone marrow transplantation.

Science.gov (United States)

Baumer, Fiona M; Kamihara, Junne; Gorman, Mark P

2015-01-01

Central nervous system complications of bone marrow transplant are a common occurrence and the differential diagnosis is quite broad, including opportunistic infections, medications toxicities, graft versus host disease, and other autoimmune processes. We summarize previously reported cases of autoimmune myelitis in post-transplant patients and discuss a 17-year-old boy who presented with seronegative neuromyelitis optica after a bone marrow transplant for acute myeloid leukemia. Our patient had a marked improvement in symptoms after plasmapheresis. Including our patient, there have been at least eight cases of post-transplant autoimmune myelitis presented in the literature, and at least three of these are suspicious for neuromyelitis optica. Several of these patients had poor outcomes with persistent symptoms after the myelitis. Autoimmune processes such as neuromyelitis optica should be carefully considered in patients after transplant as aggressive treatment like early plasmapheresis may improve outcomes. Copyright © 2015 Elsevier Inc. All rights reserved.

Hypertrophic pachymeningitis accompanying neuromyelitis optica spectrum disorder: A case report.

Science.gov (United States)

Kon, Tomoya; Nishijima, Haruo; Haga, Rie; Funamizu, Yukihisa; Ueno, Tatsuya; Arai, Akira; Suzuki, Chieko; Nunomura, Jin-ichi; Baba, Masayuki; Takahashi, Toshiyuki; Tomiyama, Masahiko

2015-10-15

We report a case of idiopathic cerebral hypertrophic pachymeningitis accompanying neuromyelitis optica spectrum disorder. No other identifiable cause of pachymeningitis was detected. Corticosteroid therapy was effective for both diseases. Hypertrophic pachymeningitis is closely related to autoimmune inflammatory disease of the central nervous system. This case supports the hypothesis that hypertrophic pachymeningitis can be a rare comorbidity of neuromyelitis optica spectrum disorder. Copyright © 2015. Published by Elsevier B.V.

Immunology of neuromyelitis optica during pregnancy.

OpenAIRE

Bove, Riley; Davoudi, V; Keyhanian, K; Bove, RM; Chitnis, T

2016-01-01

Anti-aquaporin-4 (AQP4) autoantibody plays a key role in the pathogenesis of neuromyelitis optica (NMO). Studies have shown increased relapse rates in patients with NMO during pregnancy and postpartum. High estrogen levels during pregnancy can increase act

Imaging the Visual Pathway in Neuromyelitis Optica

OpenAIRE

Pfueller, Caspar F.; Paul, Friedemann

2011-01-01

The focus of this paper is to summarize the current knowledge on visual pathway damage in neuromyelitis optica (NMO) assessed by magnetic resonance imaging (MRI) and optical coherence tomography (OCT).

Cognitive impairment in Chinese neuromyelitis optica

NARCIS (Netherlands)

Zhang, N.; Li, Y.J.; Fu, Y.; Shao, J.H.; Luo, L.L.; Yang, L.; Shi, F.D.; Liu, Y.

2015-01-01

Background: Cognitive dysfunction is frequently seen in neuromyelitis optica (NMO). However, the features and influencing factors of cognitive impairment of Chinese NMO patients are unclear. Objective: To investigate the patterns of cognitive impairment in Chinese NMO patients, and correlate the

Neuromyelitis optica antibody in Leber hereditary optic neuropathy: case report

Directory of Open Access Journals (Sweden)

Luciano Mesquita Simão

2012-08-01

Full Text Available Neuromyelitis optica antibody (or aquaporin-4 antibody is a well stablished serum marker associated to high-risk neuromyelitis optica syndrome that presents as an inflammatory demyelinating disease characterized by the occurrence of bilateral and simultaneous optic neuritis without complete visual recovery or it occurs as an isolated episode of transverse myelitis accompanied by longitudinally extensive spinal cord lesions. On the other hand, Leber hereditary optic neuropathy is a primarily hereditary disorder that affects all tissues of the body and its clinical presentation is tissue-specific for the optic nerve and, eventually, it might reach the spinal cord. Overlapping clinical features of neuromyelitis optica and Leber hereditary optic neuropathy may suggest common target organ diseases. The case report described herein emphasizes the coexistence of serum markers of both diseases, and suggests that further investigation of this challenging clinical presentation is warranted to confirm or rule out this association.

Diagnostik og behandling af neuromyelitis optica

DEFF Research Database (Denmark)

Nielsen, Helle Hvilsted; Ravnborg, Mads; Illes, Zsolt

2014-01-01

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease characterized by antibodies against aquaporin-4 in up to 80% of the cases and even less in the NMO spectrum disorders, which may be difficult to distinguish from early multiple sclerosis. While immunosuppressive therapy should...

Interferon alpha association with neuromyelitis optica

DEFF Research Database (Denmark)

Asgari, Nasrin; Voss, Anne; Steenstrup, Troels

2013-01-01

Interferon-alpha (IFN- α ) has immunoregulatory functions in autoimmune inflammatory diseases. The goal of this study was to determine occurrence and clinical consequences of IFN- α in neuromyelitis optica (NMO) patients. Thirty-six NMO and 41 multiple sclerosis (MS) patients from a population...

Subclinical primary retinal pathology in neuromyelitis optica spectrum disorder.

Science.gov (United States)

Jeong, In Hye; Kim, Ho Jin; Kim, Nam-Hee; Jeong, Kyoung Sook; Park, Choul Yong

2016-07-01

Foveal thickness may be a more sensitive indicator of primary retinal pathology than retinal nerve fiber layer thickness since the fovea contains no or sparse retinal nerve fiber layer, which coalesces into axons of the optic nerve. To our knowledge, few quantitative in vivo studies have investigated foveal thickness. By using optical coherence tomography, we measured foveal thickness to evaluate intrinsic retinal pathology. Seventy-two neuromyelitis optica spectrum disorder patients (99 eyes with optic neuritis and 45 eyes without optic neuritis) and 34 age-matched controls were included. Foveal thinning was observed both in eyes with non-optic neuritis (185.1 µm, p optica spectrum disorder, foveal thickness correlated with 2.5 % low contrast visual acuity, while retinal nerve fiber layer thickness correlated with high or low contrast visual acuity, extended disability status scale, and disease duration. In this study, we observed foveal thinning irrespective of optic neuritis; thus, we believe that subclinical primary retinal pathology, prior to retinal nerve fiber layer thinning, may exist in neuromyelitis optica spectrum disorder.

Hydrocephalus in neuromyelitis optica

OpenAIRE

Clardy, Stacey L.; Lucchinetti, Claudia F.; Krecke, Karl N.; Lennon, Vanda A.; O'Toole, Orna; Weinshenker, Brian G.; Boyd, Clara D.; Krieger, Stephen; McGraw, Corey; Guo, Yong; Pittock, Sean J.

2014-01-01

A majority of patients with neuromyelitis optica (NMO) spectrum disorders (NMOSD) have MRI brain abnormalities, some of which are “NMO-typical” with localization in aquaporin 4 (AQP4)–rich circumventricular and periaqueductal regions.1 Although uncommon in adult patients, symptomatic brain involvement occurs in approximately 50% of NMO–immunoglobulin G (IgG) seropositive children. Here we report the clinical characteristics, type, and frequency of hydrocephalus in NMOSD.

Imaging the Visual Pathway in Neuromyelitis Optica

Directory of Open Access Journals (Sweden)

Caspar F. Pfueller

2011-01-01

Full Text Available The focus of this paper is to summarize the current knowledge on visual pathway damage in neuromyelitis optica (NMO assessed by magnetic resonance imaging (MRI and optical coherence tomography (OCT.

Aquaporin-4 serostatus does not predict response to immunotherapy in neuromyelitis optica spectrum disorders.

Science.gov (United States)

Mealy, Maureen A; Kim, Su-Hyun; Schmidt, Felix; López, Reydmar; Jimenez Arango, Jorge A; Paul, Friedemann; Wingerchuk, Dean M; Greenberg, Benjamin M; Kim, Ho Jin; Levy, Michael

2017-08-01

Debate exists about whether neuromyelitis optica spectrum disorder seronegative disease represents the same immune-mediated attack on astrocytic aquaporin-4 as in seropositive disease. We investigated whether response to common treatments for neuromyelitis optica spectrum disorder differed by serostatus, as assessed by change in annualized relapse rate. We performed a multicenter retrospective analysis of 245 patients with neuromyelitis optica spectrum disorder who were treated with either rituximab or mycophenolate mofetil as their first-line immunosuppressive treatment for disease prevention. Patients were followed for a minimum of 6 months following treatment initiation. In those started on rituximab, the pre-treatment annualized relapse rates for seropositive and seronegative patients were 1.81 and 1.93, respectively. On-treatment annualized relapse rates significantly declined to 0.32 (seropositive; p optica spectrum disorder patients, treatment was effective regardless of serostatus. This suggests that treatment should not differ when considering these treatments.

Optics study of liquid scintillation counting systems; Estudio de la Optica en sistemas de medida por centelle liquido

Energy Technology Data Exchange (ETDEWEB)

Duran Ramiro, M. T.; Garcia-Torano, E.

2005-07-01

Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

Movement disorders in multiple sclerosis and neuromyelitis optica: A clinical marker of neurological disability.

Science.gov (United States)

Candeias da Silva, Carolina; Bichuetti, Denis Bernardi; Azevedo Silva, Sonia Maria Cesar de; Ferraz, Henrique Ballalai; Oliveira, Enedina Maria Lobato de; Borges, Vanderci

2018-03-03

Movement disorders are not rare in demyelinating diseases but there are few studies comparing their frequency between multiple sclerosis and neuromyelitis optica spectrum disorder. Our aim was to determine the frequency and the related features of movement disorders in a cohort of patients with multiple sclerosis and neuromyelitis optica spectrum disorder. It is a cross-sectional study of patients with multiple sclerosis and neuromyelitis optica spectrum disorder. Patients were evaluated by a movement disorder specialist. Data from a personal interview and neurological examination were collected. Fahn-Tolosa-Marin tremor rating scale was used for tremor evaluation. Health-related quality of life was assessed using EuroQol instrument. Two hundred fifty-three patients were included (mean [SD] age, 40 [12] years; 74.3% female; median [IQR] EDSS score 2.5 [1.0-6.0]); 26% presented with movement disorders. Paroxysmal dystonia (n = 32) and tremor (n = 27) were the most common movement disorders. Patients with multiple sclerosis and low Expanded Disability Status Scale score (below 4.0) have fewer movement disorders than patients with neuromyelitis optica spectrum disorder. The diagnosis of neuromyelitis optica spectrum disorder was strongly associated with paroxysmal dystonia (OR = 22.07, 95% CI = 2.56-189.78; p = 0.005). Patients with multiple sclerosis and patients without movement disorders have a slightly better quality of life. Paroxysmal dystonia was the most common movement disorder in demyelinating diseases and strongly associated with neuromyelitis optica spectrum disorder. Copyright © 2018 Elsevier Ltd. All rights reserved.

Suspected bacterial meningomyelitis: The first presenting clinical feature of neuromyelitis optica spectrum disorder.

Science.gov (United States)

Li, Xiang; Lin, Jie; Pan, Sipei; Weng, Yiyun; Li, Jia; Zhang, Xu; Xia, Junhui; Tong, Qiaowen

2017-08-15

A rare case of neuromyelitis optica spectrum disorder, suspected to be bacterial meningomyelitis as the initial manifestation, is reported. The patient presented with initial symptoms of meningomyelitis and fever. Cerebrospinal fluid analysis revealed pleocytosis (1280×10 6 /L [98% lymphocytes]) and glucose level of 1.8mmol/L. Magnetic resonance imaging revealed >3 vertebral, longitudinally extensive transverse myelitis and area postrema lesions. Right optic neuritis was experienced 20months after the first attack. Serum anti-aquaporin-4 antibody was positive, and a diagnosis of neuromyelitis optica spectrum disorder was made, supporting the hypothesis that the pathogenesis of neuromyelitis optica is triggered by infection. Copyright © 2017. Published by Elsevier B.V.

Transverse myelitis associated with an itchy rash and hyperckemia: neuromyelitis optica associated with dermatitis herpetiformis.

Science.gov (United States)

Iyer, Anand; Rathnasabapathi, Devipriya; Elsone, Liene; Mutch, Kerry; Terlizzo, Monica; Footitt, David; Jacob, Anu

2014-05-01

Neuromyelitis optica is associated with severe neurodisability if not recognized and treated promptly. Several autoimmune disorders are associated with this condition and may vary in their presentation. It is essential that clinicians are aware of the uncommon presenting features of neuromyelitis optica and associated autoimmune conditions. A 53-year-old woman presented with nausea and vomiting and was noted to have an asymptomatic elevated creatinine kinase level, which improved with conservative management. She had a history of iron-deficiency anemia due to long-standing celiac disease that was managed with a gluten-free diet. She then presented with recurrent transverse myelitis and a vesicobullous rash over her arms and feet that was pruritic and excoriating. Skin biopsy results confirmed a clinical diagnosis of dermatitis herpetiformis and antibody test findings against aquaporin-4 were positive, leading to a diagnosis of neuromyelitis optica spectrum disorder. She was treated with methylprednisolone sodium succinate, plasma exchange, and azathioprine and has remained in remission. This report highlights the association of neuromyelitis optica with dermatitis herpetiformis, which can present even without clinical features of celiac disease. Nausea, vomiting, and asymptomatic hyperCKemia should be recognized as rare presenting features of neuromyelitis optica.

Olfactory dysfunction in neuromyelitis optica spectrum disorders

NARCIS (Netherlands)

Zhang, L.J.; Zhao, N.; Fu, Y.; Zhang, D.Q.; Wang, J.; Qin, W.; Zhang, N.N.N.; Wood, K.; Liu, Y.; Yu, C.S.; Shi, F.D.; Yang, L.

2015-01-01

Few data were available for the understanding of olfactory function in neuromyelitis optica spectrum disorders (NMOSDs). The aims of our study were to investigate the incidence of olfactory dysfunction and characterize olfactory structures, using MRI, in patients with NMOSDs. Olfactory function was

Neuro-ophthalmic manifestation of neuromyelitis optica spectrum disorders

Directory of Open Access Journals (Sweden)

Xiao-jun ZHANG

2014-10-01

Full Text Available Neuromyelitis optica spectrum disorders (NMOSDs include classic neuromyelitis optica (NMO, opticospinal multiple sclerosis (OSMS, limited form of NMO and isolated optic neuritis or myelitis accompanied by either systemic autoimmune diseases or typical MRI findings of NMO. The common neuro-ophthalmic features of NMOSDs include simultaneous or consecutive bilateral optic neuritis, more commonly seen optic disk edema and surrounding exudate, poor visual recovery, steroid responsiveness and dependency. Combined with serum aquaporin 4 (AQP4 antibody and brain MRI examination, these clinical features can be helpful to the early differential diagnosis between NMOSDs and MS. Some types of eye movement abnormalities have been reported in patients with NMOSDs, but further investigation needs to be done before the specificity of these features are confirmed. doi: 10.3969/j.issn.1672-6731.2014.10.003

Serological prevalence of celiac disease in Brazilian population of multiple sclerosis, neuromyelitis optica and myelitis.

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de Oliveira, Pérola; de Carvalho, Daniel Rocha; Brandi, Ivar Viana; Pratesi, Riccardo

2016-09-01

Comorbidity of celiac disease with demyelinating diseases of the central nervous system has been reported since the 1960s. The objective of this study was to determine the serological prevalence of celiac disease in the largest series of patients diagnosed with multiple sclerosis, neuromyelitis optica, or myelitis. A prevalence study was conducted with patients evaluated at Sarah Network of Rehabilitation Hospitals between March 2012 and September 2013. They were previously diagnosed with multiple sclerosis, neuromyelitis optica, or idiopathic myelitis. The serum levels of antibodies against tissue transglutaminase and endomysium were assessed. Of the 379 patients evaluated, 249 (65.70%) were diagnosed with multiple sclerosis, 37 (9.56%) with neuromyelitis optica, and 96 (24.54%) with idiopathic myelitis. Two patients (0.53%), one with multiple sclerosis and other with myelitis, tested positive for both antibodies. Our study do not confirm the relationship between celiac serological antibodies with multiple sclerosis, neuromyelitis optica and inflammatory myelitis of an unknown etiology. Copyright © 2016 Elsevier B.V. All rights reserved.

Features of anti-aquaporin 4 antibody-seropositive Chinese patients with neuromyelitis optica spectrum optic neuritis.

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Li, Hongyang; Wang, Yanling; Xu, Quangang; Zhang, Aidi; Zhou, Huanfen; Zhao, Shuo; Kang, Hao; Peng, Chunxia; Cao, Shanshan; Wei, Shihui

2015-10-01

The detection of anti-aquaporin-4 autoantibody (AQP-4 Ab) is crucial to detect patients who will develop neuromyelitis optica (NMO); however, there are few studies on the AQP-4 Ab serostatus of patients with neuromyelitis optica spectrum ON. We analyzed the clinical and paraclinical features of neuromyelitis optica spectrum ON patients in China according to the patients' AQP4-Ab serostatus. 125 patients with recurrent and bilateral ON with simultaneous attacks were divided into AQP-4 Ab-seropositive and -seronegative groups. Demographic, clinical, serum autoantibody data, connective tissue disorders (CTDs), visual performance were compared. A Visual Acuity (VA) of less than 0.1 during acute ON attacks occurred more frequently in the seropositive group (p = 0.023); however, there was not a significant difference between groups on VA recovery after the first attack. The seropositive group experienced the worst outcome during the last attack (p = 0.017). Other co-existing autoimmunity antibodies (p optica spectrum ON.

Neuromyelitis optica (NMO) - an autoimmune disease of the central nervous system (CNS)

DEFF Research Database (Denmark)

Asgari, N; Owens, T; Frøkiaer, J

2010-01-01

Asgari N, Owens T, Frøkiaer J, Stenager E, Lillevang ST, Kyvik KO. Neuromyelitis optica (NMO) - an autoimmune disease of the central nervous system (CNS).
Acta Neurol Scand: DOI: 10.1111/j.1600-0404.2010.01416.x.
© 2010 John Wiley & Sons A/S. In the past 10 years, neuromyelitis optica (NMO) has...... or by intrathecal administration to naive mice. NMO may be characterized as a channelopathy of the central nervous system with autoimmune characteristics....

Neuromyelitis optica with linear enhancement of corpus callosum in brain magnetic resonance imaging with contrast: a case report.

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Sahraian, Mohammad Ali; Moghadasi, Abdorreza Naser; Owji, Mahsa; Naghshineh, Hoda; Minagar, Alireza

2015-06-10

Neuromyelitis optica is a demyelinating disease of the central nervous system with various patterns of brain lesions. Corpus callosum may be involved in both multiple sclerosis and neuromyelitis optica. Previous case reports have demonstrated that callosal lesions in neuromyelitis optica are usually large and edematous and have a heterogeneous intensity showing a "marbled pattern" in the acute phase. Their size and intensity may reduce with time or disappear in the chronic stages. In this report, we describe a case of a 25-year-old Caucasian man with neuromyelitis optica who presented clinically with optic neuritis and myelitis. His brain magnetic resonance imaging demonstrated linear enhancement of the corpus callosum. Brain images with contrast agent added also showed linear ependymal layer enhancement of the lateral ventricles, which has been reported in this disease previously. Linear enhancement of corpus callosum in magnetic resonance imaging with contrast agent could help in diagnosing neuromyelitis optica and differentiating it from other demyelinating disease, especially multiple sclerosis.

Immunotherapy of Neuromyelitis Optica

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2013-01-01

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that affects the optic nerves and spinal cord resulting in visual impairment and myelopathy. There is a growing body of evidence that immunotherapeutic agents targeting T and B cell functions, as well as active elimination of proinflammatory molecules from the peripheral blood circulation, can attenuate disease progression. In this review, we discuss the immunotherapeutic options and the treatment strategies in NMO. We also analyze the pathogenic mechanisms of the disease in order to provide recommendations regarding treatments. PMID:24455211

Neuromyelitis optica, atypical hemophagocytic lymphohistiocytosis and heterozygous perforin A91V mutation.

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Palterer, Boaz; Brugnolo, Francesca; Sieni, Elena; Barilaro, Alessandro; Parronchi, Paola

2017-10-15

Neuromyelitis optica is an autoimmune demyelinating inflammatory disease characterized by optic neuritis and myelitis with anti-aquaporin 4 antibodies. Hemophagocytic lymphohistiocytosis is a severe systemic inflammatory syndrome that can present in a genetic primary form or secondarily to infective, neoplastic or autoimmune diseases. Our case discusses the first reported case of atypical late-onset hemophagocytic lymphohistiocytosis in a patient with neuromyelitis optica, with multiple triggering factors and carrying the common A91V hypomorphic perforin mutation, that blurs the distinction between primary and secondary forms. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuromyelitis optica-- en vigtig differentialdiagnose til multipel sklerose

DEFF Research Database (Denmark)

Holbech, Jakob Vormstrup; Falah, Masoud

2009-01-01

Neuromyelitis optica (Devic's disease) is a rare autoimmune neuroinflammatory disease. The disease can often be difficult to distinguish from multiple sclerosis. It is important to be familiar with the disease because of the risk of rapid progression to disability or even death. We describe a 15...

Seronegative neuromyelitis optica after cardiac transplantation.

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Kim, Elecia; Van Vrancken, Michael; Shaji, Mohamed; Mir, Osman; Spak, Cedric W; Gupta, Manu; Shamim, Sadat A

2016-01-01

We report a case of a 42-year-old man who presented with progressive weakness and blindness over the course of several months and met criteria for seronegative neuromyelitis optica. This presentation was in the setting of immunosuppression following cardiac transplant. No infectious causes were found within the neuroaxis, and he ultimately died with complete blindness, quadriplegia, and respiratory failure attributed to panmyelitis and brain stem inflammation despite aggressive therapies.

Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators

International Nuclear Information System (INIS)

Archambault, Louis; Arsenault, Jean; Gingras, Luc; Sam Beddar, A.; Roy, Rene; Beaulieu, Luc

2005-01-01

Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter

EFNS guidelines on diagnosis and management of neuromyelitis optica

DEFF Research Database (Denmark)

Sellner, J; Boggild, M; Clanet, M

2010-01-01

Neuromyelitis optica (NMO) or Devic's disease is a rare inflammatory and demyelinating autoimmune disorder of the central nervous system (CNS) characterized by recurrent attacks of optic neuritis (ON) and longitudinally extensive transverse myelitis (LETM), which is distinct from multiple sclerosis...

EFNS guidelines on diagnosis and management of neuromyelitis optica

NARCIS (Netherlands)

Sellner, J.; Boggild, M.; Clanet, M.; Hintzen, R.Q.; Illes, Z.; Montalban, X.; Du Pasquier, R.A.; Polman, C.H.; Sorensen, P.S.; Hemmer, B.

2010-01-01

Background and purpose: Neuromyelitis optica (NMO) or Devic's disease is a rare inflammatory and demyelinating autoimmune disorder of the central nervous system (CNS) characterized by recurrent attacks of optic neuritis (ON) and longitudinally extensive transverse myelitis (LETM), which is distinct

[Topics of neuromyelitis optica].

Science.gov (United States)

Miyamoto, Katsuichi

2014-01-01

Neuromyelitis optica (NMO) has been revealed the difference in the pathology of multiple sclerosis since the anti-aquaporin 4 (AQP4) antibody associated with NMO has been found. The clinical epidemiological study has been reviewed, NMO-related patient number in Japan is estimated to be about 4400 people. The antibody-positive patients against myelin-oligodendrocyte glycoprotein (MOG) are present in anti-AQP4 antibody-negative NMO patients. These patients have a characteristic with high frequency of optic neuritis and good response to therapy. In addition, by research in recent years, a new treatment such as anti-IL-6 therapy or anti-complement therapy has been attempted to NMO.

Structural MRI substrates of cognitive impairment in neuromyelitis optica

NARCIS (Netherlands)

Liu, Y.; Fu, Y.; Schoonheim, M.M.; Zhang, N.; Fan, M.L.; Su, L.; Shen, Y.; Yan, Y.P.; Yang, L.; Wang, Q.H.; Zhang, N.N.N.; Yu, C.S.; Barkhof, F.; Shi, F.D.

2015-01-01

Objective: To identify the clinical and structural MRI markers for predicting cognitive impairment (CI) in patients with neuromyelitis optica (NMO). Methods: Fifty-four patients with NMO and 27 healthy controls underwent extensive neuropsychological testing and multimodal 3.0T MRI. The patient group

Multisystem involvement in neuromyelitis optica

Directory of Open Access Journals (Sweden)

Megan M Langille

2015-01-01

Full Text Available We describe a case of pediatric neuromyelitis optica (NMO with muscle and lung involvement in addition to central nervous system disease. Our patient initially presented with features of area postrema syndrome, then subsequently with optic neuritis. The patient also had recurrent hyperCKemia that responded to corticosteroids. Finally, axillary and hilar adenopathy with pulmonary consolidation were noted as well and responded to immunomodulation. Our case highlights multisystem involvement in NMO including non-infectious pulmonary findings which have not been described in the pediatric population previously.

Characterization of neuromyelitis optica and neuromyelitis optica spectrum disorder patients with a late onset.

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Collongues, N; Marignier, R; Jacob, A; Leite, M I; Siva, A; Paul, F; Zephir, H; Akman-Demir, G; Elsone, L; Jarius, S; Papeix, C; Mutch, K; Saip, S; Wildemann, B; Kitley, J; Karabudak, R; Aktas, O; Kuscu, D; Altintas, A; Palace, J; Confavreux, C; De Seze, J

2014-07-01

Few data are available for patients with a late onset (≥ 50 years) of neuromyelitis optica (LONMO) or neuromyelitis optica spectrum disease (LONMOSD), defined by an optic neuritis/longitudinally extensive transverse myelitis with aquaporin-4 antibodies (AQP4-Ab). To characterize LONMO and LONMOSD, and to analyze their predictive factors of disability and death. We identified 430 patients from four cohorts of NMO/NMOSD in France, Germany, Turkey and UK. We extracted the late onset patients and analyzed them for predictive factors of disability and death, using the Cox proportional model. We followed up on 63 patients with LONMO and 45 with LONMOSD during a mean of 4.6 years. This LONMO/LONMOSD cohort was mainly of Caucasian origin (93%), women (80%), seropositive for AQP4-Ab (85%) and from 50 to 82.5 years of age at onset. No progressive course was noted. At last follow-up, the median Expanded Disability Status Scale (EDSS) scores were 5.5 and 6 in the LONMO and LONMOSD groups, respectively. Outcome was mainly characterized by motor disability and relatively good visual function. At last follow-up, 14 patients had died, including seven (50%) due to acute myelitis and six (43%) because of opportunistic infections. The EDSS 4 score was independently predicted by an older age at onset, as a continuous variable after 50 years of age. Death was predicted by two independent factors: an older age at onset and a high annualized relapse rate. LONMO/LONMOSD is particularly severe, with a high rate of motor impairment and death. © The Author(s) 2013.

Idiopathic Transverse Myelitis and Neuromyelitis Optica: Clinical Profiles, Pathophysiology and Therapeutic Choices

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Awad, Amer; Stüve, Olaf

2011-01-01

Transverse myelitis is a focal inflammatory disorder of the spinal cord which may arise due to different etiologies. Transverse myelitis may be idiopathic or related/secondary to other diseases including infections, connective tissue disorders and other autoimmune diseases. It may be also associated with optic neuritis (neuromyelitis optica), which may precede transverse myelitis. In this manuscript we review the pathophysiology of different types of transverse myelitis and neuromyelitis optica and discuss diagnostic criteria for idiopathic transverse myelitis and risk of development of multiple sclerosis after an episode of transverse myelitis. We also discuss treatment options including corticosteroids, immunosuppressives and monoclonal antibodies, plasma exchange and intravenous immunoglobulins. PMID:22379456

Seronegative neuromyelitis optica spectrum disorder patients diagnosed using new diagnostic criteria.

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Uzawa, Akiyuki; Mori, Masahiro; Uchida, Tomohiko; Masuda, Hiroki; Ohtani, Ryohei; Kuwabara, Satoshi

2016-09-01

Recently, new diagnostic criteria for neuromyelitis optica spectrum disorders (NMOSD) were published. Our primary aim was to evaluate the usefulness of the new diagnostic criteria in anti-aquaporin 4 (AQP4) antibody-negative cases. Consecutive 471 patients whose anti-AQP4 antibody was measured at Chiba University were reviewed. Four anti-AQP4 antibody negative-patients, who fulfilled the new diagnostic criteria for NMOSD but not 2006 diagnostic criteria for neuromyelitis optica (NMO), were identified. They showed high cerebrospinal fluid interleukin-6 and glial fibrillary acidic protein levels, an absence of oligoclonal bands and/or cloud-like enhancement on magnetic resonance imaging, which are compatible findings for NMO. The new diagnostic criteria are clinically useful in seronegative NMOSD. © The Author(s), 2015.

Neuromyelitis Optica: An Often Forgotten Cause of Intractable Nausea and Vomiting

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Chijioke Enweluzo

2013-07-01

Full Text Available Neuromyelitis optica, also known as Devic's disease, is a rare autoimmune disorder in which a patient's immune system affects the optic nerves and the spinal cord, leading to loss of vision and spinal cord dysfunction. We present our experience with a 38-year-old female who presented to our facility with complaints of intractable nausea and vomiting. After extensive evaluation, she was found to have neuromyelitis optica. Her symptoms completely resolved following institution of appropriate therapy. She made a significant recovery and has since been placed on chronic immunosuppressive therapy. Through this article we hope to bring attention to a significant cause of intractable nausea and vomiting that may often be forgotten in general medicine or gastroenterology services.

Systemic manifestations and pathogenesis exploration of neuromyelitis optica spectrum disorders

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Hong JIANG

2014-09-01

Full Text Available Objective To investigate the immunological abnormalities beyond central nervous system (CNS associated with neuromyelitis optica spectrum disorders (NMOSDs.  Methods Clinical data of 56 patients with NMOSDs from January 2010 to December 2013 enrolled in Department of Neurology at Peking University People's Hospital were analyzed retrospectively. All patients were divided into 2 groups: neuromyelitis optica (N = 33 and non-neuromyelitis optica (N = 23. Each patient underwent detailed physical examination including internal medicine and nervous system. Records of complicated autoimmune diseases as well as scoring of Expanded Disability Status Scale (EDSS were used to evaluate disease severity. Part of patients received detection of multiple immunological indicators.  Results In all patients with NMOSDs, there were 3 cases with Hashimoto thyroiditis, one case with systemic lupus erythematosus (SLE and Sjögren's syndrome (SS, asthma, hyperthyroidism, rheumatoid arthritis and iridocyclitis, respectively. In patients whose immunological indices were available, the first three abnormal immunological changes were abnormal thyroid function (10/17, positive anti-nuclear antibody (14/28 and positive complement 3 (8/19. In addition, NMOSDs got worsen in 2 cases after delivery.  Conclusions NMOSDs coexist with many kinds of autoimmune diseases and multiple autoantibodies. The above-mentioned autoimmunity may be related to the pathogenesis of NMOSDs. Besides, pregnancy or delivery may aggravate the disease severity of NMOSDs. doi: 10.3969/j.issn.1672-6731.2014.09.009

Severe optic neuritis in a patient with combined neuromyelitis optica spectrum disease and primary Sjögren’s syndrome: a case report

Directory of Open Access Journals (Sweden)

Tan Petrina

2012-11-01

Full Text Available Abstract Introduction Optic neuritis, although uncommon, can be the initial presentation of Sjögren’s syndrome. Coexisting Sjögren’s syndrome has also been reported with neuromyelitis optica spectrum disorder. This case report highlights the association between the two diseases and the importance of rheumatological and neurological evaluations in patients with such diagnoses. Distinction of neuromyelitis optica with coexisting connective tissue disease has both prognostic and therapeutic significance for the patient. Case presentation We report a case of a 56-year-old Chinese woman who presented with bilateral asymmetric visual loss secondary to optic neuritis. She was subsequently found to be seropositive for neuromyelitis optica immunoglobulin G (NMO-IgG (anti-aquaporin-4 antibody and was diagnosed with neuromyelitis optica spectrum disorder. She also fulfilled the international criteria for Sjögren’s syndrome. Despite initial high dose immunosuppressive therapy, she failed to regain vision in one eye. Conclusion Patients presenting with optic neuritis and severe visual loss should be screened for neuromyelitis optica and treated appropriately. Neuromyelitis optica has been associated with systemic autoimmune diseases, in particular Sjögren’s syndrome, and current evidence indicates that they are two distinct entities. We recommend that both diagnoses be considered in cases of optic neuritis with severe visual loss.

Update on neuromyelitis optica: natural history and management

Science.gov (United States)

Jindahra, Panitha; Plant, T

2012-01-01

Neuromyelitis optica or Devic disease is an inflammatory disorder of the central nervous system. It is caused by antibodies that attack aquaporin 4 water channels in the cell membrane of astrocytic foot processes at the blood brain barrier. It can involve the optic nerve, the spinal cord and beyond. Here we review its pathophysiology, clinical features, and therapy. PMID:28539779

Higher frequency of brain abnormalities in neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome.

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Gu, Li-Na; Zhang, Min; Zhu, Hui; Liu, Jing-Yao

2016-10-01

Neuromyelitis optica spectrum disorder often co-exists with primary Sjögren's syndrome. We compared the clinical features of 16 neuromyelitis optica spectrum disorder patients with ( n = 6) or without primary Sjögren's syndrome ( n = 10). All patients underwent extensive clinical, laboratory, and MRI evaluations. There were no statistical differences in demographics or first neurological involvement at onset between neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome. The laboratory findings of cerebrospinal fluid oligoclonal banding, serum C-reactive protein, antinuclear autoantibody, anti-Sjögren's-syndrome-related antigen A antibodies, anti-Sjögren's-syndrome-related antigen B antibodies, and anti-Sm antibodies were significantly higher in patients with primary Sjögren's syndrome than those without. Anti-aquaporin 4 antibodies were detectable in 67% (4/6) of patients with primary Sjögren's syndrome and in 60% (6/10) of patients without primary Sjögren's syndrome. More brain abnormalities were observed in patients without primary Sjögren's syndrome than in those with primary Sjögren's syndrome. Segments lesions (> 3 centrum) were noted in 50% (5/10) of patients without primary Sjögren's syndrome and in 67% (4/6) of patients with primary Sjögren's syndrome. These findings indicate that the clinical characteristics of neuromyelitis optica spectrum disorder patients with and without primary Sjögren's syndrome are similar. However, neuromyelitis optica spectrum disorder patients without primary Sjögren's syndrome have a high frequency of brain abnormalities.

OPTICA: Our Path Together Initiating Cultural Access. Final Report.

Science.gov (United States)

Jackson, Susan, Comp.

This final report describes the activities and outcomes of OPTICA (Our Path Together Initiating Cultural Access) programs. For each program an information sheet indicates the goal, total participation, status of the goal, and activities of the program. Programs included: (1) Hands On: ASL Creative Story Telling, a program that used children's…

Neuromyelitis Optica Spectrum Disorders.

Science.gov (United States)

Akaishi, Tetsuya; Nakashima, Ichiro; Sato, Douglas Kazutoshi; Takahashi, Toshiyuki; Fujihara, Kazuo

2017-05-01

Neuromyelitis optica (NMO) is clinically characterized by severe optic neuritis and transverse myelitis, but recent studies with anti-aquaporin-4-antibody specific to NMO have revealed that the clinical spectrum is wider than previously thought. International consensus diagnostic criteria propose NMO spectrum disorders (NMOSD) as the term to define the entire spectrum including typical NMO, optic neuritis, acute myelitis, brain syndrome, and their combinations. NMOSD is now divided into anti-aquaporin-4-antibody-seropositive NMOSD and -seronegative NMOSD (or unknown serostatus). MR imaging and optical coherence tomography are indispensable in the diagnosis and evaluation of NMOSD. This article reviews the clinical and MR imaging findings of anti-aquaporin-4-antibody-seropositive and anti-myelin oligodendrocyte glycoprotein-antibody-seropositive NMOSD. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuromyelitis optica with clinical and histopathological involvement of the brain.

NARCIS (Netherlands)

Hengstman, G.J.D.; Wesseling, P.; Frenken, C.W.; Jongen, P.J.H.

2007-01-01

Diagnostic criteria for neuromyelitis optica (NMO) state that there should be no active disease outside the optic nerves and spinal cord. However, several cases have been described with symptomatic brain involvement. We describe an autopsy case of a patient with NMO and symptomatic involvement of

Neuromyelitis optica spectrum disorders in Algeria: A preliminary study in the region of Tizi Ouzou.

Science.gov (United States)

Daoudi, Smail; Bouzar, Melissa

2016-03-01

Neuromyelitis optica (NMO) is a disabling inflammatory condition that targets astrocytes in the optic nerves and spinal cord. Recent advances led to the individualization of a set of conditions now referred as NMO spectrum disorder (NMOSD). To describe the prevalence and characteristics of NMO SD in north Algeria. The present study is a retrospective and descriptive work which took place in Nedir Mohamed teaching hospital, Tizi-Ouzou, Algeria. 938 Medical files of patients with CNS inflammatory demyelinating diseases were reviewed then patients with optic neuritis and/or myelitis were preselected. Patients who met the 2015 neuromyelitis optica spectrum disorders criteria were selected and analyzed 08 Patients (3.4%) met the 2015 criteria for neuromyelitis optica spectrum disorders, 3/8 (37.5%) were positive to AQ4-IgG and 5/8 (62.5%) were negative. Mean age of onset was 29 years, female to male ratio was 3:1, cerebral MRI was normal in 75% of cases and longitudinally extensive transverse myelitis was present in 75% of cases. 37/232 Patients (15.9%) were considered at high risk of neuromyelitis optica spectrum disorders The present study suggests that the spectrum of NMO disorders is a rare entity among patients with optic nerve and spinal cord demyelinating lesions in north Algeria. However, the lack of accurate AQ4-IgG test certainly underestimates its real prevalence. Copyright © 2015 Elsevier B.V. All rights reserved.

Diagnosis and management of Neuromyelitis Optica Spectrum Disorder (NMOSD) in Iran

DEFF Research Database (Denmark)

Sahraian, Mohammad Ali; Moghadasi, Abdorreza Naser; Azimi, Amir Reza

2017-01-01

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a relapsing neuro inflammatory disease of the central nervous system that typically presents with optic neuritis or myelitis and may cause severe disability. The diagnostic criteria have been updated and several immunosuppressive agents have been...

Quantifying visual pathway axonal and myelin loss in multiple sclerosis and neuromyelitis optica.

Science.gov (United States)

Manogaran, Praveena; Vavasour, Irene M; Lange, Alex P; Zhao, Yinshan; McMullen, Katrina; Rauscher, Alexander; Carruthers, Robert; Li, David K B; Traboulsee, Anthony L; Kolind, Shannon H

2016-01-01

The optic nerve is frequently injured in multiple sclerosis and neuromyelitis optica, resulting in visual dysfunction, which may be reflected by measures distant from the site of injury. To determine how retinal nerve fiber layer as a measure of axonal health, and macular volume as a measure of neuronal health are related to changes in myelin water fraction in the optic radiations of multiple sclerosis and neuromyelitis optica participants with and without optic neuritis and compared to healthy controls. 12 healthy controls, 42 multiple sclerosis (16 with optic neuritis), and 10 neuromyelitis optica participants (8 with optic neuritis) were included in this study. Optical coherence tomography assessment involved measurements of the segmented macular layers (total macular, ganglion cell layer, inner plexiform layer, and inner nuclear layer volume) and paripapillary retinal nerve fiber layer thickness. The MRI protocol included a 32-echo T2-relaxation GRASE sequence. Average myelin water fraction values were calculated within the optic radiations as a measure of myelin density. Multiple sclerosis and neuromyelitis optica eyes with optic neuritis history had lower retinal nerve fiber layer thickness, total macular, ganglion cell and inner plexiform layer volumes compared to eyes without optic neuritis history and controls. Inner nuclear layer volume increased in multiple sclerosis with optic neuritis history (mean = 0.99 mm(3), SD = 0.06) compared to those without (mean = 0.97 mm(3), SD = 0.06; p = 0.003). Mean myelin water fraction in the optic radiations was significantly lower in demyelinating diseases (neuromyelitis optica: mean = 0.098, SD = 0.01, multiple sclerosis with optic neuritis history: mean = 0.096, SD = 0.01, multiple sclerosis without optic neuritis history: mean = 0.098, SD = 0.02; F3,55 = 3.35, p = 0.03) compared to controls. Positive correlations between MRI and optical coherence tomography measures were also apparent

Use of advanced magnetic resonance imaging techniques in neuromyelitis optica spectrum disorder

NARCIS (Netherlands)

S. Kremer (Stephane); F. Renard (Felix); S. Achard (Sophie); M.A. Lana-Peixoto (Marco A.); J. Palace (Jacqueline); N. Asgari (Nasrin); E.C. Klawiter (Eric C.); S. Tenembaum (Silvia); B. Banwell (Brenda); B.M. Greenberg (Benjamin M.); J.L. Bennett (Jeffrey); M. Levy (Michael); P. Villoslada (Pablo); A. Saiz (Albert Abe); K. Fujihara (Kazuo); K.H. Chan (Koon Ho); S. Schippling (Sven); F. Paul (Friedemann); H.J. Kim (Ho Jin); J. De Seze (Jerome); J.T. Wuerfel (Jens T.); P. Cabre (Philippe); R. Marignier (Romain); T. Tedder (Thomas); E.D. van Pelt - Gravesteijn (Daniëlle); S. Broadley (Simon); T. Chitnis (Tanuja); D. Wingerchuk (Dean); L. Pandit (Lekha); M.I. Leite (M. Isabel); M. Apiwattanakul (Metha); I. Kleiter (Ingo); N. Prayoonwiwat (Naraporn); M. Han (May); K. Hellwig (Kerstin); K. Van Herle (Katja); G. John (Gareth); D.C. Hooper (D. Craig); I. Nakashima (Ichiro); D. Sato (Douglas); M.R. Yeaman (Michael R.); E. Waubant (Emmanuelle); S. Zamvil (Scott); O. Stüve (Olaf); O. Aktas (Orhan); T.J. Smith (Terry J.); A. Jacob (Anu); K. O'Connor (Kevin)

2015-01-01

textabstractBrain parenchymal lesions are frequently observed on conventional magnetic resonance imaging (MRI) scans of patients with neuromyelitis optica (NMO) spectrum disorder, but the specific morphological and temporal patterns distinguishing them unequivocally from lesions caused by other

New onset neuromyelitis optica in a young Nigerian woman with possible antiphospholipid syndrome: a case report

Directory of Open Access Journals (Sweden)

Komolafe Morenikeji A

2008-11-01

Full Text Available Abstract Introduction Devic's neuromyelitis optica is an inflammatory demyelinating disease that targets the optic nerves and spinal cord. It has a worldwide distribution and distinctive features that distinguish it from multiple sclerosis. There has been no previous report of neuromyelitis optica from our practice environment, and we are not aware of any case associated with antiphospholipid syndrome in an African person. Case presentation We report the case of a 28-year-old Nigerian woman who presented with neck pain, paroxysmal tonic spasms, a positive Lhermitte's sign and spastic quadriplegia. She later developed bilateral optic neuritis and had clinical and biochemical features of antiphospholipid syndrome. Her initial magnetic resonance imaging showed a central linear hyperintense focus in the intramedullary portion of C2 to C4. Repeat magnetic resonance imaging after treatment revealed resolution of the signal intensity noticed earlier. Conclusion Neuromyelitis optica should be considered in the differential diagnoses of acute myelopathy in Africans. We also highlight the unusual association with antiphospholipid syndrome. Physicians should screen such patients for autoimmune disorders.

A Rare Case of Neuromyelitis Optica Spectrum Disorder in Patient with Sjogren’s Syndrome

Directory of Open Access Journals (Sweden)

Supat Thongpooswan

2014-01-01

Full Text Available We report a 48-year-old female with the history of Sjogren’s syndrome who presented with 3-week history of tingling, numbness, and shooting back, waist, and bilateral leg pain and numbness in the pelvic region with urinary and bowel incontinence. Physical examination was remarkable for reduced motor power in both lower extremities with spasticity. Sensory deficit was noted at the T6 level. Laboratory investigation revealed elevated ESR and CRP and positive serum antiaquaporin-4 IgG. Thoracic and lumbar magnetic resonance imaging revealed abnormal patchy areas, leptomeningeal enhancement through the thoracic cord extending from T3 through T6 levels, without evidence of cord compression. Impression of neuromyelitis optica spectrum disorder was made and patient was treated with methylprednisolone intravenously followed by tapering oral prednisone. Neurological symptoms gradually improved with resolution of bowel and urinary incontinence. In a patient with Sjogren’s syndrome who presents with neurological complaints, the possibility of neuromyelitis optica or neuromyelitis optica spectrum disorder should be considered. Awareness of the possibility of CNS disease is important due to the serious nature of CNS complications, some of which are treatable with immunosuppressants. Our patient with Sjogren’s syndrome who presented with myelopathy benefited from early recognition and institution of appropriate therapy.

Acquired Demyelinating Syndromes: Focus on Neuromyelitis Optica and childhood-onset Multiple Sclerosis

NARCIS (Netherlands)

E.D. van Pelt - Gravesteijn (Daniëlle)

2016-01-01

markdownabstractAcquired demyelinating syndromes (ADS) cover a broad spectrum of central nervous system (CNS) inflammatory demyelinating syndromes, of which multiple sclerosis (MS) is the most common subtype. This thesis focuses on two relatively rare clinical subtypes of ADS: neuromyelitis optica

The history of neuromyelitis optica

Science.gov (United States)

2013-01-01

The discovery of a novel serum autoantibody (termed NMO-IgG or AQP4-Ab) in a subset of patients in 2004 has revived interest in neuromyelitis optica (NMO). While the history of classical multiple sclerosis has been extensively studied, only little is known about the history of NMO. In the present article, we provide a comprehensive review of the early history of this rare but intriguing syndrome. We trace the origins of the concept of NMO in the 19th century medical literature and follow its evolution throughout the 20th and into the 21st century. Finally, we discuss recent proposals to revise the concept of NMO and explain why there is indeed a need for a more systematic and descriptive nomenclature. PMID:23320783

Neuromyelitis optica and neuromyelitis optica spectrum disorder: Natural history and long-term outcome, an Indian experience

Directory of Open Access Journals (Sweden)

Sujit Abajirao Jagtap

2015-01-01

Full Text Available Background: Neuromyelitis optica (NMO has evolved from devic′s classical description to a broader disease spectrum, from monophasic illness to a polyphasic illness with multiple recurrences, disease confined to optic nerve and spinal cord to now brain stem, cerebrum and even endocrinopathy due to hypothalamic involvement. Objectives: To report, the epidemiological characteristics, clinical presentations, recurrence rate, treatment and response to therapy in 26 patients with NMO and NMO spectrum disorder among the Indian population. Methods: We performed observational, retrospective analysis of our prospectively maintained data base of patients with NMO, longitudinally extensive transverse myelitis during the period of January 2003-December 2012 who satisfied the national multiple sclerosis society (NMSS task force criteria for diagnosis of NMO and NMO spectrum disorder. Results: There were 26 patients (female: male, 21:5, the mean age of onset of symptom was 27 years (range 9-58, standard deviation = 12. Twenty-one patients (80% fulfilled NMSS criteria for NMO while rest 5 patients (20% were considered as NMO spectrum disorder. Seven patients (27% had a monophasic illness, 19 patients (73% had a polyphasic illness with recurrences. The Median recurrence rate was 4/patient in the polyphasic group. 13 (50% patient were tested for aquaporin 4 antibody, 8 (61% were positive while 5 patients (39% were negative. All patients received intravenous methyl prednisolone, 9 patients (35% required further treatment for acute illness in view of unresponsiveness to steroids. Thirteen patients (50% received disease-modifying agents for recurrences. Mean duration of follow-up was 5 years. All patients had a good outcome (modified Rankin scale, <3 except one who had poor visual recovery. Conclusion: Neuromyelitis optica/NMO spectrum disorder is demyelinating disorder with female predominance, polyphasic course, myelitis being most common event although brain

Iron and Non-Iron-Related Characteristics of Multiple Sclerosis and Neuromyelitis Optica Lesions at 7T MRI.

Science.gov (United States)

Chawla, S; Kister, I; Wuerfel, J; Brisset, J-C; Liu, S; Sinnecker, T; Dusek, P; Haacke, E M; Paul, F; Ge, Y

2016-07-01

Characterization of iron deposition associated with demyelinating lesions of multiple sclerosis and neuromyelitis optica has not been well studied. Our aim was to investigate the potential of ultra-high-field MR imaging to distinguish MS from neuromyelitis optica and to characterize tissue injury associated with iron pathology within lesions. Twenty-one patients with MS and 21 patients with neuromyelitis optica underwent 7T high-resolution 2D-gradient-echo-T2* and 3D-susceptibility-weighted imaging. An in-house-developed algorithm was used to reconstruct quantitative susceptibility mapping from SWI. Lesions were classified as "iron-laden" if they demonstrated hypointensity on gradient-echo-T2*-weighted images and/or SWI and hyperintensity on quantitative susceptibility mapping. Lesions were considered "non-iron-laden" if they were hyperintense on gradient-echo-T2* and isointense or hyperintense on quantitative susceptibility mapping. Of 21 patients with MS, 19 (90.5%) demonstrated at least 1 quantitative susceptibility mapping-hyperintense lesion, and 11/21 (52.4%) had iron-laden lesions. No quantitative susceptibility mapping-hyperintense or iron-laden lesions were observed in any patients with neuromyelitis optica. Iron-laden and non-iron-laden lesions could each be further characterized into 2 distinct patterns based on lesion signal and morphology on gradient-echo-T2*/SWI and quantitative susceptibility mapping. In MS, most lesions (n = 262, 75.9% of all lesions) were hyperintense on gradient-echo T2* and isointense on quantitative susceptibility mapping (pattern A), while a small minority (n = 26, 7.5% of all lesions) were hyperintense on both gradient-echo-T2* and quantitative susceptibility mapping (pattern B). Iron-laden lesions (n = 57, 16.5% of all lesions) were further classified as nodular (n = 22, 6.4%, pattern C) or ringlike (n = 35, 10.1%, pattern D). Ultra-high-field MR imaging may be useful in distinguishing MS from neuromyelitis optica. Different

Painful tonic spasms and brainstem involvement in a patient with neuromyelitis optica spectrum disorder.

Science.gov (United States)

Roman-Filip, Corina; Ungureanu, Aurelian; Cernuşcă-Miţaru, Mihaela

2016-01-01

Neuromyelitis optica (NMO) is an inflammatory-demyelinating disease of the central nervous system classically characterized by optic neuritis and severe myelitis. New diagnostic criteria defined neuromyelitis optica spectrum disorder as limited forms of NMO or diverse neurologic presentations in the presence of specific antiaquaporin-4 antibodies. We report the case of a 57-year-old woman admitted in our department for recurrent attacks of optic neuritis, tetraparesis with severe painful tonic spasms of the left limbs and brainstem involvement. Painful tonic spasms have been described as movement disorders associated with multiple sclerosis, but a growing number of reports describe them in cases of NMO. Copyright © 2015 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Scintillation response of organic and inorganic scintillators

CERN Document Server

Papadopoulos, L M

1999-01-01

A method to evaluate the scintillation response of organic and inorganic scintillators to different heavy ionizing particles is suggested. A function describing the rate of the energy consumed as fluorescence emission is derived, i.e., the differential response with respect to time. This function is then integrated for each ion and scintillator (anthracene, stilbene and CsI(Tl)) to determine scintillation response. The resulting scintillation responses are compared to the previously reported measured responses. Agreement to within 2.5% is observed when these data are normalized to each other. In addition, conclusions regarding the quenching parameter kB dependence on the type of the particle and the computed values of kB for certain ions are included. (author)

Neuromyelitis Optica (Devic's Syndrome): an Appraisal.

Science.gov (United States)

Crout, Teresa M; Parks, Laura P; Majithia, Vikas

2016-08-01

Neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD), previously known as Devic's syndrome, are a group of inflammatory disorders of the central nervous system (CNS) characterized by severe, immune-mediated demyelination and axonal damage, predominantly targeting optic nerves and the spinal cord typically associated with a disease-specific serum NMO-IgG antibody that selectively binds aquaporin-4 (AQP4). The classic and best-defined features of NMOSD include acute attacks of bilateral or rapidly sequential optic neuritis (leading to visual loss) or transverse myelitis (often causing limb weakness and bladder dysfunction) or both with a typically relapsing course. The diagnosis of NMO/NMOSD requires a consistent history and examination with typical clinical presentations, findings on spinal cord neuroimaging with MRI, cerebrospinal fluid analysis along with determination of AQP4-IgG serum autoantibody status, and exclusion of other disorders. Two major advances in this field has been the development of diagnostic criteria and treatment recommendations. Consensus diagnostic criteria have been established and were recently revised and published in 2015, enhancing the ability to make a diagnosis and appropriately evaluate these disorders. Expert recommendations and uncontrolled trials form the basis of treatment guidelines. All patients with suspected NMOSD should be treated for acute attacks as soon as possible with high-dose intravenous methylprednisolone -1 gram daily for three to five consecutive days and in some cases, plasma exchange should be used. It is recommended that every patient with NMOSD be started on an immunosuppressive agent, such as, azathioprine, methotrexate, or mycophenolate and in some cases, rituximab, soon after the acute attack and usually be treated for about 5 years after the attack. These advances have helped improve the prognosis and outcome in these disorders.

Association between TPMT*3C and decreased thiopurine S-methyltransferase activity in patients with neuromyelitis optica spectrum disorders in China.

Science.gov (United States)

Gong, Xiaoqing; Mei, Shenghui; Li, Xindi; Li, Xingang; Zhou, Heng; Liu, Yonghong; Zhou, Anna; Yang, Li; Zhao, Zhigang; Zhang, Xinghu

2018-06-01

Thiopurines are effective drugs in treating neuromyelitis optica spectrum disorders and other diseases. Thiopurines' toxicity is mainly imputed to thiopurine S-methyltransferase activity. In Chinese population, the most common and important variation of thiopurine S-methyltransferase is TPMT*3C (rs1142345). This study aims to reveal the association between thiopurine S-methyltransferase activity and genetic polymorphisms of thiopurine S-methyltransferase in patients with neuromyelitis optica spectrum disorders in China. A liquid chromatography tandem mass/mass method was used to evaluate the thiopurine S-methyltransferase activity by using 6-mercapthioprine as the substrate in human erythrocyte haemolysate via 1 h incubation at 37 °C to form its methylated product 6-methylmercaptopurine. The amount of 6-methylmercaptopurine was adjusted by haematocrit and normalized to 8 × 10 8 erythrocytes. The selected polymorphisms of thiopurine S-methyltransferase were identified using MassARRAY system (Sequenom) and multiple SNaPshot technique. In 69 patients with neuromyelitis optica spectrum disorders, thiopurine S-methyltransferase activity was 80.29-154.53 (127.51 ± 16.83) pmol/h/8 × 10 8 erythrocytes. TPMT*3C (rs1142345) was associated with lower thiopurine S-methyltransferase activity (BETA = -25.37, P = 0.011). Other selected variants were not associated with thiopurine S-methyltransferase activity. TPMT*3C affects TPMT activity in Chinese patients with neuromyelitis optica spectrum disorders. Further studies are warranted to confirm the results. TPRs = thiopurines; NMOSD = neuromyelitis optica spectrum disorders; TPMT = thiopurine S-methyltransferase; LC-MS/MS = liquid chromatography tandem mass/mass; 6-MMP = 6-methylmercaptopurine; IS = internal standard; SNP = single nucleotide polymorphism; MAF = minor allele frequency; HWE = Hardy-Weinberg equilibrium; BETA = regression coefficients; UTR-3 = untranslated region 3.

The Urine Proteome Profile Is Different in Neuromyelitis Optica Compared to Multiple Sclerosis

DEFF Research Database (Denmark)

Nielsen, Helle H; Beck, Hans C; Kristensen, Lars P

2015-01-01

OBJECTIVES: Inflammatory demyelinating diseases of the CNS comprise a broad spectrum of diseases like neuromyelitis optica (NMO), NMO spectrum disorders (NMO-SD) and multiple sclerosis (MS). Despite clear classification criteria, differentiation can be difficult. We hypothesized that the urine...

Influence of female sex and fertile age on neuromyelitis optica spectrum disorders.

Science.gov (United States)

Borisow, Nadja; Kleiter, Ingo; Gahlen, Anna; Fischer, Katrin; Wernecke, Klaus-Dieter; Pache, Florence; Ruprecht, Klemens; Havla, Joachim; Krumbholz, Markus; Kümpfel, Tania; Aktas, Orhan; Ringelstein, Marius; Geis, Christian; Kleinschnitz, Christoph; Berthele, Achim; Hemmer, Bernhard; Angstwurm, Klemens; Weissert, Robert; Stellmann, Jan-Patrick; Schuster, Simon; Stangel, Martin; Lauda, Florian; Tumani, Hayrettin; Mayer, Christoph; Zeltner, Lena; Ziemann, Ulf; Linker, Ralf A; Schwab, Matthias; Marziniak, Martin; Then Bergh, Florian; Hofstadt-van Oy, Ulrich; Neuhaus, Oliver; Winkelmann, Alexander; Marouf, Wael; Rückriem, Lioba; Faiss, Jürgen; Wildemann, Brigitte; Paul, Friedemann; Jarius, Sven; Trebst, Corinna; Hellwig, Kerstin

2017-07-01

Gender and age at onset are important epidemiological factors influencing prevalence, clinical presentation, and treatment response in autoimmune diseases. To evaluate the impact of female sex and fertile age on aquaporin-4-antibody (AQP4-ab) status, attack localization, and response to attack treatment in patients with neuromyelitis optica (NMO) and its spectrum disorders (neuromyelitis optica spectrum disorder (NMOSD)). Female-to-male ratios, diagnosis at last visit (NMO vs NMOSD), attack localization, attack treatment, and outcome were compared according to sex and age at disease or attack onset. A total of 186 NMO/SD patients (82% female) were included. In AQP4-ab-positive patients, female predominance was most pronounced during fertile age (female-to-male ratio 23:1). Female patients were more likely to be positive for AQP4-abs (92% vs 55%; p 40 years. Our data suggest an influence of sex and age on susceptibility to AQP4-ab-positive NMO/SD. Genetic and hormonal factors might contribute to pathophysiology of NMO/SD.

Scintillation properties of quantum-dot doped styrene based plastic scintillators

International Nuclear Information System (INIS)

Park, J.M.; Kim, H.J.; Hwang, Y.S.; Kim, D.H.; Park, H.W.

2014-01-01

We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator

Scintillation properties of quantum-dot doped styrene based plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Park, J.M.; Kim, H.J., E-mail: hongjooknu@gmail.com; Hwang, Y.S.; Kim, D.H.; Park, H.W.

2014-02-15

We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator.

Scintillator structures

International Nuclear Information System (INIS)

Cusano, D.A.; Prener, J.S.

1978-01-01

Distributed phosphor scintillator structures providing superior optical coupling to photoelectrically responsive devices together with methods for fabricating said scintillator structures are disclosed. In accordance with one embodiment of the invention relating to scintillator structures, the phosphor is distributed in a 'layered' fashion with certain layers being optically transparent so that the visible wavelength output of the scintillator is better directed to detecting devices. In accordance with another embodiment of the invention relating to scintillator structures, the phosphor is distributed throughout a transparent matrix in a continuous fashion whereby emitted light is more readily transmitted to a photodetector. Methods for fabricating said distributed phosphor scintillator structures are also disclosed. (Auth.)

Liquid scintillation solutions

International Nuclear Information System (INIS)

Long, E.C.

1976-01-01

The liquid scintillation solution described includes a mixture of: a liquid scintillation solvent, a primary scintillation solute, a secondary scintillation solute, a variety of appreciably different surfactants, and a dissolving and transparency agent. The dissolving and transparency agent is tetrahydrofuran, a cyclic ether. The scintillation solvent is toluene. The primary scintillation solute is PPO, and the secondary scintillation solute is dimethyl POPOP. The variety of appreciably different surfactants is composed of isooctylphenol-polyethoxyethanol and sodium dihexyl sulphosuccinate [fr

Müller cells and retinal axons can be primary targets in experimental neuromyelitis optica spectrum disorder.

Science.gov (United States)

Zeka, Bleranda; Lassmann, Hans; Bradl, Monika

2017-01-01

Recent work from our laboratory, using different models of experimental neuromyelitis optica spectrum disorder (NMOSD), has led to a number of observations that might be highly relevant for NMOSD patients. For example: (i) in the presence of neuromyelitis optica immunoglobulin G, astrocyte-destructive lesions can be initiated by CD4+ T cells when these cells recognize aquaporin 4 (AQP4), but also when they recognize other antigens of the central nervous system. The only important prerequisite is that the T cells have to be activated within the central nervous system by "their" specific antigen. Recently activated CD4+ T cells with yet unknown antigen specificity are also found in human NMOSD lesions. (ii) The normal immune repertoire might contain AQP4-specific T cells, which are highly encephalitogenic on activation. (iii) The retina might be a primary target of AQP4-specific T cells and neuromyelitis optica immunoglobulin G: AQP4-specific T cells alone are sufficient to cause retinitis with low-grade axonal pathology in the retinal nerve fiber/ganglionic cell layer. A thinning of these layers is also observed in NMOSD patients, where it is thought to be a consequence of optic neuritis. Neuromyelitis optica immunoglobulin G might target cellular processes of Müller cells and cause their loss of AQP4 reactivity, when AQP4-specific T cells open the blood-retina barrier in the outer plexiform layer. Patchy loss of AQP4 reactivity on Müller cells of NMOSD patients has been recently described. Cumulatively, our findings in experimental NMOSD suggest that both CD4+ T cell and antibody responses directed against AQP4 might play an important role in the pathogenesis of tissue destruction seen in NMOSD.

Scintillation properties of acrylate based plastic scintillator by photoploymerization method

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Hwan [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Lee, Joo Il [Dept. of of Radiology, Daegu Health College, Daegu (Korea, Republic of)

2016-12-15

In this study, we prepared and characterized a acrylate based UV-curable plastic scintillator. It was used co-polymers TMPTA, DHPA and Ultima GoldTM LLT organic scintillator. The emission spectrum of the plastic scintillator was located in the range of 380⁓520 nm, peaking at 423 nm. And the scintillator is more than 50% transparent in the range of 400⁓ 800 nm. The emission spectrum is well match to the quantum efficiency of photo-multiplier tube and the fast decay time of the scintillation is 12 ns, approximately. This scintillation material provides the possibility of combining 3D printing technology, and then the applications of the plastic scintillator may be expected in human dosimetry etc.

Neuromyelitis optica spectrum disorders: beyond longitudinally extensive transverse myelitis

International Nuclear Information System (INIS)

Lemos, M.D.; Carvalho, G.B.S.; Carvalho, R.S.; Bichuetti, D.B.; Oliveira, E.M.L. de; Abdala, N.

2015-01-01

Aim: To describe the neuroradiological features and their prevalence in patients with neuromyelitis optica (NMO). Materials and methods: Two neuroradiologists independently reviewed 35 spinal cord and 37 brain MRI studies from patients with NMO. The examinations were analysed for the presence of lesion, topography, enhancement, and brain lesions suggestive of multiple sclerosis and/or NMO. Results: Seventy percent of the spinal cord lesions involved over three or more vertebral segments. Seventy-eight percent of brain scans were abnormal, and the most prevalent findings were non-specific foci of T2 hyperintensities in the cerebral white matter (55%) and brainstem lesions (52%). One patient had lesions disseminated in space compatible with multiple sclerosis according to 2010 revised McDonald criteria. Brain lesions suggestive of NMO occurred at least once in 17 (59%) patients. Conclusion: Spinal cord lesions were often longitudinally extensive and brain lesions were common, with the majority of patients having at least one distinctive NMO lesion. - Highlights: • Neuromyelitis optica (NMO) affects mainly the spinal cord but also the brain. • We accessed the radiological features of patients with NMO in brain and spinal cord. • We found a high prevalence of extensive myelitis and specific brain lesions. • Some brainstem lesions could be misdiagnosed if not actively searched. • A practical approach to evaluate suspected NMO images is presented

Membranous nephropathy with Neuromyelitis optica spectrum disorder.

Science.gov (United States)

Li, Xiangling; Wang, YanQiang

2017-07-01

Membranous nephropathy (MN) accompanying Neuromyelitis optica spectrum disorders (NMOSD) has rarely been described previously. We recently presented a 45-year-old Chinese male presenting with recurrent lower extremity pitting edema, or eyelid edema, proteinuria and hyperlipidemia. especially intractable hiccup and vomiting, painful tonic spasm (PTS) as the revealing symptom of a demyelinating disorder of central nervous system. The kindey biopsy specimen showed MN stage 2. Serological testing revealed antibodies AQP4, MRI head and spine revealed medulla oblongata and C1-C2 cervical vertebra lesions. Treatment with methylprednisolone, cyclophosphamide, azathioprine resulted in consistent clinical improvement. Copyright © 2017 Elsevier B.V. All rights reserved.

Clinical characteristics of late-onset neuromyelitis optica spectrum disorder: A multicenter retrospective study in Korea.

Science.gov (United States)

Seok, Jin Myoung; Cho, Hye-Jin; Ahn, Suk-Won; Cho, Eun Bin; Park, Min Su; Joo, In-Soo; Shin, Ha Young; Kim, Sun-Young; Kim, Byung-Jo; Kim, Jong Kuk; Cho, Joong-Yang; Huh, So-Young; Kwon, Ohyun; Lee, Kwang-Ho; Kim, Byoung Joon; Min, Ju-Hong

2017-11-01

There are currently few studies regarding late-onset neuromyelitis optica spectrum disorder (LO-NMOSD). We aimed to describe the characteristic features of patients with LO-NMOSD in Korea. Anti-aquaporin-4 antibody-positive patients with neuromyelitis optica spectrum disorder (NMOSD) from nine tertiary hospitals were reviewed retrospectively. The patients were divided into two groups based on age of onset: LO-NMOSD (⩾50 years of age at onset) versus early-onset neuromyelitis optica spectrum disorder (EO-NMOSD) (<50 years of age at onset). Clinical, laboratory, and magnetic resonance imaging (MRI) parameters were investigated. Among a total of 147 patients (125 female; age of onset, 39.4 ± 15.2 years), 45 patients (30.6%) had an age of onset of more than 50 years. Compared to patients with EO-NMOSD, patients with LO-NMOSD had more frequent isolated spinal cord involvement at onset (64.4% vs 37.2%, p = 0.002), less frequent involvement of the optic nerve (40.0% vs 67.7%, p = 0.002), and less frequent brain MRI lesions (31.1% vs 50.0%, p = 0.034). Furthermore, there was a significant positive correlation between age of onset and Expanded Disability Status Scale (EDSS) score at last follow-up ( r = 0.246, p = 0.003). Age of onset could be an important predictor of lesion location and clinical course of patients with NMOSD.

Brain perfusion SPECT analysis : New insights in mild cognitive impairment and neuromyelitis optica

NARCIS (Netherlands)

Sánchez Catasùs, Carlos Alfredo

2018-01-01

Het doel van dit proefschrift was om aan te tonen dat hersenperfusie SPECT kan helpen bij het verhelderen van belangrijke vragen met betrekking tot het prodromale “Mild Cognitive Impairment” (MCI) stadium van de ziekte van Alzheimer (AD) en recidiverende Neuromyelitis Optica (NMO). Dit is niet

Th17 cells in neuromyelitis optica spectrum disorder: a review.

Science.gov (United States)

Lin, Jie; Li, Xiang; Xia, Junhui

2016-12-01

Neuromyelitis optica spectrum disorder (NMOSD) has been identified as a central nervous system (CNS) autoimmune inflammatory disorder, which has been recognized as a B cell-mediated humoral immune disease. However, cases have been reported indicating that some of the neuromyelitis optica (NMO) patients have been resistant to B cell-related treatments. Recently, more and more evidence has shown that T cell-mediated immunity may take part in the pathogenesis of NMOSD, especially in the Th17 phenotype. In our PUBMED search, we used the following keywords: Th17 cell, Th17 cell-related cytokines, T cells, B cells, B cell-related productions, NMO, NMOSD, recurrent/bilateral optic neuritis, recurrent transverse myelitis and longitudinally extensive transverse myelitis. We systemically reviewed the role of Th17 cells and Th17 cell-related cytokines in NMOSD. We found that Th17 cells and Th17-related cytokines, such as IL-6, IL-1β, IL-17, IL-21, IL-22, IL-23 and TGF-β, are not only directly involved in the pathogenesis but also collaborated with B cells and B cell-related antibody production to induce CNS lesions. Th17 cell-related therapy has also been reviewed in this article, and the data suggested that Th17 may be a new therapeutic target of NMOSD.

High risk of postpartum relapses in neuromyelitis optica spectrum disorder.

Science.gov (United States)

Klawiter, Eric C; Bove, Riley; Elsone, Liene; Alvarez, Enrique; Borisow, Nadja; Cortez, Melissa; Mateen, Farrah; Mealy, Maureen A; Sorum, Jaime; Mutch, Kerry; Tobyne, Sean M; Ruprecht, Klemens; Buckle, Guy; Levy, Michael; Wingerchuk, Dean; Paul, Friedemann; Cross, Anne H; Jacobs, Anu; Chitnis, Tanuja; Weinshenker, Brian

2017-11-28

To study the effect of pregnancy on the frequency of neuromyelitis optica spectrum disorder (NMOSD) relapse and evaluate rates of pregnancy-related complications in an international multicenter setting. We administered a standardized survey to 217 women with NMOSD from 7 medical centers and reviewed their medical records. We compared the annualized relapse rate (ARR) during a baseline period 2 years prior to a participant's first pregnancy to that during pregnancy and to the 9 months postpartum. We also assessed pregnancy-related complications. There were 46 informative pregnancies following symptom onset in 31 women with NMOSD. Compared to baseline (0.17), ARR was increased both during pregnancy (0.44; p = 0.035) and during the postpartum period (0.69; p = 0.009). The highest ARR occurred during the first 3 months postpartum (ARR 1.33). A total of 8 of 76 (10.5%) with onset of NMOSD prior to age 40 experienced their initial symptom during the 3 months postpartum, 2.9 times higher than expected. The postpartum period is a particularly high-risk time for initial presentation of NMOSD. In contrast to published observations in multiple sclerosis, in neuromyelitis optica, relapse rate during pregnancy was also increased, although to a lesser extent than after delivery. © 2017 American Academy of Neurology.

Scintillation Counters

Science.gov (United States)

Bell, Zane W.

Scintillators find wide use in radiation detection as the detecting medium for gamma/X-rays, and charged and neutral particles. Since the first notice in 1895 by Roentgen of the production of light by X-rays on a barium platinocyanide screen, and Thomas Edison's work over the following 2 years resulting in the discovery of calcium tungstate as a superior fluoroscopy screen, much research and experimentation have been undertaken to discover and elucidate the properties of new scintillators. Scintillators with high density and high atomic number are prized for the detection of gamma rays above 1 MeV; lower atomic number, lower-density materials find use for detecting beta particles and heavy charged particles; hydrogenous scintillators find use in fast-neutron detection; and boron-, lithium-, and gadolinium-containing scintillators are used for slow-neutron detection. This chapter provides the practitioner with an overview of the general characteristics of scintillators, including the variation of probability of interaction with density and atomic number, the characteristics of the light pulse, a list and characteristics of commonly available scintillators and their approximate cost, and recommendations regarding the choice of material for a few specific applications. This chapter does not pretend to present an exhaustive list of scintillators and applications.

Antibodies against aquaporin-4 in neuromyelitis optica: distinction between recurrent and monophasic patients

NARCIS (Netherlands)

Ketelslegers, I.A.; Modderman, P.W.; Vennegoor, A.; Killestein, J.; Hamann, D.; Hintzen, R.Q.

2011-01-01

The detection of antibodies against aquaporin-4 (AQP4) has improved the diagnosis of neuromyelitis optica (NMO). We evaluated a recently established cell-based anti-AQP4 assay in 273 patients with inflammatory CNS demyelination. The assay had a specificity of 99% and a sensitivity of 56% to detect

The Treatment of Neuromyelitis Optica

Science.gov (United States)

Kowarik, Markus C.; Soltys, John; Bennett, Jeffrey L.

2014-01-01

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system directed against astrocytes. Initially diagnosed in individuals with monophasic or relapsing optic neuritis and transverse myelitis, NMO is now recognized as a demyelinating disorder with pleiotropic presentations due to the identification of a specific autoantibody response against the astrocyte water channel aquaporin-4 in the majority of individuals. As visual impairment and neurologic dysfunction in NMO are commonly severe, aggressive treatment of relapses and prophylactic immunomodulatory therapy are the focus of treatment. Although there are no approved treatments for NMO, medications and therapeutic interventions for acute and chronic treatment have been the subject of retrospective study and case reports. The goal of this review is to familiarize the reader with biologic and clinical data supporting current treatments in NMO and highlight future strategies based on advancements in our understanding of NMO pathogenesis. PMID:24531318

Treatment-resistant neuromyelitis optica spectrum disorders associated with Toxocara canis infection: A case report.

Science.gov (United States)

Kambe, Daisuke; Takeoka, Kayo; Ogawa, Kenta; Doi, Kosuke; Maruyama, Haruhiko; Yoshida, Ayako; Suenaga, Toshihiko; Kageyama, Takashi

2017-04-01

A 53-year-old woman was admitted to the department of neurology in Tenri Hospital because of progressive thoracic myelitis a month after she had eaten uncooked bovine liver. A previous episode of right optic neuritis and a positive test for serum anti-aquaporin-4 antibodies indicated a diagnosis of neuromyelitis optica spectrum disorders. Although the patient initially recovered with the reduction of anti-aquaporin-4 antibodies during treatment with intravenous methylprednisolone infusion and plasma exchange, her neurological symptoms deteriorated soon after the completion of plasma exchange. Western blotting analysis detected anti-Toxocara canis antibodies in the serum; thus, the patient underwent oral albendazole treatment. This resulted in the alleviation of her symptoms. We therefore consider that rigorous investigation should be encouraged to detect rare pathogens including parasites in cases of treatment-resistant neuromyelitis optica spectrum disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuromyelitis optica med udtalte cerebrale magnetisk resonans-skannings-forandringer hos en niårig pige

DEFF Research Database (Denmark)

Trautner, Simon; Pedersen, Hans Peder; Bendtson, Inger

2009-01-01

Neuromyelitis optica (NMO) is a rare inflammatory disorder characterised by optic neuritis and transverse myelitis. We report a severe pediatric case presenting with impaired vision, tetraparesis, bladder retention and lower extremity pain. Magnetic resonance imaging demonstrated longitudinally...

Scintillators

International Nuclear Information System (INIS)

Cusano, D.A.; Holub, F.F.; Prochazka, S.

1979-01-01

Scintillator bodies comprising phosphor materials and having high optical translucency with low light absorption, and methods of making the scintillator bodies, are described. Fabrication methods include (a) a hot-pressing process, (b) cold-pressing followed by sintering, (c) controlled cooling from a melt, and (d) hot-forging. The scintillator bodies that result are easily machined to desired shapes and sizes. Suitable phosphors include BaFCl:Eu, LaOBr:Tb, CsI:Tl, CaWO 4 and CdWO 4 . (U.K.)

Gaze palsy, hypogeusia and a probable association with miscarriage of pregnancy--the expanding clinical spectrum of non-opticospinal neuromyelitis optica spectrum disorders: a case report.

Science.gov (United States)

Chang, Thashi; Withana, Milinda

2015-02-10

Neuromyelitis optica is characterised by optic neuritis, longitudinally-extensive transverse myelitis and presence of anti-aquaporin-4 antibodies in the serum. However, non-opticospinal central nervous system manifestations have been increasingly recognised. Awareness of the widening clinical spectrum of neuromyelitis optica (unified within the nosology of 'neuromyelitis optica spectrum disorders') is key to earlier diagnosis and appropriate therapy. We report 2 patients to illustrate the varied clinical manifestations of neuromyelitis optica spectrum disorders while postulating an effect of anti-aquaporin-4 antibodies on the miscarriage of pregnancy. This is the first report of horizontal gaze palsy as a presenting symptom of neuromyelitis optica spectrum disorders. Patient 1: A 17-year-old Sri Lankan female presented with hypersomnolence, lateral gaze palsy and loss of taste of 1 week duration. Two years previously she had presented with intractable hiccups and vomiting followed by a brainstem syndrome. Magnetic resonance imaging showed a lesion in the left cerebellum extending into the pons while lesions in bilateral hypothalami and medulla noted 2 years ago had resolved. Autoimmune, vasculitis and infection screens were negative. Anti-aquaporin-4 antibodies were detected in serum. All her symptoms resolved with immunosuppressive therapy. Patient 2: A 47-Year-old Sri Lankan female presented with persistent vomiting lasting over 3 weeks. Three years previously, at 25-weeks of her 4(th) pregnancy, she had presented with quadriparesis and was found to have a longitudinally extensive transverse myelitis from C2 to T2 vertebral levels, which gradually improved following intravenous steroid therapy. Magnetic resonance imaging showed a hyper-intense lesion in the area postrema and longitudinally extensive atrophy of the cord corresponding to her previous myelitis. Autoimmune, vasculitis and infection screens were negative. Anti-aquaporin-4 antibodies were detected in

Scintillation scanner

International Nuclear Information System (INIS)

Mehrbrodt, A.W.; Mog, W.F.; Brunnett, C.J.

1977-01-01

A scintillation scanner having a visual image producing means coupled through a lost motion connection to the boom which supports the scintillation detector is described. The lost motion connection is adjustable to compensate for such delays as may occur between sensing and recording scintillations. 13 claims, 5 figures

Liquid scintillation solution

International Nuclear Information System (INIS)

Long, E.C.

1977-01-01

A liquid scintillation solution is described which includes (1) a scintillation solvent (toluene and xylene), (2) a primary scintillation solute (PPO and Butyl PBD), (3) a secondary scintillation solute (POPOP and Dimethyl POPOP), (4) a plurality of substantially different surfactants and (5) a filter dissolving and/or transparentizing agent. 8 claims

Scintillation camera

International Nuclear Information System (INIS)

Zioni, J.; Klein, Y.; Inbar, D.

1975-01-01

The scintillation camera is to make pictures of the density distribution of radiation fields created by the injection or administration radioactive medicaments into the body of the patient. It contains a scintillation crystal, several photomultipliers and computer circuits to obtain an analytical function at the exits of the photomultiplier which is dependent on the position of the scintillations at the time in the crystal. The scintillation crystal is flat and spatially corresponds to the production site of radiation. The photomultipliers form a pattern whose basic form consists of at least three photomultipliers. They are assigned to at least two crossing parallel series groups where a vertical running reference axis in the crystal plane belongs to each series group. The computer circuits are each assigned to a reference axis. Each series of a series group assigned to one of the reference axes in the computer circuit has an adder to produce a scintillation dependent series signal. Furthermore, the projection of the scintillation on this reference axis is calculated. A series signal is used for this which originates from a series chosen from two neighbouring photomultiplier series of this group. The scintillation must have appeared between these chosen series. They are termed as basic series. The photomultiplier can be arranged hexagonally or rectangularly. (GG/LH) [de

Neuromyelitis optica with Hashimoto′s thyroiditis: A new syndrome or just coincidence

Directory of Open Access Journals (Sweden)

Abhishek Singhai

2015-01-01

Full Text Available Neuromyelitis optica (NMO is an uncommon disease syndrome of the central nervous system that affects the optic nerves and spinal cord. NMO with endocrinopathies has been described as being unique to black Antillean and Afro-Brazilian women. We describe one case of NMO with hashimoto′s thyroiditis in a young female, probably first case report in India.

Radiation damage studies on new liquid scintillators and liquid-core scintillating fibers

International Nuclear Information System (INIS)

Golovkin, S.V.

1994-01-01

The radiation resistant of some new liquid scintillation and capillaries filled with liquid scintillators has been presented. It was found that scintillation efficiency of the scintillator based on 1-methyl naphthalene with a new R39 only by 10% at the dose of 190 Mrad and the radiation resistance of thin liquid-core scintillating was decreased fibers exceeded 60 Mrad. 35 refs

Liquid scintillation solution

International Nuclear Information System (INIS)

Long, E.C.

1976-01-01

The invention deals with a liquid scintillation solution which contains 1) a scintillation solvent (toluol), 2) a primary scintillation solute (PPO), 3) a secondary scintillation solute (dimethyl POPOP), 4) several surfactants (iso-octyl-phenol polyethoxy-ethanol and sodium di-hexyl sulfosuccinate) essentially different from one another and 5) a filter resolution and/or transparent-making agent (cyclic ether, especially tetrahydrofuran). (HP) [de

Brainstem and limbic encephalitis with paraneoplastic neuromyelitis optica.

Science.gov (United States)

Moussawi, Khaled; Lin, David J; Matiello, Marcelo; Chew, Sheena; Morganstern, Daniel; Vaitkevicius, Henrikas

2016-01-01

The spectrum of disorders associated with anti-neuromyelitis optica (NMO) antibody is being extended to include infrequent instances associated with cancer. We describe a patient with brainstem and limbic encephalitis from NMO-immunoglobulin G in serum and cerebrospinal fluid in the context of newly diagnosed breast cancer. The neurological features markedly improved with excision of her breast cancer and immune suppressive therapy. This case further broadens the NMO spectrum disorders (NMOSD) by an association between NMOSD and cancer and raises the question of coincidental occurrence and the appropriate circumstances to search for a tumor in certain instances of NMO. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cognitive Impairment and Whole Brain Diffusion in Patients with Neuromyelitis Optica after Acute Relapse

Science.gov (United States)

He, Diane; Wu, Qizhu; Chen, Xiuying; Zhao, Daidi; Gong, Qiyong; Zhou, Hongyu

2011-01-01

The objective of this study investigated cognitive impairments and their correlations with fractional anisotropy (FA) and mean diffusivity (MD) in patients with neuromyelitis optica (NMO) without visible lesions on conventional brain MRI during acute relapse. Twenty one patients with NMO and 21 normal control subjects received several cognitive…

Neuromyelitis optica spectrum disorder presenting with repeated hypersomnia due to involvement of the hypothalamus and hypothalamus-amygdala linkage.

Science.gov (United States)

Kume, Kodai; Deguchi, Kazushi; Ikeda, Kazuyo; Takata, Tadayuki; Kokudo, Yohei; Kamada, Masaki; Touge, Tetsuo; Takahashi, Toshiyuki; Kanbayashi, Takashi; Masaki, Tsutomu

2015-06-01

We report the case of a 46-year-old Japanese woman with neuromyelitis optica spectrum disorder presenting with repeated hypersomnia accompanied by decreased CSF orexin level. First episode associated with hypothalamic-pituitary dysfunction showed bilateral hypothalamic lesions that can cause secondary damage to the orexin neurons. The second episode associated with impaired memory showed a left temporal lesion involving the amygdala. The mechanism remains unknown, but the reduced blood flow in the hypothalamus ipsilateral to the amygdala lesion suggested trans-synaptic hypothalamic dysfunction secondary to the impaired amygdala. A temporal lesion involving the amygdala and hypothalamus could be responsible for hypersomnia due to neuromyelitis optica spectrum disorder. © The Author(s), 2015.

An update on the evidence for the efficacy and safety of rituximab in the management of neuromyelitis optica

Science.gov (United States)

Collongues, Nicolas; de Seze, Jérôme

2016-01-01

Neuromyelitis optica spectrum disorders (NMOSDs) is a new concept which includes classical neuromyelitis optica (NMO) and partial forms of NMO such as recurrent optic neuritis with positive aquaporin-4 antibodies (AQP4) or brainstem symptoms (intractable hiccups or vomiting). This disease is clearly distinguished from multiple sclerosis (MS) and the therapeutic approach is clearly different. Rituximab is actually considered to be one of the most efficient treatments of NMOSD, even if class I studies are clearly lacking. In the present review, we describe the state of the art about rituximab treatment in NMOSD, including adults and children, plus its efficacy and tolerance and we also underline the questions that should be addressed in the near future. PMID:27134673

An update on the evidence for the efficacy and safety of rituximab in the management of neuromyelitis optica.

Science.gov (United States)

Collongues, Nicolas; de Seze, Jérôme

2016-05-01

Neuromyelitis optica spectrum disorders (NMOSDs) is a new concept which includes classical neuromyelitis optica (NMO) and partial forms of NMO such as recurrent optic neuritis with positive aquaporin-4 antibodies (AQP4) or brainstem symptoms (intractable hiccups or vomiting). This disease is clearly distinguished from multiple sclerosis (MS) and the therapeutic approach is clearly different. Rituximab is actually considered to be one of the most efficient treatments of NMOSD, even if class I studies are clearly lacking. In the present review, we describe the state of the art about rituximab treatment in NMOSD, including adults and children, plus its efficacy and tolerance and we also underline the questions that should be addressed in the near future.

Acute Respiratory Failure due to Neuromyelitis Optica Treated Successfully with Plasmapheresis

Directory of Open Access Journals (Sweden)

Massa Zantah

2016-01-01

Full Text Available Neuromyelitis Optica (NMO is a demyelinating autoimmune disease involving the central nervous system. Acute respiratory failure from cervical myelitis due to NMO is known to occur but is uncommon in monophasic disease and is treated with high dose steroids. We report a case of a patient with NMO who developed acute respiratory failure related to cervical spinal cord involvement, refractory to pulse dose steroid therapy, which resolved with plasmapheresis.

Solid scintillator 'Ready Cap' for measurement with a liquid scintillation counter

International Nuclear Information System (INIS)

Ijiri, Kenichi; Endo, Masashi; Nogawa, Norio; Tsuda, Shoko; Nakamura, Aiko; Morikawa, Naotake; Osaki, Susumu.

1990-01-01

'Ready Cap', a small plastic container coated with solid scintillator has recently been introduced (Beckman Instruments, Inc.). Pulse height spectra and counting efficiencies obtained with a liquid scintillator and Ready Cap using a liquid scintillation counter were compared for 15 different radionuclides. For radionuclides emitting low-energy β-rays or characteristic X-rays, the spectra for Ready Cap shifted toward the higher energy side compared with the spectra for the liquid scintillator. This tendency was reversed for the nuclides emitting higher-energy β-radiations ( 36 Cl and 32 P). Generally, counting efficiencies both in Ready Cap and in liquid scintillator increased with increase in the energy of β- or X-rays. For some nuclides, Ready Cap gave higher counting efficiencies and for others it gave lower values than in the liquid scintillator. However, the differences were not large within each nuclide. The use of Ready Cap is recommended for measurements of radionuclides when liquid scintillation cocktails have no means of waste disposal under the present Japanese radioisotope regulation. (author)

High efficiency scintillation detectors

International Nuclear Information System (INIS)

Noakes, J.E.

1976-01-01

A scintillation counter consisting of a scintillation detector, usually a crystal scintillator optically coupled to a photomultiplier tube which converts photons to electrical pulses is described. The photomultiplier pulses are measured to provide information on impinging radiation. In inorganic crystal scintillation detectors to achieve maximum density, optical transparency and uniform activation, it has been necessary heretofore to prepare the scintillator as a single crystal. Crystal pieces fail to give a single composite response. Means are provided herein for obtaining such a response with crystal pieces, such means comprising the combination of crystal pieces and liquid or solid organic scintillator matrices having a cyclic molecular structure favorable to fluorescence. 8 claims, 6 drawing figures

Synthesis of plastic scintillation microspheres: Evaluation of scintillators

International Nuclear Information System (INIS)

Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

2013-01-01

The use of plastic scintillation microspheres (PSm) appear to be an alternative to liquid scintillation for the quantification of alpha and beta emitters because it does not generate mixed wastes after the measurement (organic and radioactive). In addition to routine radionuclide determinations, PSm can be used for further applications, e.g. for usage in a continuous monitoring equipment, for measurements of samples with a high salt concentration and for an extractive scintillation support which permits the separation, pre-concentration and measurement of the radionuclides without additional steps of elution and sample preparation. However, only a few manufacturers provide PSm, and the low number of regular suppliers reduces its availability and restricts the compositions and sizes available. In this article, a synthesis method based on the extraction/evaporation methodology has been developed and successfully used for the synthesis of plastic scintillation microspheres. Seven different compositions of plastic scintillation microspheres have been synthesised; PSm1 with polystyrene, PSm2 with 2,5-Diphenyloxazol(PPO), PSm3 with p-terphenyl (pT), PSm4 with PPO and 1,4-bis(5-phenyloxazol-2-yl) (POPOP), PSm5 pT and (1,4-bis [2-methylstyryl] benzene) (Bis-MSB), PSm6 with PPO, POPOP and naphthalene and PSm7 with pT, Bis-MSB and naphthalene. The synthesised plastic scintillation microspheres have been characterised in terms of their morphology, detection capabilities and alpha/beta separation capacity. The microspheres had a median diameter of approximately 130 μm. Maximum detection efficiency values were obtained for the PSm4 composition as follows 1.18% for 3 H, 51.2% for 14 C, 180.6% for 90 Sr/ 90 Y and 76.7% for 241 Am. Values of the SQP(E) parameter were approximately 790 for PSm4 and PSm5. These values show that the synthesised PSm exhibit good scintillation properties and that the spectra are at channel numbers higher than in commercial PSm. Finally, the addition

Continuous Positive Airway Pressure (CPAP for prevention of recurrent pneumonia in the Neuromyelitis Optica patient

Directory of Open Access Journals (Sweden)

James A. Welker

2014-01-01

Conclusions: Patients with Neuromyelitis Optica differ from those with traumatic spinal cord injury as they have a chronic progressive systemic illness that causes continued deterioration of their nervous system resulting in the need for routine monitoring that ensures the timely addition of CPAP for the prevention of pneumonia and its associated medical expenses.

Plastic scintillator

International Nuclear Information System (INIS)

Andreeshchev, E.A.; Kilin, S.F.; Kavyrzina, K.A.

1978-01-01

A plastic scintillator for ionizing radiation detectors with high time resolution is suggested. To decrease the scintillation pulse width and to maintain a high light yield, the 4 1 , 4 5 -dibromo-2 1 , 2 5 , 5 1 , 5 5 -tetramethyl-n-quinquiphenyl (Br 2 Me 4 Ph) in combination with n-terphenyl (Ph 3 ) or 2, 5-diphenyloxadiazol-1, 3, 4 (PPD) is used as a luminescent addition. Taking into consideration the results of a special study, it is shown, that the following ratio of ingradients is the optimum one: 3-4 mass% Ph 3 or 4-7 mas% PPD + 2-5 mass% Br 2 Me 4 Ph + + polymeric base. The suggested scintillator on the basis of polystyrene has the light yield of 0.23-0.26 arbitrary units and the scintillation pulse duration at half-height is 0.74-0.84 ns

A Case of Neuromyelitis Optica Masquerading as Miller Fisher Syndrome

Directory of Open Access Journals (Sweden)

Yuka Furutani

2014-10-01

Full Text Available A 22-year-old woman presented with double vision that she had experienced since an infection 2 weeks previously. A neurological examination showed limited bilateral eye abduction, mimicking Miller Fisher syndrome. However, T2-weighted magnetic resonance imaging of her brain revealed hyperintense areas in the tegmentum of the pons, including the abducens nucleus, and her serum anti-aquaporin-4 antibody test was positive. She was finally diagnosed with neuromyelitis optica. Intravenous high-dose steroid therapy immediately improved the patient's abduction palsy, but bilateral optic neuritis manifested during the treatment. Subsequent treatment with plasma exchange improved her optic neuritis symptoms.

Scintillator device using a combined organic-inorganic scintillator as dose ratemeter

International Nuclear Information System (INIS)

Kolb, W.; Lauterbach, U.

1974-01-01

The dose ratemeter independent of energy in the energy region 17 keV to 3 MeV consists of an organic and an inorganic scintillator. The organic scintillation material of an anthracene monocrystal is surrounded by ZnS surface coating. The coating thickness of the inorganic scintillator ZnS is measured in such a manner for gamma and X-radiation below 100 keV that the light produced due to the incident radiation compensates for the decrease of light produced in the organic scintillator. The whole energy and dose rate region of interest for radiation protection can thus be measured with a detector volume of 135 cm 3 . (DG) [de

Neuromyelitis Optica: A Case Report

Directory of Open Access Journals (Sweden)

Wei-Chia Chia

2010-12-01

Full Text Available Neuromyelitis optica (NMO, Devic's syndrome is a demyelinating disease of the central nervous system that predominantly affects the spinal cord and optic nerves. It is often confused with multiple sclerosis. Early discrimination between NMO and multiple sclerosis is important because the two diseases have different natural histories and treatment regimens. Seropositivity for NMO-IgG and longitudinally extensive spinal cord lesions (3 or more spinal segments are characteristic of NMO. Despite the absence of a definitive therapeutic strategy for NMO syndrome, methylprednisolone pulse therapy is recommended in the acute phase. Treatment strategies in relapse phases are aimed at preventing relapses, and increasing evidence shows a better clinical response of immunosuppressive therapy than immuno-modulating therapy (a standard multiple sclerosis-modulating therapy. We describe a 10-year-old girl who had visual loss due to acute optic neuritis at 6 years old and suffered repetitive myelitis 2 years later. NMO was diagnosed because of characteristic longitudinal myelitis and positive NMO-IgG. After combining therapy with prednisolone and an immunosuppressant (cyclophosphamide, the patient's medical condition was stable and no relapse symptoms were observed.

Performance of molded plastic scintillators

International Nuclear Information System (INIS)

Gen, N.S.; Leman, V.E.; Solomonov, V.M.

1989-01-01

The performance of molded plastic scintillators is studied. The plastic scintillators studied were formed by transfer molding and intrusion from a scintillation composition consisting of polystyrene and a standard system of luminescent additives: 2 mass % of paraterphenyl + 0.06 mass % 1,4-di-/2-[5-phenyloxazoyly]/benzene and a plasticizer. The combined effect of mechanical load and temperature was studied. The effect of radiation on molded plastic scintillators was studied using gamma radiation from a 60 Co source. The studies show that the main operating characteristics of molded plastic scintillators are on a par with those of polymerized plastic scintillators. At the same time, molded plastic scintillators are superior in thermal stability at temperatures below the glass transition temperature and with respect to their working temperature range

Scintillation hodoscopes on the basis of hodoscopic photomultipliers using scintillation fibers

International Nuclear Information System (INIS)

Alimova, T.V.; Vasil'chenko, V.G.; Vechkanov, G.N.

1986-01-01

Scintillation hodoscopes characteristics and their design features have been considered. The space resolution for hodoscopes consisting of 4 layers of scintillation fibres 200 mm long and 1 mm in diameter is 0.4-0.6 mm. With 2 fibres layer 1 m long and 3.8 mm in diameter the space resolution 3 mm has been obtained. A possibility to construct 0.1 mm resolution scintillation hodoscopes is discussed

Change in autoantibody and cytokine responses during the evolution of neuromyelitis optica in patients with systemic lupus erythematosus

DEFF Research Database (Denmark)

Kovacs, Katalin T; Kalluri, Sudhakar Reddy; Boza-Serrano, Antonio

2016-01-01

BACKGROUND: Neuromyelitis optica (NMO)-systemic lupus erythematosus (SLE) association is a rare condition characterized by multiple autoantibodies. OBJECTIVE: To examine if, during the evolution of NMO, anti-AQP4 responses are part of polyclonal B cell activation, and if T cell responses contribute...

Convergence spasm due to aquaporin-positive neuromyelitis optica spectrum disorder

Directory of Open Access Journals (Sweden)

Pınar Özçelik

2017-06-01

Full Text Available A female 27 presented with nausea and diplopia for 1 week. On examination she had normal vertical gaze but would develop convergence with miosis whenever she made horizontal saccades. Pupils were 6 mm and unreactive to light. MRI showed extensive hyperintensity in the dorsal midbrain and thalamus. Spinal MRI and CSF were both normal. Serum aquaporin-4-antibody was positive. She was treated with steroids and plasmapheresis and after 3 months convergence spasm resolved but pupils remained unreactive. Neuromyelitis optica often presents with brainstem signs, rarely a dorsal midbrain syndrome. Convergence spasm is occasionally of organic neurologic origin.

Autoantibodies in patients with neuromyelitis optica

Directory of Open Access Journals (Sweden)

Xin FAN

2016-10-01

Full Text Available Neuromyelitis optica (NMO is an autoimmune disease of the central nervous system (CNS which primarily involves the optic nerve and spinal cord. Aquaporin 4 (AQP4 is the main objective antigen, and its specific antibody was NMO-IgG. It was found in clinic that most of NMO-IgG-positive patients were female, whose clinical symptoms were more severe, bilateral optic neuritis (BON or optic neuritis (ON and myelitis were more likely to appear at the same time, and involved spinal segments were longer. Recent studies discovered that anti-aquaporin 1 (AQP1 and anti-myelin oligodendrocyte glycoprotein (MOG antibodies existed in the serum of patients with NMO-IgG-negative. It was discovered that low proportions of women, more cases of long-segment spinal cord lesion, and rare cases of ON appeared in anti-AQP1 antibody-positive patients. Most of anti-MOG antibody-positive patients were male. ON was common, especially bilateral optic nerves involved at the same time, and thoracolumbar involvement was common. DOI: 10.3969/j.issn.1672-6731.2016.10.004

Neuromyelitis optica presenting with horner syndrome: A case report and review of literature.

Science.gov (United States)

Uludağ, İrem Fatma; Sarıteke, Alp; Öcek, Levent; Zorlu, Yaşar; Şener, Ufuk; Tokuçoğlu, Figen; Uludağ, Burhanettin

2017-05-01

Neuromyelitis optica (NMO) is a demyelinating disease of the central nervous system that predominantly affects the spinal cord and optic nerves. We describe a 19 years old woman with left Horner syndrome (HS), who was diagnosed as NMO with characteristic longitudinally extensive myelitis and positive serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Our report describes one of the very rare ocular motor symptoms in NMO patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Scintillating properties of frozen new liquid scintillators

CERN Document Server

Britvich, G I; Golovkin, S V; Martellotti, G; Medvedkov, A M; Penso, G; Soloviev, A S; Vasilchenko, V G

1999-01-01

The light emission from scintillators which are liquid at room temperature was studied in the interval between $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C, where the phase transition from liquid to solid takes place. The light yield measured at $-120$~$^{\\circ}$C is about twice as much as that observed at $+20$~$^{\\circ}$C. By cooling the scintillator from $+20$~$^{\\circ}$C to $-120$~$^{\\circ}$C and then heating it from $-120$~$^{\\circ}$C to $+20$~$^{\\circ}$C, the light yield varies in steps at well defined temperatures, which are different for the cooling and heating processes. These hysteresis phenomena appear to be related to the solvent rather than to the dopant. The decay time of scintillation light was measured at $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C. Whilst at room temperature most of the light is emitted with a decay time of 6--8 ns, at $-120$~$^{\\circ}$C a slower component, with a decay time of 25--35 ns, becomes important.

Scintillator manufacture at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Mellott, K.; Bross, A.; Pla-Dalmau, A.

1998-08-01

A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

Extruding plastic scintillator at Fermilab

International Nuclear Information System (INIS)

Pla-Dalmau, Anna; Bross, Alain D.; Rykalin, Viktor V.

2003-01-01

An understanding of the costs involved in the production of plastic scintillators and the development of a less expensive material have become necessary with the prospects of building very large plastic scintillation detectors. Several factors contribute to the high cost of plastic scintillating sheets, but the principal reason is the labor-intensive nature of the manufacturing process. In order to significantly lower the costs, the current casting procedures had to be abandoned. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. This concept was tested and high quality extruded plastic scintillator was produced. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. This paper will discuss the characteristics of extruded plastic scintillator and its raw materials, the different manufacturing techniques and the current R andD program at Fermilab

Scintillation counting apparatus

International Nuclear Information System (INIS)

Noakes, J.E.

1978-01-01

Apparatus is described for the accurate measurement of radiation by means of scintillation counters and in particular for the liquid scintillation counting of both soft beta radiation and gamma radiation. Full constructional and operating details are given. (UK)

Liquid scintillation measurement. I

International Nuclear Information System (INIS)

Rexa, R.; Tykva, R.

1983-01-01

The individual components of scintillation solutions and their tasks are listed. Explained briefly is the scintillation process in a liquid scintillator. Factors are discussed which influence this process as are methods applied to supress their influence. They include: ionization quenching, quenching by dilution and concentration, chemical, colour, phase and photon quenching and single-photon events causing an undesirable backgorund. (M.D.)

Molecular Pathogenesis of Neuromyelitis Optica

Science.gov (United States)

Bukhari, Wajih; Barnett, Michael H; Prain, Kerri; Broadley, Simon A

2012-01-01

Neuromyelitis optica (NMO) is a rare autoimmune disorder, distinct from multiple sclerosis, causing inflammatory lesions in the optic nerves and spinal cord. An autoantibody (NMO IgG) against aquaporin-4 (AQP4), a water channel expressed on astrocytes is thought to be causative. Peripheral production of the antibody is triggered by an unknown process in genetically susceptible individuals. Anti-AQP4 antibody enters the central nervous system (CNS) when the blood brain barrier is made permeable and has high affinity for orthogonal array particles of AQP4. Like other autoimmune diseases, Th17 cells and their effector cytokines (such as interleukin 6) have been implicated in pathogenesis. AQP4 expressing peripheral organs are not affected by NMO IgG, but the antibody causes extensive astrocytic loss in specific regions of the CNS through complement mediated cytotoxicity. Demyelination occurs during the inflammatory process and is probably secondary to oligodendrocyte apoptosis subsequent to loss of trophic support from astrocytes. Ultimately, extensive axonal injury leads to severe disability. Despite rapid advances in the understanding of NMO pathogenesis, unanswered questions remain, particularly with regards to disease mechanisms in NMO IgG seronegative cases. Increasing knowledge of the molecular pathology is leading to improved treatment strategies. PMID:23202933

Cherenkov and scintillation light separation in organic liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D. [University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Yeh, M. [Brookhaven National Laboratory, Upton, NY (United States)

2017-12-15

The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ{sub r} = 0.72 ± 0.33 ns. (orig.)

Cherenkov and scintillation light separation in organic liquid scintillators

International Nuclear Information System (INIS)

Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D.; Yeh, M.

2017-01-01

The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ r = 0.72 ± 0.33 ns. (orig.)

A systematic analysis of the complement pathways in patients with neuromyelitis optica indicates alteration but no activation during remission

DEFF Research Database (Denmark)

Veszeli, Nóra; Füst, György; Csuka, Dorottya

2014-01-01

Neuromyelitis optica (NMO) is an autoimmune demyelinating inflammatory disorder, mediated by pathogenic autoantibodies against aquaporin 4 (AQP4), the main water channel of the central nervous system (CNS). NMO is characterized by local IgG deposition and complement activation within the CNS...

Sudden onset of sleep due to hypothalamic lesions in neuromyelitis optica spectrum disorder positive for anti-aquaporin-4 antibody.

Science.gov (United States)

Okuma, H; Matsumura, K; Hatanaka, Y; Saito, F; Sonoo, M

2014-09-01

We report a patient with neuromyelitis optica spectrum disorders who presented with sudden onset of sleep as the sole manifestation. Magnetic resonance imaging investigation revealed lesions in the hypothalamus bilaterally, which vanished completely after methylprednisolone pulse therapy. © The Author(s) 2014.

WORKSHOP: Scintillating fibre detectors

International Nuclear Information System (INIS)

Anon.

1989-01-01

Scintillating fibre detector development and technology for the proposed US Superconducting Supercollider, SSC, was the subject of a recent workshop at Fermilab, with participation from the high energy physics community and from industry. Sessions covered the current status of fibre technology and fibre detectors, new detector applications, fluorescent materials and scintillation compositions, radiation damage effects, amplification and imaging structures, and scintillation fibre fabrication techniques

Visual evoked potentials in neuromyelitis optica and its spectrum disorders.

Science.gov (United States)

Ringelstein, Marius; Kleiter, Ingo; Ayzenberg, Ilya; Borisow, Nadja; Paul, Friedemann; Ruprecht, Klemens; Kraemer, Markus; Cohn, Eva; Wildemann, Brigitte; Jarius, Sven; Hartung, Hans-Peter; Aktas, Orhan; Albrecht, Philipp

2014-04-01

Optic neuritis (ON) is a key feature of neuromyelitis optica (NMO). Recently, NMO patients of predominantly Afro-Brazilian origin were evaluated by visual evoked potentials (VEPs) and showed marked amplitude reductions. Here, we analyzed VEPs in a predominantly Caucasian cohort, consisting of 43 patients with definite NMO, 18 with anti-aquaporin (AQP) 4 antibody-seropositive NMO spectrum disorders and 61 matched healthy controls. We found reduced amplitudes in only 12.3%, prolonged latencies in 41.9% and a lack of response in 14.0% of NMO eyes. Delayed P100 latencies in eyes without prior ON suggested this was a subclinical affection. The data indicate heterogenous patterns in NMO, warranting further investigation.

Electron traps and scintillation mechanism in YAlO3:Ce and LuAlO3:Ce scintillators

International Nuclear Information System (INIS)

Wojtowicz, A.J.; Glodo, J.; Drozdowski, W.; Przegietka, K.R.

1998-01-01

In this paper we present the results of thermoluminescence, isothermal decay and scintillation light yield measurements on two isostructural scintillator materials, YAlO 3 :Ce and LuAlO 3 :Ce. In addition to the variety of deep traps identified by thermoluminescence and isothermal decays, scintillation light yield experiments demonstrate the presence in both materials of a number of relatively shallow traps. While the deep traps may reduce the scintillation light yield, they do not influence the kinetics of the process. The shallow traps, on the other hand, by interfering with the process of radiative recombination of charge carriers via Ce 3+ ions, can strongly affect not only the yield of the scintillation process but its kinetics as well. The presence of shallow traps provides a consistent explanation for a number of poorly understood relationships between the two scintillator materials, including a higher room temperature scintillation light yield and longer scintillation decay time in YAlO 3 :Ce, and a longer scintillation rise time in LuAlO 3 :Ce. Theoretical analysis indicates that elimination of these traps would make the two materials nearly identical in scintillator performance. Although the specific identity of all traps remains elusive, the performance of both scintillator materials is now, in practical terms, fully understood. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

Photon statistics in scintillation crystals

Science.gov (United States)

Bora, Vaibhav Joga Singh

Scintillation based gamma-ray detectors are widely used in medical imaging, high-energy physics, astronomy and national security. Scintillation gamma-ray detectors are eld-tested, relatively inexpensive, and have good detection eciency. Semi-conductor detectors are gaining popularity because of their superior capability to resolve gamma-ray energies. However, they are relatively hard to manufacture and therefore, at this time, not available in as large formats and much more expensive than scintillation gamma-ray detectors. Scintillation gamma-ray detectors consist of: a scintillator, a material that emits optical (scintillation) photons when it interacts with ionization radiation, and an optical detector that detects the emitted scintillation photons and converts them into an electrical signal. Compared to semiconductor gamma-ray detectors, scintillation gamma-ray detectors have relatively poor capability to resolve gamma-ray energies. This is in large part attributed to the "statistical limit" on the number of scintillation photons. The origin of this statistical limit is the assumption that scintillation photons are either Poisson distributed or super-Poisson distributed. This statistical limit is often dened by the Fano factor. The Fano factor of an integer-valued random process is dened as the ratio of its variance to its mean. Therefore, a Poisson process has a Fano factor of one. The classical theory of light limits the Fano factor of the number of photons to a value greater than or equal to one (Poisson case). However, the quantum theory of light allows for Fano factors to be less than one. We used two methods to look at the correlations between two detectors looking at same scintillation pulse to estimate the Fano factor of the scintillation photons. The relationship between the Fano factor and the correlation between the integral of the two signals detected was analytically derived, and the Fano factor was estimated using the measurements for SrI2:Eu, YAP

Protective effect of an elastase inhibitor in a neuromyelitis optica-like disease driven by a peptide of myelin oligodendroglial glycoprotein.

NARCIS (Netherlands)

Herges, K.; Jong, B.A. de; Kolkowitz, I.; Dunn, C.; Mandelbaum, G.; Ko, R.M.; Maini, A.; Han, M.H.; Killestein, J.; Polman, C.; Goodyear, A.L.; Dunn, J.; Steinman, L.; Axtell, R.C.

2012-01-01

BACKGROUND: The pathology of neuromyelitis optica (NMO), in contrast to multiple sclerosis, comprises granulocyte infiltrates along extensive lengths of spinal cord, as well as optic nerve. Furthermore, IFN-beta treatment worsens NMO. We recently found that experimental autoimmune encephalomyelitis

Seronegative Neuromyelitis Optica Spectrum Disorder following Exposure to Hepatitis B Vaccination

Directory of Open Access Journals (Sweden)

Richard Heekin

2015-04-01

Full Text Available Controversy exists regarding a potential link between exposure to recombinant hepatitis B vaccine (HBV and central nervous system demyelinating diseases. Here, we present a case of seronegative neuromyelitis optica spectrum disorder (NMOSD following exposure to HBV. A 28-year-old man developed painful eye movements 11 days after exposure to HBV. Within 24 h, he experienced vision loss, ascending numbness, and ataxia. T-spine MRI showed a cord lesion spanning T6-T9. Brain MRI showed bilateral optic nerve contrast enhancement and a right-sided internal capsule lesion. Cerebrospinal fluid analysis was normal, including negative oligoclonal bands and normal IgG index. AQP4-IgG serology was negative. The patient's visual symptoms improved after treatment with steroids and plasma exchange. He received plasma exchange weekly for 4 weeks with decreased numbness and tingling as well as improved coordination. Treatment with mycophenolate mofetil was started, and the patient remains clinically stable with near resolution of his prior symptoms. Neuromyelitis optica is characterized by optic neuritis and/or longitudinally extensive transverse myelitis. While our patient tested seronegative for AQP4-IgG (which remains negative in 10-50% of NMOSD cases, despite testing with the most sensitive assays available, he did meet NMOSD diagnostic criteria. In a literature review, we found 7 cases of NMOSD onset or relapse associated with exposure to various vaccines, but to our knowledge this represents the first published report of NMOSD onset following exposure to HBV. While causality between vaccination and CNS demyelinating disease remains elusive, it is important to report these cases to help develop safer vaccinations and provoke further inquiry into the pathogenesis of NMOSD.

Uranium-scintillator device

International Nuclear Information System (INIS)

Smith, S.D.

1979-01-01

The calorimeter subgroup of the 1977 ISABELLE Summer Workshop strongly recommended investigation of the uranium-scintillator device because of its several attractive features: (1) increased resolution for hadronic energy, (2) fast time response, (3) high density (i.e., 16 cm of calorimeter per interaction length), and, in comparison with uranium--liquid argon detectors, (4) ease of construction, (5) simple electronics, and (6) lower cost. The AFM group at the CERN ISR became interested in such a calorimeter for substantially the same reasons, and in the fall of 1977 carried out tests on a uranium-scintillator (U-Sc) calorimeter with the same uranium plates used in their 1974 studies of the uranium--liquid argon (U-LA) calorimeter. The chief disadvantage of the scintillator test was that the uranium plates were too small to fully contain the hadronic showers. However, since the scintillator and liquid argon tests were made with the plates, direct comparison of the two types of devices could be made

Scintillating plate calorimeter optical design

International Nuclear Information System (INIS)

McNeil, R.; Fazely, A.; Gunasingha, R.; Imlay, R.; Lim, J.

1990-01-01

A major technical challenge facing the builder of a general purpose detector for the SSC is to achieve an optimum design for the calorimeter. Because of its fast response and good energy resolution, scintillating plate sampling calorimeters should be considered as a possible technology option. The work of the Scintillating Plate Calorimeter Collaboration is focused on compensating plate calorimeters. Based on experimental and simulation studies, it is expected that a sampling calorimeter with alternating layers of high-Z absorber (Pb, W, DU, etc.) and plastic scintillator can be made compensating (e/h = 1.00) by suitable choice of the ratio of absorber/scintillator thickness. Two conceptual designs have been pursued by this subsystem collaboration. One is based on lead as the absorber, with read/out of the scintillator plates via wavelength shifter fibers. The other design is based on depleted uranium as the absorber with wavelength shifter (WLS) plate readout. Progress on designs for the optical readout of a compensating scintillator plate calorimeter are presented. These designs include readout of the scintillator plates via wavelength shifter plates or fiber readout. Results from radiation damage studies of the optical components are presented

Depressive state and chronic fatigue in multiple sclerosis and neuromyelitis optica.

Science.gov (United States)

Akaishi, Tetsuya; Nakashima, Ichiro; Misu, Tatsuro; Fujihara, Kazuo; Aoki, Masashi

2015-06-15

Depression and chronic fatigue are frequently present in multiple sclerosis (MS); however, the prevalence rates have not been investigated in neuromyelitis optica (NMO). Thirty-nine consecutive NMO and 75 MS patients were compared using self-rating questionnaires for depressive states, daily activity, and fatigue, as well as serum carnitine levels. A subgroup of patients with low carnitine levels were re-evaluated regarding depression and fatigue after levocarnitine treatment. Depression and fatigue were equally prevalent in MS and NMO and were strongly correlated with one another. Measurement of the serum carnitine levels and the administration of levocarnitine did not appear to be beneficial. Copyright © 2015 Elsevier B.V. All rights reserved.

Brain MRI abnormalities in neuromyelitis optica

Energy Technology Data Exchange (ETDEWEB)

Wang Fei, E-mail: feiwang1973@gmail.com [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053 (China); Liu Yaou, E-mail: asiaeurope80@gmail.com [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053 (China); Duan Yunyun, E-mail: duanyun2003@sohu.com [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053 (China); Li Kuncheng, E-mail: kunchengli@yahoo.com.cn [Department of Radiology, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053 (China); Education Ministry Key Laboratory for Neurodegenerative Disease, Xuanwu Hospital, Capital University of Medical Sciences, 45 Chang-Chun St, Xuanwu District, Beijing 100053 (China)

2011-11-15

Objective: The purpose of this study was to explore brain MRI findings in neuromyelitis optica (NMO) and to investigate specific brain lesions with respect to the localization of aquaporin-4 (AQP-4). Materials and methods: Forty admitted patients (36 women) who satisfied the 2006 criteria of Wingerchuk et al. for NMO were included in this study. All patients received a neurological examination and MRI scanning including brain and spinal cord. MRIs were classified as normal, nonspecific, multiple sclerosis-like, typical abnormalities. MS-like lesions were too few to satisfy the Barkhof et al. criteria for MS. Confluent lesions involving high AQP-4 regions were considered typical. Non-enhancing deep white matter lesions other than MS-like lesions or typical lesions were classified as nonspecific. Results: Brain MRI lesions were delineated in 12 patients (25%). Four patients (10%) had hypothalamus, brainstem or periventricle lesions. Six (15%) patients were nonspecific, and 2 (5%) patients had multiple sclerosis-like lesions. Conclusion: Brain MRIs are negative in most NMO, and brain lesions do not exclude the diagnosis of NMO. Hypothalamus, brainstem or periventricle lesions, corresponding to high sites of AQP-4 in the brain, are indicative of lesions of NMO.

Brain MRI abnormalities in neuromyelitis optica

International Nuclear Information System (INIS)

Wang Fei; Liu Yaou; Duan Yunyun; Li Kuncheng

2011-01-01

Objective: The purpose of this study was to explore brain MRI findings in neuromyelitis optica (NMO) and to investigate specific brain lesions with respect to the localization of aquaporin-4 (AQP-4). Materials and methods: Forty admitted patients (36 women) who satisfied the 2006 criteria of Wingerchuk et al. for NMO were included in this study. All patients received a neurological examination and MRI scanning including brain and spinal cord. MRIs were classified as normal, nonspecific, multiple sclerosis-like, typical abnormalities. MS-like lesions were too few to satisfy the Barkhof et al. criteria for MS. Confluent lesions involving high AQP-4 regions were considered typical. Non-enhancing deep white matter lesions other than MS-like lesions or typical lesions were classified as nonspecific. Results: Brain MRI lesions were delineated in 12 patients (25%). Four patients (10%) had hypothalamus, brainstem or periventricle lesions. Six (15%) patients were nonspecific, and 2 (5%) patients had multiple sclerosis-like lesions. Conclusion: Brain MRIs are negative in most NMO, and brain lesions do not exclude the diagnosis of NMO. Hypothalamus, brainstem or periventricle lesions, corresponding to high sites of AQP-4 in the brain, are indicative of lesions of NMO.

Scintillators and other particle optical detectors

International Nuclear Information System (INIS)

Chipaux, R.

2011-01-01

The author reports and comments his researcher career in the field of particle optical detectors. He addresses the cases of organic scintillators (scintillating fibers, liquid scintillators), inorganic scintillators (crystals for electromagnetic calorimetry, crystals for solar neutrino spectroscopy), and Cherenkov Effect detectors. He also reports his works on Cd Te detectors and their modelling

Eu-activated fluorochlorozirconate glass-ceramic scintillators

International Nuclear Information System (INIS)

Johnson, J. A.; Schweizer, S.; Henke, B.; Chen, G.; Woodford, J.; Newman, P. J.; MacFarlane, D. R.

2006-01-01

Rare-earth-doped fluorochlorozirconate (FCZ) glass-ceramic materials have been developed as scintillators and their properties investigated as a function of dopant level. The paper presents the relative scintillation efficiency in comparison to single-crystal cadmium tungstate, the scintillation intensity as a function of x-ray intensity and x-ray energy, and the spatial resolution (modulation transfer function). Images obtained with the FCZ glass-ceramic scintillator and with cadmium tungstate are also presented. Comparison shows that the image quality obtained using the glass ceramic is close to that from cadmium tungstate. Therefore, the glass-ceramic scintillator could be used as an alternative material for image formation resulting from scintillation. Other inorganic scintillators such as single crystals or polycrystalline films have limitations in resolution or size, but the transparent glass-ceramic can be scaled to any shape or size with excellent resolution

Neuromyelitis optica spectrum disease characteristics in Isfahan, Iran: A cross-sectional study

Directory of Open Access Journals (Sweden)

Fereshte Ashtari

2017-01-01

Full Text Available Background: Neuromyelitis optica spectrum disease (NMOSD is a severe autoimmune demyelinating disorder of the central nervous system that throughout epidemiological data, it has not been completely determined. The aim of this study was to assess characteristics of NMOSD patients in Isfahan as one of the most prevalent cities for multiple sclerosis in Iran. Materials and Methods: Forty-five patients diagnosed as neuromyelitis optica (NMO disease through 5 years enrolled in this study. Demographics and characteristics of disease such as Expanded Disability Status Scale (EDSS score, disease duration, clinical symptoms, laboratory data, and magnetic resonance imaging findings (including T1, T2, and flair protocols were recorded. NMO-immunoglobulin G serology assay was done in all of the patients by ELISA test. Results: Female to male ratio was 5.4:1. The mean age of disease onset was 29.8 ± 11.2 years. NMO antibody was positive in 24.4% of patients. The presenting symptoms were optic neuritis (55.5%, transverse myelitis (40%, and brainstem symptoms (4.5%. The interval between the first and second attack was 19.28 ± 31.27 months (range: 1 month to 17 years. The mean EDSS score of the patients was 2.8 ± 2.25. Frequency of long-extending cervical plaque was higher among men than women (85.7% vs. 57.9%. Conclusion: Based on this study, the mean age of NMOSD onset among Isfahan population was considerably lower than other studies, and there was higher frequency of long-extending cervical lesion among male patients which needs more consideration in further studies.

Enhancing Brain Lesions during Acute Optic Neuritis and/or Longitudinally Extensive Transverse Myelitis May Portend a Higher Relapse Rate in Neuromyelitis Optica Spectrum Disorders.

Science.gov (United States)

Orman, G; Wang, K Y; Pekcevik, Y; Thompson, C B; Mealy, M; Levy, M; Izbudak, I

2017-05-01

Neuromyelitis optica spectrum disorders are inflammatory demyelinating disorders with optic neuritis and/or longitudinally extensive transverse myelitis episodes. We now know that neuromyelitis optica spectrum disorders are associated with antibodies to aquaporin-4, which are highly concentrated on astrocytic end-feet at the blood-brain barrier. Immune-mediated disruption of the blood-brain barrier may manifest as contrast enhancement on brain MR imaging. We aimed to delineate the extent and frequency of contrast enhancement on brain MR imaging within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and to correlate contrast enhancement with outcome measures. Brain MRIs of patients with neuromyelitis optica spectrum disorders were evaluated for patterns of contrast enhancement (periependymal, cloudlike, leptomeningeal, and so forth). The Fisher exact test was used to evaluate differences between the proportion of contrast enhancement in patients who were seropositive and seronegative for aquaporin-4 antibodies. The Mann-Whitney test was used to compare the annualized relapse rate and disease duration between patients with and without contrast enhancement and with and without seropositivity. Brain MRIs of 77 patients were evaluated; 59 patients (10 males, 49 females) were scanned within 1 month of optic neuritis and/or longitudinally extensive transverse myelitis attacks and were included in the analysis. Forty-eight patients were seropositive, 9 were seronegative, and 2 were not tested for aquaporin-4 antibodies. Having brain contrast enhancement of any type during an acute attack was significantly associated with higher annualized relapse rates ( P = .03) and marginally associated with shorter disease duration ( P = .05). Having periependymal contrast enhancement was significantly associated with higher annualized relapse rates ( P = .03). Brain MRIs of patients with neuromyelitis optica spectrum disorders with contrast

Scintillator material. Szintillatormaterial

Energy Technology Data Exchange (ETDEWEB)

Siegmund, M; Bendig, J; Regenstein, W

1987-11-25

A scintillator material for detection and quantitative determination of ionizing radiation is discussed consisting of an acridone dissolved in a fluid or solid medium. Solvent mixtures with at least one protogenic component or polymers and copolymers are used. The scintillator material is distinguished by an excellent stability at high energy doses.

Neutrons detection by scintillation; Detection de neutrons par scintillations

Energy Technology Data Exchange (ETDEWEB)

Giraudon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-01-15

The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

Pulmonary tuberculosis with neuromyelitis optica: an uncommon association of a common disease

International Nuclear Information System (INIS)

Siddiqi, S.A.; Hashmi, M.; Azmat, Z.; Mustafa, S.; Siddiqui, K.A.

2012-01-01

Systemic tuberculosis has been reported with varying neurological manifestations like meningitis, tuberculomas, myositis and neuropathy. Neuromyelitis optica (NMO) is a well known neurological entity which has been described in association with several systemic disorders like systemic lupus erythematosis, diabetes mellitus, hypothyroidism, exposure to Mycobacterium tuberculosis. insecticides etc. However, only a few cases of NMO have been reported in association with Here, we report a case of pulmonary tuberculosis in association with NMO to highlight the under-reported association of NMO with pulmonary tuberculosis presenting in a peculiar anatomical fashion i.e. longitudinal myelitis with predominant posterior column involvement. (author)

Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

International Nuclear Information System (INIS)

Scott Ingram, W.; Robertson, Daniel; Beddar, Sam

2015-01-01

Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator’s stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent

Autoimmune thyroiditis associated with neuromyelitis optica (NMO

Directory of Open Access Journals (Sweden)

Sudulagunta, Sreenivasa Rao

2015-11-01

Full Text Available Neuromyelitis optica (NMO or Devic’s syndrome is a rare relapsing demyelinating disease of the central nervous system (CNS that mainly affects the spinal cord and optic nerves and shares many clinical and radiological features with multiple sclerosis. The association of NMO with other autoimmune diseases was reported, but very few reports described association with autoimmune thyroid disease. Early differentiation between NMO and multiple sclerosis is very important as the natural course and treatment regimens differ significantly. We report a case of a 50-year-old woman who was admitted initially with vomiting, hiccups and paraesthesias but was not diagnosed with NMO and presented with a severe progression of the disease. The patient was also diagnosed to have autoimmune thyroiditis with lymphocytic infiltration of the thyroid which progressed from hyperthyroidism to hypothyroidism. NMO diagnosis was established with seropositivity for NMO-IgG and MRI showing longitudinally extensive spinal cord lesions (3 or more spinal segments. In spite of treatment, the response was poor due to lack of early diagnosis and aggressive immunosuppressant therapy.

Ionospheric Scintillation Effects on GPS

Science.gov (United States)

Steenburgh, R. A.; Smithtro, C.; Groves, K.

2007-12-01

. Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

Inorganic liquid scintillator

International Nuclear Information System (INIS)

Pavlicek, Z.; Barta, C.; Jursova, L.

1986-01-01

An inorganic liquid scintillator is designed which contains 1 to 30 wt.% of an inorganic molecular compound as the basic active component; the compound contains a cation with an atomic number higher than 47 and a halogen anion. The basic inorganic component is dissolved in water or in an organic solvent in form of non-dissociated molecules or self-complexes in which the bond is preserved between the cation and anion components. The light yield from these scintillators ranges between 70 and 150% of the light yield of a standard organic scintillator based on toluene. They are advantageous in that that they allow to increase the water content in the sample to up to 100%. (M.D.)

Neutrons detection by scintillation; Detection de neutrons par scintillations

Energy Technology Data Exchange (ETDEWEB)

Giraudon, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-01-15

The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

Liquid scintillation, counting, and compositions

International Nuclear Information System (INIS)

Sena, E.A.; Tolbert, B.M.; Sutula, C.L.

1975-01-01

The emissions of radioactive isotopes in both aqueous and organic samples can be measured by liquid scintillation counting in micellar systems. The micellar systems are made up of scintillation solvent, scintillation solute and a mixture of surfactants, preferably at least one of which is relatively oil-soluble water-insoluble and another which is relatively water-soluble oil-insoluble

Finding NMO: The Evolving Diagnostic Criteria of Neuromyelitis Optica

Science.gov (United States)

Bennett, Jeffrey L.

2016-01-01

Neuromyelitis optica (NMO) is an autoimmune demyelinating disorder of the central nervous system (CNS) with predilection for the optic nerves and spinal cord. Since its emergence in the medical literature in the late 1800’s, the diagnostic criteria for NMO has slowly evolved from the simultaneous presentation of neurologic and ophthalmic signs to a relapsing or monophasic CNS disorder defined by clinical, neuroimaging, and laboratory criteria. Due to the identification of a specific autoantibody response against the astrocyte water channel aquaporin-4 (AQP4) in the vast majority of affected individuals, the clinical spectrum of NMO has greatly expanded necessitating the development of new international criteria for the diagnosis of NMO spectrum disorder (NMOSD). The routine application of new diagnostic criteria for NMOSD in clinical practice will be critical for future refinement and correlation with therapeutic outcomes. PMID:27529327

Seronegative neuromyelitis optica presenting with life-threatening respiratory failure.

Science.gov (United States)

Nardone, Raffaele; Zuccoli, Giulio; Brigo, Francesco; Trinka, Eugen; Fitzgerald, Ryan T

2016-11-01

Dyspnea has rarely been reported as a presenting symptom in patients with neuromyelitis optica (NMO). We report an unusual case of NMO relapse presenting with rapidly progressive respiratory failure and briefly discuss the possible pathophysiological mechanisms of this potential life-threatening complication of NMO. The 58-year-old woman with a history of bilateral optic neuritis presented to the emergency department with rapidly worsening dyspnea. Cervical spine magnetic resonance imaging showed extensive abnormal signal with involvement of the medulla oblongata. Since in our patient chest radiography failed to disclose a diaphragmatic palsy that is commonly observed in patients with phrenic nerve involvement, this acute manifestation of the disease may be attributed to brainstem involvement instead of cervical myelitis. Clinicians should be aware of this atypical presentation of NMO, which needs to be promptly recognized and aggressively treated.

Plasma Exchange in Severe Attacks of Neuromyelitis Optica

Directory of Open Access Journals (Sweden)

Mickael Bonnan

2012-01-01

Full Text Available Background. Neuromyelitis optica (NMO attacks are poorly controlled by steroids and evolve in stepwise neurological impairments. Assuming the strong humoral response underlying NMO attacks, plasma exchange (PLEX is an appropriate technique in severe NMO attacks. Objective. Presenting an up-to-date review of the literature of PLEX in NMO. Methods. We summarize the rationale of PLEX in relation with the physiology of NMO, the main technical aspects, and the available studies. Results. PLEX in severe attacks from myelitis or optic neuritis are associated with a better outcome, depending on PLEX delay (“time is cord and eyes”. NMO-IgG status has no influence. Finally, we build up an original concept linking the inner dynamic of the lesion, the timing of PLEX onset and the expected clinical results. Conclusion. PLEX is a safe and efficient add-on therapy in NMO, in synergy with steroids. Large therapeutic trials are required to definitely assess the procedure and define the time opportunity window.

Sub-nanosecond plastic scintillators

International Nuclear Information System (INIS)

Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

1977-01-01

Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

Sub-nanosecond plastic scintillators

International Nuclear Information System (INIS)

Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

1976-01-01

Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

Long wavelength scintillators for fiber-optic applications

International Nuclear Information System (INIS)

Lyons, P.B.; Franks, L.; Lutz, S.; Flournoy, J.; Fullman, E.

1980-01-01

The use of fiber optics in plasma diagnostics has spurred the development of long wavelength scintillators with fast temporal characteristics. In this paper we describe several new liquid scintillator systems with fluorescent emissions maxima up to 730 nm. Subnanosecond scintillator FWHM response times have been obtained by the operation of liquid scintillators at elevated temperatures. Data on fiber system sensitivity versus fiber length and scintillator emission wavelength will be presented

High Efficiency, Low Cost Scintillators for PET

International Nuclear Information System (INIS)

Kanai Shah

2007-01-01

Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized

The quest for the ideal inorganic scintillator

International Nuclear Information System (INIS)

Derenzo, S.E.; Weber, M.J.; Bourret-Courchesne, E.; Klintenberg, M.K.

2002-01-01

The past half century has witnessed the discovery of many new inorganic scintillator materials and numerous advances in our understanding of the basic physical processes governing the transformation of ionizing radiation into scintillation light. Whereas scintillators are available with a good combination of physical properties, none provides the desired combination of stopping power, light output, and decay time. A review of the numerous scintillation mechanisms of known inorganic scintillators reveals why none of them is both bright and fast. The mechanisms of radiative recombination in wide-bandgap direct semiconductors, however, remain relatively unexploited for scintillators. We describe how suitably doped semiconductor scintillators could provide a combination of high light output, short decay time, and linearity of response that approach fundamental limits

Multi element high resolution scintillator structure

International Nuclear Information System (INIS)

Cusano, D.A.

1980-01-01

A gamma camera scintillator structure, suitable for detecting high energy gamma photons which, in a single scintillator camera, would require a comparatively thick scintillator crystal, so resulting in unacceptable dispersion of light photons, comprises a collimator array of a high Z material with elongated, parallel wall channels with the scintillator material being disposed in one end of the channels so as to form an integrated collimator/scintillator structure. The collimator channel walls are preferably coated with light reflective material and further light reflective surfaces being translucent to gamma photons, may be provided in each channel. The scintillators may be single crystals or preferably comprise a phosphor dispersed in a thermosetting translucent matrix as disclosed in GB2012800A. The light detectors of the assembled camera may be photomultiplier tubes charge coupled devices or charge injection devices. (author)

Extruded plastic scintillator for MINERvA

International Nuclear Information System (INIS)

Pla-Dalmau, Anna; Bross, Alan D.; FermilabRykalin, Victor V.; Wood, Brian M.; NICADD, DeKalb

2005-01-01

An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. A new experiment at Fermilab is pursuing the use of extruded plastic scintillator. A new plastic scintillator strip is being tested and its properties characterized. The initial results are presented here

Real-time volumetric scintillation dosimetry

International Nuclear Information System (INIS)

Beddar, S

2015-01-01

The goal of this brief review is to review the current status of real-time 3D scintillation dosimetry and what has been done so far in this area. The basic concept is to use a large volume of a scintillator material (liquid or solid) to measure or image the dose distributions from external radiation therapy (RT) beams in three dimensions. In this configuration, the scintillator material fulfills the dual role of being the detector and the phantom material in which the measurements are being performed. In this case, dose perturbations caused by the introduction of a detector within a phantom will not be at issue. All the detector configurations that have been conceived to date used a Charge-Coupled Device (CCD) camera to measure the light produced within the scintillator. In order to accurately measure the scintillation light, one must correct for various optical artefacts that arise as the light propagates from the scintillating centers through the optical chain to the CCD chip. Quenching, defined in its simplest form as a nonlinear response to high-linear energy transfer (LET) charged particles, is one of the disadvantages when such systems are used to measure the absorbed dose from high-LET particles such protons. However, correction methods that restore the linear dose response through the whole proton range have been proven to be effective for both liquid and plastic scintillators. Volumetric scintillation dosimetry has the potential to provide fast, high-resolution and accurate 3D imaging of RT dose distributions. Further research is warranted to optimize the necessary image reconstruction methods and optical corrections needed to achieve its full potential

Neutron crosstalk between liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Verbeke, J.M., E-mail: verbeke2@llnl.gov; Prasad, M.K., E-mail: prasad1@llnl.gov; Snyderman, N.J., E-mail: snyderman1@llnl.gov

2015-09-11

A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction.

Neutron crosstalk between liquid scintillators

International Nuclear Information System (INIS)

Verbeke, J.M.; Prasad, M.K.; Snyderman, N.J.

2015-01-01

A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction

High-symmetry organic scintillator systems

Science.gov (United States)

Feng, Patrick L.

2017-07-18

An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

Temperature dependence of plastic scintillators

Science.gov (United States)

Peralta, L.

2018-03-01

Plastic scintillator detectors have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Several articles have reported undesired response dependencies on beam energy and temperature, which provides the motivation to determine appropriate correction factors. In this work, we studied the light yield temperature dependency of four plastic scintillators, BCF-10, BCF-60, BC-404, RP-200A and two clear fibers, BCF-98 and SK-80. Measurements were made using a 50 kVp X-ray beam to produce the scintillation and/or radioluminescence signal. The 0 to 40 °C temperature range was scanned for each scintillator, and temperature coefficients were obtained.

High-symmetry organic scintillator systems

Energy Technology Data Exchange (ETDEWEB)

Feng, Patrick L.

2018-03-13

An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

High-symmetry organic scintillator systems

Science.gov (United States)

Feng, Patrick L.

2018-02-06

An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

Interferon Alpha Association with Neuromyelitis Optica

Directory of Open Access Journals (Sweden)

Nasrin Asgari

2013-01-01

Full Text Available Interferon-alpha (IFN-α has immunoregulatory functions in autoimmune inflammatory diseases. The goal of this study was to determine occurrence and clinical consequences of IFN-α in neuromyelitis optica (NMO patients. Thirty-six NMO and 41 multiple sclerosis (MS patients from a population-based retrospective case series were included. Expanded Disability Status Scale (EDSS score and MRI findings determined disease activity. Linear regression was used to assess the effects of the level of IFN-α on disability (EDSS. IFN-α was determined by sensitive ELISA assays. IFN-α was detectable in sera from 9/36 NMO patients, significantly more often than in the MS group (2/41 (P=0.0197. A higher frequency of IFN-α was observed in NMO patients with acute relapse compared to NMO patients in remission (P<0.001 and compared to the MS patients with relapse (P=0.010. In NMO patients, the levels of IFN-α were significantly associated with EDSS (P=0.0062. It may be concluded that IFN-α was detectable in a subgroup of NMO patients. Association of IFN-α levels with clinical disease activity and severity suggests a role for IFN-α in disease perpetuation and may provide a plausible explanation for a negative effect of IFN-1 treatment in NMO patients.

A Review of Ionospheric Scintillation Models.

Science.gov (United States)

Priyadarshi, S

This is a general review of the existing climatological models of ionospheric radio scintillation for high and equatorial latitudes. Trans-ionospheric communication of radio waves from transmitter to user is affected by the ionosphere which is highly variable and dynamic in both time and space. Scintillation is the term given to irregular amplitude and phase fluctuations of the received signals and related to the electron density irregularities in the ionosphere. Key sources of ionospheric irregularities are plasma instabilities; every irregularities model is based on the theory of radio wave propagation in random media. It is important to understand scintillation phenomena and the approach of different theories. Therefore, we have briefly discussed the theories that are used to interpret ionospheric scintillation data. The global morphology of ionospheric scintillation is also discussed briefly. The most important (in our opinion) analytical and physical models of scintillation are reviewed here.

High-efficiency organic glass scintillators

Science.gov (United States)

Feng, Patrick L.; Carlson, Joseph S.

2017-12-19

A new family of neutron/gamma discriminating scintillators is disclosed that comprises stable organic glasses that may be melt-cast into transparent monoliths. These materials have been shown to provide light yields greater than solution-grown trans-stilbene crystals and efficient PSD capabilities when combined with 0.01 to 0.05% by weight of the total composition of a wavelength-shifting fluorophore. Photoluminescence measurements reveal fluorescence quantum yields that are 2 to 5 times greater than conventional plastic or liquid scintillator matrices, which accounts for the superior light yield of these glasses. The unique combination of high scintillation light-yields, efficient neutron/gamma PSD, and straightforward scale-up via melt-casting distinguishes the developed organic glasses from existing scintillators.

What do we know about brain contrast enhancement patterns in neuromyelitis optica?☆

Science.gov (United States)

Pekcevik, Yeliz; Orman, Gunes; Lee, In Ho; Mealy, Maureen A.; Levy, Michael; Izbudak, Izlem

2016-01-01

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system that usually presents with acute myelitis and/or optic neuritis. Recently, some brain magnetic resonance imaging findings have been described in NMO that are important in the differential diagnosis. Pencil-thin, leptomeningeal, and cloud-like enhancement may be specific to NMO. These patterns are usually seen during relapses. Recognizing these lesions and enhancement patterns may expedite the diagnosis and allows early effective treatment. The purpose of this article is to review the latest knowledge and to share our experience with the contrast enhancement patterns of NMO brain lesions. PMID:26615899

Comparison of the efficacy of azathioprine and rituximab in neuromyelitis optica spectrum disorder

DEFF Research Database (Denmark)

Nikoo, Zahra; Badihian, Shervin; Shaygannejad, Vahid

2017-01-01

Neuromyelitis optica spectrum disorder (NMOSD) often follows a relapsing course. As disability in NMOSD is attack-related, effective treatments are needed. We aimed to compare the efficacy of azathioprine (AZA) and rituximab (RIT) as maintenance therapy in NMOSD patients. An open, randomized...... = 0–7). Patients were randomized into two groups, which did not differ according to age, gender distribution, and disease duration. In the AZA group, 35 patients [20 aquaporin-4 (AQP4)-IgG positive] were started on 50 mg/day oral AZA and increased to 2–3 mg/kg/day (with oral prednisolone as adjunctive...

Epidemiological, clinical and immunological aspects of neuromyelitis optica (NMO)

DEFF Research Database (Denmark)

Asgari, Nasrin

2013-01-01

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease (IDD) of the central nervous system (CNS) and probably the most common non-multiple sclerosis (MS) CNS IDD. Serum immunoglobulin G autoantibodies have been identified in the majority of NMO patients with the water channel aquaporin...... on either the Wingerchuk 2006 criteria or the United States National Multiple Sclerosis Society 2008 criteria could be made purely on clinical grounds in a high proportion (64%) of cases. Heterogeneity of clinical NMO manifestations including optic neuritis, longitudinal extensive transverse myelitis (LETM...... with specific clinical, immunogenetic and experimental perspectives. The yearly incidence rate of NMO in the population was estimated to be 0.4 per 105 person-years (95% CI 0.30-0.54) and the prevalence was 4.4 per 105 (95% CI 3.1-5.7). The results indicated that NMO is more common in a Caucasian population...

Lower bounds on scintillation detector timing performance

International Nuclear Information System (INIS)

Clinthorne, N.H.; Rogers, W.L.; Hero, A.O. III.; Petrick, N.A.

1990-01-01

Fundamental method-independent limits on the timing performance of scintillation detectors are useful for identifying regimes in which either present timing methods are nearly optimal or where a considerable performance gain might be realized using better pulse processing techniques. Several types of lower bounds on mean-squared timing error (MSE) performance have been developed and applied to scintillation detectors. The simple Cramer-Rao (CR) bound can be useful in determining the limiting MSE for scintillators having a relatively high rate of photon problction such as BaF 2 and NaI(Tl); however, it tends to overestimate the achievalbe performance for scintillators with lower rates such as BGO. For this reason, alternative bounds have been developed using rate-distortion theory or by assuming that the conversion of energy to scintillation light must pass through excited states which have exponential lifetime densities. The bounds are functions of the mean scintillation pulse shape, the scintillation intensity, and photodetector characteristics; they are simple to evaluate and can be used to conveniently assess the limiting timing performance of scintillation detectors. (orig.)

OPTIC NEURITIS IN NEUROMYELITIS OPTICA

Science.gov (United States)

Levin, Marc H.; Bennett, Jeffrey L.; Verkman, A.S.

2013-01-01

Neuromyelitis optica (NMO) is an autoimmune demyelinating disease associated with recurrent episodes of optic neuritis and transverse myelitis, often resulting in permanent blindness and/or paralysis. The discovery of autoantibodies (AQP4-IgG) that target aquaporin-4 (AQP4) has accelerated our understanding of the cellular mechanisms driving NMO pathogenesis. AQP4 is a bidirectional water channel expressed on the plasma membranes of astrocytes, retinal Müller cells, skeletal muscle, and some epithelial cells in kidney, lung and the gastrointestinal tract. AQP4 tetramers form regular supramolecular assemblies at the cell plasma membrane called orthogonal arrays of particles. The pathological features of NMO include perivascular deposition of immunoglobulin and activated complement, loss of astrocytic AQP4, inflammatory infiltration with granulocyte and macrophage accumulation, and demyelination with axon loss. Current evidence supports a causative role of AQP4-IgG in NMO, in which binding of AQP4-IgG to AQP4 orthogonal arrays on astrocytes initiates complement-dependent and antibody-dependent cell-mediated cytotoxicity and inflammation. Immunosuppression and plasma exchange are the mainstays of therapy for NMO optic neuritis. Novel therapeutics targeting specific steps in NMO pathogenesis are entering the development pipeline, including blockers of AQP4-IgG binding to AQP4 and inhibitors of granulocyte function. However, much work remains in understanding the unique susceptibility of the optic nerves in NMO, in developing animal models of NMO optic neuritis, and in improving therapies to preserve vision. PMID:23545439

Designing an optimally proportional inorganic scintillator

Energy Technology Data Exchange (ETDEWEB)

Singh, Jai, E-mail: jai.singh@cdu.edu.au [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia); Koblov, Alexander [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia)

2012-09-01

The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

Designing an optimally proportional inorganic scintillator

International Nuclear Information System (INIS)

Singh, Jai; Koblov, Alexander

2012-01-01

The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

Random wave fields and scintillated beams

CSIR Research Space (South Africa)

Roux, FS

2009-01-01

Full Text Available F. Stef Roux CSIR National Laser Centre PO Box 395, Pretoria 0001, South Africa CSIR National Laser Centre – p.1/29 Contents . Scintillated beams and adaptive optics . Detecting a vortex — Shack-Hartmann . Remove optical vortices . Random vortex... beam. CSIR National Laser Centre – p.3/29 Weak scintillation If the scintillation is weak the resulting phase function of the optical beam is still continuous. Such a weakly scintillated beam can be corrected by an adaptive optical system. CSIR National...

Detector construction for a scintillation camera

International Nuclear Information System (INIS)

Ashe, J.B.

1977-01-01

An improved transducer construction for a scintillation camera in which a light conducting element is equipped with a layer of moisture impervious material is described. A scintillation crystal is thereafter positioned in optical communication with the moisture impervious layer and the remaining surfaces of the scintillation crystal are encompassed by a moisture shield. Affixing the moisture impervious layer to the light conducting element prior to attachment of the scintillation crystal reduces the requirement for mechanical strength in the moisture impervious layer and thereby allows a layer of reduced thickness to be utilized. Preferably, photodetectors are also positioned in optical communication with the light conducting element prior to positioning the scintillation crystal in contact with the impervious layer. 13 claims, 4 figures

A new plastic scintillator with large Stokes shift

International Nuclear Information System (INIS)

Destruel, P.; Taufer, M.

1989-01-01

We have developed a new plastic scintillator with the novel characteristic of highly localized light emission; scintillation and wavelength shifting take place within a few tens of micrometers of the primary ionization. The new scintillator consists of a scintillating polymer base [polyvinyl toluene (PVT) or polystyrene (PS)] doped with a single wavelength shifter, 1-phenyl-3-mesityl-2-pyrazoline (PMP), which has an exceptionally large Stokes shift and therefore a comparatively small self-absorption of its emitted light. In other characteristics (e.g. scintillation efficiency and decay time) the performance of the new scintillator is similar to a good quality commercial plastic scintillator such as NE110. (orig.)

Brain Abnormalities in Neuromyelitis Optica Spectrum Disorder

Directory of Open Access Journals (Sweden)

Woojun Kim

2012-01-01

Full Text Available Neuromyelitis optica (NMO is an idiopathic inflammatory syndrome of the central nervous system that is characterized by severe attacks of optic neuritis (ON and myelitis. Until recently, NMO was considered a disease without brain involvement. However, since the discovery of NMO-IgG/antiaqaporin-4 antibody, the concept of NMO was broadened to NMO spectrum disorder (NMOSD, and brain lesions are commonly recognized. Furthermore, some patients present with brain symptoms as their first manifestation and develop recurrent brain symptoms without ON or myelitis. Brain lesions with characteristic locations and configurations can be helpful in the diagnosis of NMOSD. Due to the growing recognition of brain abnormalities in NMOSD, these have been included in the NMO and NMOSD diagnostic criteria or guidelines. Recent technical developments such as diffusion tensor imaging, MR spectroscopy, and voxel-based morphometry reveal new findings related to brain abnormalities in NMOSD that were not identified using conventional MRI. This paper focuses on the incidence and characteristics of the brain lesions found in NMOSD and the symptoms that they cause. Recent studies using advanced imaging techniques are also introduced.

Monoclonal antibody therapy for neuromyelitis optica spectrum disorder: current and future.

Science.gov (United States)

Lin, Jie; Xue, Binbin; Li, Xiang; Xia, Junhui

2017-08-01

Monoclonal-antibody has been used for patients with autoimmune disorders for several years, and efficacy and safety were appreciated for these patients. Neuromyelitis optica specturm disorder (NMOSD) has been defined as an autoimmune demyelination disorder of the central nervous system (CNS) with a course of relapse-remission. Treatment of prevention is important for patients with NMOSD because of the increased disability after several attacks. Multiple factors were involved in the pathogenesis of NMOSD. Currently, targeting specific factor was favored in the research into the treatment for NMOSD. Previous studies reported the efficacy and tolerance in NMOSD for drugs such as rituximab, tocilizumab, and eculizumab. The aim of this article is to review the current monoclonal therapies for NMOSD patients, and also future alternative options.

Phosphor scintillator structure

International Nuclear Information System (INIS)

Cusano, D.A.; Prener, J.S.

1980-01-01

A method of fabricating scintillators is described in which the phosphor is distributed within the structure in such a way as to enhance the escape of the visible wavelength radiation that would otherwise be dissipated within the scintillator body. Two embodiments of the present invention are disclosed: one in which the phosphor is distributed in a layered structure and another in which the phosphor is dispersed throughout a transparent matrix. (U.K.)

Nanophosphor composite scintillator with a liquid matrix

Science.gov (United States)

McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark

2010-03-16

An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.

Quantitative Susceptibility Mapping Indicates a Disturbed Brain Iron Homeostasis in Neuromyelitis Optica ? A Pilot Study

OpenAIRE

Doring, Thomas Martin; Granado, Vanessa; Rueda, Fernanda; Deistung, Andreas; Reichenbach, Juergen R.; Tukamoto, Gustavo; Gasparetto, Emerson Leandro; Schweser, Ferdinand

2016-01-01

Dysregulation of brain iron homeostasis is a hallmark of many neurodegenerative diseases and can be associated with oxidative stress. The objective of this study was to investigate brain iron in patients with Neuromyelitis Optica (NMO) using quantitative susceptibility mapping (QSM), a quantitative iron-sensitive MRI technique. 12 clinically confirmed NMO patients (6 female and 6 male; age 35.4y±14.2y) and 12 age- and sex-matched healthy controls (7 female and 5 male; age 33.9±11.3y) underwen...

Liquid scintillation counting of chlorophyll

International Nuclear Information System (INIS)

Fric, F.; Horickova, B.; Haspel-Horvatovic, E.

1975-01-01

A precise and reproducible method of liquid scintillation counting was worked out for measuring the radioactivity of 14 C-labelled chlorophyll a and chlorophyll b solutions without previous bleaching. The spurious count rate caused by luminescence of the scintillant-chlorophyll system is eliminated by using a suitable scintillant and by measuring the radioactivity at 4 to 8 0 C after an appropriate time of dark adaptation. Bleaching of the chlorophyll solutions is necessary only for measuring of very low radioactivity. (author)

Scintillation counter based radiation dosimeter

International Nuclear Information System (INIS)

Shin, Jeong Hyun

2009-02-01

The average human exposure per year is about 240mrem which is come from Radon and human body and terrestrial and cosmic radiation and man-made source. Specially radiation exposure through air from environmental radiation sources is 80mrem/yr(= 0.01mR/hr) which come from Terrestrial and cosmic radiation. Radiation dose is defined as energy deposit/mass. There are two major methods to detect radiation. First method is the energy integration using Air equivalent material like GM counter wall material. Second method is the spectrum to dose conversion method using NaI(Tl), HPGe. These two methods are using generally to detect radiation. But these methods are expensive. So we need new radiation detection method. The research purpose is the development of economical environmental radiation dosimeter. This system consists of Plastic/Inorganic scintillator and Si photo-diode based detector and counting based circuitry. So count rate(cps) can be convert to air exposure rate(R/hr). There are three major advantages in this system. First advantages is no high voltage power supply like GM counter. Second advantage is simple electronics. Simple electronics system can be achieved by Air-equivalent scintillation detector with Al filter for the same detection efficiency vs E curve. From former two advantages, we can know the most important advantages of the this system. Third advantage is economical system. The price of typical GM counter is about $1000. But the price of our system is below $100 because of plastic scintillator and simple electronics. The role of scintillation material is emitting scintillation which is the flash of light produced in certain materials when they absorb ionizing radiation. Plastic scintillator is organic scintillator which is kind of hydrocarbons. The special point are cheap price, large size production(∼ton), moderate light output, fast light emission(ns). And the role of Al filter is equalizing counting efficiency of air and scintillator for

Radiation Damage in Scintillating Crystals

CERN Document Server

Zhu Ren Yuan

1998-01-01

Crystal Calorimetry in future high energy physics experiments faces a new challenge to maintain its precision in a hostile radiation environment. This paper discusses the effects of radiation damage in scintillating crystals, and concludes that the predominant radiation damage effect in crystal scintillators is the radiation induced absorption, or color center formation, not the loss of the scintillation light yield. The importance of maintaining crystal's light response uniformity and the feasibility to build a precision crystal calorimeter under radiation are elaborated. The mechanism of the radiation damage in scintillating crystals is also discussed. While the damage in alkali halides is found to be caused by the oxygen or hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides. Material analysis methods used to reach these conclusions are presented in details.

Use of Advanced Magnetic Resonance Imaging Techniques in Neuromyelitis Optica Spectrum Disorder

DEFF Research Database (Denmark)

Kremer, S.; Renard, F.; Achard, S.

2015-01-01

Brain parenchymal lesions are frequently observed on conventional magnetic resonance imaging (MRI) scans of patients with neuromyelitis optica (NMO) spectrum disorder but the specific morphological and temporal patterns distinguishing them uneqtaivcally from lesions caused by other disorders have...... not been identified. This literature review summarizes the literature on advanced quantitative imaging measures reported for patients with NMO spectrum disorder, including proton MR spectroscopy, diffusion tensor imaging, magnetization transfer imaging, quantitative MR voltametry, and ultrahigh...... diffusion-weighted imaging and brain tissue volumetry indicate greater white matter than gray matter degradation. These findings could be confirmed by ultrahigh-field MRI. The use of nonconventional MR I techniques may further our understanding of the pathogenic processes hi NMO spectrum disorders and may...

Shock-resistant scintillation detector

International Nuclear Information System (INIS)

Novak, W.P.

1979-01-01

A unique scintillation detector unit is disclosed which employs a special light transfer and reflector means that encases and protects the scintillator crystal against high g forces. The light transfer means comprises a flexible silicon rubber optical material bonded between the crystal and the optical window and having an axial thickness sufficient to allow the scintillator to move axially inside the container under high g forces without destroying the bonds. The reflector means comprises a soft elastic silicone rubber sleeve having a multiplicity of closely arranged tapered protrusions radiating toward and engaging the periphery of the scintillator crystal to cushion shocks effectively and having a reflective material, such as aluminum oxide powder, in the spaces between the protrusions. The reflector means provides improved shock absorption because of the uniform support and cushioning action of the protrusions and also provides the detector with high efficiency. The silicon rubber composition is specially compounded to include a large amount of aluminum oxide which enables the rubber to function effectively as a light reflector

Scintillating fiber detector performance, detector geometries, trigger, and electronics issues for scintillating fiber tracking

International Nuclear Information System (INIS)

Baumbaugh, A.E.

1994-06-01

Scintillating Fiber tracking technology has made great advances and has demonstrated great potential for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation fluors available make them very promising for use at high luminosity experiments at today's and tomorrow's colliding and fixed target experiments where high rate capability is essential. This talk will discuss the current state of Scintillating fiber performance and current Visual Light Photon Counter (VLPC) characteristics. The primary topic will be some of the system design and integration issues which should be considered by anyone attempting to design a scintillating fiber tracking system which includes a high speed tracking trigger. Design. constraints placed upon the detector system by the electronics and mechanical sub-systems will be discussed. Seemingly simple and unrelated decisions can have far reaching effects on overall system performance. SDC and DO example system designs will be discussed

Set of counts by scintillations for atmospheric samplings; Ensemble de comptages par scintillations pour prelevements atmospheriques

Energy Technology Data Exchange (ETDEWEB)

Appriou, D.; Doury, A.

1962-07-01

The author reports the development of a scintillation-based counting assembly with the following characteristics: a photo-multiplier with a wide photo-cathode, a thin plastic scintillator for the counting of beta + alpha (and possibility of mounting an alpha scintillator), a relatively small own motion with respect to activities to be counted, a weakly varying efficiency. The authors discuss the counting objective, present equipment tests (counter, proportional amplifier and pre-amplifier, input drawer). They describe the apparatus operation, discuss the selection of scintillators, report the study of the own movement (electron-based background noise, total background noise, background noise reduction), discuss counts (influence of the external source, sensitivity to alpha radiations, counting homogeneity, minimum detectable activity) and efficiencies.

Luminescence and scintillation properties of rare-earth-doped LuF.sub.3./sub. scintillation crystals

Czech Academy of Sciences Publication Activity Database

Pejchal, Jan; Fukuda, K.; Kurosawa, S.; Yokota, Y.; Yoshikawa, A.

2015-01-01

Roč. 41, Mar SI (2015), s. 58-62 ISSN 0925-3467 Institutional support: RVO:68378271 Keywords : lutetium fluoride * scintillator * scintillator * VUV luminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2015

Scintillator plate calorimetry

International Nuclear Information System (INIS)

Price, L.E.

1990-01-01

Calorimetry using scintillator plates or tiles alternated with sheets of (usually heavy) passive absorber has been proven over multiple generations of collider detectors. Recent detectors including UA1, CDF, and ZEUS have shown good results from such calorimeters. The advantages offered by scintillator calorimetry for the SSC environment, in particular, are speed (<10 nsec), excellent energy resolution, low noise, and ease of achieving compensation and hence linearity. On the negative side of the ledger can be placed the historical sensitivity of plastic scintillators to radiation damage, the possibility of nonuniform response because of light attenuation, and the presence of cracks for light collection via wavelength shifting plastic (traditionally in sheet form). This approach to calorimetry is being investigated for SSC use by a collaboration of Ames Laboratory/Iowa State University, Argonne National Laboratory, Bicron Corporation, Florida State University, Louisiana State University, University of Mississippi, Oak Ridge National Laboratory, Virginia Polytechnic Institute and State University, Westinghouse Electric Corporation, and University of Wisconsin

Seronegative Neuromyelitis Optica Spectrum - The challenges on disease definition and pathogenesis

Directory of Open Access Journals (Sweden)

Douglas Kazutoshi Sato

2014-06-01

Full Text Available Neuromyelitis optica spectrum disorders (NMOSD are characterized by severe optic neuritis and/or longitudinally extensive transverse myelitis, and some brain lesions are also unique to NMOSD. Serum autoantibodies against aquaporin-4 (AQP4 are detected in most cases of NMOSD. However, some patients with NMOSD remain seronegative despite repetitive testing during attacks with highly sensitive cell-based assays. The differential diagnosis of NMOSD is not restricted to multiple sclerosis and it includes many diseases that can produce longitudinally extensive myelitis and/or optic neuritis. We review the clinical features, imaging, and laboratory findings that can be helpful on the diagnostic work-up, discuss the differences between AQP4 antibody positive and negative patients with NMOSD, including features of NMOSD with antibodies against myelin oligodendrocyte glycoprotein.

Physics of scintillation detectors

International Nuclear Information System (INIS)

Novotny, R.

1991-01-01

The general concept of a radiation detector is based on three fundamental principles: sensitivity of the device to the radiation of interest which requires a large cross-section in the detector material, detector response function to the physical properties of the radiation. As an example, a scintillation detector for charged particles should allow to identify the charge of the particle, its kinetic energy and the time of impact combined with optimum resolutions. Optimum conversion of the detector response (like luminescence of a scintillator) into electronical signals for further processing. The following article will concentrate on the various aspects of the first two listed principles as far as they appear to be relevant for photon and charged particle detection using organic and inorganic scintillation detectors. (orig.)

Liquid scintillation counting system with automatic gain correction

International Nuclear Information System (INIS)

Frank, R.B.

1976-01-01

An automatic liquid scintillation counting apparatus is described including a scintillating medium in the elevator ram of the sample changing apparatus. An appropriate source of radiation, which may be the external source for standardizing samples, produces reference scintillations in the scintillating medium which may be used for correction of the gain of the counting system

Ion induced scintillation in organic solids: development of an average track model,degradation of the scintillation intensity and dosimetric applications

International Nuclear Information System (INIS)

Broggio, D.

2004-12-01

This work deals with a specific aspect of the ion-matter interaction: the scintillation induced by ions in organic materials. In the first chapter we tackle the issue in a theoretical way by proposing a method to compute the radial doses within the framework of the mean track model. We have developed a model based on the Lewis transport equation and on the Spencer distribution of the loss energy in order to take into account the transport of secondary electrons in a more realistic way. In the second chapter we study the physical mechanisms that trigger ion-induced scintillation. Ion-induced scintillation is featured by the dependence in charge number of the intensity of scintillation for ions with same energy loss and by the saturation of the scintillation efficiency for ions with high stopping-power. We have applied our model of radial doses to ion-induced scintillation. In the third chapter we study the gradual degradation of the scintillation intensity and ion-induced chemical damages. In the last chapter we propose a prototype of dosimeters based on the combination of scintillators and optical fibers that allows the real-time measurement of the dose delivered by a carbon ion beam in therapeutical use conditions. This dosimeter gives the relationship between the dose and the scintillation intensity but its accuracy is not yet sufficient for uses in radiotherapy. (A.C.)

Performance evaluation of GPS receiver under equatorial scintillation

Directory of Open Access Journals (Sweden)

Alison de Oliveira Moraes

2009-06-01

Full Text Available Equatorial scintillation is a phenomenon that occurs daily in the equatorial region after the sunset and affects radio signals that propagate through the ionosphere. Depending on the temporal and spatial situation, equatorial scintillation can represent a problem in the availability and precision of the Global Positioning System (GPS. This work is concerned with evaluating the impact of equatorial scintillation on the performance of GPS receivers. First, the morphology and statistical model of equatorial scintillation is briefly presented. A numerical model that generates synthetic scintillation data to simulate the effects of equatorial scintillation is presented. An overview of the main theoretical principles on GPS receivers is presented. The analytical models that describe the effects of scintillation at receiver level are presented and compared with numerical simulations using a radio software receiver and synthetic data. The results achieved by simulation agreed quite well with those predicted by the analytical models. The only exception is for links with extreme levels of scintillation and when weak signals are received.

Liquid-helium scintillation detection with germanium photodiodes

International Nuclear Information System (INIS)

Luke, P.N.; Haller, E.E.; Steiner, H.M.

1982-05-01

Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV α particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes

Scintillation light transport and detection

International Nuclear Information System (INIS)

Gabriel, T.A.; Lillie, R.A.

1986-08-01

The MORSE neutron gamma-ray transport code has been modified to allow for the transport of scintillation light. This modified code is used to analyze the light collection characteristics of a large liquid scintillator module (18 x 18 x 350 cm 3 )

4 GHz ionospheric scintillations observed at Taipei

International Nuclear Information System (INIS)

Huang, Y.N.; Jeng, B.S.

1978-01-01

In a study of ionospheric scintillations 3950 MHz beacon signals from geostationary communication satellites Intelsat-IV-F8 and Intelsat-IV-F1 were recorded on a strip chart and magnetic tape at the Taipei Earth Station. While the strip charts were used to monitor the occurrence of the scintillation, the magnetic tape output was digitized and processed by a computerized system to yield a detailed analysis of scintillation events. It was found that diurnal variations were similar to the diurnal patterns of sporadic E at greater than 5 MHz and VHF band ionospheric scintillations during daytime as reported by Huang (1978). Eight typical scintillation events were selected for the calculation of the scintillation index, S4, and other parameters. The mean S4 index for the 8 events was found to be 0.15. Numerical and graphic results are presented for the cumulative amplitude distributions, message reliability, autocorrelation functions and power spectra

Morphology of auroral zone radio wave scintillation

International Nuclear Information System (INIS)

Rino, C.L.; Matthews, S.J.

1980-01-01

This paper describes the morphology of midnight sector and morning sector auroral zone scintillation observations made over a two-year period using the Wideband satelite, which is in a sun-synchronous, low-altitude orbit. No definitive seasonal variation was found. The nighttime data showed the highest scintillation ocurrence levels, but significant amounts of morning scintillation were observed. For the most part the scintillation activity followed the general pattern of local magnetic activity. The most prominent feature in the nightime data is a localized amplitude and phase scintillation enhancement at the point where the propagation vector lies within an L shell. A geometrical effect due to a dynamic slab of sheetlike structures in the F region is hypothesized as the source of his enhancement. The data have been sorted by magnetic activity, proximity to local midnight, and season. The general features of the data are in agreement with the accepted morphology of auroral zone scintillation

A gamma-ray discriminating neutron scintillator

International Nuclear Information System (INIS)

Eschbach, P.A.; Miller, S.D.; Cole, M.C.

1994-01-01

A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

Survey meter using novel inorganic scintillators

International Nuclear Information System (INIS)

Yoshikawa, Akira; Fukuda, Kentaro; Kawaguchi, Noriaki; Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui; Kurosawa, Shunsuke; Yanagida, Takayuki

2012-01-01

Single crystal scintillator materials are widely used for detection of high-energy photons and particles. There is continuous demand for new scintillator materials with higher performance because of increasing number of medical, industrial, security and other applications. This article presents the recent development of three novel inorganic scintillators; Pr-doped Lu 3 Al 5 O 12 (Pr:LuAG), Ce doped Gd 3 (Al, Ga) 5 O 12 (Ce:GAGG) and Ce or Eu-doped 6 LiCaAlF 6 (Ce:LiCAF, Eu:LiCAF). Pr:LuAG shows very interesting scintillation properties including very fast decay time, high light yield and excellent energy resolution. Taking the advantage of these properties, positron emission mammography (PEM) equipped with Pr:LuAG were developed. Ce:GAGG shows very high light yield, which is much higher than that of Ce:LYSO. Survey meter using Ce:GAGG is developed using this scintillator. Ce:LiCAF and Eu:LiCAF were developed for neutron detection. The advantage and disadvantage are discussed comparing with halide scintillators. Eu-doped LiCAF indicated five times higher light yield than that of existing Li-glass. It is expected to be used as the alternative of 3 He. (author)

MRI characteristics of neuromyelitis optica spectrum disorder

Science.gov (United States)

Paul, Friedemann; Lana-Peixoto, Marco A.; Tenembaum, Silvia; Asgari, Nasrin; Palace, Jacqueline; Klawiter, Eric C.; Sato, Douglas K.; de Seze, Jérôme; Wuerfel, Jens; Banwell, Brenda L.; Villoslada, Pablo; Saiz, Albert; Fujihara, Kazuo; Kim, Su-Hyun

2015-01-01

Since its initial reports in the 19th century, neuromyelitis optica (NMO) had been thought to involve only the optic nerves and spinal cord. However, the discovery of highly specific anti–aquaporin-4 antibody diagnostic biomarker for NMO enabled recognition of more diverse clinical spectrum of manifestations. Brain MRI abnormalities in patients seropositive for anti–aquaporin-4 antibody are common and some may be relatively unique by virtue of localization and configuration. Some seropositive patients present with brain involvement during their first attack and/or continue to relapse in the same location without optic nerve and spinal cord involvement. Thus, characteristics of brain abnormalities in such patients have become of increased interest. In this regard, MRI has an increasingly important role in the differential diagnosis of NMO and its spectrum disorder (NMOSD), particularly from multiple sclerosis. Differentiating these conditions is of prime importance because early initiation of effective immunosuppressive therapy is the key to preventing attack-related disability in NMOSD, whereas some disease-modifying drugs for multiple sclerosis may exacerbate the disease. Therefore, identifying the MRI features suggestive of NMOSD has diagnostic and prognostic implications. We herein review the brain, optic nerve, and spinal cord MRI findings of NMOSD. PMID:25695963

Immunopathogenesis in Myasthenia Gravis and Neuromyelitis Optica

Science.gov (United States)

Wang, Zhen; Yan, Yaping

2017-01-01

Myasthenia gravis (MG) and neuromyelitis optica (NMO) are autoimmune channelopathies of the peripheral neuromuscular junction (NMJ) and central nervous system (CNS) that are mainly mediated by humoral immunity against the acetylcholine receptor (AChR) and aquaporin-4 (AQP4), respectively. The diseases share some common features, including genetic predispositions, environmental factors, the breakdown of tolerance, the collaboration of T cells and B cells, imbalances in T helper 1 (Th1)/Th2/Th17/regulatory T cells, aberrant cytokine and antibody secretion, and complement system activation. However, some aspects of the immune mechanisms are unique. Both targets (AChR and AQP4) are expressed in the periphery and CNS, but MG mainly affects the NMJ in the periphery outside of CNS, whereas NMO preferentially involves the CNS. Inflammatory cells, including B cells and macrophages, often infiltrate the thymus but not the target—muscle in MG, whereas the infiltration of inflammatory cells, mainly polymorphonuclear leukocytes and macrophages, in NMO, is always observed in the target organ—the spinal cord. A review of the common and discrepant characteristics of these two autoimmune channelopathies may expand our understanding of the pathogenic mechanism of both disorders and assist in the development of proper treatments in the future. PMID:29312313

Anti-C1q autoantibodies in patients with neuromyelitis optica spectrum disorders.

Science.gov (United States)

Yoshikura, Nobuaki; Kimura, Akio; Hayashi, Yuichi; Inuzuka, Takashi

2017-09-15

We examined anti-complement C1q (C1q) autoantibody levels in serum and cerebrospinal fluid (CSF) samples of patients with neuromyelitis optica spectrum disorders (NMOSD). We analyzed the correlations between anti-C1q autoantibody levels and the clinical and other CSF characteristics of NMOSD. Serum and CSF anti-C1q autoantibody levels increased during the acute phase of NMOSD, reverting to the same levels as controls during remission. CSF anti-C1q autoantibody levels during the acute phase correlated with several markers reflecting disease severity, Expanded Disability Status Scale worsening, spinal cord lesion length in cases with myelitis, CSF protein and interleukin-6 levels, and CSF/serum albumin ratios. Copyright © 2017 Elsevier B.V. All rights reserved.

Status of timing with plastic scintillation detectors

International Nuclear Information System (INIS)

Moszynski, M.; Bengtson, B.

1979-01-01

Timing properties of scintillators and photomultipliers as well as theoretical and experimental studies of time resolution of scintillation counters are reviewed. Predictions of the theory of the scintillation pulse generation processes are compared with the data on the light pulse shape from small samples, in which the light pulse shape depends only on the composition of the scintillator. For larger samples the influence of the light collection process and the self-absorption process on the light pulse shape are discussed. The data on rise times, fwhm's, decay times and light yield of several commercial scintillators used in timing are collected. The next part of the paper deals with the properties of photomultipliers. The sources of time uncertainties in photomultipliers as a spread of the initial velocity of photoelectrons, emission of photoelectrons under different angles and from different points at the photocathode, the time spread and the gain dispersion introduced by electron photomultiplier are reviewed. The experimental data on the time jitter, single electron response and photoelectron yield of some fast photomultipliers are collected. As the time resolution of the timing systems with scintillation counters depends also on time pick-off units, a short presentation of the timing methods is given. The discussion of timing theories is followed by a review of experimental studies of the time resolution of scintillation counters. The paper is ended by an analysis of prospects on further progress of the subnanosecond timing with scintillation counters. (Auth.)

Waveshifters and Scintillators for Ionizing Radiation Detection

International Nuclear Information System (INIS)

Baumgaugh, B.; Bishop, J.; Karmgard, D.; Marchant, J.; McKenna, M.; Ruchti, R.; Vigneault, M.; Hernandez, L.; Hurlbut, C.

2007-01-01

Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments

Experimental Neuromyelitis Optica Induces a Type I Interferon Signature in the Spinal Cord

Science.gov (United States)

Kaufmann, Nathalie; Zeka, Bleranda; Schanda, Kathrin; Fujihara, Kazuo; Illes, Zsolt; Dahle, Charlotte; Reindl, Markus; Lassmann, Hans; Bradl, Monika

2016-01-01

Neuromyelitis optica (NMO) is an acute inflammatory disease of the central nervous system (CNS) which predominantly affects spinal cord and optic nerves. Most patients harbor pathogenic autoantibodies, the so-called NMO-IgGs, which are directed against the water channel aquaporin 4 (AQP4) on astrocytes. When these antibodies gain access to the CNS, they mediate astrocyte destruction by complement-dependent and by antibody-dependent cellular cytotoxicity. In contrast to multiple sclerosis (MS) patients who benefit from therapies involving type I interferons (I-IFN), NMO patients typically do not profit from such treatments. How is I-IFN involved in NMO pathogenesis? To address this question, we made gene expression profiles of spinal cords from Lewis rat models of experimental neuromyelitis optica (ENMO) and experimental autoimmune encephalomyelitis (EAE). We found an upregulation of I-IFN signature genes in EAE spinal cords, and a further upregulation of these genes in ENMO. To learn whether the local I-IFN signature is harmful or beneficial, we induced ENMO by transfer of CNS antigen-specific T cells and NMO-IgG, and treated the animals with I-IFN at the very onset of clinical symptoms, when the blood-brain barrier was open. With this treatment regimen, we could amplify possible effects of the I-IFN induced genes on the transmigration of infiltrating cells through the blood brain barrier, and on lesion formation and expansion, but could avoid effects of I-IFN on the differentiation of pathogenic T and B cells in the lymph nodes. We observed that I-IFN treated ENMO rats had spinal cord lesions with fewer T cells, macrophages/activated microglia and activated neutrophils, and less astrocyte damage than their vehicle treated counterparts, suggesting beneficial effects of I-IFN. PMID:26990978

Ionospheric scintillation observations over Kenyan region - Preliminary results

Science.gov (United States)

Olwendo, O. J.; Xiao, Yu; Ming, Ou

2016-11-01

Ionospheric scintillation refers to the rapid fluctuations in the amplitude and phase of a satellite signal as it passes through small-scale plasma density irregularities in the ionosphere. By analyzing ionospheric scintillation observation datasets from satellite signals such as GPS signals we can study the morphology of ionospheric bubbles. At low latitudes, the diurnal behavior of scintillation is driven by the formation of large-scale equatorial density depletions which form one to two hours after sunset via the Rayleigh-Taylor instability mechanism near the magnetic equator. In this work we present ionospheric scintillation activity over Kenya using data derived from a newly installed scintillation monitor developed by CRIRP at Pwani University (39.78°E, 3.24°S) during the period August to December, 2014. The results reveal the scintillation activity mainly occurs from post-sunset to post-midnight hours, and ceases around 04:00 LT. We also found that the ionospheric scintillation tends to appear at the southwest and northwest of the station. These locations coincide with the southern part of the Equatorial Ionization Anomaly crest over Kenya region. The occurrence of post-midnight L-band scintillation events which are not linked to pre-midnight scintillation observations raises fundamental question on the mechanism and source of electric fields driving the plasma depletion under conditions of very low background electron density.

Serial quantitative MR assessment of optic neuritis in a case of neuromyelitis optica, using gadolinium-'enhanced' STIR imaging

International Nuclear Information System (INIS)

Barkhof, F.; Scheltens, P.; Valk, J.; Waalewijn, C.; Uitdehaag, B.M.J.; Polman, C.H.

1991-01-01

A patient is presented with neuromyelitis optica. MR imaging, using a short inversion time inversion recovery (STIR) technique, clearly depicted the lesion in the left optic nerve. Subsequent serial STIR imaging, with and without Gadolinium-DTPA, allowed quantitative assessment of changes parallel to improved optic nerve function. STIR imaging is a sensitive technique to demonstrate optic nerve lesions, and enables quantitative assessment to be made of the effect of (steroid) medication. (orig.)

(Alpha-) quenching temperature dependence in liquid scintillator

Energy Technology Data Exchange (ETDEWEB)

Soerensen, Arnd; Lozza, Valentina; Krosigk, Belina von; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, TU Dresden (Germany)

2015-07-01

Liquid scintillator (LS) is an effective and promising detector material, which is and will be used by many small and large scale experiments. In order to perform correct signal identification and background suppression, a very good knowledge of LS properties is crucial. One of those is the light yield from alpha particles in liquid scintillator. This light output strongly quenched, approx. 10 times compared to that of electrons, and has been precisely studied at room temperature for various LS. Big scintillator experiments, such as SNO+ and maybe future large scale detectors, will operate at different temperatures. While a strong temperature dependence is well known for solid state scintillators, due to the different scintillation process, a quenching temperature dependence in LS is usually assumed negligible. On the other hand, inconsistencies in between measurements are often explained by potential temperature effects. This study investigates LAB based liquid scintillator with an intrinsic, dissolved alpha emitter and its behaviour with temperature change. In a small, cooled and heated setup, a stabilized read-out with two PMTs is realised. First results are presented.

Systematic studies of small scintillators for new sampling calorimeter

International Nuclear Information System (INIS)

Jacosalem, E.P.; Sanchez, A.L.C.; Bacala, A.M.; Iba, S.; Nakajima, N.; Ono, H.; Miyata, H.

2007-01-01

A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R and D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are systematically studied. The scintillation light due to beta rays from a collimated 90 Sr source are collected from the scintillator by wavelength-shifting (WLS) fiber and converted into electrical signals at the PMT. The wrapped scintillator that gives the best light yield is determined by comparing the measured pulse height of each 10 x 40 x 2 mm strip scintillator covered with 3M reflective mirror film, teflon, white paint, black tape, gold, aluminum and white paint+teflon. The pulse height dependence on position, length and thickness of the 3M reflective mirror film and teflon wrapped scintillators are measured. Results show that the 3M radiant mirror film-wrapped scintillator has the greatest light yield with an average of 9.2 photoelectrons. It is observed that light yield slightly increases with scintillator length, but increases to about 100% when WLS fiber diameter is increased from 1.0 mm to 1.6 mm. The position dependence measurement along the strip scintillator showed the uniformity of light transmission from the sensor to the PMT. A dip across the strip is observed which is 40% of the maximum pulse height. The block type scintillator pulse height, on the other hand, is found to be almost proportional to scintillator thickness. (author)

Treatment of neuromyelitis optica: an evidence based review

Directory of Open Access Journals (Sweden)

Douglas Sato

2012-01-01

Full Text Available Neuromyelitis optica (NMO is an inflammatory disease of the central nervous system characterized by severe optic neuritis and transverse myelitis, usually with a relapsing course. Aquaporin-4 antibody is positive in a high percentage of NMO patients and it is directed against this water channel richly expressed on foot processes of astrocytes. Due to the severity of NMO attacks and the high risk for disability, treatment should be instituted as soon as the diagnosis is confirmed. There is increasing evidence that NMO patients respond differently from patients with multiple sclerosis (MS, and, therefore, treatments for MS may not be suitable for NMO. Acute NMO attacks usually are treated with high dose intravenous corticosteroid pulse and plasmapheresis. Maintenance therapy is also required to avoid further attacks and it is based on low-dose oral corticosteroids and non-specific immunosuppressant drugs, like azathioprine and mycophenolate mofetil. New therapy strategies using monoclonal antibodies like rituximab have been tested in NMO, with positive results in open label studies. However, there is no controlled randomized trial to confirm the safety and efficacy for the drugs currently used in NMO.

Radiation damage in plastic scintillators

International Nuclear Information System (INIS)

Majewski, S.

1990-01-01

Results of radiation damage studies in plastic scintillators are reviewed and critically analyzed from the point of view of applications of plastic scintillators in calorimetric detectors for the SSC. Damage to transmission and to fluorescent yield in different conditions is discussed. New directions in R ampersand D are outlined. Several examples are given of the most recent data on the new scintillating materials made with old and new plastics and fluors, which are exhibiting significantly improved radiation resistance. With a present rate of a vigorous R D programme, the survival limits in the vicinity of 100 MRad seem to be feasible within a couple of years

Applications of liquid scintillation tubes

International Nuclear Information System (INIS)

Broga, D.W.

1977-01-01

A new cocktail containing device for liquid scintillation counting, the scintillation tube, consists of a two-layered plastic bag which is heatsealed after the cocktail and sample have been placed in it. It is then placed in a carrying vial and counted in a conventional liquid scintillation counter. These tubes have proved to be a practical and economical alternative to vials. Some of their advantages are elimination of absorption problems, transparency, lower background and higher counting efficiency, low breakage danger and savings in waste disposal costs. Two applications for which the tubes are particularly suitable are the counting of laboratory swipes and urine analysis. (author)

New liquid scintillators for fiber-optic applications

International Nuclear Information System (INIS)

Lutz, S.S.; Franks, L.A.; Flournoy, J.M.; Lyons, P.B.

1981-01-01

New long-wavelength-emitting, high-speed, liquid scintillators have been developed and tailored specifically for plasma diagnostic experiments employing fiber optics. These scintillators offer significant advantages over commercially available plastic scintillators in terms of sensitivity and bandwidth. FWHM response times as fast as 350 ps have been measured. Emission spectra, time response data, and relative sensitivity information are presented

Photonic crystal scintillators and methods of manufacture

Science.gov (United States)

Torres, Ricardo D.; Sexton, Lindsay T.; Fuentes, Roderick E.; Cortes-Concepcion, Jose

2015-08-11

Photonic crystal scintillators and their methods of manufacture are provided. Exemplary methods of manufacture include using a highly-ordered porous anodic alumina membrane as a pattern transfer mask for either the etching of underlying material or for the deposition of additional material onto the surface of a scintillator. Exemplary detectors utilizing such photonic crystal scintillators are also provided.

Application of unimodal optic fiber to communications among electric substations; Aplicacion de fibra optica unimodal a comunicaciones entre subestaciones electricas

Energy Technology Data Exchange (ETDEWEB)

Martinez Pinon, Fernando; Hernandez Juarez, Taide [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1992-07-01

The utilization of the unimodal fiber optics technology in the electric power systems, represents one of the best communication options because of its multiple advantages, that results in a better coordination of the technical and administrative activities, needed to carry the electric energy from its generation site to the most remote locations. In this document a study, in accordance with the available options for the design of communication systems via unimodal optic fiber, is presented. With this technology, ties of more than 100 kilometers without the need of repeating stations, can be made. [Espanol] La utilizacion de la tecnologia de fibra optica unimodal en los sistemas electricos de potencia representa una de las mejores alternativas de comunicacion por sus multiples ventajas que se traducen en una mejor coordinacion de las acitividades tecnicas y administrativas necesarias para llevar la energia electrica desde el lugar de generacion hasta los puntos mas distantes. En este documento se presenta un estudio de acuerdo a las opciones disponibles para el diseno de sistemas de comunicacion por fibra optica unimodal. Con esta tecnologia se pueden realizar enlaces mayores que 100 km sin necesidad de repetidores.

Investigation of organic liquid-scintillator optical properties

Energy Technology Data Exchange (ETDEWEB)

Winter, Juergen; Feilitzsch, Franz von; Goeger-Neff, Marianne; Lewke, Timo; Meindl, Quirin; Oberauer, Lothar; Potzel, Walter; Todor, Sebastian; Wurm, Michael [Physik Department E15, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany); Marrodan Undagoitia, Teresa [Physik Department E15, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany); Physik-Institut, Universitaet Zuerich (Switzerland)

2009-07-01

The characterization of different organic liquid-scintillator mixtures is an important step towards the design of a large-scale detector such as LENA (Low Energy Neutrino Astronomy). Its physics goals, extending from particle and geological to astrophysical issues, set high demands on the optical properties of the liquid scintillator. Therefore, small-scale experiments are carried out in order to optimize the final scintillator mixture. PXE, LAB, and dodecane are under consideration as solvents. Setups for the determination of scintillator properties are presented, such as attenuation length, light yield, emission spectra, fluorescence decay times, and quenching factors. Furthermore, results are discussed.

Some adsorption characteristics of polysterene base scintillators

International Nuclear Information System (INIS)

Seredenko, T.N.; Ehkkerman, V.M.; Solomonov, V.M.; Gen, N.S.

1980-01-01

It is necessary to account for the adsorption on the surface of a scintillator when measuring nuclide activity in solutions by submerging into these solutions plastic scintillators. Dependences of 144 Ce, 90 Y, 137 Cs adsorption on specific activities (α) and pH value of solution were investigated. It is shown that K-α ratio is described by the equation K=Casup(p), where K is the specific surface activity of the polystyrene scintillator. Values of C and p are presented for investigated nuclides. The criterion estimating the possibility for repeated usage of scintillator are considered

Radiation-induced chemical processes in polystyrene scintillators

International Nuclear Information System (INIS)

Milinchuk, V.K.; Bolbit, N.M.; Klinshpont, E.R.; Tupikov, V.I.; Zhdanov, G.S.; Taraban, S.B.; Shelukhov, I.P.; Smoljanskii, A.S.

1999-01-01

The regularities established for macroradical accumulation and intensity of radioluminescence under γ-irradiation of a polystyrene scintillator prove benzyl macroradicals to be efficient quenchers of the excited scintillator molecules. Dissolved oxygen was determined to have a constant of the quenching rate 100 times lower than that of macroradicals. Oxygen is an efficient antirad because of participating in oxidation reactions and subsequent recombination of macroradicals. The method was developed to obtain a polymeric scintillator with a polystyrene matrix containing a dispersed system of pores and channels. Radiation resistance of such a scintillator is 5-10 times higher than that of standard types

Performance comparison of scintillators for alpha particle detectors

Energy Technology Data Exchange (ETDEWEB)

Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

2014-11-11

Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.

Development of scintillation materials for PET scanners

CERN Document Server

Korzhik, Mikhail; Annenkov, Alexander N; Borissevitch, Andrei; Dossovitski, Alexei; Missevitch, Oleg; Lecoq, Paul

2007-01-01

The growing demand on PET methodology for a variety of applications ranging from clinical use to fundamental studies triggers research and development of PET scanners providing better spatial resolution and sensitivity. These efforts are primarily focused on the development of advanced PET detector solutions and on the developments of new scintillation materials as well. However Lu containing scintillation materials introduced in the last century such as LSO, LYSO, LuAP, LuYAP crystals still remain the best PET species in spite of the recent developments of bright, fast but relatively low density lanthanum bromide scintillators. At the same time Lu based materials have several drawbacks which are high temperature of crystallization and relatively high cost compared to alkali-halide scintillation materials. Here we describe recent results in the development of new scintillation materials for PET application.

Comparison of plastic scintillating fibres and capillaries filled with liquid scintillator

International Nuclear Information System (INIS)

Cardini, A.; Cavasinni, V.; Girolamo, B. di; Flaminio, V.; Golovkin, S.V.; Gorin, A.M.; Kulichenko, A.V.; Kushnirenko, A.E.; Pyshev, A.I.; Manuilov, I.; Vasilchenko, V.G.

1994-01-01

A comparison is made between the light yield, attenuation length, time response and light propagation speed in plastic scintillating fibres (SCSF-38 and Kuraray-3HF) and quartz capillaries filled with liquid scintillator (LS) 1-methilnaphthalene (1MN) doped with new dyes R45 and R39. The inner diameter of capillaries and diameter of plastic fibres is 0.5 mm. The number of photoelectrons detected at the far end (2 m) was 2.9 for capillaries filled with 1MN+3 g/l R45 while it was 1.8 times smaller in the case of SCSF-38 and 3 times smaller in the case of Kuraray 3HF plastic fibres. Taking into account the quantum efficiency of the photodetector used these reduction factors became 3.0 and 2.0, respectively. Good attenuation length, high light output and also excellent radiation resistance of capillaries filled with LS (>60 Mrad, measured elsewhere) show that they are a very promising alternative to plastic scintillating fibres for future applications in tracking detectors and calorimeters. ((orig.))

Scintillation proximity assay

International Nuclear Information System (INIS)

Hart, H.

1980-01-01

In a method of immunological assay two different classes of particles which interact at short distances to produce characteristic detectable signals are employed in a modification of the usual latex fixation test. In one embodiment an aqueous suspension of antigen coated tritiated latex particles (LH) and antigen coated polystyrene scintillant particles (L*) is employed to assay antibody in the aqueous medium. The amount of (LH) (L*) dimer formation and higher order aggregation induced and therefore the concentration of antibody (or antigen) present which caused the aggregation can be determined by using standard liquid scintillation counting equipment. (author)

Microfluidic Scintillation Detectors

CERN Multimedia

Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

Estimation of Fano factor in inorganic scintillators

Energy Technology Data Exchange (ETDEWEB)

Bora, Vaibhav, E-mail: bora.vaibhav@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Barrett, Harrison H., E-mail: barrett@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Fastje, David, E-mail: dfastje@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Clarkson, Eric, E-mail: clarkson@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Furenlid, Lars, E-mail: furen@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Bousselham, Abdelkader, E-mail: abousselham@qf.org.qa [Qatar Foundation, QEERI, P.O. Box 5825, Doha (Qatar); Shah, Kanai S., E-mail: kanaishah@yahoo.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States); Glodo, Jarek, E-mail: jglodo@rmdinc.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States)

2016-01-01

The Fano factor of an integer-valued random variable is defined as the ratio of its variance to its mean. Correlation between the outputs of two photomultiplier tubes on opposite faces of a scintillation crystal was used to estimate the Fano factor of photoelectrons and scintillation photons. Correlations between the integrals of the detector outputs were used to estimate the photoelectron and photon Fano factor for YAP:Ce, SrI{sub 2}:Eu and CsI:Na scintillator crystals. At 662 keV, SrI{sub 2}:Eu was found to be sub-Poisson, while CsI:Na and YAP:Ce were found to be super-Poisson. An experiment setup inspired from the Hanbury Brown and Twiss experiment was used to measure the correlations as a function of time between the outputs of two photomultiplier tubes looking at the same scintillation event. A model of the scintillation and the detection processes was used to generate simulated detector outputs as a function of time for different values of Fano factor. The simulated outputs from the model for different Fano factors was compared to the experimentally measured detector outputs to estimate the Fano factor of the scintillation photons for YAP:Ce, LaBr{sub 3}:Ce scintillator crystals. At 662 keV, LaBr{sub 3}:Ce was found to be sub-Poisson, while YAP:Ce was found to be close to Poisson.

Geophysical analysis of coherent satellite scintillation data

Science.gov (United States)

Fremouw, E. J.; Lansinger, J. M.; Miller, D. A.

1981-11-01

In May of 1976, Air Force Satellite P76-5 was launched with the Defense Nuclear Agency's Wideband beacon, DNA-002, as its sole payload. Several researchers have employed the resulting data in studies of ionospheric structure and its effect on transionospheric radio communications. In the present work, recordings of amplitude and phase scintillation imposed on Wideband's VHF and UHF signals by the ionosphere have been used to study medium-scale structures in the auroral-zone F layer. Results include quantitative identification of a very close relationship between scintillation and solar/geomagnetic activity, together with lack of a seasonal variation in scintillation activity in the Alaskan sector. A surprisingly high correlation (90%) was found between monthly means of phase-scintillation index, on the one hand, and sunspot number and 10-cm solar radio flux, on the other. The high-latitude scintillation boundary was found to be very similar to the soft-electron precipitation boundary, including similarity in expansion rates with increasing magnetic activity. Interestingly, it is systematically shifted poleward of the precipitation boundary on the day side of the earth and equatorward on the night side. Taken together, the results of this research disclose a rather direct relationship between scintillation and soft-electron precipitation, with plasma convection likely playing an important role in generation of the scintillation-producing irregularities.

International consensus diagnostic criteria for neuromyelitis optica spectrum disorders

Science.gov (United States)

Banwell, Brenda; Bennett, Jeffrey L.; Cabre, Philippe; Carroll, William; Chitnis, Tanuja; de Seze, Jérôme; Fujihara, Kazuo; Greenberg, Benjamin; Jacob, Anu; Jarius, Sven; Lana-Peixoto, Marco; Levy, Michael; Simon, Jack H.; Tenembaum, Silvia; Traboulsee, Anthony L.; Waters, Patrick; Wellik, Kay E.

2015-01-01

Neuromyelitis optica (NMO) is an inflammatory CNS syndrome distinct from multiple sclerosis (MS) that is associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Prior NMO diagnostic criteria required optic nerve and spinal cord involvement but more restricted or more extensive CNS involvement may occur. The International Panel for NMO Diagnosis (IPND) was convened to develop revised diagnostic criteria using systematic literature reviews and electronic surveys to facilitate consensus. The new nomenclature defines the unifying term NMO spectrum disorders (NMOSD), which is stratified further by serologic testing (NMOSD with or without AQP4-IgG). The core clinical characteristics required for patients with NMOSD with AQP4-IgG include clinical syndromes or MRI findings related to optic nerve, spinal cord, area postrema, other brainstem, diencephalic, or cerebral presentations. More stringent clinical criteria, with additional neuroimaging findings, are required for diagnosis of NMOSD without AQP4-IgG or when serologic testing is unavailable. The IPND also proposed validation strategies and achieved consensus on pediatric NMOSD diagnosis and the concepts of monophasic NMOSD and opticospinal MS. PMID:26092914

Conference on Engineering of Scintillation Materials and Radiation Technologies

CERN Document Server

Gektin, Alexander

2017-01-01

This volume provides a broad overview of the latest achievements in scintillator development, from theory to applications, and aiming for a deeper understanding of fundamental processes, as well as the discovery and availability of components for the production of new generations of scintillation materials. It includes papers on the microtheory of scintillation and the initial phase of luminescence development, applications of the various materials, and development and characterization of ionizing radiation detection equipment. The book also touches upon the increased demand for cryogenic scintillators, the renaissance of  garnet materials for scintillator applications, nano-structuring in scintillator development, development and applications for security, and exploration of hydrocarbons and ecological monitoring.

Measurements of energy resolution with hemispheric scintillators

International Nuclear Information System (INIS)

Mendonca, A.C.S.; Binns, D.A.C.; Tauhata, L.; Poledna, R.

1980-01-01

The hemispheric configuration is used for plastic scintillators type NE 102 with the aiming to optimize the light collect. Scintillators at this configuration, with radii of 3,81 cm and 2,54 cm, are showing improvement about 16-17% in the energy resolution, on cilyndric scintillators with the same volume, for gamma rays of 511-1275 KeV. (E.G.) [pt

Time resolution research in liquid scintillating detection

International Nuclear Information System (INIS)

He Hongkun; Shi Haoshan

2006-01-01

The signal processing design method is introduced into liquid scintillating detection system design. By analyzing the signal of liquid scintillating detection, improving time resolution is propitious to upgrade efficiency of detecting. The scheme of realization and satisfactory experiment data is demonstrated. Besides other types of liquid scintillating detection is the same, just using more high speed data signal processing techniques and elements. (authors)

Composite scintillators for detection of ionizing radiation

Science.gov (United States)

Dai, Sheng [Knoxville, TN; Stephan, Andrew Curtis [Knoxville, TN; Brown, Suree S [Knoxville, TN; Wallace, Steven A [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

2010-12-28

Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators.

Science.gov (United States)

Wieczorek, Anna; Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm.

Scintillator structure

International Nuclear Information System (INIS)

Cusano, D.A.; Prener, J.S.

1979-01-01

A scintillator structure comprises at least one layer of transparent fused quartz with a phosphor coating on one or both sides adjacent to at least one transparent layer of epoxy resin which directs light from the phosphor to a detector. The phosphor layer may be formed from a powder optionally with a binder, a single crystal or a melt, or by evaporation or sintering. A plurality of multiple layers may be used or the structure tilted for greater absorption. The structure may be surrounded by another such structure optionally operating in cascade with the first. Many phosphors are specified. A scintillator structure comprises phosphor particles dispersed in epoxy resin or copoly imide-silicone and cast in a multi-compartment box with long sides transparent to X-rays and dividers opaque to X-rays. (UK)

Upconverting nanoparticles for optimizing scintillator based detection systems

Science.gov (United States)

Kross, Brian; McKisson, John E; McKisson, John; Weisenberger, Andrew; Xi, Wenze; Zom, Carl

2013-09-17

An upconverting device for a scintillation detection system is provided. The detection system comprises a scintillator material, a sensor, a light transmission path between the scintillator material and the sensor, and a plurality of upconverting nanoparticles particles positioned in the light transmission path.

Scintillation-Hardened GPS Receiver

Science.gov (United States)

Stephens, Donald R.

2015-01-01

CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

Perspectives on the future development of new scintillators

International Nuclear Information System (INIS)

Melcher, C.L.

2005-01-01

The search for new scintillators has become increasingly sophisticated and increasingly successful in recent years, driven to a large degree by the rapidly growing needs of medical imaging and high energy physics. Better understanding of the various scintillation mechanisms has led to innovative new materials for both gamma-ray and neutron detection, and the concept of scintillator design and engineering has emerged, whereby materials are optimized according to the scintillation properties needed by specific applications. Numerous promising candidates have been identified during the last few years, and several are currently being actively developed for commercial production. Economical crystal growth often represents a significant challenge in the practical application of new scintillation materials

A user's guide to scintillation

International Nuclear Information System (INIS)

Hewish, A.

1989-01-01

During the past four decades scintillation methods have been used for remote-sensing distant plasmas and for providing high angular resolution in radioastronomy. This brief review illustrates some of the techniques employed and explains the underlying theory in simple physical terms; it is not intended to be a complete survey of all applications of scintillation. (author)

Laser Beam Scintillation with Applications

CERN Document Server

Andrews, Larry C; Young, Cynthia

2001-01-01

Renewed interest in laser communication systems has sparked development of useful new analytic models. This book discusses optical scintillation and its impact on system performance in free-space optical communication and laser radar applications, with a detailed look at propagation phenomena and the role of scintillation on system behavior. Intended for practicing engineers, scientists, and students.

Comparative characteristics of polystyrene scintillation strips

International Nuclear Information System (INIS)

Gapienko, V.A.; Denisov, A.G.; Mel'nikov, E.A.

1992-01-01

Results are provided for a study of the main characteristics of polystyrene scintillation strips with a cross-section of 200 x 10 mm with two different scintillation-additive compositions: 1.5% p-terphenyl + 0.01% POPOP and 1.5% p-terphenyl + 0.01% DBP. The mean light-attenuation lengths are 180 cm and 260 cm, respectively, for strips with POPOP and DBP. The emittances of the polystyrene scintillators with DBP and POPOP additives have a ratio of 0.8:1.0 as recorded by an FEU-110 photomultiplier. 2 refs., 1 fig., 2 tabs

Multi-frequency GNSS robust carrier tracking for ionospheric scintillation mitigation

Science.gov (United States)

Vilà-Valls, Jordi; Closas, Pau; Curran, James T.

2017-10-01

Ionospheric scintillation is the physical phenomena affecting radio waves propagating from the space through the ionosphere to earth. The signal distortion induced by scintillation can pose a major threat to some GNSS application. Scintillation is one of the more challenging propagation scenarios, particularly affecting high-precision GNSS receivers which require high quality carrier phase measurements; and safety critical applications which have strict accuracy, availability and integrity requirements. Under ionospheric scintillation conditions, GNSS signals are affected by fast amplitude and phase variations, which can compromise the receiver synchronization. To take into account the underlying correlation among different frequency bands, we propose a new multivariate autoregressive model (MAR) for the multi-frequency ionospheric scintillation process. Multi-frequency GNSS observations and the scintillation MAR are modeled in state-space, allowing independent tracking of both line-of-sight phase variations and complex gain scintillation components. The resulting joint synchronization and scintillation mitigation problem is solved using a robust nonlinear Kalman filter, validated using real multi-frequency scintillation data with encouraging results.

Scintillation characteristics of LiPO3:Ce3+ glass scintillators

International Nuclear Information System (INIS)

Shin, S. W.; Hwang, J. H.

2003-01-01

LiPO 3 :Ce 3+ glass scintillators doped with 0.5, 0.75, 1.0, 1.25 and 1.5wt% cerium as an activator were fabricated. For the best transparency of the LiPO 3 glasses, optimum heating conditions were investigated. Optimum heating temperature and time is 950 .deg. C and 90 min with 1wt% sugar add as reductant. The lattice structure of LiPO 3 :Ce 3+ glass scintillator was monoclinic, its lattice constants(a 0 , b 0 , c 0 ) being 16,490λ, 5.427λ and 13.120λ. Photo-refraction index of LiPO 3 :Ce 3 + measured by SE(Spectroscopic ellipsometry) was 1.45 ∼ 1.5 and its bandgap energy was 2.342 eV. The absorption spectral range of LiPO 3 :Ce 3+ measured by UV-VIS spectrophotometry was 350∼ 375nm and the spectral ranges of photoluminescence(PL) were 400∼450nm and 750∼900nm, its maximum PL intensity appeared at 417nm and 791nm. LiPO 3 :Ce 3 + glass scintillator doped with 0.75wt% cerium showed the best PL intensity. The PL intensity increased until cerium content reaches 0.75wt% above which ir decreased

Production low cost plastic scintillator by using commercial polystyrene

International Nuclear Information System (INIS)

2011-01-01

Plastic Scintillators can be described as solid materials which contain organic fluorescent compounds dissolved within a polymer matrix. Transparent plastics commonly used for light scintillation are Polystyrene (or PS, poly-vinyl-benzene) and polyvinyl-toluene (or PVT, poly-methyl-styron). By changing the composition of plastic Scintillators some features such as light yield, radiation hardening, decay time etc. can be controlled. Plastic scintillation detectors have been used in nuclear and high energy physics for many decades. Among their benefits are fast response, ease of manufacture and versatility. Their main drawbacks are radiation resistance and cost. Many research projects have concentrated on improving the fundamental properties of plastic scintillators, but little attention has focussed on their cost and easier manufacturing techniques. First plastic Scintillators were produced in 1950's. Activities for production of low cost Scintillators accelerated in second half of 1970's. In 1975 acrylic based Plexipop Scintillator was developed. Despite its low cost, since its structure was not aromatic the light yield of Plexipop was about one quarter of classical Scintillators. Problems arising from slow response time and weak mechanical properties in scintillators developed, has not been solved until 1980. Within the last decade extrusion method became very popular in preparation of low cost and high quality plastic scintillators. In this activity, preliminary studies for low cost plastic scintillator production by using commercial polystyrene pellets and extrusion plus compression method were aimed. For this purpose, PS blocks consist of commercial fluorescent dopant were prepared in June 2008 by use of the extruder and pres in SANAEM. Molds suitable for accoupling to extruder were designed and manufactured and optimum production parameters such as extrusion temperature profile, extrusion rate and moulding pressure were obtained hence, PS Scintillator Blocks

Differential diagnosis of neuromyelitis optica spectrum disorders

Science.gov (United States)

Kim, Sung-Min; Kim, Seong-Joon; Lee, Haeng Jin; Kuroda, Hiroshi; Palace, Jacqueline; Fujihara, Kazuo

2017-01-01

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disorder of the central nervous system (CNS) mostly manifesting as optic neuritis and/or myelitis, which are frequently recurrent/bilateral or longitudinally extensive, respectively. As the autoantibody to aquaporin-4 (AQP4-Ab) can mediate the pathogenesis of NMOSD, testing for the AQP4-Ab in serum of patients can play a crucial role in diagnosing NMOSD. Nevertheless, the differential diagnosis of NMOSD in clinical practice is often challenging despite the phenotypical and serological characteristics of the disease because: (1) diverse diseases with autoimmune, vascular, infectious, or neoplastic etiologies can mimic these phenotypes of NMOSD; (2) patients with NMOSD may only have limited clinical manifestations, especially in their early disease stages; (3) test results for AQP4-Ab can be affected by several factors such as assay methods, serologic status, disease stages, or types of treatment; (4) some patients with NMOSD do not have AQP4-Ab; and (5) test results for the AQP4-Ab may not be readily available for the acute management of patients. Despite some similarity in their phenotypes, these NMOSD and NMOSD-mimics are distinct from each other in their pathogenesis, prognosis, and most importantly treatment. Understanding the detailed clinical, serological, radiological, and prognostic differences of these diseases will improve the proper management as well as diagnosis of patients. PMID:28670343

Magnetic Resonance Imaging Features of Neuromyelitis Optica

Energy Technology Data Exchange (ETDEWEB)

You, Sun Kyung; Song, Chang June; Park, Woon Ju; Lee, In Ho; Son, Eun Hee [Chungnam National University College of Medicine, Chungnam National University Hospital, Daejeon (Korea, Republic of)

2013-03-15

To report the magnetic resonance (MR) imaging features of the spinal cord and brain in patients of neuromyelitis optica (NMO). Between January 2001 and March 2010, the MR images (spinal cord, brain, and orbit) and the clinical and serologic findings of 11 NMO patients were retrospectively reviewed. The contrast-enhancement of the spinal cord was performed (20/23). The presence and pattern of the contrast-enhancement in the spinal cord were classified into 5 types. Acute myelitis was monophasic in 8 patients (8/11, 72.7%); and optic neuritis preceded acute myelitis in most patients. Longitudinally extensive cord lesion (average, 7.3 vertebral segments) was involved. The most common type was the diffuse and subtle enhancement of the spinal cord with a multifocal nodular, linear or segmental intense enhancement (45%). Most of the brain lesions (5/11, 10 lesions) were located in the brain stem, thalamus and callososeptal interphase. Anti-Ro autoantibody was positive in 2 patients, and they showed a high relapse rate of acute myelitis. Anti-NMO IgG was positive in 4 patients (4/7, 66.7%). The imaging findings of acute myelitis in NMO may helpful in making an early diagnosis of NMO which can result in a severe damage to the spinal cord, and to make a differential diagnosis of multiple sclerosis and inflammatory diseases of the spinal cord such as toxocariasis.

Magnetic Resonance Imaging Features of Neuromyelitis Optica

International Nuclear Information System (INIS)

You, Sun Kyung; Song, Chang June; Park, Woon Ju; Lee, In Ho; Son, Eun Hee

2013-01-01

To report the magnetic resonance (MR) imaging features of the spinal cord and brain in patients of neuromyelitis optica (NMO). Between January 2001 and March 2010, the MR images (spinal cord, brain, and orbit) and the clinical and serologic findings of 11 NMO patients were retrospectively reviewed. The contrast-enhancement of the spinal cord was performed (20/23). The presence and pattern of the contrast-enhancement in the spinal cord were classified into 5 types. Acute myelitis was monophasic in 8 patients (8/11, 72.7%); and optic neuritis preceded acute myelitis in most patients. Longitudinally extensive cord lesion (average, 7.3 vertebral segments) was involved. The most common type was the diffuse and subtle enhancement of the spinal cord with a multifocal nodular, linear or segmental intense enhancement (45%). Most of the brain lesions (5/11, 10 lesions) were located in the brain stem, thalamus and callososeptal interphase. Anti-Ro autoantibody was positive in 2 patients, and they showed a high relapse rate of acute myelitis. Anti-NMO IgG was positive in 4 patients (4/7, 66.7%). The imaging findings of acute myelitis in NMO may helpful in making an early diagnosis of NMO which can result in a severe damage to the spinal cord, and to make a differential diagnosis of multiple sclerosis and inflammatory diseases of the spinal cord such as toxocariasis.

Scintillation Detectors for Charged Particles and Photons

CERN Document Server

Lecoq, P

2011-01-01

Scintillation Detectors for Charged Particles and Photons in 'Charged Particle Detectors - Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Subsection '3.1.1 Scintillation Detectors for Charged Particles and Photons' of Section '3.1 Charged Particle Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.1.1 Scintillation Detectors for Charged Particles and Photons 3.1.1.1 Basic detector principles and scintillator requirements 3.1.1.1.1 Interaction of ionizing radiation with scintillator material 3.1.1.1.2 Important scint...

Scintillation properties of CdF2 crystal

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Fukuda, Kentaro

2015-01-01

CdF 2 single crystal was prepared by Tokuyama Corp. with the μ-PD method to investigate Auger free luminescence of this material. From optical transmittance spectrum, bandgap wavelength was around 280 nm. In X-ray induced radioluminescence spectrum, emission lines appeared around 350 nm and 420 nm. Excitation wavelength was investigated and excitation peak was around 250 nm. Photoluminescence and scintillation decay times were evaluated and decay time was few ns. Temperature dependence of X-ray induced radioluminescence was compared with conventional BaF 2 scintillator and scintillation of CdF 2 decreased when the temperature increased. Consequently, scintillation of CdF 2 is possibly emission at color centers or exciton related one. - Highlights: • CdF 2 crystal scinitillator was synthesized. • Emission wavelengths of CdF 2 appeared around 350 and 420 nm. • Scintillation decay time of CdF 2 was quite fast, 1.75 ns. • Excitation bands were investigated by using Synchrotron facility, UVSOR

Radiation converter scintillator screen and its manufacturing process

International Nuclear Information System (INIS)

Delattre, D.; Rougeot, H.; Tassin, C.

1984-01-01

The present invention concerns scintillating screens receiving X or gamma radiation and converting it in luminous photons. The screen comprises a needle structure scintillating material. Its concave surface is quite smooth. The screen is obtained by evaporation on a frame having a perfectly smooth convex surface; the constituting material has a thermal dilatation coefficient different from the scintillating material one. After evaporation, the scintillating screen is set apart from the frame by simple heating. It is used for radiological image intensifier tubes and scintigraphy tubes [fr

Scintillation {gamma} spectrography. Physical principles. Apparatus. Operation; Spectrographie {gamma} a scintillations. Principes physiques. Appareillage. Utilisation

Energy Technology Data Exchange (ETDEWEB)

Julliot, C. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of {gamma} photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by {gamma} ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the {gamma} recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a {gamma}-emitting radioelement by the spectrographic method. (author) [French] Dans l'appareillage utilise, le detecteur a scintillations constitue la piece maitresse, l'ensemble electronique presente les resultats issus du detecteur. Apres avoir brievement decrit le processus d'absorption des photons {gamma} dans la matiere, nous examinons le cas particulier du NaI(T1), le scintillateur utilise. L'intensite de la scintillation provoque par l'absorption des rayons {gamma} et les caracteristiques du photomultiplicateur jouent un role determinant dans la resolution en energie de l'appareil. Pour le spectrographe {gamma} enregistreur, nous indiquons dans quelle mesure la technique d'utilisation de l'ensemble electronique peut modifier les resultats. La-mesure de l'activite d'un radioelement emetteur {gamma} par spectrographie fait l'objet d'une description detaillee. (auteur)

Scintillation {gamma} spectrography. Physical principles. Apparatus. Operation; Spectrographie {gamma} a scintillations. Principes physiques. Appareillage. Utilisation

Energy Technology Data Exchange (ETDEWEB)

Julliot, C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of {gamma} photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by {gamma} ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the {gamma} recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a {gamma}-emitting radioelement by the spectrographic method. (author) [French] Dans l'appareillage utilise, le detecteur a scintillations constitue la piece maitresse, l'ensemble electronique presente les resultats issus du detecteur. Apres avoir brievement decrit le processus d'absorption des photons {gamma} dans la matiere, nous examinons le cas particulier du NaI(T1), le scintillateur utilise. L'intensite de la scintillation provoque par l'absorption des rayons {gamma} et les caracteristiques du photomultiplicateur jouent un role determinant dans la resolution en energie de l'appareil. Pour le spectrographe {gamma} enregistreur, nous indiquons dans quelle mesure la technique d'utilisation de l'ensemble electronique peut modifier les resultats. La-mesure de l'activite d'un radioelement emetteur {gamma} par spectrographie fait l'objet d'une description detaillee. (auteur)

Design of Fluorescent Compounds for Scintillation Detection

Energy Technology Data Exchange (ETDEWEB)

Pla-Dalmau, Anna [Northern Illinois U.

1990-01-01

Plastic scintillation detectors for high energy physics applications require the development of new fluorescent compounds to meet the demands set by the future generation of particle accelerators such as the Superconducting Supercollider (SSe). Plastic scintillators are commonly based on a polymer matrix doped with two fluorescent compounds: the primary dopant and the wavelength shifter. Their main characteristics are fast response time and high quantum efficiency. The exposure to larger radiation doses and demands for larger light output questions their survivability in the future experiments. A new type of plastic scintillator - intrinsic scintillator - has been suggested. It uses a single dopant as primary and wavelength shifter, and should be less susceptible to radiation damage....

Liquid scintillation in medical diagnosis

International Nuclear Information System (INIS)

Painter, K.

1976-01-01

With the tremendous increase in the application of radioassay, particularly radioimmunoassay, in the clinical laboratory liquid scintillation counting became an indispensable tool in diagnostic medicine. Few publications, however, have concerned themselves with problem areas which occur with the method in the clinical laboratory. The purpose of this presentation is to summarize our experiences with the liquid scintillation technique in the clinical situation

Hybrid scintillators for neutron discrimination

Science.gov (United States)

Feng, Patrick L; Cordaro, Joseph G; Anstey, Mitchell R; Morales, Alfredo M

2015-05-12

A composition capable of producing a unique scintillation response to neutrons and gamma rays, comprising (i) at least one surfactant; (ii) a polar hydrogen-bonding solvent; and (iii) at least one luminophore. A method including combining at least one surfactant, a polar hydrogen-bonding solvent and at least one luminophore in a scintillation cell under vacuum or an inert atmosphere.

Scintillating camera

International Nuclear Information System (INIS)

Vlasbloem, H.

1976-01-01

The invention relates to a scintillating camera and in particular to an apparatus for determining the position coordinates of a light pulse emitting point on the anode of an image intensifier tube which forms part of a scintillating camera, comprising at least three photomultipliers which are positioned to receive light emitted by the anode screen on their photocathodes, circuit means for processing the output voltages of the photomultipliers to derive voltages that are representative of the position coordinates; a pulse-height discriminator circuit adapted to be fed with the sum voltage of the output voltages of the photomultipliers for gating the output of the processing circuit when the amplitude of the sum voltage of the output voltages of the photomultipliers lies in a predetermined amplitude range, and means for compensating the distortion introduced in the image on the anode screen

Comparison of multifrequency equatorial scintillation - American and Pacific sectors

Science.gov (United States)

Livingston, R. C.

1980-08-01

In this paper we examine the severity of radio wave amplitude scintillation measured at two stations near the equator but far separated in longitude: Kwajelein, Marshall Islands (167 E), and Ancon, Peru (-77 E). The data used are long-term observations of the Defense Nuclear Agency (DNA) Wideband satellite signal intensity at VHF, UHF, and L band frequencies. The seasonal behavior of the scintillation at the two stations is similar; each shows a broad 8- to 9-month disturbed season centered about local summer. There is short-term variability in the scintillation occurrence statistics but no clear equinoctial maxima. Little difference is observed in the occurrence or severity of L band scintillation at the two stations, although a systematic difference in the frequency dependence of the scintillation produces significantly stronger VHF and UHF scintillation at Ancon. The VHF and UHF latitudinal distributions of scintillation are asymmetric about the geomagnetic equator at both stations.

Multi-frequency GNSS robust carrier tracking for ionospheric scintillation mitigation

Directory of Open Access Journals (Sweden)

Vilà-Valls Jordi

2017-01-01

Full Text Available Ionospheric scintillation is the physical phenomena affecting radio waves propagating from the space through the ionosphere to earth. The signal distortion induced by scintillation can pose a major threat to some GNSS application. Scintillation is one of the more challenging propagation scenarios, particularly affecting high-precision GNSS receivers which require high quality carrier phase measurements; and safety critical applications which have strict accuracy, availability and integrity requirements. Under ionospheric scintillation conditions, GNSS signals are affected by fast amplitude and phase variations, which can compromise the receiver synchronization. To take into account the underlying correlation among different frequency bands, we propose a new multivariate autoregressive model (MAR for the multi-frequency ionospheric scintillation process. Multi-frequency GNSS observations and the scintillation MAR are modeled in state-space, allowing independent tracking of both line-of-sight phase variations and complex gain scintillation components. The resulting joint synchronization and scintillation mitigation problem is solved using a robust nonlinear Kalman filter, validated using real multi-frequency scintillation data with encouraging results.

Neuromyelitis optica immunoglobulin G in Chinese patients detected by immunofluorescence assay on a monkey brain substrate.

Science.gov (United States)

Long, Youming; Hu, Xueqiang; Peng, Fuhua; Lu, Zhengqi; Wang, Yuge; Yang, Yu; Qiu, Wei

2012-01-01

Serum neuromyelitis optica immunoglobulin G (NMO-IgG) is used as a biomarker to differentiate between neuromyelitis optica (NMO) and multiple sclerosis (MS). However, the original assay is expensive and complex and shows low sensitivity. Here, we investigated the potential of NMO-IgG detection using an indirect immunofluorescence (IIF) assay on monkey brains. NMO-IgG seroprevalence was determined in 168 samples by an IIF assay on a monkey brain substrate. The data were compared with those from a standard mouse brain IIF assay using McNemar and kappa tests. Thirty-one of 50 (62%) NMO patients, 7 of 18 (38.9%) longitudinally extensive transverse myelitis patients, 6 of 57 (10.5%) MS patients, and 5 of 10 (50%) optic neuritis patients were seropositive for NMO-IgG. None of the acute partial transverse myelitis patients (n = 3) or healthy controls (n = 20) was positive. Thus, the sensitivity of the test was 62% for the patients with clinically definite NMO. The specificity was 89.5%, considering the 57 MS patients as the control group. The modified IIF assay on monkey brains and the standard IIF assay based on mouse brains were not significantly different (McNemar test; p = 1.000). The two assays were concordant in 39 seropositive samples and 100 seronegative samples (kappa test; kappa = 0.592, p monkey brain assay was no better than the standard mouse brain IIF assay, we affirmed that NMO-IgG is a sensitive and specific biomarker to differentiate between NMO and MS. Copyright © 2011 S. Karger AG, Basel.

2003: A centennial of spinthariscope and scintillation counting

International Nuclear Information System (INIS)

Kolar, Z.I.; Hollander, W. den

2004-01-01

In 1903 W. Crookes demonstrated in England his 'spinthariscope' for the visual observation of individual scintillations caused by alpha particles impinging upon a ZnS screen. In contrast to the analogue methods of radiation measurements in that time the spinthariscope was a single-particle counter, being the precursor of scintillation counters since. In the same period F. Giesel, J. Elster and H. Geitel in Germany also found that scintillations from ZnS represent single particle events. This paper summarises the historical events relevant to the advent of scintillation counting

Preparation and characterization of a novel UV-curable plastic scintillator

Energy Technology Data Exchange (ETDEWEB)

Zhu, Jun [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ding, Yunyu [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Jiayi [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Qi, Di [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Su, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Xu, Yewei; Bi, Yutie [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Lin, Runxiong, E-mail: qdlrx@qust.edu.cn [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhang, Lin, E-mail: zhlmy@sina.com [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

2016-05-01

A novel UV-curable plastic scintillator was first prepared by using the technology of photosensitivity rapid prototyping. It used the copolymer of 621A-80, TPGDA and styrene as the matrix doped with PPO and POPOP. Its fluorescence spectra displayed a maximum emission wavelength at 428 nm. The light yield of the plastic scintillator was approximately 7.1% of anthracene on the basis of a comparison with the commercially available scintillator (ST-401). The as-prepared plastic scintillator also displayed a fast scintillation decay. Its decay time is 2.6 ns approximately. Importantly, through the technology of photosensitivity rapid prototyping, the plastic scintillator could be prepared in a short period of time at low temperature. What's more, this preparation method provides the possibility of combining the plastic scintillator with 3D printing technology, and then the applications of the plastic scintillator may be expanded greatly.

Influence of coma aberration on aperture averaged scintillations in oceanic turbulence

Science.gov (United States)

Luo, Yujuan; Ji, Xiaoling; Yu, Hong

2018-01-01

The influence of coma aberration on aperture averaged scintillations in oceanic turbulence is studied in detail by using the numerical simulation method. In general, in weak oceanic turbulence, the aperture averaged scintillation can be effectively suppressed by means of the coma aberration, and the aperture averaged scintillation decreases as the coma aberration coefficient increases. However, in moderate and strong oceanic turbulence the influence of coma aberration on aperture averaged scintillations can be ignored. In addition, the aperture averaged scintillation dominated by salinity-induced turbulence is larger than that dominated by temperature-induced turbulence. In particular, it is shown that for coma-aberrated Gaussian beams, the behavior of aperture averaged scintillation index is quite different from the behavior of point scintillation index, and the aperture averaged scintillation index is more suitable for characterizing scintillations in practice.

Quantitative MRI analysis of the brain after twenty-two years of neuromyelitis optica indicates focal tissue damage

DEFF Research Database (Denmark)

Aradi, Mihaly; Koszegi, Edit; Orsi, Gergely

2013-01-01

). In such abnormal NAWM regions, biexponential diffusion analysis and quantitative spectroscopy indicated extracellular edema and axonal loss, respectively. Repeated analysis 6 months later identified the same alterations. Such patchy alterations were not detectable in the NAWM of the 3 cases with short-term NMO......BACKGROUND: The long-term effect of neuromyelitis optica (NMO) on the brain is not well established. METHODS: After 22 years of NMO, a patient's brain was examined by quantitative T1- and T2-weighted mono- and biexponential diffusion and proton spectroscopy. It was compared to 3 cases with short...

Neutron-gamma discrimination of boron loaded plastic scintillator

International Nuclear Information System (INIS)

Wang Dong; He Bin; Zhang Quanhu; Wu Chuangxin; Luo Zhonghui

2010-01-01

Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to 10B. Both reactions have large cross sections, and results in high detection efficiency of incident neutrons. However, similar with other organic scintillators, boron loaded plastic scintillator is sensitive to gamma rays and neutrons. So gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BC454 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and flow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons' energy becomes larger. (authors)

Surface preparation and coupling in plastic scintillator dosimetry

International Nuclear Information System (INIS)

Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc

2006-01-01

One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity

Mounting LHCb hadron calorimeter scintillating tiles

CERN Multimedia

Maximilien Brice

2004-01-01

Scintillating tiles are carefully mounted in the hadronic calorimeter for the LHCb detector. These calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

Detection of gamma rays using scintillation optical fibers

International Nuclear Information System (INIS)

Park, J. W.; Hong, S. B.

2002-01-01

Scintillating optical fibers have several advantages over other conventional materials used for radiation detection. We have used glass and plastic scintillating fibers to detect gamma rays emitted from 60 Co and 137 Cs, and beta rays from 90 Sr. The sensors are constructed of single strand or multi-strand fibers of 1 mm diameter. The glass scintillating fiber used contains cerium-activated lithium-silicate as scintillating material and the plastic scintillating fiber used is Bicron model BCF-12. In this paper, we report the pulse-height spectra obtained by both sensor types, and analyze them in the aspect of their usability for radiation detectors. Our investigation suggests that the glass fiber can be used to develop gamma ray detectors which will function in high and low gamma ray flux environments. Use of the sensor for the beta ray detection was not satisfactory. The plastic fiber sensor did not work satisfactorily for the weak gamma sources, but did produce somewhat promising results. The scintillating plastic fiber offers some feasibility as beta ray sensor material

Gamma spectrometry and plastic-scintillator inherent background

International Nuclear Information System (INIS)

Pomerantsev, V.V.; Gagauz, I.B.; Mitsai, L.I.; Pilipenko, V.S.; Solomonov, V.M.; Chernikov, V.V.; Tsirlin, Y.A.

1988-01-01

The authors measured the energy resolution for a linear dependence of light yield on gamma radiation energy of gamma spectrometers based on plastic scintillation detectors for several plastic scintillators. If there were several gamma lines from the source the line with the highest energy was used to eliminate distortion due to overlap from the Compton background from gamma radiation of higher energy. Attenuation lengths were calculated. The tests were based on three modes of interaction between the gamma radiation and the scintillator: Compton scattering, the photoelectric effect, and pair formation. The contribution from light collection was also considered. The scintillators tested included polystyrene, polymethyl methacrylate, cesium iodide, and sodium iodide. Gamma sources included cesium 137, sodium 22, potassium 40, yttrium 88, thorium 232, and plutonium-beryllium

Thallium bromide photodetectors for scintillation detection

CERN Document Server

Hitomi, K; Shoji, T; Hiratate, Y; Ishibashi, H; Ishii, M

2000-01-01

A wide bandgap compound semiconductor, TlBr, has been investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TMZ method using materials purified by many pass zone refining. The performance of the photodetectors has been evaluated by measuring their leakage current, quantum efficiency, spatial uniformity, direct X-ray detection and scintillation detection characteristics. The photodetectors have shown high quantum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection characteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a sup 1 sup 0 sup 9 Cd radioactive source have been obtained. Detection of blue scintillation from GSO and LSO scintillators irradiated with a sup 2 sup 2 Na radioactive source has been done successfully by using the photodetectors at room temperature. A clear full-energy pea...

Cherenkov and scintillation light separation on the CheSS experiment

Science.gov (United States)

Caravaca, Javier; Land, Benjamin; Descamps, Freija; Orebi Gann, Gabriel D.

2016-09-01

Separation of the scintillation and Cherenkov light produced in liquid scintillators enables outstanding capabilities for future particle detectors, the most relevant being: particle directionality information in a low energy threshold detector and improved particle identification. The CheSS experiment uses an array of small, fast photomultipliers (PMTs) and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in liquid scintillator using two techniques: based on the photon density and using the photon hit time information. A charged particle ionizing a scintillation medium produces a prompt Cherenkov cone and late isotropic scintillation light, typically delayed by several ns. The fast response of our PMTs and DAQ provides a precision well below the ns level, making possible the time separation. Furthermore, the usage of the new developed water-based liquid scintillators (WbLS) enhances the separation since it allows tuning of the Cherenkov/Scintillation ratio. Latest results on the separation for pure liquid scintillators and WbLS will be presented.

Co-doping effects on luminescence and scintillation properties of Ce doped Lu3Al5O12 scintillator

International Nuclear Information System (INIS)

Kamada, Kei; Nikl, Martin; Kurosawa, Shunsuke; Beitlerova, Alena; Nagura, Aya; Shoji, Yasuhiro; Pejchal, Jan; Ohashi, Yuji; Yokota, Yuui; Yoshikawa, Akira

2015-01-01

The Mg, Ca, Sr and Ba 200 ppm co-doped Ce:Lu 3 Al 5 O 12 single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of the co-doping. The scintillation decays were accelerated by both Mg and Ca co-dopants. The Mg co-doped samples showed the fastest decay and the highest light yield among the co-doped samples

Scintillator detector array

International Nuclear Information System (INIS)

Cusano, D.A.; Dibianca, F.A.

1981-01-01

This patent application relates to a scintillator detector array for use in computerized tomography and comprises a housing including a plurality of chambers, the said housing having a front wall transmissive to x-rays and side walls opaque to x-rays, such as of tungsten and tantalum, a liquid scintillation medium including a soluble fluor, the solvent for the fluor being disposed in the chambers. The solvent comprises either an intrinsically high Z solvent or a solvent which has dissolved therein a high Z compound e.g. iodo or bromonaphthalene; or toluene, xylene or trimethylbenzene with a lead or tin alkyl dissolved therein. Also disposed about the chambers are a plurality of photoelectric devices. (author)

Clinical analysis of neuromyelitis optica presenting as intractable nausea, vomiting and hiccups.

Science.gov (United States)

Jin, Xuehong; Pei, Shaofang; Liu, Yi; Li, Xia

2017-10-01

Vomiting and hiccups can be the manifestations of numerous systemic and neurological illnesses. Intractable nausea, vomiting and hiccups (INH) are reported as possible initial manifestations of neuromyelitis optica (NMO), but not correctly identified. Awareness of these atypical presentations is conducive to NMO early diagnosis and proper treatment to prevent further disability. In this paper, 12 NMO were reported, whose intractable vomiting and hiccups were the sole manifestations of the first attack and other attacks involving spinal cord and optic nerves developed later. All the patients were women and serum aquaporin 4 antibody (AQP4-Ab) of 83% patients was positive. MRI of 50% patients showed T2-weighted imaging/fluid attenuated inversion recovery hyperintensity which were longitudinally extensive transverse myelitis or linear signal changes. Sixty-seven percent of patients had medulla lesions, in which dorsomedial and area postrema were involved.

Development of new Polysiloxane Based Liquid Scintillators

Energy Technology Data Exchange (ETDEWEB)

Dalla Palma, M.; Quaranta, A. [Department of Industrial Engineering, University of Trento,Via Sommarive, 9, 38123 Trento (Italy); INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Gramegna, F.; Marchi, T.; Cinausero, M. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Carturan, S.; Collazuol, G.; Checchia, C. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Department of Physics and Astronomy, University of Padova, Via Marzolo, 8, 35131 Padova (Italy); Degerlier, M. [Department of Physics, Nevsehir Haci Bektas Veli University, Science and Art Faculty, 50300 Nevsehir (Turkey)

2015-07-01

In the last decade, attention toward neutron detection has been growing in the scientific community, driven by new requirements in different fields of application ranging from homeland security to medical and material analysis, from research physics, to nuclear energy production. So far neutron detection, with particular attention to fast neutrons, has been mainly based on organic liquid scintillators, owing to their good efficiency and pulse shape discrimination (PSD) capability. Most of these liquids have however some main drawbacks given by toxicity, flammability, volatility and sensitivity to dissolved oxygen that limits the duration and the quality of their performances with worse handiness and increased costs. Phenyl-substituted polysiloxanes could address most of these issues, being characterized by low toxicity, low volatility and low flammability. Their optical properties can be tailored by changing the phenyl distribution and concentration thus allowing to increase the solubility of organic dyes, to modify the fluorescence spectra and to vary the refractive index of the medium. Furthermore, polysiloxanes have been recently exploited for the production of plastic scintillators with very good chemical and thermal stability and very good radiation hardness and the development of polysiloxane liquid scintillators could allow to combine these interesting properties with the supremacy of liquid scintillators as regarding PSD over plastics. For these reasons, the properties of several phenyl-substituted polysiloxane with different phenyl amounts and different viscosities have been investigated, with particular attention to the scintillation response and the pulse shape discrimination capability, and the results of the investigation are reported in this work. More in details, the scintillation light yield towards gamma rays ({sup 60}Co and {sup 137}Cs) of several polysiloxane liquids has been analyzed and compared with the light yield of a commercial non

Some possible improvements in scintillation calorimeters

International Nuclear Information System (INIS)

Lorenz, E.

1985-03-01

Two ideas for improvements of scintillation calorimeters will be presented: a) improved readout of scintillating, totally active electromagnetic calorimeters with combinations of silicon photodiodes and fluorescent panel collectors, b) use of time structure analysis on calorimetry, both for higher rate applications and improved resolution for hadron calorimeters. (orig.)

Unexpected exacerbations following initiation of disease-modifying drugs in neuromyelitis optica spectrum disorder: Which factor is responsible, anti-aquaporin 4 antibodies, B cells, Th1 cells, Th2 cells, Th17 cells, or others?

Science.gov (United States)

Kira, Jun-Ichi

2017-08-01

Some disease-modifying drugs for multiple sclerosis, which mainly act on T cells, are ineffective for neuromyelitis optica spectrum disorder and induce unexpected relapses. These include interferon beta, glatiramer acetate, fingolimod, natalizumab, and alemtuzumab. The cases reported here suggest that dimethyl fumarate, which reduces the number of Th1 and Th17 cells and induces IL-4-producing Th2 cells, is also unsuitable for neuromyelitis optica spectrum disorder, irrespective of anti-aquaporin 4 IgG serostatus. Although oral dimethyl fumarate with manageable adverse effects is easy to initiate in the early course of multiple sclerosis, special attention should be paid for atypical demyelinating cases.

Study of polystyrene scintillators-WLS fiber elements and scintillating tile-WLS prototypes for New CHOD detector of CERN NA-62 experiment

CERN Document Server

Semenov, Vitaliy; Gorin, Aleksandr; Khudyakov, Aleksey; Rykalin, Vladimir; Yushchenko, Oleg

2016-01-01

We measured the light output and the time resolution of few sets comprised of polystyrene scintillator and wavelength shifting (WLS) fibers as readout. The samples of different thickness (7-30 mm) have been made in the shape of bricks and plates with the areas of 25×80, 108×134 and 108×268 of mm2. In addition to samples of “ordinary” scintillator with additions of 2% p- Terphenyl + 0.05% POPOP, the rapid ultraviolet scintillator with single 2% additive PBD was tested. For the light collection WLS-fibers BCF92, Y11 and scintillation fiber SCSF-78M as reemitting were checked. The fibers were glued into the grooves on the front surface of scintillators. As the photo detectors silicon photomultipliers (SiPM) produced by CPTA (Russia) and SensL (Ireland) were used. It is shown that the dependence of light output on the thickness of scintillator is nonlinear and close to the square root function, which is also confirmed by the calculations carried out by Monte Carlo. The measured value of a light output make...

Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

International Nuclear Information System (INIS)

Bircher, Chad; Shao Yiping

2012-01-01

Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm 2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used to

Report on radiation exposure of lead-scintillator stack

International Nuclear Information System (INIS)

Underwood, D.G.

1990-01-01

A stack of lead and scintillator was placed in a neutral beam obtained from targeting 800 GeV protons. Small pieces of film containing radiochromic dye were placed adjacent to the layers of scintillator for the purpose of measuring the radiation dose to the scintillator. Our motivation was to calibrate the radiation dose obtainable in this manner for future tests of scintillator for SSC experiments and to relate dose to flux to check absolute normalization for calculations. We also observed several other radiation effects which should be considered for both damage and compensation in a calorimeter

Role of hot electron transport in scintillators: A theoretical study

Energy Technology Data Exchange (ETDEWEB)

Huang, Huihui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen Univ. (China); Li, Qi [Physical Sciences Division, IBM TJ Watson Research Center, Yorktown Heights, NY (United States); Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Lu, Xinfu; Williams, R.T. [Department of Physics, Wake Forest University, Winston Salem, NC (United States); Qian, Yiyang [College of Engineering and Applied Science, Nanjing University (China); Wu, Yuntao [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States)

2016-10-15

Despite recent intensive study on scintillators, several fundamental questions on scintillator properties are still unknown. In this work, we use ab-initio calculations to determine the energy dependent group velocity of the hot electrons from the electronic structures of several typical scintillators. Based on the calculated group velocities and optical phonon frequencies, a Monte-Carlo simulation of hot electron transport in scintillators is carried out to calculate the thermalization time and diffusion range in selected scintillators. Our simulations provide physical insights on a recent trend of improved proportionality and light yield from mixed halide scintillators. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Scintillation properties of polycrystalline LaxY1-xO3 ceramic

Science.gov (United States)

Sahi, Sunil; Chen, Wei; Kenarangui, Rasool

2015-03-01

Scintillators are the material that absorbs the high-energy photons and emits visible photons. Scintillators are commonly used in radiation detector for security, medical imaging, industrial applications and high energy physics research. Two main types of scintillators are inorganic single crystals and organic (plastic or liquid) scintillators. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, some efficient inorganic scintillator such as NaI and CsI are not environmental friendly. But on the other hand, organic scintillators have low density and hence poor energy resolution which limits their use in gamma spectroscopy. Polycrystalline ceramic can be a cost effective alternative to expensive inorganic single crystal scintillators. Here we have fabricated La0.2Y1.8O3 ceramic scintillator and studied their luminescence and scintillation properties. Ceramic scintillators were fabricated by vacuum sintering of La0.2Y1.8O3 nanoparticles at temperature below the melting point. La0.2Y1.8O3 ceramic were characterized structurally using XRD and TEM. Photoluminescence and radioluminescence studies were done using UV and X-ray as an excitation source. We have used gamma isotopes with different energy to studies the scintillation properties of La0.2Y1.8O3 scintillator. Preliminary studies of La0.2Y1.8O3 scintillator shows promising result with energy resolution comparable to that of NaI and CsI.

Developments of scintillator-based soft x-ray diagnostic in LHD with CsI:Tl and P47 scintillators

Energy Technology Data Exchange (ETDEWEB)

Bando, T., E-mail: bando.takahiro@nifs.ac.jp [SOKENDAI (The Graduate University for Advanced Studies), 322-6 Oroshi-cho, Toki 509-5292 (Japan); Ohdachi, S.; Suzuki, Y. [SOKENDAI (The Graduate University for Advanced Studies), 322-6 Oroshi-cho, Toki 509-5292 (Japan); National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

2016-11-15

Multi-channel soft x-ray (SX) diagnostic has been used in the large helical device (LHD) to research magnetohydrodynamic equilibria and activities. However, in the coming deuterium plasma experiments of LHD, it will be difficult to use semiconductor systems near LHD. Therefore, a new type of SX diagnostic, a scintillator-based type diagnostic, has been investigated in order to avoid damage from the radiation. A fiber optic plate coated by P47 scintillator will be used to detect SX emission. Scintillation light will be transferred by pure silica core optical fibers and detected by photomultiplier tubes. A vertically elongated section of LHD will be covered by a 13 ch. array. Effects from the Deuterium Deuterium neutrons can be negligible when the scintillator is covered by a Pb plate 4 cm in thickness to avoid gamma-rays.

Optical and structural characterization of the pure and doped BaY{sub 2}F{sub 8} with rare earths for application in radiation detectors and scintillators; Caracterizacao optica e estrutural do BaY{sub 2}F{sub 8} puro e dopado com terras raras visando aplicacao em detectores de radiacao e cintiladores

Energy Technology Data Exchange (ETDEWEB)

Mello, Ana Carolina Santana de

2008-07-01

In this work Barium Yttrium Fluoride (BaY{sub 2}F{sub 8} -BaYF) doped with different concentrations of ions Tb{sup 3+}, Er{sup 3+}, Tm{sup 3+} e Nd{sup 3+} were characterized, aiming the application in radiation detection devices that use the scintillating properties. Two types of samples were produced in the CLA-IPEN-SP, polycrystalline samples, obtained via solid state reaction of BaF{sub 2} and YF{sub 3} under HF atmosphere, and single crystals, obtained via the zone melting method also in a HF atmosphere. The samples were characterized using the following experimental techniques: X-ray powder diffraction, Radioluminescence (RL), Optical Absorption and Dispersive X-ray Absorption Spectroscopy (DXAS). The X-ray diffraction pattern showed the presence of the phase BaY{sub 2}F{sub 8} and a small amount of the phase Ba{sub 4}Y{sub 3}F{sub 17} in the polycrystalline pure and Tb{sup 3+}doped samples. The other samples showed only the desired BaY{sub 2}F{sub 8} phase. The radioluminescence measurements of the doped BaYF, when irradiated with X-rays, showed emission peaks in energies that are characteristics of the 4f-4f transitions of rare earths. The RL of the samples with 2 mol por cent and 3 mold of Tb{sup 3+}showed quite intense peaks with a maximum emission peak at 545 nm. The Tm{sup 3+}doped BYF showed that the scintillation efficiency is not directly proportional to the doping level, and the highest RL emission were obtained for the polycrystalline samples doped with 1 mol por cent, showing a maximum peak intensity at 456 nm (the blue region of the visible spectrum). All samples showed a phosphorescent decay time of the order of seconds. Single crystals of BaYF doped with 2 mol por cent of Er{sup 3+}, in addition to one of the highest phosphorescence time, presents a quite strong Rl in the green region of the spectra. The radiation damage was evaluated by the optical absorption techniques and the results showed that the formation of the absorption bands can be

Alkali metal hafnium oxide scintillators

Science.gov (United States)

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

2018-05-08

The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Factors determining radiation stability of plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Barashkov, N.N. [Texas Univ., Richardson, TX (United States). Dept. of Chemistry; Gunder, O.A.; Voronkina, N.I. [National Ukrainian Academy of Science, Kharkov (Ukraine). Inst. for Single Crystals; Milinchuk, V.K. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

1996-11-01

Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators u.v.-Vis spectrophotometry, luminescence and ESR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as the primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3) benzene (POPOP) as the secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed by irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (author).

Factors determining radiation stability of plastic scintillators

International Nuclear Information System (INIS)

Barashkov, N.N.

1996-01-01

Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators u.v.-Vis spectrophotometry, luminescence and ESR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as the primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3) benzene (POPOP) as the secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed by irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (author)

Serial quantitative MR assessment of optic neuritis in a case of neuromyelitis optica, using gadolinium-'enhanced' STIR imaging

Energy Technology Data Exchange (ETDEWEB)

Barkhof, F.; Scheltens, P.; Valk, J. (Vrije Univ., Amsterdam (Netherlands). Dept. of Diagnostic Radiology); Waalewijn, C.; Uitdehaag, B.M.J.; Polman, C.H. (Vrije Univ., Amsterdam (Netherlands). Dept. of Neurology)

1991-02-01

A patient is presented with neuromyelitis optica. MR imaging, using a short inversion time inversion recovery (STIR) technique, clearly depicted the lesion in the left optic nerve. Subsequent serial STIR imaging, with and without Gadolinium-DTPA, allowed quantitative assessment of changes parallel to improved optic nerve function. STIR imaging is a sensitive technique to demonstrate optic nerve lesions, and enables quantitative assessment to be made of the effect of (steroid) medication. (orig.).

Scintillation device of X-ray detection

International Nuclear Information System (INIS)

Polack, F.; Bigler, E.

1985-01-01

The detection device comprises a screen made of microtubes transparent to the light emitted by a scintillator material in the microtube channels. The scintillator material optical index is greater than the microtube material index, so as to constitute optical fiber, with index rise, guiding the light toward the outside [fr

The expanded spectrum of neuromyelitis optica: evidences for a new definition

Directory of Open Access Journals (Sweden)

Marco A Lana-Peixoto

2012-10-01

Full Text Available Neuromyelitis optica (NMO has been traditionally described as the association of recurrent or bilateral optic neuritis and longitudinally extensive transverse myelitis (LETM. Identification of aquaporin-4 antibody (AQP4-IgG has deeply changed the concept of NMO. A spectrum of NMO disorders (NMOSD has been formulated comprising conditions which include both AQP4-IgG seropositivity and one of the index events of the disease (recurrent or bilateral optic neuritis and LETM. Most NMO patients harbor asymptomatic brain MRI lesions, some of them considered as typical of NMO. Some patients with aquaporin-4 autoimmunity present brainstem, hypothalamic or encephalopathy symptoms either preceding an index event or occurring isolatedly with no evidence of optic nerve or spinal involvement. On the opposite way, other patients have optic neuritis or LETM in association with typical lesions of NMO on brain MRI and yet are AQP4-IgG seronegative. An expanded spectrum of NMO disorders is proposed to include these cases.

Neuromyelitis optica and multiple sclerosis: Seeing differences through optical coherence tomography

Science.gov (United States)

Bennett, JL; de Seze, J; Lana-Peixoto, M; Palace, J; Waldman, A; Schippling, S; Tenembaum, S; Banwell, B; Greenberg, B; Levy, M; Fujihara, K; Chan, KH; Kim, HJ; Asgari, N; Sato, DK; Saiz, A; Wuerfel, J; Zimmermann, H; Green, A; Villoslada, P

2015-01-01

Neuromyelitis optica (NMO) is an inflammatory autoimmune disease of the central nervous system that preferentially targets the optic nerves and spinal cord. The clinical presentation may suggest multiple sclerosis (MS), but a highly specific serum autoantibody against the astrocytic water channel aquaporin-4 present in up to 80% of NMO patients enables distinction from MS. Optic neuritis may occur in either condition resulting in neuro-anatomical retinal changes. Optical coherence tomography (OCT) has become a useful tool for analyzing retinal damage both in MS and NMO. Numerous studies showed that optic neuritis in NMO typically results in more severe retinal nerve fiber layer (RNFL) and ganglion cell layer thinning and more frequent development of microcystic macular edema than in MS. Furthermore, while patients’ RNFL thinning also occurs in the absence of optic neuritis in MS, subclinical damage seems to be rare in NMO. Thus, OCT might be useful in differentiating NMO from MS and serve as an outcome parameter in clinical studies. PMID:25662342

Detection and clinical value of NMO-IgG in neuromyelitis optica

Directory of Open Access Journals (Sweden)

De-hui HUANG

2014-09-01

Full Text Available Neuromyelitis optica (NMO is an inflammatory demyelinating disease of the central nervous system (CNS of autoimmune etiology which predominantly affects the optic nerves and spinal cord. In 2004, a highly specific serum antibody, NMO-IgG, was found in the sera of NMO patients. Subsequently, the target antigen of NMO-IgG was identified as aquaporin 4 (AQP4, a water channel densely expressed in optic nerves, spinal cord and area around cerebral ventricles. NMO-IgG/AQP4 antibody has demonstrated extreme importance for the diagnosis and differential diagnosis, the evaluation of disease activity, therapeutic effect and prognosis of NMO. In recent years, different techniques have been used to examine NMO-IgG in serum and cerebrospinal fluid, including tissue-based, cell-based and protein-based assays. In this review, the authors give an overview of the tests currently available for the detection of NMO-IgG and their clinical significance. doi: 10.3969/j.issn.1672-6731.2014.09.003

Radioactivity measurements by liquid scintillation spectroscopy

International Nuclear Information System (INIS)

Cassette, Ph.

2004-01-01

The activity measurement techniques by liquid scintillation spectroscopy consist to mix the radioactive solution to measure with a scintillating liquid and to transform the ionizing radiations, resulting from decays, into light, detectable and quantifiable. The main advantages of these techniques are the easiness of preparation of the radioactive sources, the geometric efficiency of detection of 4π and the possibility of detection of low-level energy radiations. There are one of the only methods giving the possibility to measure the activity of pure β radionuclides; indeed, the nuclear disintegration is not accompanied of gamma radiations detectable by other techniques. There are one of the only methods too of measurement of radionuclides which disintegrate by electron capture and especially those leading to the emission of low-level energy ionizing radiations. Liquid scintillation spectroscopy can be used as an absolute method of activity measurement that is to say without the use of a calibration standard. The modern liquid scintillation counting devices can be very sensitive; the measurement of micro-activities being possible. Some of the applications of these activity measurement techniques are the carbon 14 dating and the geological tracing. Their main disadvantage is the global energetic yield which is low and variable in terms of the composition of the scintillation source necessitating to calculate the detection yield for each condition of measurement. (O.M.)

Analysis of low-intensity scintillation spectra

International Nuclear Information System (INIS)

Muravsky, V.; Tolstov, S.A.

2002-01-01

The maximum likelihood algorithms for nuclides activities estimation from low intensity scintillation γ-ray spectra have been created. The algorithms treat full energy peaks and Compton parts of spectra, and they are more effective than least squares estimators. The factors that could lead to the bias of activity estimates are taken into account. Theoretical analysis of the problem of choosing the optimal set of initial spectra for the spectrum model to minimize errors of the activities estimation has been carried out for the general case of the N-components with Gaussian or Poisson statistics. The obtained criterion allows to exclude superfluous initial spectra of nuclides from the model. A special calibration procedure for scintillation γ-spectrometers has been developed. This procedure is required for application of the maximum likelihood activity estimators processing all the channels of the scintillation γ-spectrum, including the Compton part. It allows one to take into account the influence of the sample mass density variation. The algorithm for testing the spectrum model adequacy to the processed scintillation spectrum has been developed. The algorithms are realized in Borland Pascal 7 as a library of procedures and functions. The developed library is compatible with Delphi 1.0 and higher versions. It can be used as the algorithmic basis for analysis of highly sensitive scintillation γ- and β-spectrometric devices. (author)

Characteristics of plastic scintillators fabricated by a polymerization reaction

Energy Technology Data Exchange (ETDEWEB)

Lee, Cheol Ho; Son, Jaebum; Kim, Tae Hoon; Kim, Yong Kyun [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

2017-04-15

Three plastic scintillators of 4.5 cm diameter and 2.5-cm length were fabricated for comparison with commercial plastic scintillators using polymerization of the styrene monomer 2.5-diphenyloxazole (PPO) and 1,4-bis benzene (POPOP). Their maximum emission wavelengths were determined at 426.06 nm, 426.06 nm, and 425.00 nm with a standard error of 0.2% using a Varian spectrophotometer (Agilent, Santa Clara, CA, USA). Compton edge spectra were measured using three gamma ray sources [i.e., cesium 137 ({sup 137}Cs), sodium 22 ({sup 22}Na), and cobalt 60 ({sup 60}Co)]. Energy was calibrated by analyzing the Compton edge spectra. The fabricated scintillators possessed more than 99.7% energy linearity. Light output was comparable to that of the BC-408 scintillator (Saint-Gobain, Paris, France). The fabricated scintillators showed a light output of approximately 59–64% of that of the BC-408 scintillator.

Methods for the continuous production of plastic scintillator materials

Science.gov (United States)

Bross, Alan; Pla-Dalmau, Anna; Mellott, Kerry

1999-10-19

Methods for producing plastic scintillating material employing either two major steps (tumble-mix) or a single major step (inline-coloring or inline-doping). Using the two step method, the polymer pellets are mixed with silicone oil, and the mixture is then tumble mixed with the dopants necessary to yield the proper response from the scintillator material. The mixture is then placed in a compounder and compounded in an inert gas atmosphere. The resultant scintillator material is then extruded and pelletized or formed. When only a single step is employed, the polymer pellets and dopants are metered into an inline-coloring extruding system. The mixture is then processed under a inert gas atmosphere, usually argon or nitrogen, to form plastic scintillator material in the form of either scintillator pellets, for subsequent processing, or as material in the direct formation of the final scintillator shape or form.

Neuromyelitis optica accompanied by nephrotic syndrome and autoimmune-related pancytopenia.

Science.gov (United States)

ZhangBao, Jingzi; Zhou, Lei; Lu, Jiahong; Xi, Jianying; Zhao, Chongbo; Quan, Chao

2016-05-01

Neuromyelitis optica (NMO) associated with nephrotic syndrome and autoimmune-related pancytopenia has not been reported previously. We report herein a young woman who initially presented with bilateral blurring of vision and numbness in her hands. MRI disclosed multiple white matter lesions and a long cervical spinal cord lesion extending to the medulla oblongata. Serum aquaporin-4 antibody was positive and the patient was diagnosed with NMO. While in the hospital, she presented with hypoproteinemia and heavy proteinuria, meeting the diagnostic criteria of nephrotic syndrome. After high-dose methylprednisolone treatment, her vision improved significantly and urine protein quantity decreased. However, the patient subsequently developed severe pancytopenia with a positive Coombs' test. Thrombocytopenia finally led to uncontrollable gastrointestinal bleeding as the direct cause of the patient's death. This case illustrates the extremely rare condition of concurrence of NMO, nephrotic syndrome, and autoimmune pancytopenia in one patient, which suggests the involvement of organs beyond the central nervous system in NMO spectrum disorders. Copyright © 2016 Elsevier B.V. All rights reserved.

Catálogo de Radio-Fuentes Opticas con Astrolabio Fotoeléctrico PAII

Science.gov (United States)

Manrique, W. T.; Podestá, R. C.; Alonso, E.; Actis, E. V.; Pacheco, A. M.; Bustos, G.; Lizhi, L.; Zezhi, W.; Fanmiao, Z.; Hongqi, W.; Perdomo, R.

Usando los datos observados en San Juan con el Astrolabio Fotoeléctrico PAII desde Febrero de 1992 hasta Marzo de 1997, se ha realizado el Catálogo de Radio-Fuentes Opticas de San Juan conteniendo 69 estrellas. Las observaciones de las posiciones de las radio-fuentes están realizadas para la época y equinoccio J2000,0 y en un sistema cercano al del FK5. Las precisiones medias son ± 2,2 ms y ± 0,"035 en ascensión recta y declinación respectivamente. Las magnitudes de las estrellas son desde 0,9 a 10,7 . Las declinaciones son desde --2,5 grados a --60 grados. La época media es 1995,1. Se muestran también los resultados comparados con el Catálogo Hiparcos.

Development of radiation hard scintillators

International Nuclear Information System (INIS)

Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G.; Blackburn, R.

1992-05-01

Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro

Study on determination of 90Sr by liquid scintillation spectrometry

International Nuclear Information System (INIS)

Zhai Xiufang; Li Weiping; Tian Mei; Zou Ronghu

2012-01-01

Both of Liquid scintillation counting and Cerenkov counting can be used to determinate 90 Sr in samples by Liquid scintillation spectrometry. In this work, effects of scintillation vials wit-h different material, Liquid scintillation cocktails, sample volume, Strontium carrier, pH, quenching (chemical quenching and color quenching)are studied, and both counting methods are compared. For Liquid scintillation counting. The results show that the best appropriate volume ratio of sample and liquid scintillation cocktail is 8:12 for OPTIPHASE HISAFE-3 and OPTIPHASE HISAFE-2, stability of solution decreased when sample load exceeds the maximum load for both Liquid scintillation cocktails, and OPTIPHASE HISAFE-3 also show superior performance for high saline solution. The type of scintillation vial haven't clear influence on the MDA of 90 Sr. Chemical quenching and color quenching can decrease the counting efficiency. For Cerenkov counting, the lowest MDA is obtained when polyethylene plastic vial is used and sample volume is 20 ml. Color quenching decreases the counting efficiency, while there isn't chemical quenching for Cerenkov counting. The MDA of 90 Sr is 1.19 and 1.00 Bq/L for Liquid scintillation counting and Cerenkov counting with the optimal labeling condition. (authors)

Factors determining radiation stability of plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Gunder, O.A.; Voronkina, N.I. [National Ukranian Academy of Science, Kharkov (Ukraine). Inst. for Single Crystals; Barashkov, N.N.; Milinchuk, V.K.; Jdanov, G.S. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

1995-07-01

Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (Author).

Factors determining radiation stability of plastic scintillators

Science.gov (United States)

Gunder, O. A.; Voronkina, N. I.; Barashkov, N. N.; Milinchuk, V. K.; Jdanov, G. S.

1995-07-01

Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed.

Factors determining radiation stability of plastic scintillators

International Nuclear Information System (INIS)

Gunder, O.A.; Voronkina, N.I.

1995-01-01

Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (Author)

DETECTORS: scintillating fibres

International Nuclear Information System (INIS)

Anon.

1994-01-01

In the continual search for improved detection techniques, new materials are continually proving profitable. A good example is scintillating plastic fibres - tiny transparent threads sometimes finer than a human hair which transmit light. The narrowness and flexibility of these fibres was a major breakthrough for endoscopy - non-invasive techniques for viewing the otherwise inaccessible in surgery or machine inspection. In a more sophisticated form, these fibres find ready application in communications technology, where the goal is to transmit information rather than electrical power, replacing conventional and unwieldy current-carrying wire conductors. In particle physics, fibres have long been used to take the tiny scintillations produced when high energy particles hit fluorescent materials and 'conduct' them to photosensitive detectors some distance away

Red Emitting Phenyl-Polysiloxane Based Scintillators for Neutron Detection

International Nuclear Information System (INIS)

Dalla Palma, Matteo; Quaranta, Alberto; Marchi, Tommaso; Gramegna, Fabiana; Cinausero, Marco; Carturan, Sara; Collazuol, Gianmaria

2013-06-01

In this work, the performances of new red emitting phenyl- substituted polysiloxane based scintillators are described. Three dyes were dispersed in a phenyl-polysiloxane matrix in order to shift the scintillation wavelength towards the red part of the visible spectrum. PPO, Lumogen Violet (BASF) and Lumogen Red (BASF) were mixed to the starting resins with different wt. % and the analysis of the different samples was performed by means of fluorescence measurements. The scintillation yield to alpha particles at the different dye ratios was monitored by detecting either the full spectrum or the red part of the emitted light. Finally, thin red scintillators with selected compositions were coupled to Avalanche Photodiode sensors, which are usually characterized by higher efficiency in the red part of the spectrum. An increased light output of about 17% has been obtained comparing the red scintillators to standard blue emitting systems. Preliminary results on the detection of fast neutrons with the APD-red scintillator system are also presented. (authors)

Permanent automatic recalibration system for scintillation camera

International Nuclear Information System (INIS)

Auphan, Michel.

1974-01-01

A permanent automatic recalibration system for a scintillation camera, of the type consisting chiefly of a collimator if necessary, a scintillator, a light guide and a network of n photomultipliers coupled to a display system, is described. It uses a device to form a single reference light signal common to all the photomultiplication lines, integrated to these latter and associated with a periodic calibration control generator. By means of associated circuits governed by the control generator the gain in each line is brought to and/or maintained at a value between fixed upper and lower limits. Steps are taken so that any gain variation in a given line is adjusted with respect to the reference light signal common to all the lines. The light signal falls preferably in the same part of the spectrum as the scintillations formed in the scintillator [fr

Scintillation camera with second order resolution

International Nuclear Information System (INIS)

Muehllehner, G.

1976-01-01

A scintillation camera for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area is described in which means is provided for second order positional resolution. The phototubes, which normally provide only a single order of resolution, are modified to provide second order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

Scintillation camera with second order resolution

International Nuclear Information System (INIS)

1975-01-01

A scintillation camera is described for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area in which means is provided for second-order positional resolution. The phototubes which normally provide only a single order of resolution, are modified to provide second-order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

Posterior reversible encephalopathy syndrome masquerading as progressive multifocal leukoencephalopathy in rituximab treated neuromyelitis optica.

Science.gov (United States)

Berger, Joseph R; Neltner, Janna; Smith, Charles; Cambi, Franca

2014-11-01

Both progressive multifocal leukoencephalopathy (PML) and posterior reversible encephalopathy syndrome (PRES) have been reported as complications of rituximab therapy. These disorders may appear indistinguishable on magnetic resonance imaging (MRI). We report on a 42 year old woman with neuromyelitis optica (NMO) of 10 years duration who developed extensive white matter disease affecting chiefly both parietal lobes 6 months after her first and only dose of rituximab. The MRI findings suggested the diagnosis of PML, but her history was more consistent with PRES. Ultimately, a brain biopsy was performed which was consistent with the diagnosis of PRES. PRES and PML may have overlapping symptomatology and be indistinguishable on MRI. An approach to distinguishing between these two disorders is addressed. Copyright © 2014. Published by Elsevier B.V.

Endocrinopathies in paediatric-onset neuromyelitis optica spectrum disorder with aquaporin 4 (AQP4) antibody.

Science.gov (United States)

Hacohen, Yael; Messina, Silvia; Gan, Hoong-Wei; Wright, Sukhvir; Chandratre, Saleel; Leite, Maria Isabel; Fallon, Penny; Vincent, Angela; Ciccarelli, Olga; Wassmer, Evangeline; Lim, Ming; Palace, Jacqueline; Hemingway, Cheryl

2018-04-01

The involvement of the diencephalic regions in neuromyelitis optica spectrum disorder (NMOSD) may lead to endocrinopathies. In this study, we identified the following endocrinopathies in 60% (15/25) of young people with paediatric-onset aquaporin 4-Antibody (AQP4-Ab) NMOSD: morbid obesity ( n = 8), hyperinsulinaemia ( n = 5), hyperandrogenism ( n = 5), amenorrhoea ( n = 5), hyponatraemia ( n = 4), short stature ( n = 3) and central hypothyroidism ( n = 2) irrespective of hypothalamic lesions. Morbid obesity was seen in 88% (7/8) of children of Caribbean origin. As endocrinopathies were prevalent in the majority of paediatric-onset AQP4-Ab NMOSD, endocrine surveillance and in particular early aggressive weight management is required for patients with AQP4-Ab NMOSD.

Development of TOF-PET using Compton scattering by plastic scintillators

International Nuclear Information System (INIS)

Kuramoto, M.; Nakamori, T.; Kimura, S.; Gunji, S.; Takakura, M.; Kataoka, J.

2017-01-01

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Development of TOF-PET using Compton scattering by plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Kuramoto, M., E-mail: kuramoto@maxwell.kj.yamagata-u.ac.jp [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Nakamori, T., E-mail: nakamori@maxwell.kj.yamagata-u.ac.jp [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Kimura, S.; Gunji, S.; Takakura, M. [Yamagata University, Kojirakawa 1-4-12, Yamagata 990-8560 (Japan); Kataoka, J. [Waseda University, Okubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan)

2017-02-11

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Development of TOF-PET using Compton scattering by plastic scintillators

Science.gov (United States)

Kuramoto, M.; Nakamori, T.; Kimura, S.; Gunji, S.; Takakura, M.; Kataoka, J.

2017-02-01

We propose a time-of-flight (TOF) technique using plastic scintillators which have fast decay time of a few ns for positron emission tomography (PET). While the photoelectric absorption probability of the plastic for 511 keV gamma rays are extremely low due to its small density and effective atomic number, the cross section of Compton scattering is comparable to that of absorption by conventional inorganic scintillators. We thus propose TOF-PET using Compton scattering with plastic scintillators (Compton-PET), and performed fundamental experiments towards exploration of the Compton-PET capability. We demonstrated that the plastic scintillators achieved the better time resolution in comparison to LYSO(Ce) and GAGG(Ce) scintillators. In addition we evaluated the depth-of-interaction resolving capability with the plastic scintillators.

Scintillation properties of CdF{sub 2} crystal

Energy Technology Data Exchange (ETDEWEB)

Yanagida, Takayuki, E-mail: yanagida@lsse.kyutech.ac.jp [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196 (Japan); Fujimoto, Yutaka; Koshimizu, Masanori [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Fukuda, Kentaro [Tokuyama Corp., 1-1 Mikage-cho, Shunan-shi, Yamaguchi 745-8648 Japan (Japan)

2015-01-15

CdF{sub 2} single crystal was prepared by Tokuyama Corp. with the μ-PD method to investigate Auger free luminescence of this material. From optical transmittance spectrum, bandgap wavelength was around 280 nm. In X-ray induced radioluminescence spectrum, emission lines appeared around 350 nm and 420 nm. Excitation wavelength was investigated and excitation peak was around 250 nm. Photoluminescence and scintillation decay times were evaluated and decay time was few ns. Temperature dependence of X-ray induced radioluminescence was compared with conventional BaF{sub 2} scintillator and scintillation of CdF{sub 2} decreased when the temperature increased. Consequently, scintillation of CdF{sub 2} is possibly emission at color centers or exciton related one. - Highlights: • CdF{sub 2} crystal scinitillator was synthesized. • Emission wavelengths of CdF{sub 2} appeared around 350 and 420 nm. • Scintillation decay time of CdF{sub 2} was quite fast, 1.75 ns. • Excitation bands were investigated by using Synchrotron facility, UVSOR.

Optimization of light collection from crystal scintillators for cryogenic experiments

International Nuclear Information System (INIS)

Mokina, V.M.; Danevich, F.A.; Kobychev, V.V.; Kraus, H.; Mikhailik, V.B.; Nagornaya, L.L.

2012-01-01

Cryogenic scintillation bolometers are a promising technique to search for dark matter and neutrinoless double decay. Improvement of light collection and energy resolution are important requirements in such experiments. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO 4 scintillation crystals of different shapes (cylinder 20x20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector materials and shapes, optical contact and surface properties (polished and diffused) were measured. The crystal scintillator of hexagonal shape shows the better energy resolution and pulse amplitude. The best energy resolution (FWHM = 9.3 % for 662 keV γ quanta of 137 Cs) was obtained with a hexagonal scintillator with all surfaces diffuse, in optical contact with a PMT and surrounded by a reflector (3M) of size 26x25 mm. In the geometry w ithout optical contact r epresenting the conditions of light collection for a cryogenic scintillating bolometer the best energy resolution and relative pulse amplitude was obtained for a hexagonal shape scintillator with diffuse side and polished face surfaces, surrounded by a reflector with a gap between the scintillator and the reflector

Some results of ionospheric scintillation observations at Lumping

International Nuclear Information System (INIS)

Huang, Yinn-Nien

1983-01-01

The ionospheric scintillation data obtained at Lunping by use of 136.1124 MHz beacon signal transmitted from the geostationary satellite, ETS-2, have been used to analyze the diurnal, seasonal and solar cycle variations of scintillation activity. The effect of the geomagnetic activity on the scintillation activity has been studied by use of superposed epoch method. The effect is not unique but depends on season and solar activity. (author)

Paraffin scintillator for radioassay of solid support samples

International Nuclear Information System (INIS)

Fujii, Haruo; Takiue, Makoto

1989-01-01

A new paraffin scintillator used for solid support sample counting has been proposed, and its composition and various characteristics are described. The solid support sample treated with this scintillator can be easily handled because of rigid sample conditions. This technique provides great advantages such as the elimination of a large volume of scintillator and little radioactive waste material by using an economical polyethylene bag instead of the conventional counting vial. (author)

Scintillators for positron emission tomography

International Nuclear Information System (INIS)

Moses, W.W.; Derenzo, S.E.

1995-09-01

Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ''ultimate'' scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length (≤ 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times ≤ 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so ≤5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ''fully-3D'' cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm

Energy resolution of scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Moszyński, M., E-mail: M.Moszynski@ncbj.gov.pl; Syntfeld-Każuch, A.; Swiderski, L.; Grodzicka, M.; Iwanowska, J.; Sibczyński, P.; Szczęśniak, T.

2016-01-01

According to current knowledge, the non-proportionality of the light yield of scintillators appears to be a fundamental limitation of energy resolution. A good energy resolution is of great importance for most applications of scintillation detectors. Thus, its limitations are discussed below; which arise from the non-proportional response of scintillators to gamma rays and electrons, being of crucial importance to the intrinsic energy resolution of crystals. The important influence of Landau fluctuations and the scattering of secondary electrons (δ-rays) on intrinsic resolution is pointed out here. The study on undoped NaI and CsI at liquid nitrogen temperature with a light readout by avalanche photodiodes strongly suggests that the non-proportionality of many crystals is not their intrinsic property and may be improved by selective co-doping. Finally, several observations that have been collected in the last 15 years on the influence of the slow components of light pulses on energy resolution suggest that more complex processes are taking place in the scintillators. This was observed with CsI(Tl), CsI(Na), ZnSe(Te), and undoped NaI at liquid nitrogen temperature and, finally, for NaI(Tl) at temperatures reduced below 0 °C. A common conclusion of these observations is that the highest energy resolution, and particularly intrinsic resolution measured with the scintillators, characterized by two or more components of the light pulse decay, is obtainable when the spectrometry equipment integrates the whole light of the components. In contrast, the slow components observed in many other crystals degrade the intrinsic resolution. In the limiting case, afterglow could also be considered as a very slow component that spoils the energy resolution. The aim of this work is to summarize all of the above observations by looking for their origin.

Set of counts by scintillations for atmospheric samplings

International Nuclear Information System (INIS)

Appriou, D.; Doury, A.

1962-01-01

The author reports the development of a scintillation-based counting assembly with the following characteristics: a photo-multiplier with a wide photo-cathode, a thin plastic scintillator for the counting of beta + alpha (and possibility of mounting an alpha scintillator), a relatively small own motion with respect to activities to be counted, a weakly varying efficiency. The authors discuss the counting objective, present equipment tests (counter, proportional amplifier and pre-amplifier, input drawer). They describe the apparatus operation, discuss the selection of scintillators, report the study of the own movement (electron-based background noise, total background noise, background noise reduction), discuss counts (influence of the external source, sensitivity to alpha radiations, counting homogeneity, minimum detectable activity) and efficiencies

Liquid emulsion scintillators which solidify for facile disposal

International Nuclear Information System (INIS)

O'Brien, R.E.; Krieger, J.K.

1981-01-01

A liquid organic scintillation cocktail is described which counts solutions of radiolabelled compounds containing up to ten % by volume of water with high efficiency and is readily polymerizable to a solid for easy disposal. The cocktail comprises a polymerizable organic solvent, a solubilizing agent, an intermediate solvent, and an organic scintillator. A method of disposing of liquid organic scintillation cocktail waste and a kit useful for practising the method are also described. (U.K.)

The measurement of temperature effect of light output of scintillators

International Nuclear Information System (INIS)

Ji Changsong; Zhou Zaiping; Zhang Longfang

1999-01-01

The author describes a experiment equipment used for measurement of temperature effect of light output of scintillators; gives some measurement results of temperature effect of light output for NaI(Tl), CsI(Tl), plastic scintillator, ZnS(Ag), anthracene crystal glass scintillator; analyzes the error factors affecting the measurement results. The total uncertainty of the temperature effect measurement for NaI(Tl) and plastic scintillator is 11%

Current status of liquid scintillation counting

International Nuclear Information System (INIS)

Klingler, G.W.

1981-01-01

Scintillation counting of alpha particles has been used since the turn of the century. The advent of pulse shape discrimination has made this method of detection accurate and reliable. The history, concepts and development of scintillation counting and pulse shape discrimination are discussed. A brief look at the ongoing work in the consolidation of components now used for pulse shape discrimination is included

Scintillation camera with improved output means

International Nuclear Information System (INIS)

Lange, K.; Wiesen, E.J.; Woronowicz, E.M.

1978-01-01

In a scintillation camera system, the output pulse signals from an array of photomultiplier tubes are coupled to the inputs of individual preamplifiers. The preamplifier output signals are coupled to circuitry for computing the x and y coordinates of the scintillations. A cathode ray oscilloscope is used to form an image corresponding with the pattern in which radiation is emitted by a body. Means for improving the uniformity and resolution of the scintillations are provided. The means comprise biasing means coupled to the outputs of selected preamplifiers so that output signals below a predetermined amplitude are not suppressed and signals falling within increasing ranges of amplitudes are increasingly suppressed. In effect, the biasing means make the preamplifiers non-linear for selected signal levels

BC-454 boron-loaded plastic scintillator

International Nuclear Information System (INIS)

Bellian, J.G.

1984-01-01

Prototype samples of plastic scintillators containing up to 10% by weight of natural boron have been produced. The maximum size scintillators made to date are 28 mm dia. x 100 mm long. Rods containing up to 2% boron are now made routinely and work is progressing on higher concentrations. The plastics are clear and emit the same blue fluorescence as other common plastic scintillators. It is expected that rods up to 3'' dia. containing 5% boron will be produced during the next few months. BC-454 is particularly useful in neutron research, materials studies, some types of neutron dosimetry, and monitoring of medium to high energy neutrons in the presence of other types radiation. It combines attractive features that enhance its usefulness to the physics community

Seasonal ionospheric scintillation analysis during increasing solar activity at mid-latitude

Science.gov (United States)

Ahmed, Wasiu Akande; Wu, Falin; Agbaje, Ganiyu Ishola; Ednofri, Ednofri; Marlia, Dessi; Zhao, Yan

2017-09-01

Monitoring of ionospheric parameters (such as Total Electron Content and scintillation) is of great importance as it affects and contributes to the errors encountered by radio signals. It thus requires constant measurements to avoid disastrous situation for space agencies, parastatals and departments that employ GNSS applications in their daily operations. The research objective is to have a better understanding of the behaviour of ionospheric scintillation at midlatitude as it threatens the performances of satellite communication, navigation systems and military operations. This paper adopts seasonal ionospheric scintillation scenario. The mid-latitude investigation of ionospheric effect of scintillation was conducted during the increasing solar activity from 2011-2015. Ionospheric scintillation data were obtained from four ionospheric monitoring stations located at mid-latitude (i.e Shenzhen North Station, Beijing Changping North Station Branch, Beijing North Station and Beijing Miyun ground Station). The data was collected from January 2011 to December 2015. There were absence of data due to software problem or system failure at some locations. The scintillation phenomenon was computed using Global Ionospheric Scintillation and TEC Monitoring Model. There are four seasons which existed in China namely: Spring, Summer, Autumn and Winter. The relationship between TEC, amplitude and phase scintillation were observed for each of these seasons. The results indicated that the weak amplitude scintillation was observed as against phase scintillation which was high. Phase scintillation was gradually enhanced from 2011 to 2012 and later declined till 2014. TEC was also at peak around 00:00-10:00 UT (08:00-18:00 LT). The seasonal events temporal density characteristics comply with solar cycle prediction as such it ascended from 2011 to 2013 and then scintillation parameters declined significantly afterwards.

Fiber-optic multipoint radiation sensing system using waveguide scintillators

International Nuclear Information System (INIS)

Maekawa, Tatsuyuki; Yoda, Masaki; Tanaka, Koutarou; Masumaru, Tarou; Morimoto, Souichirou.

1996-01-01

Novel fiber-optic radiation sensors and a multipoint measurement method that takes advantage of them have been developed. The new sensor design, which we call a 'waveguide scintillator', consists of a scintillating material and a wavelength-shifting fiber (WLSF). The WLSF is embedded in the scintillating material, and each end is connected to a transparent optical fiber. These waveguide scintillators can be connected in series along an optical fiber loop to form a radiation monitoring system, and each end of the fiber loop is terminated with a photodetector. This new radiation monitoring arrangement dispenses with the need for electronic apparatus at each measuring point and consequently improves resistance to noise. Furthermore, it offers the advantages of multipoint monitoring - meaning that radiation intensity can be measured at multiple sensors - using only two photodetectors. We have examined the light output characteristics and time resolution of a prototype arrangement of these new waveguide scintillators, thus confirming the feasibility of multipoint measurements using a system of multiple waveguide scintillators connected in series in an optical fiber loop. (author)

Detection of gamma-neutron radiation by solid-state scintillation detectors. Detection of gamma-neutron radiation by novel solid-state scintillation detectors

Energy Technology Data Exchange (ETDEWEB)

Ryzhikov, V.; Grinyov, B.; Piven, L.; Onyshchenko, G.; Sidletskiy, O. [Institute for Scintillation Materials of the NAS of Ukraine, Kharkov, (Ukraine); Naydenov, S. [Institute for Single Crystals of the National Academy of Sciences of Ukraine, Kharkov, (Ukraine); Pochet, T. [DETEC-Europe, Vannes (France); Smith, C. [Naval Postgraduate School, Monterey, CA (United States)

2015-07-01

It is known that solid-state scintillators can be used for detection of both gamma radiation and neutron flux. In the past, neutron detection efficiencies of such solid-state scintillators did not exceed 5-7%. At the same time it is known that the detection efficiency of the gamma-neutron radiation characteristic of nuclear fissionable materials is by an order of magnitude higher than the efficiency of detection of neutron fluxes alone. Thus, an important objective is the creation of detection systems that are both highly efficient in gamma-neutron detection and also capable of exhibiting high gamma suppression for use in the role of detection of neutron radiation. In this work, we present the results of our experimental and theoretical studies on the detection efficiency of fast neutrons from a {sup 239}Pu-Be source by the heavy oxide scintillators BGO, GSO, CWO and ZWO, as well as ZnSe(Te, O). The most probable mechanism of fast neutron interaction with nuclei of heavy oxide scintillators is the inelastic scattering (n, n'γ) reaction. In our work, fast neutron detection efficiencies were determined by the method of internal counting of gamma-quanta that emerge in the scintillator from (n, n''γ) reactions on scintillator nuclei with the resulting gamma energies of ∼20-300 keV. The measured efficiency of neutron detection for the scintillation crystals we considered was ∼40-50 %. The present work included a detailed analysis of detection efficiency as a function of detector and area of the working surface, as well as a search for new ways to create larger-sized detectors of lower cost. As a result of our studies, we have found an unusual dependence of fast neutron detection efficiency upon thickness of the oxide scintillators. An explanation for this anomaly may involve the competition of two factors that accompany inelastic scattering on the heavy atomic nuclei. The transformation of the energy spectrum of neutrons involved in the (n, n

Development of scintillation materials for medical imaging and other applications

International Nuclear Information System (INIS)

Melcher, C. L.

2013-01-01

Scintillation materials that produce pulses of visible light in response to the absorption of energetic photons, neutrons, and charged particles, are widely used in various applications that require the detection of radiation. The discovery and development of new scintillators has accelerated in recent years, due in large part to their importance in medical imaging as well as in security and high energy physics applications. Better understanding of fundamental scintillation mechanisms as well as the roles played by defects and impurities have aided the development of new high performance scintillators for both gamma-ray and neutron detection. Although single crystals continue to dominate gamma-ray based imaging techniques, composite materials and transparent optical ceramics potentially offer advantages in terms of both synthesis processes and scintillation performance. A number of promising scintillator candidates have been identified during the last few years, and several are currently being actively developed for commercial production. Purification and control of raw materials and cost effective crystal growth processes can present significant challenges to the development of practical new scintillation materials.

Study of the correlation of scintillation decay and emission wavelength

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Yamaji, Akihiro; Kawaguchi, Noriaki; Kamada, Kei; Totsuka, Daisuke; Fukuda, Kentaro; Yamanoi, Kohei; Nishi, Ryosuke; Kurosawa, Shunsuke; Shimizu, Toshihiko; Sarukura, Nobuhiko

2013-01-01

In photoluminescence which directly excites the emission center of phosphor material is known to have a correlation between the emission wavelength and the decay time based on quantum mechanics. In scintillation phenomenon, host lattice of the material is first excited by ionizing radiation and then the excitation energy is transferred to emission centers. For the first time, we investigated the correlation between the scintillation decay and the emission wavelength by using pulse X-ray equipped streak camera system which could observe time and wavelength resolved scintillation phenomenon. Investigated materials were Ce 3+ , Pr 3+ and Nd 3+ doped oxides and fluorides which all showed 5d-4f transition based emission. As a result, we obtained the relation that τ (scintillation decay time) was proportional to the λ 2.15 (emission wavelength). -- Highlights: ► The correlation between emission wavelength and scintillation decay time is investigated. ► Photoluminescence decay times are also evaluated and compared with scintillation decay times. ► It is proved the relaxation process in emission center is dominant even in scintillation decay

LET dependence of scintillation yields in liquid argon

Energy Technology Data Exchange (ETDEWEB)

Doke, Tadayoshi; Hitachi, Akira; Kikuchi, Jun; Crawford, H J; Lindstrom, P J; Masuda, Kimiaki; Shibamura, Eido; Takahashi, Tan

1988-06-01

Scintillation yields (scintillation intensity per unit absorbed energy) in liquid argon for ionizing particles are reviewed as a function of LET for the particles. The maximum scintillation yield, which is obtained for relativistic heavy ions from Ne to La, is about 1.2 times larger than that for gamma rays in NaI(Tl) crystal. In the low LET region, the scintillation yields for relativistic electrons, protons and He ions are 10-20% lower than the maximum yield. This tendency can be explained by taking into account the existence of the electrons which have escaped from their parent ions. In the high LET region, a quenching effect due to high ionization density is observed for alpha particles, fission fragments and relativistic Au ions.

Liquid scintillation cocktails comparison for tritium contamination measurements

International Nuclear Information System (INIS)

Bazzarri, S.; Belloni, P.

1996-01-01

Liquid scintillation counting is one of the most used techniques for the measurements of tritium contamination. Until few years ago a problem related to this kind of measurement was the potential toxicity of the liquid cocktails used to produce the required scintillation. Some new products that guarantee an almost negligible impact on the environment and that are no longer toxic for the operators are now available. Some of this new scintillation cocktail are suitable to be used for tritium measurement. Due to the great benefit from the health point of view of these new materials a test of their scintillation performance has been done at the ENEA centers to select the product having the best characteristics for tritium measurement. (author)

Charged particle scintillation mass spectrometer

International Nuclear Information System (INIS)

Baranov, P.S.; Zhuravlev, E.E.; Nafikov, A.A.; Osadchi , A.I.; Raevskij, V.G.; Smirnov, P.A.; Cherepnya, S.N.; Yanulis, Yu.P.

1982-01-01

A scintillation mass-spectrometer for charged particle identification by the measured values of time-of-flight and energy operating on line with the D-116 computer is described. Original time detectors with 100x100x2 mm 3 and 200x2 mm 2 scintillators located on the 1- or 2 m path length are used in the spectrometer. The 200x200x200 mm 3 scintillation unit is used as a E-counter. Time-of-flight spectra of the detected particles on the 2 m path length obtained in spectrometer test in the beam of charged particles escaping from the carbon target at the angle of 130 deg under 1.2 GeV bremsstrahlung beam of the ''Pakhra'' PIAS synchrotron are presented. Proton and deuteron energy spectra as well as mass spectrum of all the particles detected by the spectrometer are given. Mass resolution obtained on the 2 m path length for π-mesons is +-25%, for protons is +-5%, for deuterons is +-3%

Liquid scintillation alpha spectrometry techniques

International Nuclear Information System (INIS)

McKlveen, J.W.; McDowell, W.J.

1984-01-01

Accurate, quantitative determinations of alpha emitting nuclides by conventional plate counting methods are difficult, because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive alternative with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination, to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium and colonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds of the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications. (orig.)

The MICE scintillating-fibre tracker

Energy Technology Data Exchange (ETDEWEB)

Matsushita, T [Imperial College London (United Kingdom)], E-mail: T.Matsushita@imperial.ac.uk

2008-06-15

The international Muon Ionization Cooling Experiment (MICE) collaboration will carry out a systematic investigation of the ionization cooling of a muon beam. An ionization cooling channel is required to compress the phase-space volume occupied by the muon beam prior to acceleration in the baseline conceptual designs for both the Neutrino Factory and the Muon Collider. Muons entering and leaving the cooling channel will be measured in two solenoidal spectrometers, each of which is instrumented with a scintillating-fibre tracker. Each tracker is composed of five planar scintillating fibre stations, each station being composed of three planar layers of 350 micron scintillating fibres. The devices will be read out using the Visible Light Photon Counters (VLPCs) developed for use in the D0 experiment at the Tevatron. The design of the system will be presented along with the status of the tracker-construction project. The expected performance of prototypes of the full tracker will be summarised.

Ionospheric scintillation monitoring and modelling

Directory of Open Access Journals (Sweden)

Mariusz Pozoga

2009-06-01

Full Text Available

This paper presents a review of the ionospheric scintillation monitoring and modelling by the European groups

involved in COST 296. Several of these groups have organized scintillation measurement campaigns at low and

high latitudes. Some characteristic results obtained from the measured data are presented. The paper also addresses the modeling activities: four models, based on phase screen techniques, with different options and application domains are detailed. Finally some new trends for research topics are given. This includes the wavelet analysis, the high latitudes analysis, the construction of scintillation maps and the mitigation techniques.

International Colloquium on Scattering and Scintillation in Radio Astronomy

CERN Document Server

Coles, W A; Rickett, B J; Bird, M K; Efimov, A I; Samoznaev, L N; Rudash, V K; Chashei, I V; Plettemeier, D; Spangler, S R; Tokarev, Y; Belov, Y; Boiko, G; Komrakov, G; Chau, J; Harmon, J; Sulzer, M; Kojima, M; Tokumaru, M; Fujiki, K; Janardhan, P; Jackson, B V; Hick, P P; Buffington, A; Olyak, M R; Fallows, R A; Nechaeva, M B; Gavrilenko, V G; Gorshenkov, Yu N; Alimov, V A; Molotov, I E; Pushkarev, A B; Shanks, R; Tuccari, G; Lotova, N A; Vladimirski, K V; Obridko, V N; Gubenko, V N; Andreev, V E; Stinebring, D R; Gwinn, C; Lovell, J E J; Jauncey, D L; Senkbeil, C; Shabala, S; Bignall, H E; MacQuart, J P; Kedziora-Chudczer, L; Smirnova, T V; Malofeev, V M; Malov, O I; Tyulbashev, S A; Jessner, A; Sieber, W; Wielebinski, R; Scattering and Scintillation in Radio Astronomy

2006-01-01

Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html

Scintillation properties of transparent ceramic and single crystalline Nd:YAG scintillators

International Nuclear Information System (INIS)

Yanagida, Takayuki; Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui; Yoshikawa, Akira; Yagi, Hideki; Yanagitani, Takagimi

2011-01-01

Nd 0.1, 1.1, 2, 4, and 6 mol% doped YAG transparent ceramics are manufactured by the sintering method and their scintillation properties are compared with those of single crystalline Nd 1 mol% doped YAG grown by the micro-pulling down method. They show ∼80% transmittance at wavelengths longer than 300 nm and strong emission lines due to Nd 3+ 4f-4f emission in their radio-luminescence spectra. Among them, the single crystalline sample shows the highest light yield of 11,000 ph/MeV under γ-ray excitation and the second highest one is from Nd 1.1 mol% doped transparent ceramic, which shows 6000 ph/MeV. In these scintillators, dominant decay time constant is around 2-3 μs due to Nd 3+ 4f-4f transitions.

Testing of the scintillation sandwich prototype

International Nuclear Information System (INIS)

Vashkevich, V.

1995-06-01

The 3 m 2 prototype of the surface detector using optical fiber readout was completely prepared for testing measurements in February 1995 at Fermilab. Two 25 mm thick, 3 m 2 acrylic scintillation plates (1.2 x 2.5 m 2 ) are used for light collection in the upper (above the 25 mm steel plate) and lower (below the steel) counters of the sandwich. The light is collected with the help of 1 mm diameter wavelength shifter fiber loops 3 m long inserted in the grooves on the top surface of the scintillator, 3 fibers per groove. We used Kurary Y11, 200 ppm of shifter dye, and double clad fibers. 1.5 m of clear fibers spliced to each end of the shifter fiber transport the light to the phototube. Spacing between the grooves is 5 cm. The counter's edges were painted with BICRON (BC620) white reflective paint. The scintillation plates were wrapped with Dupont Tyvek. The glued bundle of fibers is connected to an EMI-9902KB 38 mm phototube through the simple light mixer bar. Used PM has a ''green extended'' rubidium bialkali photocathode. The report contains information on the testing of the scintillation sandwich

Organic scintillators with long luminescent lifetimes for radiotherapy dosimetry

DEFF Research Database (Denmark)

Beierholm, Anders Ravnsborg; Lindvold, Lars René; Andersen, Claus Erik

2011-01-01

of experiments performed using two organic scintillators, one commercially available and one custom made. The luminescent lifetimes of the scintillators have been measured using i) optical excitation by pulsed UV light, and ii) irradiative excitation using high-energy X-rays from a linac. A luminescent lifetime...... component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long...

An efficient energy response model for liquid scintillator detectors

Science.gov (United States)

Lebanowski, Logan; Wan, Linyan; Ji, Xiangpan; Wang, Zhe; Chen, Shaomin

2018-05-01

Liquid scintillator detectors are playing an increasingly important role in low-energy neutrino experiments. In this article, we describe a generic energy response model of liquid scintillator detectors that provides energy estimations of sub-percent accuracy. This model fits a minimal set of physically-motivated parameters that capture the essential characteristics of scintillator response and that can naturally account for changes in scintillator over time, helping to avoid associated biases or systematic uncertainties. The model employs a one-step calculation and look-up tables, yielding an immediate estimation of energy and an efficient framework for quantifying systematic uncertainties and correlations.

Plastic scintillators with {beta}-diketone Eu complexes for high ionizing radiation detection

Energy Technology Data Exchange (ETDEWEB)

Adadurov, A.F., E-mail: adadurov@isma.kharkov.ua [Institute for Scintillating Materials, NAN of Ukraine, Lenin Avenue 60, 61001 Kharkov (Ukraine); Zhmurin, P.N.; Lebedev, V.N.; Kovalenko, V.N. [Institute for Scintillating Materials, NAN of Ukraine, Lenin Avenue 60, 61001 Kharkov (Ukraine)

2011-10-15

Luminescent and scintillation properties of polystyrene-based plastic scintillators with {beta}-diketone Eu complexes are investigated. A scintillator with dibenzoylmethane Eu complex containing two phenyl groups demonstrates the maximum scintillating efficiency. It is shown that plastic scintillators efficiency is dramatically decreased if {beta}-diketone derivatives contain no phenyl groups as substituents. This fact can be explained by exciplex mechanism of energy transfer from a matrix to Eu complex. - Highlights: > Fluorescent properties of polystyrene scintillators with {beta}-diketone complexes of Eu were studied. > Scintillating efficiency is increased with the number of phenyl groups in Eu complex. > This is related to exciplex mechanism of energy transfer from a polymer matrix to Eu complex.

Large liquid-scintillator trackers for neutrino experiments

CERN Document Server

Benussi, L; D'Ambrosio, N; Déclais, Y; Dupraz, J P; Fabre, Jean-Paul; Fanti, V; Forton, E; Frekers, D; Frenkel, A; Girerd, C; Golovkin, S V; Grégoire, G; Harrison, K; Jonkmans, G; Jonsson, P; Katsanevas, S; Kreslo, I; Marteau, J; Martellotti, G; Martínez, S; Medvedkov, A M; Moret, G; Niwa, K; Novikov, V; Van Beek, G; Penso, G; Vasilchenko, V G; Vuilleumier, J L; Wilquet, G; Zucchelli, P; Kreslo, I E

2002-01-01

Results are given on tests of large particle trackers for the detection of neutrino interactions in long-baseline experiments. Module prototypes have been assembled using TiO$_2$-doped polycarbonate panels. These were subdivided into cells of $\\sim 1$~cm$^2$ cross section and 6~m length, filled with liquid scintillator. A wavelength-shifting fibre inserted in each cell captured a part of the scintillation light emitted when a cell was traversed by an ionizing particle. Two different fibre-readout systems have been tested: an optoelectronic chain comprising an image intensifier and an Electron Bombarded CCD (EBCCD); and a hybrid photodiode~(HPD). New, low-cost liquid scintillators have been investigated for applications in large underground detectors. Testbeam studies have been performed using a commercially available liquid scintillator. The number of detected photoelectrons for minimum-ionizing particles crossing a module at different distances from the fibre readout end was 6 to 12 with the EBCCD chain and ...

Low cost plastic scintillator by using commercial polystyrene

International Nuclear Information System (INIS)

Oktar, O.; Ari, G.; Guenduez, O.; Demirel, H.; Demirbas, A.

2009-01-01

Plastic scintillation detectors have been used in nuclear and high energy physics for many decades. Among their benefits are fast response, ease of manufacture and versatility. Their main drawbacks are radiation resistance and cost. Plastic Scintillators can be described as solid materials which contain organic fluorescent compounds dissolved within a polymer matri10. Transparent plastics commonly used for light scintillation are Polystyrene (or PS, poly-vinyl-benzene) and polyvinyl-toluene (or PVT, poly-methyl-styron). In this activity, preliminary studies for low cost plastic scintillator production by using commercial polystyrene pellets and extrusion method were aimed. For this purpose, PS blocks consist of commercial fluorescent dopant were prepared by an extruder in SANAEM. Molds suitable for extruder were designed and manufactured and optimum production parameters such as extrusion temperature profile, extrusion rate and pressure were obtained. Plastic blocks prepared were optically and mechanically tested and its response against various radioactive sources was measured.This study has shown that plastic scintillators imported can be produced in SANAEM domestically and be used for detection of radioactive materials within the country or border gates.

Cerium doped lanthanum halides: fast scintillators for medical imaging

International Nuclear Information System (INIS)

Selles, O.

2006-12-01

This work is dedicated to two recently discovered scintillating crystals: cerium doped lanthanum halides (LaCl 3 :Ce 3+ and LaBr 3 :Ce 3+ ).These scintillators exhibit interesting properties for gamma detection, more particularly in the field of medical imaging: a short decay time, a high light yield and an excellent energy resolution. The strong hygroscopicity of these materials requires adapting the usual experimental methods for determining physico-chemical properties. Once determined, these can be used for the development of the industrial manufacturing process of the crystals. A proper comprehension of the scintillation mechanism and of the effect of defects within the material lead to new possible ways for optimizing the scintillator performance. Therefore, different techniques are used (EPR, radioluminescence, laser excitation, thermally stimulated luminescence). Alongside Ce 3+ ions, self-trapped excitons are involved in the scintillation mechanism. Their nature and their role are detailed. The knowledge of the different processes involved in the scintillation mechanism leads to the prediction of the effect of temperature and doping level on the performance of the scintillator. A mechanism is proposed to explain the thermally stimulated luminescence processes that cause slow components in the light emission and a loss of light yield. Eventually the study of afterglow reveals a charge transfer to deep traps involved in the high temperature thermally stimulated luminescence. (author)

Modular scintillation camera

International Nuclear Information System (INIS)

Barrett, H. H.

1985-01-01

Improved optical coupling modules to be used in coded-aperture-type radiographic imaging systems. In a first system, a rotating slit coded-aperture is employed between the radioactive object and the module. The module consists of one pair of side-by-side photomultipliers receiving light rays from a scintillation crystal exposed to the object via the coded-aperture. The light rays are guided to the photomultipliers by a mask having a central transverse transparent window, or by a cylindrical lens, the mask or lens being mounted in a light-conveying quartz block assembly providing internal reflections at opposite faces of the assembly. This generates output signals from the photomultipliers which can be utilized to compute one-dimensional coordinate values for restoring the image of the radioactive object on a display screen. In another form of optical coupling module, usable with other types of coded-apertures, four square photomultipliers form a substantially square block and receive light rays from scintillations from a scintillation crystal exposed to the radioactive object via the coded-aperture. The light rays are guided to the photomultipliers by a square mask or a centrally transparent square lens configuration mounted in a light-conveying assembly formed by internally reflecting quartz blocks, the optical rays being directed to the respective photomultipliers so as to generate resultant output signals which can be utilized to compute image coordinate values for two-dimensional representation of the radioactive object being examined

Time resolution measurements with an improved discriminator and conical scintillators

International Nuclear Information System (INIS)

McGervey, J.D.; Vogel, J.; Sen, P.; Knox, C.

1977-01-01

A new constant fraction discriminator with improved stability and walk characteristics is described. The discriminator was used with RCA C31024 photomultiplier tubes to test scintillators of conical and cylindrical shapes. Conical scintillators of 2.54 cm base diameter, 1.0 cm top diameter, and 2.54 cm height gave a fwhm of 155 ps for 60 Co gamma rays; larger conical scintillators gave an improvement of 10-15% in fwhm over cylindrical scintillators of equal volume. (Auth.)

Cesium hafnium chloride scintillator coupled with an avalanche photodiode photodetector

Czech Academy of Sciences Publication Activity Database

Kurosawa, S.; Kodama, S.; Yokota, Y.; Horiai, T.; Yamaji, A.; Shoji, Y.; Král, Robert; Pejchal, Jan; Ohashi, Y.; Kamada, K.; Nikl, Martin; Yoshikawa, A.

2017-01-01

Roč. 12, Feb (2017), s. 1-8, č. článku C02042. ISSN 1748-0221 Grant - others:AV ČR(CZ) JSPS-17-18 Program:Bilaterální spolupráce Institutional support: RVO:68378271 Keywords : gamma detectors * scintillators and scintillating fibres * scintillators * scintillation and light emission processes Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.220, year: 2016

NMO-IgG: A Specific Biomarker for Neuromyelitis Optica

Directory of Open Access Journals (Sweden)

Brian G. Weinshenker

2006-01-01

Full Text Available Neuromyelitis optica (NMO is an inflammatory demyelinating disease that principally targets the optic nerves and spinal cord and often leads to severe disability and occasionally life threatening respiratory failure. Although its clinical manifestations overlap with those of multiple sclerosis (MS, in established cases these two conditions can be distinguished on the basis of clinical, radiological, and routine spinal fluid studies. The diagnosis in early cases or limited forms of NMO is difficult. We recently discovered a unique IgG autoantibody (NMO-IgG that is highly specific to patients with NMO and thus a valuable diagnostic aid. Its antigen, aquaporin-4 (AQP4, is the central nervous system’s predominant water channel protein. This antibody has not yet been proven to be pathogenic, but several facts suggest that it might be, including the similarity of the immunohistochemical pattern of NMO-(AQP4 IgG binding to mouse CNS tissues to the pattern of immune complex deposition in autopsied patients’ spinal cord tissue. The spectrum of diseases identified by NMO-IgG is broader than has previously been recognized clinically and includes incomplete forms of NMO, such as recurrent transverse myelitis without optic neuritis and recurrent optic neuritis without myelitis.

Ovarian Reserve in Women With Neuromyelitis Optica Spectrum Disorder

Directory of Open Access Journals (Sweden)

Jan Thöne

2018-06-01

Full Text Available Neuromyelitis optica spectrum disorder (NMOSD is a neuroinflammatory disease. The majority of NMOSD patients is seropositive for aquaporin-4 (AQP4 antibodies. AQP4 is the main water channel protein in the central nervous system, but has also been identified in the female reproductive system. Fertility issues and ovarian reserve has not yet been studied in females with NMOSD. The purpose of this study was to measure serum Anti-Müllerian hormone (AMH in females with NMOSD compared to healthy controls (HC, in combination with other lifestyle and reproduction parameters. AMH is independent from the menstrual cycle and a reliable indicator of both ovarian reserve and ovarian function. We included a total of 32 reproductive-age females, 18 HC and 14 with NMOSD. We used an enzymatically amplified two-site immunoassay to determine serum AMH level. In comparison to HC, mean AMH value was reduced in NMOSD. Apart from that significantly more women with NMOSD showed low AMH levels (< 0.8 ng/ml. Low AMH was associated with disease activity. In contrast, none of the immunotherapies for NMOSD, neither any reproductive life style parameter was associated with a decreased AMH. Our results contribute to understanding of hindered fertility in females with NMOSD and enables neurologists to better counsel female patients.

Neuromyelitis optica in pregnancy complicated by posterior reversible encephalopathy syndrome, eclampsia and fetal death.

Science.gov (United States)

Igel, Catherine; Garretto, Diana; Robbins, Matthew S; Swerdlow, Michael; Judge, Nancy; Dayal, Ashlesha

2015-03-01

Neuromyelitis optica (NMO) is a demyelinating syndrome characterized by optic neuritis and acute myelitis with poor recovery and a progressive course. We report a poor outcome complicated by posterior reversible encephalopathy syndrome (PRES) and eclampsia and review available literature and current evidence for anticipation of adverse fetal and maternal effects. After a pregnancy complicated by multiple admissions for painful NMO exacerbations, a primiparous patient with seropositive NMO presented at 31 + 3/7 weeks with eclampsia, HELLP and subsequent fetal death. MRI confirmed PRES. NMO may be associated with eclampsia and leads to adverse maternal and fetal outcomes. Posited mechanisms include antibody-mediated placental damage and a heightened risk of eclampsia-associated PRES. Further characterization of the course of NMO and its relationship with pregnancy outcomes in larger series would be invaluable.

The primary research for the development of the plastic scintillator

International Nuclear Information System (INIS)

Huang Bing; Li Wei; Yang Yan

2014-01-01

In this study, We adopted the theory of the polymerism to synthesize the scintillator, and we composed the scintillating material (2, 5-diphenyloxazole (PPO) and 1, 4-bis-(2-(5-phenyloxazolyl))-benzene (POPOP)) to the plastic (PMMA) successfully by the polymerization. We found that the scintillating material (PPO and POPOP) spread well into the plastic and the scintillator could be well seasoned with many different environmental condition through the spectroanalysis and the mechanical testing. We also found that the scintillator was well responded to the γ-ray testing which we did. According to the increase of the content for the PPO, the radiant efficiency of the γ-ray testing was increase too. (authors)

Plastic scintillators with β-diketone Eu complexes for high ionizing radiation detection

International Nuclear Information System (INIS)

Adadurov, A.F.; Zhmurin, P.N.; Lebedev, V.N.; Kovalenko, V.N.

2011-01-01

Luminescent and scintillation properties of polystyrene-based plastic scintillators with β-diketone Eu complexes are investigated. A scintillator with dibenzoylmethane Eu complex containing two phenyl groups demonstrates the maximum scintillating efficiency. It is shown that plastic scintillators efficiency is dramatically decreased if β-diketone derivatives contain no phenyl groups as substituents. This fact can be explained by exciplex mechanism of energy transfer from a matrix to Eu complex. - Highlights: → Fluorescent properties of polystyrene scintillators with β-diketone complexes of Eu were studied. → Scintillating efficiency is increased with the number of phenyl groups in Eu complex. → This is related to exciplex mechanism of energy transfer from a polymer matrix to Eu complex.

A lens-coupled scintillation counter in cryogenic environment

International Nuclear Information System (INIS)

Stoykov, A; Scheuermann, R; Amato, A; Bartkowiak, M; Konter, J A; Rodriguez, J; Sedlak, K

2011-01-01

In this work we present an elegant solution for a scintillation counter to be integrated into a cryogenic system. Its distinguishing feature is the absence of a continuous light guide coupling the scintillation and the photodetector parts, operating at cryogenic and room temperatures respectively. The prototype detector consists of a plastic scintillator with glued-in wavelength-shifting fiber located inside a cryostat, a Geiger-mode Avalanche Photodiode (G-APD) outside the cryostat, and a lens system guiding the scintillation light re-emitted by the fiber to the G-APD through optical windows in the cryostat shields. With a 0.8 mm diameter multiclad fiber and a 1 mm active area G-APD the coupling efficiency of the 'lens light guide' is about 50%. A reliable performance of the detector down to 3 K is demonstrated.

Default-mode network and deep gray-matter analysis in neuromyelitis optica patients.

Science.gov (United States)

Rueda-Lopes, Fernanda C; Pessôa, Fernanda M C; Tukamoto, Gustavo; Malfetano, Fabíola Rachid; Scherpenhuijzen, Simone Batista; Alves-Leon, Soniza; Gasparetto, Emerson L

2018-02-20

The aim of our study was to detect functional changes in default-mode network of neuromyelitis optica (NMO) patients using resting-state functional magnetic resonance images and the evaluation of subcortical gray-matter structures volumes. NMO patients (n=28) and controls patients (n=19) were enrolled. We used the integrated registration and segmentation tool, part of FMRIB's Software Library (FSL) to segment subcortical structures including the thalamus, caudate nucleus, putamen, hippocampus and amygdalae. Resting-state functional magnetic resonance images were post-processed using the Multivariate Exploratory Linear Optimized Decomposition into Independent Components, also part of FSL. Average Z-values extracted from the default-mode network were compared between patients and controls using t-tests (P values default-mode network of patients compared to controls, notably in the precuneus and right hippocampus (corrected Pdefault-mode network. The hyperactivity of certain default-mode network areas may reflect cortical compensation for subtle structural damage in NMO patients. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Neuromyelitis optica spectrum disorder in patient with systemic lupus erythematosus - our experience

Directory of Open Access Journals (Sweden)

Božić Ksenija

2018-01-01

Full Text Available Introduction. Neuromyelitis optica spectrum disorder (NMOSD is a rare demyelinating immune-mediated central nervous system disease. It is extremely rare to occur in patients with systemic lupus erythematosus (SLE, and it represents a diagnostic and therapeutic challenge. Case report. A 38-year-old Caucasian woman with medical history of SLE and new onset of flaccid paraparesis, fecal and urinary incontinence, persistent nausea and vomiting was admitted to our hospital. Based on the clinical presentation, magnetic resonance imaging findings and positive aquaporin 4 (AQP4 antibodies, a NMOSD with coexisting SLE were diagnosed. Pulse-doses of cyclophosphamide and glucocorticoids were efficient in patient treatment. Conclusion. In a patient with SLE and symptoms of longitudinal extensive transverse myelitis and/or optic neuritis and area postrema syndrome, assessment of AQP4 antibodies is neccessary for diagnosing NMOSD. Accurate diagnosis, and timely and long-term administration of immunosuppressive therapy are crucial for favorable outcome of these two coexisting diseases.

Investigation on neutron/gamma discrimination phenomena in plastic scintillators

International Nuclear Information System (INIS)

Blanc, Pauline

2014-01-01

This PhD topic was born from misunderstandings and incomplete knowledge of the mechanism and relative effectiveness of neutron and gamma-ray (n/γ) discrimination between plastic scintillators compared to liquid scintillators. The shape of the light pulse these materials generate following interaction with an ionizing particle (predominantly recoil protons in the case of neutrons and electrons in the case of gamma-rays) is different in time in a way that depends on the detected particle (nature and energy). It is this fact that enables separation (PSD). The behavior in liquid scintillators has been extensively studied experimentally for practical applications. Only recently has it been shown that a weak separation can also be achieved using specially prepared plastics. The study of this system presents an open field and the understanding of both liquids and plastics with respect to their PSD properties is far from complete. This work is dedicated to exploring the fundamental photophysical phenomena at play in the generation of luminescence emission, following the interaction of ionizing radiation with organic scintillators. For this purpose, firstly a detailed literature review of the state-of-the-art has been conducted extending from 1960 to the present day. Secondly a complete characterization of the main scintillating materials has been conducted to define their fluorescence properties and the characteristics of their scintillation under irradiation. Thirdly a proton beam has been used to simulate recoil protons to quantify under controlled laboratory conditions their specific energy deposition in a plastic scintillator with PSD properties. The fourth part of this thesis is devoted to the study of PSD efficiency of scintillators as a function of their molecular structure. This investigation has led to a plastic scintillator prepared in our laboratory with good PSD properties and a patent submission. Finally, photophysical experiments were performed using a

Measurement of light emission in scintillation vials

International Nuclear Information System (INIS)

Duran Ramiro, M. Teresa; Garcia-Torano, Eduardo

2005-01-01

The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection

Scintillating fibre detectors using position-sensitive photomultipliers

International Nuclear Information System (INIS)

Agoritsas, V.; Bergdolt, A.M.; Bing, O.; Bravar, A.; Ditta, J.; Drevenak, R.

1995-01-01

Scintillating fibre technology has made substantial progress, and has demonstrated great potential for fast tracking and triggering in high luminosity experiments in Particle Physics. Some recent issues of the RD-17 project at CERN are presented for fast and precise readout of scintillating fibre arrays, as well as for upgrade of position-sensitive photomultipliers. Excellent matching of the scintillating fibre and the position-sensitive photomultiplier, in particular in time characteristics, allowed to achieve excellent detector performances, typically a spatial resolution of ∼ 125 μm with time resolution better than 1 ns and detection efficiency greater than 95%. (author)10 refs.; 25 figs.; 1 tab

Scintillation densimeter for liquids and an isotopic conveyor weighers with plastic scintillator

International Nuclear Information System (INIS)

Makhaj, B.; Antonyak, V.; Plyater, Z.

1979-01-01

The method is described of the weighted material's mass measuring according to the results of the conveyor momentary load measurement derived from the attenuation of radiation in the transmission geometry, conveyor belt velocity measurement and digital processing of the signals from the measurement of the bouth values. In the measuring gage there are located: the point type gamma source of cesium-137 with 4 mCi capacity, the scintillation detector with plastic cylindric scintillator of 5 cm in diameter and with the length approximately equal to the width of the conveyor belt and also the tachometer-generator. The conveyor weighers described is intended for use with conveyor having belt; from 60 to 180 cm wide. The results are given of industrial exploitation of the instrument [ru

The γ rays sensitivity measurement of CeF3 scintillator detector

International Nuclear Information System (INIS)

Hu Mengchun; Zhou Dianzhong; Li Rurong; Wang Zhentong; Yang Hongqiong; Zhang Jianhua; Hu Qingyuan; Peng Taiping

2003-01-01

The CeF 3 is an abio-scintillator developed in recent years, which are insensitive to neutron and sensitive to gamma rays and respond quickness. The relationship of CeF 3 scintillation detector gamma rays sensitivity with the change of crystal thickness was measured. The CeF 3 scintillation detector is composed by high liner current photomultiplier tube of CHφT3, CHφT5 and CeF 3 scintillator. The detector gamma rays sensitivity of purple photocell and common photocell with CeF 3 scintillator were measured too

Optimum plastic scintillator and optical fiber combination for brachytherapy dosimetry

International Nuclear Information System (INIS)

Arnfield, Mark R.; Gaballa, Hani E.; Zwicker, Robert D.; Islam, Quazi; Schmidt-Ullrich, Rupert

1995-01-01

Purpose/Objective: There have been several recent reports using plastic scintillators to measure dose in photon and electron beams. External beam measurements agreed well with standard ion chamber dosimetry. This was implemented by using two identical, parallel optical fibers with a small piece of plastic scintillator attached to one. We have constructed a similar device for application to brachytherapy. Brachytherapy dosimetry is a more difficult problem than external beam because of high dose gradients and widely ranging photon energies. Based on detailed spectral measurements, we have designed a dosimeter specifically to meet the unique, stringent needs of brachytherapy. Materials and Methods: The work consisted of two stages. In the first stage, we measured the optical spectra emitted by commercial plastic scintillators and silica core optical fibers in the presence of a 10 Curie iridium 192 HDR source. In the second stage, the spectral information was used to select an optimum combination of scintillator and fiber which were incorporated in the dosimeter. Equipment for the spectral measurements included a 0.1 meter monochromator with a sensitive photomultiplier (PMT) with flat response across the visible. The resolution of spectral scans was 4 nm. The dosimeter was constructed with a 1mm x 3mm piece of plastic scintillator bonded with optical cement to a 0.6 mm diameter silica core optical fiber. A second, identical optical fiber running alongside the first, with no scintillator attached, was used for background subtraction. Two PMTs with high sensitivity in the visible were used at the fiber distal ends. There was a space for an optical filter between the fiber and the PMTs, whose purpose is described below. The PMTs were connected to a differential pair whose output was transferred to a current source for measurement by a standard electrometer. Results: The scintillation spectra of six different types of silica core optical fibers in the presence of the

The use of energy information in plastic scintillator materia

International Nuclear Information System (INIS)

Ely, J.; Anderson, K.; Bates, D.; Kouzes, R.; Lo Presti, C.; Runkle, R.; Siciliano, E.; Weier, D.

2008-01-01

Plastic scintillator material is often used for gamma-ray detection in many applications due to its relatively good sensitivity and cost-effectiveness compared to other detection materials. However, due to the dominant Compton scattering interaction mechanism, full energy peaks are not observed in plastic scintillator spectra and isotopic identification is impossible. Typically plastic scintillator detectors are solely gross count detectors. In some safeguards and security applications, such as radiation portal monitors for vehicle screening, naturally-occurring radioactive material (NORM) often triggers radiation alarms and results in innocent or nuisance alarms. The limited energy information from plastic scintillator material can be used to discriminate the NORM from targeted materials and reduce the nuisance alarm rate. An overview of the utilization of the energy information from plastic scintillator material will be presented, with emphasis on the detection capabilities and potential limitations for safeguards and security applications. (author)

Magnetic fields and scintillator performance

International Nuclear Information System (INIS)

Green, D.; Ronzhin, A.; Hagopian, V.

1995-06-01

Experimental data have shown that the light output of a scintillator depends on the magnitude of the externally applied magnetic fields, and that this variation can affect the calorimeter calibration and possibly resolution. The goal of the measurements presented here is to study the light yield of scintillators in high magnetic fields in conditions that are similar to those anticipated for the LHC CMS detector. Two independent measurements were performed, the first at Fermilab and the second at the National High Magnetic Field Laboratory at Florida State University

New heavy scintillating materials for precise heterogeneous EM-calorimeters

International Nuclear Information System (INIS)

Britvich, G.I.; Britvich, I.G.; Vasil'chenko, V.G.; Lishin, V.A.; Obraztsov, V.F.; Polyakov, V.A.; Solovjev, A.S.; Ryzhikov, V.D.

2001-01-01

This investigation shows some optical and scintillation properties of new scintillating media, based on heavy composite materials and an inorganic crystal CsI:Br, intended for the creation of precise heterogeneous EM-calorimeters with the energy resolution σ/E congruent with 4-5% E-radical. The possibility to use cheap heavy scintillating plates based on optical ceramics as active media in heterogeneous EM-calorimeters is considered

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

International Nuclear Information System (INIS)

Ji, Xiaoling; Deng, Jinping

2014-01-01

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence

Effect of spherical aberration on scintillations of Gaussian beams in atmospheric turbulence

Energy Technology Data Exchange (ETDEWEB)

Ji, Xiaoling, E-mail: jiXL100@163.com; Deng, Jinping

2014-07-18

The effect of spherical aberration on scintillations of Gaussian beams in weak, moderate and strong turbulence is studied using numerical simulation method. It is found that the effect of the negative spherical aberration on the on-axis scintillation index is quite different from that of the positive spherical aberration. In weak turbulence, the positive spherical aberration results in a decrease of the on-axis scintillation index on propagation, but the negative spherical aberration results in an increase of the on-axis scintillation index when the propagation distance is not large. In particular, in weak turbulence the negative spherical aberration may cause peaks of the on-axis scintillation index, and the peaks disappear in moderate and strong turbulence, which is explained in physics. The strong turbulence leads to less discrepancy among scintillations of Gaussian beams with and without spherical aberration. - Highlights: • In weak turbulence scintillations can be suppressed using positive spherical aberration. • In weak turbulence scintillations may be very large due to negative spherical aberration. • The effect of spherical aberration on scintillations is less with increasing of turbulence.

Liquid scintillation spectrometer survey 155Eu liquid activity

International Nuclear Information System (INIS)

Zhang Zuhua

2002-01-01

In the countrywide contrasting survey of 155 Eu activity, 155 Eu liquid activity was determined for the first time through using liquid scintillation spectrometer survey 155 Eu β ray. In survey total uncertainty, determining activity accord with determining activity average value of all a wide variety of survey instrument entering into contrasting survey. But using liquid scintillation spectrometer survey, it is simple and save time, is beyond compare for other survey method. It indicate liquid scintillation spectrometer survey β-γ nuclide activity is effective as well

Scintillation properties of transparent ceramic and single crystalline Nd:YAG scintillators

Energy Technology Data Exchange (ETDEWEB)

Yanagida, Takayuki, E-mail: t_yanagi@tagen.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yagi, Hideki; Yanagitani, Takagimi [Konoshima Chemical Co., Ltd., 80 Kouda, Takuma, Mitoyo-gun, Kagawa 769-1103 (Japan)

2011-03-01

Nd 0.1, 1.1, 2, 4, and 6 mol% doped YAG transparent ceramics are manufactured by the sintering method and their scintillation properties are compared with those of single crystalline Nd 1 mol% doped YAG grown by the micro-pulling down method. They show {approx}80% transmittance at wavelengths longer than 300 nm and strong emission lines due to Nd{sup 3+} 4f-4f emission in their radio-luminescence spectra. Among them, the single crystalline sample shows the highest light yield of 11,000 ph/MeV under {gamma}-ray excitation and the second highest one is from Nd 1.1 mol% doped transparent ceramic, which shows 6000 ph/MeV. In these scintillators, dominant decay time constant is around 2-3 {mu}s due to Nd{sup 3+} 4f-4f transitions.

The Contribution of Optical Coherence Tomography in Neuromyelitis Optica Spectrum Disorders

Science.gov (United States)

Mateo, Javier; Esteban, Olivia; Martínez, Mireya; Grzybowski, Andrzej; Ascaso, Francisco Javier

2017-01-01

Neuromyelitis optica spectrum disorders (NMOSD) comprises a group of central nervous system disorders of inflammatory autoimmune origin that mainly affect the optic nerves and the spinal cord and can cause severe visual and general disability. The clinical signs are similar to those of multiple sclerosis (MS), with the result that it is often difficult to differentiate between the two, thus leading to misdiagnosis. As the treatment and prognosis of NMOSD and MS are different, it is important to make an accurate and early diagnosis of NMOSD. Optical coherence tomography (OCT) is a non-invasive technique that enables a quantitative study of the changes that the optic nerve and the macula undergo in several neurodegenerative diseases. Many studies have shown that some of these changes, such as retinal nerve fiber layer thinning or microcystic macular edema, can be related to alterations in the brain due to neurodegenerative disorders. The purpose of this mini-review is to show how OCT can be useful for the diagnosis of NMOSD and follow-up of affected patients, as well as for the differential diagnosis with MS. PMID:29085325

GAGG:ce single crystalline films: New perspective scintillators for electron detection in SEM

International Nuclear Information System (INIS)

Bok, Jan; Lalinský, Ondřej; Hanuš, Martin; Onderišinová, Zuzana; Kelar, Jakub; Kučera, Miroslav

2016-01-01

Single crystal scintillators are frequently used for electron detection in scanning electron microscopy (SEM). We report gadolinium aluminum gallium garnet (GAGG:Ce) single crystalline films as a new perspective scintillators for the SEM. For the first time, the epitaxial garnet films were used in a practical application: the GAGG:Ce scintillator was incorporated into a SEM scintillation electron detector and it showed improved image quality. In order to prove the GAGG:Ce quality accurately, the scintillation properties were examined using electron beam excitation and compared with frequently used scintillators in the SEM. The results demonstrate excellent emission efficiency of the GAGG:Ce single crystalline films together with their very fast scintillation decay useful for demanding SEM applications. - Highlights: • First practical application of epitaxial garnet films demonstrated in SEM. • Improved image quality of SEM equipped with GAGG:Ce single crystalline thin film scintillator. • Scintillation properties of GAGG:Ce films compared with standard bulk crystal scintillators.

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

Energy Technology Data Exchange (ETDEWEB)

Westerdale, S.; Xu, J.; Shields, E.; Froborg, F.; Calaprice, F.; Alexander, T.; Aprahamian, A.; Back, H. O.; Casarella, C.; Fang, X.; Gupta, Y. K.; Lamere, E.; Liu, Q.; Lyons, S.; Smith, M.; Tan, W.

2017-08-01

Organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of $^{10}$B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on $^{10}$B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem. In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57--467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in $dE/dx$ best describes the measurements, with $\\chi^2$/NDF$=1.6$. This result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.

Quenching measurements and modeling of a boron-loaded organic liquid scintillator

International Nuclear Information System (INIS)

Westerdale, S.; Xu, J.; Shields, E.; Froborg, F.; Calaprice, F.; Alexander, T.; Back, H.O.; Aprahamian, A.; Casarella, C.; Fang, X.; Gupta, Y.K.; Lamere, E.; Liu, Q.; Lyons, S.; Smith, M.; Tan, W.

2017-01-01

Organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of 10 B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on 10 B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem. In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57–467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in dE / dx best describes the measurements, with χ 2 /NDF=1.6. This result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.

High-resolution x-ray imaging using a structured scintillator

Energy Technology Data Exchange (ETDEWEB)

Hormozan, Yashar, E-mail: hormozan@kth.se; Sychugov, Ilya; Linnros, Jan [Materials and Nano Physics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, Kista, Stockholm SE-16440 (Sweden)

2016-02-15

Purpose: In this study, the authors introduce a new generation of finely structured scintillators with a very high spatial resolution (a few micrometers) compared to conventional scintillators, yet maintaining a thick absorbing layer for improved detectivity. Methods: Their concept is based on a 2D array of high aspect ratio pores which are fabricated by ICP etching, with spacings (pitches) of a few micrometers, on silicon and oxidation of the pore walls. The pores were subsequently filled by melting of powdered CsI(Tl), as the scintillating agent. In order to couple the secondary emitted photons of the back of the scintillator array to a CCD device, having a larger pixel size than the pore pitch, an open optical microscope with adjustable magnification was designed and implemented. By imaging a sharp edge, the authors were able to calculate the modulation transfer function (MTF) of this finely structured scintillator. Results: The x-ray images of individually resolved pores suggest that they have been almost uniformly filled, and the MTF measurements show the feasibility of a few microns spatial resolution imaging, as set by the scintillator pore size. Compared to existing techniques utilizing CsI needles as a structured scintillator, their results imply an almost sevenfold improvement in resolution. Finally, high resolution images, taken by their detector, are presented. Conclusions: The presented work successfully shows the functionality of their detector concept for high resolution imaging and further fabrication developments are most likely to result in higher quantum efficiencies.

Neuromyelitis optica-IgG testing in an Indian cohort with neuromyelitis optica and related demyelinating disorders: Our experience

Directory of Open Access Journals (Sweden)

Narayanan Unni

2013-01-01

Full Text Available Background: Neuromyelitis optica (NMO is an immune-mediated inflammatory demyelinating disorder of the central nervous system with a predilection for the optic nerves and the spinal cord. Immunopathological evidence suggests that the target antigen of the disease is aquaporin-4. An IgG antibody against this protein has been explored as a molecular marker for the disease and as a diagnostic tool due to its high sensitivity and specificity in various populations. Objective: To assess the value of NMO-IgG testing in Indian patients with clinical and magnetic resonance imaging features consistent with NMO and longitudinally extensive transverse myelitis (LETM. Materials and Methods: Forty-five patients with clinical and magnetic resonance imaging features consistent with NMO, LETM, and MS were tested for serum NMO-IgG. Of these patients, 22 patients satisfied revised (2006 Wingerchuk criteria for NMO (excluding NMO-IgG status and 11 patients had LETM. Twelve patients satisfied the revised (2010 McDonald criteria for multiple sclerosis (MS. Results: Of the 21 patients, satisfying the criteria for NMO and for whom the test results were available, 17 were positive for NMO-IgG (80.9%, and of the 11 patients having LETM, 6 (54.5% were positive for NMO-IgG. In one patient with NMO, the test result was not available. None of the 12 patients satisfying McDonald criteria for MS showed NMO-IgG seropositivity. Conclusion: Our study suggests that it is worthwhile to pursue NMO-IgG testing as a diagnostic tool for patients with clinical and Magnetic Resonance Imaging (MRI features consistent with NMO and LETM in the Indian population.

Semiconductor high-energy radiation scintillation detector

International Nuclear Information System (INIS)

Kastalsky, A.; Luryi, S.; Spivak, B.

2006-01-01

We propose a new scintillation-type detector in which high-energy radiation generates electron-hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible attenuation. We discuss two ways to accomplish this, one based on doping the semiconductor with shallow impurities of one polarity type, preferably donors, the other by heterostructure bandgap engineering. The proposed semiconductor scintillator combines the best properties of currently existing radiation detectors and can be used for both simple radiation monitoring, like a Geiger counter, and for high-resolution spectrography of the high-energy radiation. An important advantage of the proposed detector is its fast response time, about 1 ns, essentially limited only by the recombination time of minority carriers. Notably, the fast response comes without any degradation in brightness. When the scintillator is implemented in a qualified semiconductor material (such as InP or GaAs), the photo-detector and associated circuits can be epitaxially integrated on the scintillator slab and the structure can be stacked-up to achieve virtually any desired absorption capability

Collimated trans-axial tomographic scintillation camera

International Nuclear Information System (INIS)

1980-01-01

The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

The Origins of Scintillator Non-Proportionality

Science.gov (United States)

Moses, W. W.; Bizarri, G. A.; Williams, R. T.; Payne, S. A.; Vasil'ev, A. N.; Singh, J.; Li, Q.; Grim, J. Q.; Choong, W.-S.

2012-10-01

Recent years have seen significant advances in both theoretically understanding and mathematically modeling the underlying causes of scintillator non-proportionality. The core cause is that the interaction of radiation with matter invariably leads to a non-uniform ionization density in the scintillator, coupled with the fact that the light yield depends on the ionization density. The mechanisms that lead to the luminescence dependence on ionization density are incompletely understood, but several important features have been identified, notably Auger-like processes (where two carriers of excitation interact with each other, causing one to de-excite non-radiatively), the inability of excitation carriers to recombine (caused either by trapping or physical separation), and the carrier mobility. This paper reviews the present understanding of the fundamental origins of scintillator non-proportionality, specifically the various theories that have been used to explain non-proportionality.

Radiation effects in polymers for plastic scintillation detectors

International Nuclear Information System (INIS)

Pla-Dalmau, A.; Bross, A.D.; Hurlbut, C.R.; Moser, S.W.

1994-01-01

Recent developments in both scintillating plastic optical fibers and photon detection devices have spawned new applications for plastic scintillator detectors. This renewed attention has encouraged research that addresses the radiation stability of plastic scintillators. The optical quality of the polymer degrades with exposure to ionizing radiation and thus the light yield of the detector decreases. A complete understanding of all the mechanisms contributing to this radiation-induced degradation of the polymer can lead to techniques that will extend the radiation stability of these materials. Various radiation damage studies have been performed under different atmospheres and dose rates. Currently, the use of additives to preserve the optical properties of the polymer matrix under radiation is being investigated. The authors discuss the effect of certain antioxidants, plasticizers, and cross-linking agents on the radiation resilience of plastic scintillators

General considerations for SSC scintillator calorimeters (For the scintillator general subgroup)

International Nuclear Information System (INIS)

Nodulman, L.

1989-01-01

The Scintillator Calorimetry group divided into three subgroups: a conventional uranium and plate design ala ZEUS, fiber design, and a group on general considerations. The considerations of the third group are reported here on geometrical and technical issues. 1 fig

WORKSHOP: Scintillating crystals

Energy Technology Data Exchange (ETDEWEB)

Anon.

1992-12-15

Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry.

WORKSHOP: Scintillating crystals

International Nuclear Information System (INIS)

Anon.

1992-01-01

Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry

Performance of Water-Based Liquid Scintillator: An Independent Analysis

Directory of Open Access Journals (Sweden)

D. Beznosko

2014-01-01

Full Text Available The water-based liquid scintillator (WbLS is a new material currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This material strives to achieve the novel detection techniques by combining the Cerenkov rings and scintillation light, as well as the total cost reduction compared to pure liquid scintillator (LS. The independent light yield measurement analysis for the light yield measurements using three different proton beam energies (210 MeV, 475 MeV, and 2000 MeV for water, two different WbLS formulations (0.4% and 0.99%, and pure LS conducted at Brookhaven National Laboratory, USA, is presented. The results show that a goal of ~100 optical photons/MeV, indicated by the simulation to be an optimal light yield for observing both the Cerenkov ring and the scintillation light from the proton decay in a large water detector, has been achieved.

Research to Operations of Ionospheric Scintillation Detection and Forecasting

Science.gov (United States)

Jones, J.; Scro, K.; Payne, D.; Ruhge, R.; Erickson, B.; Andorka, S.; Ludwig, C.; Karmann, J.; Ebelhar, D.

Ionospheric Scintillation refers to random fluctuations in phase and amplitude of electromagnetic waves caused by a rapidly varying refractive index due to turbulent features in the ionosphere. Scintillation of transionospheric UHF and L-Band radio frequency signals is particularly troublesome since this phenomenon can lead to degradation of signal strength and integrity that can negatively impact satellite communications and navigation, radar, or radio signals from other systems that traverse or interact with the ionosphere. Although ionospheric scintillation occurs in both the equatorial and polar regions of the Earth, the focus of this modeling effort is on equatorial scintillation. The ionospheric scintillation model is data-driven in a sense that scintillation observations are used to perform detection and characterization of scintillation structures. These structures are then propagated to future times using drift and decay models to represent the natural evolution of ionospheric scintillation. The impact on radio signals is also determined by the model and represented in graphical format to the user. A frequency scaling algorithm allows for impact analysis on frequencies other than the observation frequencies. The project began with lab-grade software and through a tailored Agile development process, deployed operational-grade code to a DoD operational center. The Agile development process promotes adaptive promote adaptive planning, evolutionary development, early delivery, continuous improvement, regular collaboration with the customer, and encourage rapid and flexible response to customer-driven changes. The Agile philosophy values individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a rigid plan. The end result was an operational capability that met customer expectations. Details of the model and the process of

Scintillation γ spectrography. Physical principles. Apparatus. Operation

International Nuclear Information System (INIS)

Julliot, C.

1960-01-01

The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of γ photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by γ ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the γ recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a γ-emitting radioelement by the spectrographic method. (author) [fr

Performance and characteristics of a new scintillator

CERN Document Server

Czirr, J B; MacGillivray, R R; Seddon, P J

1999-01-01

A new class of scintillators for neutron imaging, based upon lithium gadolinium borate, is described. These scintillators offer the ability to tailor their response to the neutron spectrum by varying the relative absorption of neutrons by the key constituents (lithium, gadolinium and boron). The isotopic compositions of each constituent can be varied in order to change the spectral response.

Radiation-resistant composite scintillators based on GSO and GPS grains

Energy Technology Data Exchange (ETDEWEB)

Boyarintsev, A.Yu. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine); Galunov, N.Z. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine); V.N. Karasin Kharkov National University, 4 Svobody Sq., 61022 Kharkiv (Ukraine); Gerasymov, Ia.V.; Karavaeva, N.L. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine); Krech, A.V., E-mail: AntonKrech@gmail.com [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine); Levchuk, L.G.; Popov, V.F. [National Science Center, Kharkov Institute of Physics and Technology, 1 Akademicheskaya Str., 61108 Kharkiv (Ukraine); Sidletskiy, O.Ts. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine); Sorokin, P.V. [National Science Center, Kharkov Institute of Physics and Technology, 1 Akademicheskaya Str., 61108 Kharkiv (Ukraine); Tarasenko, O.A. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Nauki Avenue, 61001 Kharkiv (Ukraine)

2017-01-01

The effect of irradiation on the scintillation light output, optical transmittance, and luminescent spectra of composite scintillators based on grains of single crystals Gd{sub 2}SiO{sub 5}:Ce (GSO) and Gd{sub 2}Si{sub 2}O{sub 7}:Ce (GPS) is studied. The dielectric gel Sylgard-184 is the base and the binder for the grains inside the composite scintillator. The paper presents and analyzes the results obtained for the scintillators exposed by 10 MeV electrons from the linear electron accelerator at room temperature. The exposure doses D≤250 Mrad. The dose rate is 0.2 or 1500 Mrad/h. The study has shown that the composite scintillators based on the grains of GSO and GPS are radiation-resistant over the range of the irradiation.

Polysiloxane scintillator composition

Science.gov (United States)

Walker, J.K.

1992-05-05

A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing radiation to detectable light.

Neuromyelitis optica: a positive appraisal of seronegative cases.

Science.gov (United States)

Bernard-Valnet, R; Liblau, R S; Vukusic, S; Marignier, R

2015-12-01

Neuromyelitis optica (NMO) is a rare inflammatory disorder of the central nervous system. The hallmark of NMO is the presence of specific autoantibodies directed against aquaporin 4 (AQP4-IgG). AQP4-IgG, included in diagnostic criteria, has enlarged the clinical spectrum of NMO and serves to predict relapses. Moreover AQP4-IgG has provided unprecedented insight in the immunopathology of NMO, representing a rationale for therapeutic intervention with relevant novel treatment strategies specific for NMO. However, some patients remain seronegative for AQP4-IgG despite a definite diagnosis of NMO and the use of the finest methods for antibody detection. Interestingly, seronegative NMO (NMO(neg)) patients exhibit different demographic and disease-related characteristics in comparison to seropositive patients. The recent association with autoantibodies specific for myelin oligodendrocyte glycoprotein (MOG) is the main indication that disease mechanisms might differ in NMO(pos) and NMO(neg), challenging the position of NMO(neg) patients in the spectrum of demyelinating diseases and therapeutic strategies to be adopted. Thus, a reappraisal of the NMO(neg) population is needed to improve NMO care. Here the current knowledge regarding NMO(neg) is reviewed and hypotheses on its pathogenesis are made including a comprehensive description of detection methods and the prevalence of AQP4-IgG and a review of the epidemiological, clinical and paraclinical characteristics of NMO(neg); finally an integrated view of the general pathophysiological mechanisms underlying NMO(neg) is provided. © 2015 EAN.

Scintillation and optical stimulated luminescence of Ce-doped CaF2

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro; Kawaguchi, Noriaki; Miyamoto, Yuka; Nanto, Hidehito

2014-01-01

Scintillation and optical stimulated luminescence of Ce 0.1–20% doped CaF 2 crystals prepared by Tokuyama Corp. were investigated. In X-ray induced scintillation spectra, luminescence due to Ce 3+ 5d–4f transition appeared around 320 nm with typically 40 ns decay time. By 241 Am 5.5 MeV α-ray irradiation, 0.1% doped one showed the highest scintillation light yield and the light yield monotonically decreased with Ce concentrations. Optically stimulated luminescence after X-ray irradiation was observed around 320 nm under 550 or 830 nm stimulation in all samples. As a result, intensities of optically stimulated luminescence were proportional to Ce concentrations. Consequently, scintillation and optically stimulated luminescence resulted to have a complementary relation in Ce-doped CaF 2 system. - Highlights: • Optical, scintillation, and OSL properties of Ce 0.1–20% doped CaF 2 were studied. • Scintillation light yield exhibited inverse proportionality to Ce concentrations. • OSL intensities showed proportionality to Ce concentrations. • Complementary relation of scintillation and OSL was experimentally confirmed

A different approach to the analysis of GPS scintillations data

International Nuclear Information System (INIS)

Forte, B.; Radicella, S.M.; Ezquer, R.G.

2001-09-01

Amplitude scintillations data from GPS have been analyzed. The objective is to estimate the impact of ionospheric scintillations at Satellite-Based Augmentation System (SBAS) Ranging and Integrity Monitoring Station (RIMS) level and at GPS user level. For this purpose a new approach to the problem has been considered. Data have been studied from the point of view of the impact of scintillations on the calculation of VTEC at pierce points and ionospheric grid points. An ionospheric grid of 5 deg. by 5 deg. surface squares has been assumed. From geometrical considerations and taking into account the basic principle to compute VTEC at grid points, with the data analyzed it is shown that very seldom scintillations can affect the calculation of a grid point VTEC. Data from all the RIMS and for the entire GPS satellites network must be analyzed simultaneously to describe a realistic scenario for the impact of scintillations on SBAS. Finally, GPS scintillation data have been analyzed at user level: service availability problems have been encountered. (author)

Production of the Large-area Plastic Scintillator for Beta-ray Detection using Epoxy Resin

International Nuclear Information System (INIS)

Nam, Jong Soo; Choi, Yong Seok; Hong, Sang Bum; Seo, Bum Kyung; Moon, Jei Kwon; Choi, Jong Won

2016-01-01

In this study, we prepared a plastic scintillator whose manufacturing process is simple and can be freely shaped. A thin plate of the plastic scintillator was manufactured using epoxy resin as a polymer. The plastic scintillator was made by mixing epoxy resin and organic scintillators under various conditions. The optimal mixture ratio to prepare the plastic scintillator was derived from the above results. Using the derived results, we made the large-area plastic scintillator which can quickly measure the contamination site and evaluated characteristics of the large-area plastic scintillator in the laboratory. A thin plate of a plastic scintillator with a simple preparation process can be freely shaped using epoxy resin and organic scintillators such as PPO and POPOP. PPO emits scintillation of light in the ultraviolet range, and POPOP is a wave shifter for moving the wavelength responsible for the PMT. The mixture ratio of PPO and POPOP was determined using their emission spectra. The optimal weight percentage of PPO and POPOP in an organic scintillator was determined to be 0.2 wt%:0.01 wt%. Based on the above results, the large-area plastic scintillator of the window size of a typical pancake-type αβ surface contamination counter was prepared. We want to evaluate the characteristics of the large-area plastic scintillator. However, there were the difficulties in evaluating characteristics of the large-area plastic scintillator. The cross-sectional area of the large-area plastic scintillator is significantly different to PMT

Production of the Large-area Plastic Scintillator for Beta-ray Detection using Epoxy Resin

Energy Technology Data Exchange (ETDEWEB)

Nam, Jong Soo; Choi, Yong Seok; Hong, Sang Bum; Seo, Bum Kyung; Moon, Jei Kwon; Choi, Jong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

In this study, we prepared a plastic scintillator whose manufacturing process is simple and can be freely shaped. A thin plate of the plastic scintillator was manufactured using epoxy resin as a polymer. The plastic scintillator was made by mixing epoxy resin and organic scintillators under various conditions. The optimal mixture ratio to prepare the plastic scintillator was derived from the above results. Using the derived results, we made the large-area plastic scintillator which can quickly measure the contamination site and evaluated characteristics of the large-area plastic scintillator in the laboratory. A thin plate of a plastic scintillator with a simple preparation process can be freely shaped using epoxy resin and organic scintillators such as PPO and POPOP. PPO emits scintillation of light in the ultraviolet range, and POPOP is a wave shifter for moving the wavelength responsible for the PMT. The mixture ratio of PPO and POPOP was determined using their emission spectra. The optimal weight percentage of PPO and POPOP in an organic scintillator was determined to be 0.2 wt%:0.01 wt%. Based on the above results, the large-area plastic scintillator of the window size of a typical pancake-type αβ surface contamination counter was prepared. We want to evaluate the characteristics of the large-area plastic scintillator. However, there were the difficulties in evaluating characteristics of the large-area plastic scintillator. The cross-sectional area of the large-area plastic scintillator is significantly different to PMT.

Development of scintillating fiber tracker

International Nuclear Information System (INIS)

Ishikawa, Shuzo; Kawai, Toshihide; Kozaki, Tetsuo

1995-01-01

In order to use thin scintillating fiber (diameter 500 micron) as a particle tracking detector, we have developed a method to construct precise multi-layer scintillating fiber sheets. We have also developed dedicated machines for this purpose. This paper presents the details of the method and the machines. Using these machines, we have produced fiber sheets for CERN WA95/CHORUS, which intend to detect a neutrino oscillation in the νμ-ντ channel using Hybrid Emulsion Set-up. Fiber Trackers are used as a vertex detector which support the neutrino event location in the nuclear emulsion target. (author)

Properties of the ukrainian polystyrene-based plastic scintillator UPS 923A

International Nuclear Information System (INIS)

Artikov, A.; Budagov, Yu.; Chirikov-Zorin, I.; Lyablin, M.; Chokheli, D.; Bellettini, G.; Mensione, A.; Tokar, S; Giokaris, N.; Manousakis-Katsikakis, A.

2005-01-01

The polystyrene-based scintillator UPS 923A was chosen for upgrading of the muon system for the CDF detector at the Fermilab Tevatron. Properties of this scintillator such as light output, light attenuation, long-term stability and also timing characteristics of the scintillator and wavelength shifting fibers were investigated. The method for the Bulk Attenuation Length measurements of the scintillator to its own light emitted was proposed. Comparative measurements of the characteristics of the UPS 923A and the polyvinyltoluene-based scintillator NE 114 were performed. It was found that natural aging of the NE 114 was two times faster than that of the UPS 923A

Composition for use in scintillator systems

International Nuclear Information System (INIS)

Tarkkanen, V.

1976-01-01

A liquid scintillation counting composition of the type comprising an aromatic hydrocarbon solvent, an ethoxylated alkyl phenol surfactant, and a scintillation solute, containing a small amount of a substituted ethoxylated carboxylate acid and/or a tertiary amine salt or a quaternary ammonium salt of such acid is described. The free acid reduces chemiluminescence upon the addition of an alkaline sample to the composition, while the tertiary amine or quaternary ammonium salt enhances the water miscibility of the composition

Predicting ionospheric scintillation: Recent advancements and future challenges

Science.gov (United States)

Carter, B. A.; Currie, J. L.; Terkildsen, M.; Bouya, Z.; Parkinson, M. L.

2017-12-01

Society greatly benefits from space-based infrastructure and technology. For example, signals from Global Navigation Satellite Systems (GNSS) are used across a wide range of industrial sectors; including aviation, mining, agriculture and finance. Current trends indicate that the use of these space-based technologies is likely to increase over the coming decades as the global economy becomes more technology-dependent. Space weather represents a key vulnerability to space-based technology, both in terms of the space environment effects on satellite infrastructure and the influence of the ionosphere on the radio signals used for satellite communications. In recent decades, the impact of the ionosphere on GNSS signals has re-ignited research interest into the equatorial ionosphere, particularly towards understanding Equatorial Plasma Bubbles (EPBs). EPBs are a dominant source of nighttime plasma irregularities in the low-latitude ionosphere, which can cause severe scintillation on GNSS signals and subsequent degradation on GNSS product quality. Currently, ionospheric scintillation event forecasts are not being routinely released by any space weather prediction agency around the world, but this is likely to change in the near future. In this contribution, an overview of recent efforts to develop a global ionospheric scintillation prediction capability within Australia will be given. The challenges in understanding user requirements for ionospheric scintillation predictions will be discussed. Next, the use of ground- and space-based datasets for the purpose of near-real time ionospheric scintillation monitoring will be explored. Finally, some modeling that has shown significant promise in transitioning towards an operational ionospheric scintillation forecasting system will be discussed.

A more rugged ZnS(Ag) alpha scintillation detector

International Nuclear Information System (INIS)

McElhaney, S.A.; Ramsey, J.A.; Bauer, M.L.; Chiles, M.M.

1990-01-01

Conventional alpha scintillation detectors comprise a phosphor-coated light-pipe covered by a thin aluminized Mylar layer. This opaque radiation entrance window serves as a shield against ambient light entering the detector with minimum alpha attenuation. Unfortunately, Mylar is extremely fragile and easily punctured or torn by sticks, stones, and screws encountered during regular radiation surveys. The authors have been developing an alpha scintillation detector more rugged and durable than conventional models. This paper presents the scintillator assembly, which consists of a mixture of silver-activated zinc sulfide [ZnS(Ag)] and clear epoxy. The ZnS(Ag) scintillation powder is mixed with a low-viscosity, optically transparent epoxy and poured into a glass-smooth mold of desired shape and size

Trigger and electronics issues for scintillating fiber tracking

International Nuclear Information System (INIS)

Baumbaugh, A.E.

1994-01-01

Scintillating Fiber technology has made great advances and has demonstrated great promise for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation floors available, make them very promising for use at high luminosity experiments at today's and tomorrow's colliding and fixed target experiments where high rate capability is essential. This paper will discuss some of the system aspects which should be considered by anyone attempting to design a scintillating fiber tracking system and high speed tracking trigger. As the reader will see, seemingly simple decisions can have far reaching effects on overall system performance

Radiation damage studies on polystyrene-based scintillators

International Nuclear Information System (INIS)

Britvich, G.I.; Peresypkin, A.I.; Rykalin, V.I.

1991-01-01

The radiation resistance of polystyrene-based scintillators containing various scintillation dopes is reported. All samples were irradiated to 137 Cs gamma rays in air at room temperature. The examination of radiation resistance of about thirty fluorescence compounds has been made. The most radiation-hard fluores are X25, X31, 3HF and M3HF. 1 fig.; 6 tabs

Scintillating fibres

Energy Technology Data Exchange (ETDEWEB)

Nahnhauer, R. [IHEP Zeuthen (Germany)

1990-11-15

In the search for new detector techniques, scintillating fibre technology has already gained a firm foothold, and is a strong contender for the extreme experimental conditions of tomorrow's machines. Organized by a group from the Institute of High Energy Physics, Berlin-Zeuthen, a workshop held from 3-5 September in the nearby village of Blossin brought together experts from East and West, and from science and industry.

Radiocarbon dating methods using benzene liquid scintillation

International Nuclear Information System (INIS)

Togashi, Shigeko; Matsumoto, Eiji

1983-01-01

The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

Scintillating fiber detector development for the SSC: Annual progress report

International Nuclear Information System (INIS)

Ruchti, R.C.

1989-01-01

During the past year, considerable effort has been applied to the development of scintillating fiber detectors in several areas: new scintillation liquids and studies of their fluorescence properties; new fluorescent dyes based on non-intramolecular proton transfer; new dyes based on intramolecular proton transfer; incorporation of these new dyes in plastic (polystyrene) and liquid scintillation solutions; development of small cross section glass capillaries for the containment of liquid scintillators; studies of waveguide characteristics; studies of image intensifier phosphor screen characteristics; initial steps to form a collaboration to study and develop appropriate new properties of the Solid State Photomultiplier; construction of a new laboratory at Notre Dame to enhance our capabilities for further measurements and studies; and organization of and execution of a Workshop on Scintillating Fiber Detector Development for the SSC, held at Fermilab, November 14--16, 1988

Light pulse shapes from plastic scintillators

International Nuclear Information System (INIS)

Moszynski, M.; Bengtson, B.

1977-01-01

A detailed study of the light pulse shape from the binary NE 111 and the ternary Pilot U, Naton 136, KL 236, NE 102A, NE 104 and NE 110 plastic scintillators was performed by the single photon method using XP 1021 and C 31024 photomultipliers. The analysis of the shape of the light pulses determined experimentally for several samples of different dimensions gave the following conclusions. The original light pulse shape from the binary NE 111 scintillator, as measured with a 5 mm thick polished sample is described analytically by the convolution integral of a Gaussian and an exponential function. The Gaussian function may reflect a deexcitation of several higher levels of the solvent molecules excited by nuclear particles preceding an intermolecular energy transfer in the scintillator. It may introduce a rather important limitation of the speed of plastic scintillators as the standard deviation of the Gaussian function is equal to 0.2 ns. The light pulse shape from the ternary plastics is described by the convolution integral of a Gaussian and two exponential functions. The Gaussian function presents the rate of energy transfer from nuclear particles to the primary solute as in the binary plastics. The exponential functions describe the energy transfer from the primary solute to the wavelength shifter and the final emission of the light. (Auth.)

Gadolinium-loaded gel scintillators for neutron and antineutrino detection

Science.gov (United States)

Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

2016-11-29

A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

First-principles Electronic Structure Calculations for Scintillation Phosphor Nuclear Detector Materials

Science.gov (United States)

Canning, Andrew

2013-03-01

Inorganic scintillation phosphors (scintillators) are extensively employed as radiation detector materials in many fields of applied and fundamental research such as medical imaging, high energy physics, astrophysics, oil exploration and nuclear materials detection for homeland security and other applications. The ideal scintillator for gamma ray detection must have exceptional performance in terms of stopping power, luminosity, proportionality, speed, and cost. Recently, trivalent lanthanide dopants such as Ce and Eu have received greater attention for fast and bright scintillators as the optical 5d to 4f transition is relatively fast. However, crystal growth and production costs remain challenging for these new materials so there is still a need for new higher performing scintillators that meet the needs of the different application areas. First principles calculations can provide a useful insight into the chemical and electronic properties of such materials and hence can aid in the search for better new scintillators. In the past there has been little first-principles work done on scintillator materials in part because it means modeling f electrons in lanthanides as well as complex excited state and scattering processes. In this talk I will give an overview of the scintillation process and show how first-principles calculations can be applied to such systems to gain a better understanding of the physics involved. I will also present work on a high-throughput first principles approach to select new scintillator materials for fabrication as well as present more detailed calculations to study trapping process etc. that can limit their brightness. This work in collaboration with experimental groups has lead to the discovery of some new bright scintillators. Work supported by the U.S. Department of Homeland Security and carried out under U.S. Department of Energy Contract no. DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory.

Near-infrared scintillation of liquid argon

Energy Technology Data Exchange (ETDEWEB)

Alexander, T. [Fermilab; Escobar, C. O. [Campinas State U.; Lippincott, W. H. [Fermilab; Rubinov, P. [Fermilab

2016-03-03

Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

ATLAS ALFA—measuring absolute luminosity with scintillating fibres

CERN Document Server

Franz, S

2009-01-01

ALFA is a high-precision scintillating fibre tracking detector under construction for the absolute determination of the LHC luminosity at the ATLAS interaction point. This detector, mounted in so-called Roman Pots, will track protons elastically scattered under μrad angles at IP1.In total there are four pairs of vertically arranged detector modules which approach the LHC beam axis to mm distance. Each detector module consists of ten layers of two times 64 scintillating fibres each (U and V planes). The fibres are coupled to 64 channels Multi-Anodes PhotoMultipliers Tubes read out by compact front-end electronics. Each detector module is complemented by so-called overlap detectors: Three layers of two times 30 scintillating fibres which will be used to measure the relative positioning of two vertically arranged main detectors. The total number of channels is about 15000. Conventional plastic scintillator tiles are mounted in front of the fibre detectors and will serve as trigger counter. The extremely restric...

Use of pliable bags in liquid scintillation counting

International Nuclear Information System (INIS)

Simonnet, G.; Jacquet, M.A.; Sharif, A.; Engler, R.

1981-01-01

Pliable plastic bags have been used to replace glass or plastic vials for liquid scintillation counting. The two major advantages of this method are the lower cost of the plastic bags and the fact that, per sample, the radioactive waste is significantly reduced. The following parameters have been checked: the impermeability of the bags to various scintillator mixtures and the fact that neither the irregular shape of the bags nor their position in the counting chamber had any effect on the results of the counting. The latter was also constant with time, at least over a period of 10 days. The technique has been used to count the radioactivity of 3 H-DNA precipitates prepared from bacteria and lymphocytes and deposited on filters impregnated with only 200 μl scintillator. It is a method that can be applied to the counting of any samples deposited on filters and insoluble in scintillator. (author)

Detection of ionospheric scintillation effects using LMD-DFA

Science.gov (United States)

Tadivaka, Raghavendra Vishnu; Paruchuri, Bhanu Priyanka; Miriyala, Sridhar; Koppireddi, Padma Raju; Devanaboyina, Venkata Ratnam

2017-08-01

The performance and measurement accuracy of global navigation satellite system (GNSS) receivers is greatly affected by ionospheric scintillations. Rapid amplitude and phase variations in the received GPS signal, known as ionospheric scintillation, affects the tracking of signals by GNSS receivers. Hence, there is a need to investigate the monitoring of various activities of the ionosphere and to develop a novel approach for mitigation of ionospheric scintillation effects. A method based on Local Mean Decomposition (LMD)-Detrended Fluctuation Analysis (DFA) has been proposed. The GNSS data recorded at Koneru Lakshmaiah (K L) University, Guntur, India were considered for analysis. The carrier to noise ratio (C/N0) of GNSS satellite vehicles were decomposed into several product functions (PF) using LMD to extract the intrinsic features in the signal. Scintillation noise was removed by the DFA algorithm by selecting a suitable threshold. It was observed that the performance of the proposed LMD-DFA was better than that of empirical mode decomposition (EMD)-DFA.

Multisector scintillation detector with fiber-optic light collection

Science.gov (United States)

Ampilogov, N. V.; Denisov, S. P.; Kokoulin, R. P.; Petrukhin, A. A.; Prokopenko, N. N.; Shulzhenko, I. A.; Unatlokov, I. B.; Yashin, I. I.

2017-07-01

A new type of scintillation detector for the use in high energy physics is described. The octagonal detector consists of eight triangular scintillator sectors with total area of 1 m2. Each sector represents two plates of 2 cm thick plastic scintillator. Seven 1 mm thick WLS fibers are laid evenly between the plates. The space between the fibers is filled with silicone compound to provide better light collection. Fiber ends from all eight sectors are gathered in the central part of the detector into a bunch and docked to the cathode of a FEU-115m photomultiplier. The read-out of the counter signals is carried out from 7th and 12th dynodes, providing a wide dynamic range up to about 10000 particles. The front-end electronics of the detector is based on the flash-ADC with a sampling frequency of 200 MHz. The features of detecting and recording systems of the multisector scintillation detector (MSD) and the results of its testing are discussed.

Radioactive flow detectors: liquid or solid scintillators

International Nuclear Information System (INIS)

Reich, A.R.

1983-01-01

During the past five years, two schools of thought have emerged producing two different types of radio-HPLC detectors. Based on the naphthalene-in-the-vial principle, manufacturers have developed heterogeneous scintillation detectors. In these detectors the anthracene or naphthalene crystals are replaced by other scintillators. In order to avoid dead space and turbulence, a narrow diameter tube is used, either straight, or more popularly formed into a coil or a 'U' as the cell. To optimize light transmission to the photomultiplier tubes, mirrors are used. Due to limiting factors in this technique the counting efficiency for tritium is below the 10 percent level. The other school of radio-HPLC detectors based their design on classical liquid scintillation counting technology. In a homogeneous detector, the effluent from the HPLC system is mixed with a suitable liquid scintillator before entering the counting cell. The cell design is typically a flat glass or Teflon coil tightly sandwiched between two photomultiplier tubes, making good optical contact without the use of mirrors. Depending on the chromatographic effluent, 3 H efficiencies between 25 to 50 percent, and 14 C counting efficiencies up to 85 percent can be achieved

Waveshifting fiber readout of lanthanum halide scintillators

International Nuclear Information System (INIS)

Case, G.L.; Cherry, M.L.; Stacy, J.G.

2006-01-01

Newly developed high-light-yield inorganic scintillators coupled to waveshifting optical fibers provide the capability of efficient X-ray detection and millimeter scale position resolution suitable for high-energy cosmic ray instruments, hard X-ray/gamma ray astronomy telescopes and applications to national security. The CASTER design for NASA's proposed Black Hole Finder Probe mission, in particular, calls for a 6-8 m 2 hard X-ray coded aperture imaging telescope operating in the 20-600 keV energy band, putting significant constraints on cost and readout complexity. The development of new inorganic scintillator materials (e.g., cerium-doped LaBr 3 and LaCl 3 ) provides improved energy resolution and timing performance that is well suited to the requirements for national security and astrophysics applications. LaBr 3 or LaCl 3 detector arrays coupled with waveshifting fiber optic readout represent a significant advance in the performance capabilities of scintillator-based gamma cameras and provide the potential for a feasible approach to affordable, large area, extremely sensitive detectors. We describe some of the applications and present laboratory test results demonstrating the expected scintillator performance

Is pruritus an indicator of aquaporin-positive neuromyelitis optica?

Science.gov (United States)

Netravathi, Manjunath; Saini, Jitender; Mahadevan, Anita; Hari-Krishna, Bollampalli; Yadav, Ravi; Pal, Pramod Kumar; Satishchandra, Parthasarathy

2017-05-01

Recently, pruritus has been recognised as an important association with neuromyelitis optica spectrum disorders (NMOSD). To determine the clinical and radiological characteristics of patients with NMOSD and pruritus. Among 57 consecutive patients with NMOSD, 15 (26.3% women) reported pruritus. All had aquaporin-4 (AQP4) antibodies. The mean age was 34.5 ± 9.1 years, age at onset was 31.3 ± 11.0 years and the duration of illness was 3.9 ± 3.1 years. Pruritus preceded the neurological disturbances in all the patients. Predominant patients experienced pruritus in the cervical dermatome (66.7%) followed by cervicothoracic region (13.3%), trigeminal nerve (13.3%) and lumbar region (6.7%). Lesions extending from cervicomedullary junction up to the thoracic segment was the most common site of affection (40%) followed by cervicothoracic (26.7%), cervicomedullary junction to cervical cord (13.3%), cervical cord (6.7%) and thoracic segment (6.7%). This report is one of the largest series reporting the close association of pruritus with onset of neurological symptoms in NMOSD. It highlights the importance of recognising this rare symptom which may help in making a correct diagnosis in a patient with suspected demyelinating disorder. In a patient with NMOSD, early treatment with immunomodulation during pruritus may prevent or minimise occurrence of neurological dysfunction.

New scintillating crystals for PET scanners

CERN Document Server

Lecoq, P

2002-01-01

Systematic R&D on basic mechanism in inorganic scintillators, initiated by the Crystal Clear Collaboration at CERN 10 years ago, has contributed not to a small amount, to the development of new materials for a new generation of medical imaging devices with increased resolution and sensitivity. The first important requirement for a scintillator to be used in medical imaging devices is the stopping power for the given energy range of X and gamma rays to be considered, and more precisely the conversion efficiency. A high light yield is also mandatory to improve the energy resolution, which is essentially limited by the photostatistics and the electronic noise at these energies. A short scintillation decay time allows to reduce the dead time and therefore to increase the limiting counting rate. When all these requirements are fulfilled the sensitivity and image contrast are increased for a given patient dose, or the dose can be reduced. Examples of new materials under development by the Crystal Clear Collabor...

GAGG:ce single crystalline films: New perspective scintillators for electron detection in SEM.

Science.gov (United States)

Bok, Jan; Lalinský, Ondřej; Hanuš, Martin; Onderišinová, Zuzana; Kelar, Jakub; Kučera, Miroslav

2016-04-01

Single crystal scintillators are frequently used for electron detection in scanning electron microscopy (SEM). We report gadolinium aluminum gallium garnet (GAGG:Ce) single crystalline films as a new perspective scintillators for the SEM. For the first time, the epitaxial garnet films were used in a practical application: the GAGG:Ce scintillator was incorporated into a SEM scintillation electron detector and it showed improved image quality. In order to prove the GAGG:Ce quality accurately, the scintillation properties were examined using electron beam excitation and compared with frequently used scintillators in the SEM. The results demonstrate excellent emission efficiency of the GAGG:Ce single crystalline films together with their very fast scintillation decay useful for demanding SEM applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Qualitative and quantitative autoradiographic investigations on DNA-repair in the pars optica retinae of the rabbit

International Nuclear Information System (INIS)

Kellner, G.; Reindl, E.; Pichler, L.; Hofer, H.

1974-01-01

In vitro and in vivo investigations into the incorporation of 3 H-thymidine into the nuclei of pars optica retinae of rabbits after β-irradiation with 60 krad were performed. The results of the in vitro and in vivo experiments are comparable with the in vitro data showing smaller statistical deviations. The rate comparable with the in vitro data showing smaller statistical deviations. The rate of incorporation of 3 H-thymidine into the nuclei of Ggl. opticum and Ggl. retinae is about the same, but it is significantly lower in the nuclei of photoreceptor cells by one order of magnitude. The in vitro experiment demonstrates that ganglion cells are capable of DNA repair even after circulation has been stopped for 15 or more minutes. (author)

Contribution of spinal cord biopsy to diagnosis of aquaporin-4 antibody positive neuromyelitis optica spectrum disorder.

Science.gov (United States)

Ringelstein, M; Metz, I; Ruprecht, K; Koch, A; Rappold, J; Ingwersen, J; Mathys, C; Jarius, S; Brück, W; Hartung, H-P; Paul, F; Aktas, O

2014-06-01

Longitudinally extensive transverse myelitis is characteristic but not pathognomonic for neuromyelitis optica spectrum disorders (NMOSDs) and may mimic local tumors. In this retrospective study based on a cohort of 175 NMOSD patients we identified seven patients who initially presented with a longitudinally extensive spinal cord lesion and underwent spinal cord biopsy due to magnetic resonance imaging (MRI)-suspected malignancies. Remarkably, routine neuropathology was inconclusive and did not guide the diagnostic process to anti-aquaporin-4 (AQP4)-seropositive NMOSD. Serious postoperative complications occurred in 5/7 patients and persisted during follow-up in 2/7 patients (29%). Considering these sequelae, AQP4-antibody testing should be mandatory in patients with inconclusive longitudinally extensive spinal cord lesions prior to biopsy. © The Author(s) 2013.

Presentation of Neuromyelitis Optica with Recurrent Severe Myelitis and Acute Respiratory Failure in an Old Woman

Directory of Open Access Journals (Sweden)

Saeed Razmeh

2017-06-01

Full Text Available Neuromyelitis Optica (NMO is a rare disease of the central nervous system that causes optic nerve and spinal cord involvement. The our patient first developed acute paraplegia that was treated with intravenous methylprednisolone with diagnosis of acute thoracic myelitis according to magnetic resonance imaging (MRI finding , concurrently with tapering of oral prednisolone, again affected by quadriplegia and respiratory failure. She was seropositivity for NMO-IgG that was negative in first admission and MRI of spine shows hyperintense lesion in whole cervical and upper thoracic MRI. With considering the findings, NMO was diagnosed and the plasmapheresis starts for her. We report a case of this syndrome because it can increase the physician’s awareness of the unusual manifestations of this syndrome.

First light from a kilometer-baseline Scintillation Auroral GPS Array.

Science.gov (United States)

Datta-Barua, S; Su, Y; Deshpande, K; Miladinovich, D; Bust, G S; Hampton, D; Crowley, G

2015-05-28

We introduce and analyze the first data from an array of closely spaced Global Positioning System (GPS) scintillation receivers established in the auroral zone in late 2013 to measure spatial and temporal variations in L band signals at 100-1000 m and subsecond scales. The seven receivers of the Scintillation Auroral GPS Array (SAGA) are sited at Poker Flat Research Range, Alaska. The receivers produce 100 s scintillation indices and 100 Hz carrier phase and raw in-phase and quadrature-phase samples. SAGA is the largest existing array with baseline lengths of the ionospheric diffractive Fresnel scale at L band. With an initial array of five receivers, we identify a period of simultaneous amplitude and phase scintillation. We compare SAGA power and phase data with collocated 630.0 nm all-sky images of an auroral arc and incoherent scatter radar electron precipitation measurements, to illustrate how SAGA can be used in multi-instrument observations for subkilometer-scale studies. A seven-receiver Scintillation Auroral GPS Array (SAGA) is now at Poker Flat, Alaska SAGA is the largest subkilometer array to enable phase/irregularities studies Simultaneous scintillation, auroral arc, and electron precipitation are observed.

Alpha scintillation radon counting

International Nuclear Information System (INIS)

Lucas, H.F. Jr.

1977-01-01

Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222 Rn and 226 Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

Final LDRD report : advanced plastic scintillators for neutron detection.

Energy Technology Data Exchange (ETDEWEB)

Vance, Andrew L.; Mascarenhas, Nicholas; O' Bryan, Greg; Mrowka, Stanley

2010-09-01

This report summarizes the results of a one-year, feasibility-scale LDRD project that was conducted with the goal of developing new plastic scintillators capable of pulse shape discrimination (PSD) for neutron detection. Copolymers composed of matrix materials such as poly(methyl methacrylate) (PMMA) and blocks containing trans-stilbene (tSB) as the scintillator component were prepared and tested for gamma/neutron response. Block copolymer synthesis utilizing tSBMA proved unsuccessful so random copolymers containing up to 30% tSB were prepared. These copolymers were found to function as scintillators upon exposure to gamma radiation; however, they did not exhibit PSD when exposed to a neutron source. This project, while falling short of its ultimate goal, demonstrated the possible utility of single-component, undoped plastics as scintillators for applications that do not require PSD.

Recent developments in plastic scintillators with pulse shape discrimination

Science.gov (United States)

Zaitseva, N. P.; Glenn, A. M.; Mabe, A. N.; Carman, M. L.; Hurlbut, C. R.; Inman, J. W.; Payne, S. A.

2018-05-01

The paper reports results of studies conducted to improve scintillation performance of plastic scintillators capable of neutron/gamma pulse-shape discrimination (PSD). Compositional modifications made with the polymer matrix improved physical stability, allowing for increased loads of the primary dye that, in combination with selected secondary dyes, provided enhanced PSD especially important for the lower energy ranges. Additional measurements were made with a newly-introduced PSD plastic EJ-276, that replaces the first commercially produced EJ-299. Comparative studies conducted with the new materials and EJ-309 liquids at large scale (up to 10 cm) show that current plastics may provide scintillation and PSD performance sufficient for the replacement of liquid scintillators. Comparison to stilbene single crystals compliments the information about the status of the solid-state materials recently developed for fast neutron detection applications.

Improvements to well scintillation counters

International Nuclear Information System (INIS)

Farukhi, M.R.; Mataraza, G.A.; Wimer, O.D.

1977-01-01

This invention relates to the field of ionising radiation detection. It concerns in particular scintillation detectors of the type that is commonly used in conjunction with a photomultiplier tube and that is used for monitoring radiation, for instance in the clinical measurements of isotopes. This invention enables well scintillation counters to be made, characterised by a high efficiency in measuring the thindown rate of radio-pharmaceutical solutions and to resolve the distribution of energy emanating from the radioactive source. It particularly consists in improving the uniformity of the luminous efficiency, the quality of the resolution and the efficiency whilst improving the reception of light [fr

Plastic scintillator-based hodoscope for the characterization of large ...

Indian Academy of Sciences (India)

Plastic scintillator-based hodoscope for the characterization of large-area resistive plate chambers. V K S KASHYAP C YADAV ... Keywords. Plastic scintillators; resistive plate chambers. ... Pramana – Journal of Physics | News. © 2017 Indian ...

Equatorial Scintillation Study at Ilorin and Nsukka, Nigeria during Year 2011-2012

Science.gov (United States)

Akala, A.

2017-12-01

This study presents GNSS scintillations over Ilorin (8.48 oN, 4.54 oE, and mag lat: 1.83oS) and Nsukka (6.84 oN, 7.37 oE, and mag lat: 2.94oS), Nigeria during year 2011-2012. The two stations are located within the inner flank of the equatorial ionization anomaly. Firstly, we investigated the climatology of equatorial scintillations at the two stations. We suppressed multipath effects on the data by imposing a 300 elevation masking on the data. In addition, we investigated scintillation occurrences at the two locations on a satellite-by-satellite basis at varying elevation angles. The source of scintillation records at low-elevation angle is attributed to multipath, while that at high-elevation angle is attributed to ionospheric irregularities. Seasonally, scintillations recorded highest occurrences during March equinox, and the least during June solstice. The trend of scintillations, at both low- and high-elevation angles at the two stations were almost the same. EGNOS satellites signals scintillated at the two locations during the time intervals when GPS satellites signals experienced scintillations. These results could support the development of scintillation models for equatorial Africa, and could also be of benefit to GPS and EGNOS service providers and designers, with a view to providing robust services for GNSS user community in Africa.

Scintillating fibres

International Nuclear Information System (INIS)

Nahnhauer, R.

1990-01-01

In the search for new detector techniques, scintillating fibre technology has already gained a firm foothold, and is a strong contender for the extreme experimental conditions of tomorrow's machines. Organized by a group from the Institute of High Energy Physics, Berlin-Zeuthen, a workshop held from 3-5 September in the nearby village of Blossin brought together experts from East and West, and from science and industry

Optics study of liquid scintillation counting systems

International Nuclear Information System (INIS)

Duran Ramiro, M. T.; Garcia-Torano, E.

2005-01-01

Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

Pulse shape discrimination with scintillation detectors

International Nuclear Information System (INIS)

Winyard, R.A.

A quantitative study of pulse shape discrimination with scintillation counters has been undertaken using a crossover timing technique. The scintillators investigated included experimental and commercial liquids and plastics in addition to inorganic phosphors. The versatility of the pulse shape discrimination system has been demonstrated by extending the measurements to investigate phoswiches and liquids loaded with radioactive materials and by its application to the suppression of unwanted backgrounds in delayed coincidence counting for the measurement of nuclear half-lives and isotope identification have been carried out. (author)

Electron response of some low-Z scintillators in wide energy range

International Nuclear Information System (INIS)

Swiderski, L; Marcinkowski, R; Moszynski, M; Czarnacki, W; Szawlowski, M; Szczesniak, T; Pausch, G; Plettner, C; Roemer, K

2012-01-01

Light yield nonproportionality and the intrinsic resolution of some low atomic number scintillators were studied by means of the Wide Angle Compton Coincidence (WACC) technique. The plastic and liquid scintillator response to Compton electrons was measured in the energy range of 10 keV up to 4 MeV, whereas a CaF 2 :Eu sample was scanned from 3 keV up to 1 MeV. The nonproportionality of the CaF 2 :Eu light yield has characteristics typical for inorganic scintillators of the multivalent halides group, whereas tested organic scintillators show steeply increasing nonproportionality without saturation point. This is in contrast to the behavior of all known inorganic scintillators having their nonproportionality curves at saturation above energies between tens and several hundred keV.

Electron response of some low-Z scintillators in wide energy range

Science.gov (United States)

Swiderski, L.; Marcinkowski, R.; Moszynski, M.; Czarnacki, W.; Szawlowski, M.; Szczesniak, T.; Pausch, G.; Plettner, C.; Roemer, K.

2012-06-01

Light yield nonproportionality and the intrinsic resolution of some low atomic number scintillators were studied by means of the Wide Angle Compton Coincidence (WACC) technique. The plastic and liquid scintillator response to Compton electrons was measured in the energy range of 10 keV up to 4 MeV, whereas a CaF2:Eu sample was scanned from 3 keV up to 1 MeV. The nonproportionality of the CaF2:Eu light yield has characteristics typical for inorganic scintillators of the multivalent halides group, whereas tested organic scintillators show steeply increasing nonproportionality without saturation point. This is in contrast to the behavior of all known inorganic scintillators having their nonproportionality curves at saturation above energies between tens and several hundred keV.

Long-distance transmission of light in a scintillator-based radiation detector

Science.gov (United States)

Dowell, Jonathan L.; Talbott, Dale V.; Hehlen, Markus P.

2017-07-11

Scintillator-based radiation detectors capable of transmitting light indicating the presence of radiation for long distances are disclosed herein. A radiation detector can include a scintillator layer and a light-guide layer. The scintillator layer is configured to produce light upon receiving incident radiation. The light-guide layer is configured to receive light produced by the scintillator layer and either propagate the received light through the radiation detector or absorb the received light and emit light, through fluorescence, that is propagated through the radiation detector. A radiation detector can also include an outer layer partially surrounding the scintillator layer and light-guide layer. The index of refraction of the light-guide layer can be greater than the index of refraction of adjacent layers.

Pulse discrimination of scintillator detector with artificial neural network

International Nuclear Information System (INIS)

Chen Man; Cai Yuerong; Yang Chaowen

2006-01-01

The features of signal for scintillator detectors are analyzed. According to the difference in the fraction of slow and fast scintillation for different particles, three intrinsic parameters (signal amplitude, integration of signal during rinsing, integration of frequency spectrum of signals in middle frequencies) of signals are defined. The artificial neural network method for pulse discrimination of scintillator detector is studied. The signals with different shapes under real condition are simulated with computer, and discriminated by the method. Results of discrimination are gotten and discussed. (authors)

Challenges and opportunities in designing clinical trials for neuromyelitis optica

Science.gov (United States)

Barron, Gerard; Behne, Jacinta M.; Bennett, Jeffery L.; Chin, Peter S.; Cree, Bruce A.C.; de Seze, Jerome; Flor, Armando; Fujihara, Kazuo; Greenberg, Benjamin; Higashi, Sayumi; Holt, William; Khan, Omar; Knappertz, Volker; Levy, Michael; Melia, Angela T.; Palace, Jacqueline; Smith, Terry J.; Sormani, Maria Pia; Van Herle, Katja; VanMeter, Susan; Villoslada, Pablo; Walton, Marc K.; Wasiewski, Warren; Wingerchuk, Dean M.; Yeaman, Michael R.

2015-01-01

Current management of neuromyelitis optica (NMO) is noncurative and only partially effective. Immunosuppressive or immunomodulatory agents are the mainstays of maintenance treatment. Safer, better-tolerated, and proven effective treatments are needed. The perceived rarity of NMO has impeded clinical trials for this disease. However, a diagnostic biomarker and recognition of a wider spectrum of NMO presentations has expanded the patient population from which study candidates might be recruited. Emerging insights into the pathogenesis of NMO have provided rationale for exploring new therapeutic targets. Academic, pharmaceutical, and regulatory communities are increasingly interested in meeting the unmet needs of patients with NMO. Clinical trials powered to yield unambiguous outcomes and designed to facilitate rapid evaluation of an expanding pipeline of experimental agents are needed. NMO-related disability occurs incrementally as a result of attacks; thus, limiting attack frequency and severity are critical treatment goals. Yet, the severity of NMO and perception that currently available agents are effective pose challenges to study design. We propose strategies for NMO clinical trials to evaluate agents targeting recovery from acute attacks and prevention of relapses, the 2 primary goals of NMO treatment. Aligning the interests of all stakeholders is an essential step to this end. PMID:25841026

Using LEDs to stimulate the recovery of radiation damage to plastic scintillators

Energy Technology Data Exchange (ETDEWEB)

Wetzel, J., E-mail: james-wetzel@uiowa.edu [The University of Iowa, Iowa City, IA (United States); Tiras, E. [The University of Iowa, Iowa City, IA (United States); Bilki, B. [The University of Iowa, Iowa City, IA (United States); Beykent University, Istanbul (Turkey); Onel, Y. [The University of Iowa, Iowa City, IA (United States); Winn, D. [Fairfield University, Fairfield, CT (United States)

2017-03-15

In this study, we consider using LEDs to stimulate the recovery of scintillators damaged from radiation in high radiation environments. We irradiated scintillating tiles of polyethylene naphthalate (PEN), Eljen brand EJ-260 (EJN), an overdoped EJ-260 (EJ2P), and a lab-produced elastomer scintillator (ES) composed of p-terphenyl (ptp) in epoxy. Two different high-dose irradiations took place, with PEN dosed to 100 kGy, and the others to 78 kGy. We found that the ‘blue’ scintillators (PEN and ES) recovered faster and maximally higher with LEDs than without. Conversely exposing the ‘green’ scintillators (EJ-260) to LED light had a nearly negligible effect on the recovery. We hypothesize that the ‘green’ scintillators require wavelengths that match their absorption and emission spectra for LED stimulated recovery.

Pruritus may be a common symptom related to neuromyelitis optica spectrum disorders.

Science.gov (United States)

He, Zhiyong; Ren, Ming; Wang, Xiaofeng; Guo, Qifeng; Qi, Xiaokun

2017-04-01

To evaluate pruritus in patients with neuromyelitis optica spectrum disorders (NMOSD) and to characterize the relationship between pruritus and lesions of NMOSD. 61 patients with NMOSD were included in the study and their medical records were reviewed for pruritus, neurological symptoms and magnetic resonance imaging (MRI) images. We focused on the patients' history of pruritus, especially the severity, duration, region, and the relationship of pruritus with other symptoms of NMOSD. Of the 61 patients with NMOSD, 59 had longitudinally extensive transverse myelitis (LETM). 38 of these patients (64.4%) reported pruritus during the course of their illness, with 16 patients reporting pruritus as the initial symptoms followed by limb weakness. In 35 of 38 patients (92.1%), pruritus was located within the dermatomes innervated by the spinal nerves from the involved spinal cord. Our results show that pruritus is a common symptom of NMOSD and relates to the lesions in the spinal cord. Pruritus may indicate a new episode of myelitis in patients with NMOSD. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of Advanced Magnetic Resonance Imaging Techniques in Neuromyelitis Optica Spectrum Disorder

Science.gov (United States)

Kremer, Stephane; Renard, Felix; Achard, Sophie; Lana-Peixoto, Marco A.; Palace, Jacqueline; Asgari, Nasrin; Klawiter, Eric C.; Tenembaum, Silvia N.; Banwell, Brenda; Greenberg, Benjamin M.; Bennett, Jeffrey L.; Levy, Michael; Villoslada, Pablo; Saiz, Albert; Fujihara, Kazuo; Chan, Koon Ho; Schippling, Sven; Paul, Friedemann; Kim, Ho Jin; de Seze, Jerome; Wuerfel, Jens T.

2016-01-01

Brain parenchymal lesions are frequently observed on conventional magnetic resonance imaging (MRI) scans of patients with neuromyelitis optica (NMO) spectrum disorder, but the specific morphological and temporal patterns distinguishing them unequivocally from lesions caused by other disorders have not been identified. This literature review summarizes the literature on advanced quantitative imaging measures reported for patients with NMO spectrum disorder, including proton MR spectroscopy, diffusion tensor imaging, magnetization transfer imaging, quantitative MR volumetry, and ultrahigh-field strength MRI. It was undertaken to consider the advanced MRI techniques used for patients with NMO by different specialists in the field. Although quantitative measures such as proton MR spectroscopy or magnetization transfer imaging have not reproducibly revealed diffuse brain injury, preliminary data from diffusion-weighted imaging and brain tissue volumetry indicate greater white matter than gray matter degradation. These findings could be confirmed by ultrahigh-field MRI. The use of nonconventional MRI techniques may further our understanding of the pathogenic processes in NMO spectrum disorders and may help us identify the distinct radiographic features corresponding to specific phenotypic manifestations of this disease. PMID:26010909

Water-equivalent one-dimensional scintillating fiber-optic dosimeter for measuring therapeutic photon beam

International Nuclear Information System (INIS)

Moon, Jinsoo; Won Jang, Kyoung; Jae Yoo, Wook; Han, Ki-Tek; Park, Jang-Yeon; Lee, Bongsoo

2012-01-01

In this study, we fabricated a one-dimensional scintillating fiber-optic dosimeter, which consists of 9 scintillating fiber-optic dosimeters, septa, and PMMA blocks for measuring surface and percentage depth doses of a therapeutic photon beam. Each dosimeter embedded in the 1-D scintillating fiber-optic dosimeter is composed of square type organic scintillators and plastic optical fibers. Also black PVC films are used as septa to minimize cross-talk between the scintillating fiber-optic dosimeters. To construct a dosimeter system, a 1-D scintillating fiber-optic dosimeter and a CMOS image sensor were combined with 20 m-length plastic optical fibers. Using the dosimeter system, we measured surface and percentage depth doses of 6 and 15 MV photon beams and compared the results with those of EBT films and an ionization chamber. - Highlights: ► Fabrication of a one-dimensional scintillating fiber-optic dosimeter. ► The one-dimensional scintillating fiber-optic dosimeter has 9 scintillating fiber-optic dosimeters. ► Measurements of surface and percentage depth doses of a therapeutic photon beam. ► The results were compared with those of EBT films and an ionization chamber.

A new technique for infrared scintillation measurements

Energy Technology Data Exchange (ETDEWEB)

Chiossi, F., E-mail: federico.chiossi@studenti.unipd.it [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Brylew, K. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Borghesani, A.F. [CNISM Unit and Dip. di Fisica e Astronomia, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Braggio, C.; Carugno, G. [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Drozdowski, W. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Guarise, M. [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy)

2017-05-21

We propose a new technique to measure the infrared scintillation light yield of rare earth doped crystals by comparing it to near UV–visible scintillation of a calibrated Pr:(Lu{sub 0.75}Y{sub 0.25}){sub 3}Al{sub 5}O{sub 12} sample. As an example, we apply this technique to provide the light yield in visible and infrared range up to 1700 nm of this crystal.

A new technique for infrared scintillation measurements

International Nuclear Information System (INIS)

Chiossi, F.; Brylew, K.; Borghesani, A.F.; Braggio, C.; Carugno, G.; Drozdowski, W.; Guarise, M.

2017-01-01

We propose a new technique to measure the infrared scintillation light yield of rare earth doped crystals by comparing it to near UV–visible scintillation of a calibrated Pr:(Lu_0_._7_5Y_0_._2_5)_3Al_5O_1_2 sample. As an example, we apply this technique to provide the light yield in visible and infrared range up to 1700 nm of this crystal.

Cognitive impairment differs between neuromyelitis optica spectrum disorder and multiple sclerosis.

Science.gov (United States)

Kim, Su-Hyun; Kwak, Kichang; Jeong, In Hye; Hyun, Jae-Won; Jo, Hyo-Jin; Joung, AeRan; Yu, Eun-Seung; Kim, Ji-Hee; Lee, Sang Hyun; Yun, Sooin; Joo, Jungnam; Lee, Dong-Kyun; Lee, Jong-Min; Kim, Ho Jin

2016-12-01

To compare the frequency and pattern of cognitive impairment (CI) between patients with neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). A total of 82 NMOSD patients, 58 MS patients, and 45 healthy controls (HCs) underwent a neuropsychological assessment. CI was observed in 29% of NMOSD and 50% of MS patients (p < 0.001); CI was considered present if a patient scored lower than the fifth percentile compared with HCs in at least three domains. A lower frequency of CI was consistently found when CI was indicated by at least two failed tests (p < 0.001). MS patients performed worse than did NMOSD patients on verbal learning and verbal and visual memory tests. Levels of education and depression and the interval from disease onset to treatment were associated with a negative influence on cognition in patients with NMOSD. CI in patients with NMOSD may be not as common as in patients with MS. MS patients exhibited severe impairment, particularly on learning and memory tests, compared with NMOSD patients. Differential prevalence and patterns of CI between NMOSD and MS patients suggest that the two diseases have different mechanisms of brain injury. © The Author(s), 2016.

The Contribution of Optical Coherence Tomography in Neuromyelitis Optica Spectrum Disorders

Directory of Open Access Journals (Sweden)

Javier Mateo

2017-09-01

Full Text Available Neuromyelitis optica spectrum disorders (NMOSD comprises a group of central nervous system disorders of inflammatory autoimmune origin that mainly affect the optic nerves and the spinal cord and can cause severe visual and general disability. The clinical signs are similar to those of multiple sclerosis (MS, with the result that it is often difficult to differentiate between the two, thus leading to misdiagnosis. As the treatment and prognosis of NMOSD and MS are different, it is important to make an accurate and early diagnosis of NMOSD. Optical coherence tomography (OCT is a non-invasive technique that enables a quantitative study of the changes that the optic nerve and the macula undergo in several neurodegenerative diseases. Many studies have shown that some of these changes, such as retinal nerve fiber layer thinning or microcystic macular edema, can be related to alterations in the brain due to neurodegenerative disorders. The purpose of this mini-review is to show how OCT can be useful for the diagnosis of NMOSD and follow-up of affected patients, as well as for the differential diagnosis with MS.

A Scintillator Purification System for the Borexino Solar Neutrino Detector

OpenAIRE

Benziger, J.; Cadonati, L.; Calaprice, F.; Chen, M.; Corsi, A.; Dalnoki-Veress, F.; Fernholz, R.; Ford, R.; Galbiati, C.; Goretti, A.; Harding, E.; Ianni, Aldo; Ianni, Andrea; Kidner, S.; Leung, M.

2007-01-01

Purification of the 278 tons of liquid scintillator and 889 tons of buffer shielding for the Borexino solar neutrino detector was performed with a system that combined distillation, water extraction, gas stripping and filtration. The purification of the scintillator achieved unprecedented low backgrounds for the large scale liquid scintillation detector. This paper describes the principles of operation, design, construction and commissioning of the purification system, and reviews the require...

PMP, a novel solute for liquid and plastic scintillation counting

International Nuclear Information System (INIS)

Gusten, Hans

1983-01-01

The excellent fluorescence properties of PMP ( 11-phenyl-3-mesityl-2-pyrazoline) such as long wavelength emission of over 400 nm, and high fluorescence quantum yield with a short decay time together with a solubility of more than one Mol/L in toluene make this compound a promising solute for scintillation counting. The Stokes' shift of PMP of over 10,000 cm -1 is twice as large as that of the commonly used PPO. Due to this unusually large Stokes' shift PMP can be used as a primary solute without requiring a secondary solute as wavelength shifter. A comparison of the scintillation properties of PMP and PPO in toluene reveals that the counting efficiency for 14 C is better for PMP while the 3 H efficiency is equally good. Due to the large Stokes' shift, PMP is about 50 percent less sensitive to color quenching than PPO. Compared to the solute combinations PPO/secondary solutes, the scintillation counting efficiency of PMP for 14 C in toluene or xylene is the same, while the absolute 3 H efficiency of PPO/secondary solutes in cocktails with emulsifiers is about 10 percent higher. The PMP scintillation efficiency for 14 C as well as 3 H in chemical quenching by urine is more or less the same as for PPO/dimethyl-POPOP. PMP is more sensitive to quenching by halogenated solvents. In the dioxane-based scintillation, this sensitivity to chemical quenching by CHCl 3 vanishes and the counting efficiencies for 14 C and 3 H are as good as for PPO/dimethyl-POPOP or PPO/bis-MSB. Due to the large Stokes' shift, the self-absorption of the scintillation light by PMP is lower than in conventional scintillators. This offers good possibilities in very large-volume applications of liquid as well as plastic scintillators

Low-latitude scintillation occurrences around the equatorial anomaly crest over Indonesia

Directory of Open Access Journals (Sweden)

P. Abadi

2014-01-01

Full Text Available We investigated low-latitude ionospheric scintillation in Indonesia using two GPS receivers installed at Bandung (107.6° E, 6.9° S; magnetic latitude 17.5° S and Pontianak (109.3° E, 0.02° S; magnetic latitude 8.9° S. This study aimed to characterise climatological and directional ionospheric scintillation occurrences, which are useful not only for the physics of ionospheric irregularities but also for practical use in GNSS (global navigation satellite system-based navigation. We used the deployed instrument's amplitude scintillation (S4 index data from 2009, 2010, and 2011; the yearly SSN (sunspot-smoothed numbers were 3.1, 16.5, and 55.9, respectively. In summary, (1 scintillation occurrences in the post-sunset period (18:00–01:00 LT during equinox months (plasma bubble season at the two sites can be ascribed to the plasma bubble; (2 using directional analyses of the two sites, we found that the distribution of scintillation occurrences is generally concentrated between the two sites, indicating the average location of the EIA (equatorial ionisation anomaly crest; (3 scintillation occurrence enhancements for the two sites in field-aligned directions are herein reported for the first time by ground-based observation in a low-latitude region; (4 distribution of scintillation occurrences at Pontianak are concentrated in the southern sky, especially in the southwest direction, which is very likely associated with the plasma bubble tilted westward with increasing latitude; and (5 scintillation occurrence in the post-midnight period in the non-plasma-bubble season is the most intriguing variable occurring between the two sites (i.e. post-midnight scintillations are observed more at Bandung than Pontianak. Most of the post-midnight scintillations observed at Bandung are concentrated in the northern sky, with low elevation angles. This might be due to the amplitude of irregularities in certain directions, which may be effectively enhanced by

Scintillation trigger system of the liquid argon neutrino detector

International Nuclear Information System (INIS)

Belikov, S.V.; Gurzhiev, S.N.; Gutnikov, Yu.E.; Denisov, A.G.; Kochetkov, V.I.; Matveev, M.Yu.; Mel'nikov, E.A.; Usachev, A.P.

1994-01-01

This paper presents the organization of the Scintillation Trigger System (STS) for the Liquid Argon Neutrino Detector of the Tagged Neutrino Facility. STS is aimed at the effective registration of the needed neutrino interaction type and production of a fast trigger signal with high time resolution. The fast analysis system of analog signal from the trigger scintillation planes for rejection of the trigger signals from background processes is described. Real scintillation trigger planes characteristics obtained on the basis of the presented data acquisition system are shown. 10 refs., 12 figs., 3 tabs

Amplitude scintillations of ATS-6 radio signals in Lannion

International Nuclear Information System (INIS)

Cornec, J.P.

1978-01-01

The paper reports the results of a study of the scintillations observed on the amplitude of signal transmitted by the geostationary satellite ATS-6 on 40, 140, and 360 MHz, received at Lannion, France. Diffraction patterns caused bubbles of irregularities are studied and found to be mainly a summer phenomenon. It is concluded that there is a great increase in frequency occurrence and in the strength of scintillations from winter to summer, and that for the whole observation period, scintillation is mainly a nighttime pheonomenon, reaching its maximum activity at 2100-2200

Method for measuring multiple scattering corrections between liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Verbeke, J.M., E-mail: verbeke2@llnl.gov; Glenn, A.M., E-mail: glenn22@llnl.gov; Keefer, G.J., E-mail: keefer1@llnl.gov; Wurtz, R.E., E-mail: wurtz1@llnl.gov

2016-07-21

A time-of-flight method is proposed to experimentally quantify the fractions of neutrons scattering between scintillators. An array of scintillators is characterized in terms of crosstalk with this method by measuring a californium source, for different neutron energy thresholds. The spectral information recorded by the scintillators can be used to estimate the fractions of neutrons multiple scattering. With the help of a correction to Feynman's point model theory to account for multiple scattering, these fractions can in turn improve the mass reconstruction of fissile materials under investigation.

Design and Prototyping of a High Granularity Scintillator Calorimeter

International Nuclear Information System (INIS)

Zutshi, Vishnu

2016-01-01

A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

Design and Prototyping of a High Granularity Scintillator Calorimeter

Energy Technology Data Exchange (ETDEWEB)

Zutshi, Vishnu [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics

2016-03-27

A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

A new lutetia-based ceramic scintillator for X-ray imaging

CERN Document Server

Lempicki, A; Szupryczynski, P; Lingertat, H; Nagarkar, V V; Tipnis, S V; Miller, S R

2002-01-01

We report a new scintillator based on a transparent ceramic of Lu sub 2 O sub 3 :Eu. The material has an extremely high density of 9.4 g/cm sup 3 , a light output comparable to CsI:Tl, and a narrow band emission at 610 nm that falls close to the maximum of the response curve of CCDs. Pixelation of the scintillator to prevent lateral spread of light enhances the spatial and contrast resolution, providing imaging performance that equals or surpasses all other currently known scintillators. Upon further development of readout technologies to take full advantage of its transparency, the new scintillator should play a major role in digital radiographic systems.

Discrimination of Naturally Occurring Radioactive Material in Plastic Scintillator Material

International Nuclear Information System (INIS)

Ely, James H.; Kouzes, Richard T.; Geelhood, Bruce D.; Schweppe, John E.; Warner, Ray A.

2003-01-01

Plastic scintillator material is used in many applications for the detection of gamma-rays from radioactive material, primarily due to the sensitivity per unit cost compared to other detection materials. However, the resolution and lack of full-energy peaks in the plastic scintillator material prohibits detailed spectroscopy. Therefore, other materials such as doped sodium iodide are used for spectroscopic applications. The limited spectroscopic information can however be exploited in plastic scintillator materials to provide some discrimination. The discrimination between man-made and naturally occurring sources would be useful in reducing alarm screening for radiation detection applications which target man-made sources. The results of applying the limited energy information from plastic scintillator material for radiation portal monitors are discussed.

Scintillation camera for high activity sources

International Nuclear Information System (INIS)

Arseneau, R.E.

1978-01-01

The invention described relates to a scintillation camera used for clinical medical diagnosis. Advanced recognition of many unacceptable pulses allows the scintillation camera to discard such pulses at an early stage in processing. This frees the camera to process a greater number of pulses of interest within a given period of time. Temporary buffer storage allows the camera to accommodate pulses received at a rate in excess of its maximum rated capability due to statistical fluctuations in the level of radioactivity of the radiation source measured. (U.K.)

Performance evaluation of X-ray CT using visible scintillation light

International Nuclear Information System (INIS)

Kodama, Kiyoyuki; Hamada, Minoru; Suzuki, Tamotsu; Hashimoto, Masatoshi; Hanada, Takashi; Ide, Tatsuya; Maruyama, Koichi

2004-01-01

We proposed a new method of performance evaluation for X-ray CT using visible scintillation light and examined its usefulness in this study. When we scanned a plastic scintillator disk in a gantry opening of the X-ray CT, we could observe visible scintillation light. The rotation of the light-emitting area of the disk corresponded to that of the X-ray tube. We were able to record the scintillation light by digital video camera. By analyzing the area of visible scintillation light, the rotation speed of the X-ray tube, angular spread of the X-ray beam, uniformity of the incident X-rays, and change in X-ray energy were measured. No other method is available to obtain the above parameters of X-ray CT during a single CT scan. In the measurements of the uniformity of incident X-rays and change of X-ray energy, our method showed good accuracy in detecting the attenuation caused by the couch between the X-ray tube and the plastic scintillator disc. The proposed method is inexpensive and easy-to-use. We conclude that the method is a useful tool for performance evaluation as well as a maintenance tool for X-ray CT. (author)

Toward the Probabilistic Forecasting of High-latitude GPS Phase Scintillation

Science.gov (United States)

Prikryl, P.; Jayachandran, P.T.; Mushini, S. C.; Richardson, I. G.

2012-01-01

The phase scintillation index was obtained from L1 GPS data collected with the Canadian High Arctic Ionospheric Network (CHAIN) during years of extended solar minimum 2008-2010. Phase scintillation occurs predominantly on the dayside in the cusp and in the nightside auroral oval. We set forth a probabilistic forecast method of phase scintillation in the cusp based on the arrival time of either solar wind corotating interaction regions (CIRs) or interplanetary coronal mass ejections (ICMEs). CIRs on the leading edge of high-speed streams (HSS) from coronal holes are known to cause recurrent geomagnetic and ionospheric disturbances that can be forecast one or several solar rotations in advance. Superposed epoch analysis of phase scintillation occurrence showed a sharp increase in scintillation occurrence just after the arrival of high-speed solar wind and a peak associated with weak to moderate CMEs during the solar minimum. Cumulative probability distribution functions for the phase scintillation occurrence in the cusp are obtained from statistical data for days before and after CIR and ICME arrivals. The probability curves are also specified for low and high (below and above median) values of various solar wind plasma parameters. The initial results are used to demonstrate a forecasting technique on two example periods of CIRs and ICMEs.

A projective geometry lead fiber scintillator detector

International Nuclear Information System (INIS)

Paar, H.; Thomas, D.; Sivertz, M.; Ong, B.; Acosta, D.; Taylor, T.; Shreiner, B.

1990-01-01

The Superconducting Super Collider (SSC), presently under construction near Dallas, Texas requires highly sophisticated particle detectors. The energy and particle flux at the SSC are more than an order of magnitude higher than the highest machine located at the Fermi National Accelerator near Chicago. An important element of particle detectors for the SSC is the calorimeter. It measures a particle's energy by sampling its energy deposit in heavy material, such as (depleted) uranium or lead. The sampling medium must be interspersed with heavy absorber material. In the case of scintillating plastic, two methods are under consideration: plates and fibers. In the case of plates, a sandwich of scintillator plates and uranium plates is constructed. In the use of fibers (still in the prototype stage), 1 mm. diameter cylindrical scintillating fibers are inserted into grooves that are machined into lead layers. The layers are stacked and epoxied together to form the required geometrical shape of the detector. Lead and scintillating plastic sampling can meet the physics requirements of the detector. This has been shown in an R ampersand D program which is underway at the University of California at San Diego (UCSD), High Energy Physics Group. This R ampersand D is funded by the Department of Energy, High Energy Physics and SSC Divisions

Measurement of gamma quantum interaction point in plastic scintillator with WLS strips

Energy Technology Data Exchange (ETDEWEB)

Smyrski, J., E-mail: smyrski@if.uj.edu.pl [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, S. Łojasiewicza 11, 30-348 Cracow (Poland); Alfs, D.; Bednarski, T.; Białas, P.; Czerwiński, E.; Dulski, K.; Gajos, A.; Głowacz, B.; Gupta-Sharma, N. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, S. Łojasiewicza 11, 30-348 Cracow (Poland); Gorgol, M.; Jasińska, B. [Department of Nuclear Methods, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin (Poland); Kajetanowicz, M.; Kamińska, D.; Korcyl, G. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, S. Łojasiewicza 11, 30-348 Cracow (Poland); Kowalski, P. [Świerk Computing Centre, National Centre for Nuclear Research, 05-400 Otwock-Świerk (Poland); Krzemień, W. [High Energy Department, National Centre for Nuclear Research, 05-400 Otwock-Świerk (Poland); Krawczyk, N.; Kubicz, E.; Mohammed, M.; Niedźwiecki, Sz. [Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, S. Łojasiewicza 11, 30-348 Cracow (Poland); and others

2017-04-11

The feasibility of measuring the aśxial coordinate of a gamma quantum interaction point in a plastic scintillator bar via the detection of scintillation photons escaping from the scintillator with an array of wavelength-shifting (WLS) strips is demonstrated. Using a test set-up comprising a BC-420 scintillator bar and an array of sixteen BC-482A WLS strips we achieved a spatial resolution of 5 mm (σ) for annihilation photons from a {sup 22}Na isotope. The studied method can be used to improve the spatial resolution of a plastic-scintillator-based PET scanner which is being developed by the J-PET collaboration.

BC404 scintillators as gamma locators studied via Geant4 simulations

Science.gov (United States)

Cortés, M. L.; Hoischen, R.; Eisenhauer, K.; Gerl, J.; Pietralla, N.

2014-05-01

In many applications in industry and academia, an accurate determination of the direction from where gamma rays are emitted is either needed or desirable. Ion-beam therapy treatments, the search for orphan sources, and homeland security applications are examples of fields that can benefit from directional sensitivity to gamma-radiation. Scintillation detectors are a good option for these types of applications as they have relatively low cost, are easy to handle and can be produced in a large range of different sizes. In this work a Geant4 simulation was developed to study the directional sensitivity of different BC404 scintillator geometries and arrangements. The simulation includes all the physical processes relevant for gamma detection in a scintillator. In particular, the creation and propagation of optical photons inside the scintillator was included. A simplified photomultiplier tube model was also simulated. The physical principle exploited is the angular dependence of the shape of the energy spectrum obtained from thin scintillator layers when irradiated from different angles. After an experimental confirmation of the working principle of the device and a check of the simulation, the possibilities and limitations of directional sensitivity to gamma radiation using scintillator layers was tested. For this purpose, point-like sources of typical energies expected in ion-beam therapy were used. Optimal scintillator thicknesses for different energies were determined and the setup efficiencies calculated. The use of arrays of scintillators to reconstruct the direction of incoming gamma rays was also studied. For this case, a spherical source emitting Bremsstrahlung radiation was used together with a setup consisting of scintillator layers. The capability of this setup to identify the center of the extended source was studied together with its angular resolution.

Progress in the development of LuAlO3 based scintillators

CERN Document Server

Belsky, A; Lecoq, P; Dujardin, C; Garnier, N; Canibano, H; Pédrini, C; Petrosian, A

2000-01-01

LuAlO3:Ce3+ (LuAP) and LuxY1-xAlO3:Ce3+ (LuYAP) crystals are the promote scintillation materials for Positron Emission Tomography. Actual study of these scintillators develops in the tree directions: (i) growth of large size LuAP crystals with stable properties, (ii) relationship between composition of LuYAP crystals and scintillation properties, and (iii) scintillation mechanisms in lutetium compounds. After improving of growth conditions a large size samples (length greater than 40 mm) have been prepared. Crystals show a good correlation between growth parameters, light yield and transmission spectra. We performed a series of samples with calibrated size (2x2x10 mm3) and compare the light yield with a standard BGO and LSO samples. Mixed crystals with composition of 0.6 less than x less than 0.8 show a significant increase of light yield. We suggest that the short order clusterisation in mixed crystals may by playing an important role in governing the scintillation efficiency. In order to clarify the scintil...

Scintillation Reduction using Conjugate-Plane Imaging (Abstract)

Science.gov (United States)

Vander Haagen, G. A.

2017-12-01

(Abstract only) All observatories are plagued by atmospheric turbulence exhibited as star scintillation or "twinkle" whether a high altitude adaptive optics research or a 30-cm amateur telescope. It is well known that these disturbances are caused by wind and temperature-driven refractive gradients in the atmosphere and limit the ultimate photometric resolution of land-based facilities. One approach identified by Fuchs (1998) for scintillation noise reduction was to create a conjugate image space at the telescope and focus on the dominant conjugate turbulent layer within that space. When focused on the turbulent layer little or no scintillation exists. This technique is described whereby noise reductions of 6 to 11/1 have been experienced with mathematical and optical bench simulations. Discussed is a proof-of-principle conjugate optical train design for an 80-mm, f7 telescope.

Current trends in scintillator detectors and materials

International Nuclear Information System (INIS)

Moses, W.W.

2002-01-01

The last decade has seen a renaissance in inorganic scintillator development for gamma ray detection. Lead tungstate (PbWO 4 ) has been developed for high-energy physics experiments, and possesses exceptionally high density and radiation hardness, albeit with low luminous efficiency. Lutetium orthosilicate or LSO (Lu 2 SiO 5 :Ce) possesses a unique combination of high luminous efficiency, high density, and reasonably short decay time, and is now incorporated in commercial positron emission tomography cameras. There have been advances in understanding the fundamental mechanisms that limit energy resolution, and several recently discovered materials (such as LaBr 3 :Ce) possess energy resolution that approaches that of direct solid state detectors. Finally, there are indications that a neglected class of scintillator materials that exhibit near band-edge fluorescence could provide scintillators with sub-nanosecond decay times and high luminescent efficiency

Prospects for first-principle calculations of scintillator properties

International Nuclear Information System (INIS)

Derenzo, Stephen E.; Weber, Marvin J.

1999-01-01

Several scintillation processes can be modeled from first principles using quantum chemistry cluster calculations and recently available high-performance computers. These processes include the formation of excitons and trapping centers, the diffusion of ionization energy (electrons and holes) through a host crystal, and the efficient capture of these carriers by an activator atom to form a luminous, non-quenched excited state. As examples of such calculations, results are presented for (1) hole transport in the known scintillator host crystal CsI, (2) hole trapping in the non-scintillator PbF 2 , (3) hole transport in the experimentally unexplored PbF 4 , and (4) the electronic nature of excited states of CsI : Tl and CsI : Na

First scintillating bolometer tests of a CLYMENE R&D on Li2MoO4 scintillators towards a large-scale double-beta decay experiment

Science.gov (United States)

Buşe, G.; Giuliani, A.; de Marcillac, P.; Marnieros, S.; Nones, C.; Novati, V.; Olivieri, E.; Poda, D. V.; Redon, T.; Sand, J.-B.; Veber, P.; Velázquez, M.; Zolotarova, A. S.

2018-05-01

A new R&D on lithium molybdate scintillators has begun within a project CLYMENE (Czochralski growth of Li2MoO4 crYstals for the scintillating boloMeters used in the rare EveNts sEarches). One of the main goals of the CLYMENE is a realization of a Li2MoO4 crystal growth line to be complementary to the one recently developed by LUMINEU in view of a mass production capacity for CUPID, a next-generation tonne-scale bolometric experiment to search for neutrinoless double-beta decay. In the present paper we report the investigation of performance and radiopurity of 158-g and 13.5-g scintillating bolometers based on a first large-mass (230 g) Li2MoO4 crystal scintillator developed within the CLYMENE project. In particular, a good energy resolution (2-7 keV FWHM in the energy range of 0.2-5 MeV), one of the highest light yield (0.97 keV/MeV) amongst Li2MoO4 scintillating bolometers, an efficient alpha particles discrimination (10 σ) and potentially low internal radioactive contamination (below 0.2-0.3 mBq/kg of U/Th, but 1.4 mBq/kg of 210Po) demonstrate prospects of the CLYMENE in the development of high quality and radiopure Li2MoO4 scintillators for CUPID.

Monte Carlo simulation of electron thermalization in scintillator materials: Implications for scintillator nonproportionality

Energy Technology Data Exchange (ETDEWEB)

Prange, Micah P. [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Xie, YuLong [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Campbell, Luke W. [National Security Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Gao, Fei [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA; Kerisit, Sebastien [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

2017-12-21

The lack of reliable quantitative estimates of the length and time scales associated with hot electron thermalization after a gamma-ray induced energy cascade obscures the interplay of various microscopic processes controlling scintillator performance and hampers the search for improved detector materials. We apply a detailed microscopic kinetic Monte Carlo model of the creation and subsequent thermalization of hot electrons produced by gamma irradiation of six important scintillating crystals to determine the spatial extent of the cloud of excitations produced by gamma rays and the time required for the cloud to thermalize with the host lattice. The main ingredients of the model are ensembles of microscopic track structures produced upon gamma excitation (including the energy distribution of the excited carriers), numerical estimates of electron-phonon scattering rates, and a calculated particle dispersion to relate the speed and energy of excited carriers. All these ingredients are based on first-principles density functional theory calculations of the electronic and phonon band structures of the materials. Details of the Monte Carlo model are presented along with results for thermalization time and distance distributions. These results are discussed in light of previous work. It is found that among the studied materials, calculated thermalization distances are positively correlated with measured nonproportionality. In the important class of halide scintillators, the particle dispersion is found to be more influential than the largest phonon energy in determining the thermalization distance.

Some history of liquid scintillator development at Los Alamos

International Nuclear Information System (INIS)

Ott, D.G.

1979-01-01

The early developments in liquid scintillation counting made at Los Alamos Scientific Laboratory are reviewed. Most of the work was under the direction of F.N. Hayes and included counter development and applications as well as synthesis and chemistry of liquid scintillators

Boron-Loaded Silicone Rubber Scintillators

Energy Technology Data Exchange (ETDEWEB)

Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

2003-05-12

Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

Studying the properties of the new class of organic scintillators-salicylic acid derivatives

International Nuclear Information System (INIS)

Mandzhukov, I.G.; Mandzhukova, B.V.; Bonchev, Ts.V.; Lazarova, G.I.

1981-01-01

Li, Na, K, Mg, Ca, Sr, Ba, La, Cd, Al, Sn, NH 4 salicylates are synthesized. Their relative scintillation efficiency during irradiation with α-particles of 5.156 MeV energy (sup(239)Pu) is determined. Scintillation efficiency of salicylates has been evaluated by comparing amplitude of scintillation pulse from salicylate with pulse amplitude from anthracene and other classical scintillators. Amplitude analysis has been conducted by standard methods. The analysis of the results obtained shows that sodium salicylate has the highest relative scintillation efficiency comparable with naphthalene efficiency. Salicylates of alkali Li and K metals as well as Ca and Cd salicylates have high relative scintillation efficiency. It is concluded that the investigated salicylates can be used for detection of (n, α), (n, p) and other reactions accompanying neutron capture not only during their reactions but by measuring activity induced in the scintillator [ru

Search of new scintillation materials for nuclear medicine application

CERN Document Server

Korzhik, M

2001-01-01

Oxide crystals have a great potential to develop new advanced scintillation materials which are dense, fast, and bright. This combination of parameters, when combined to affordable price, gives a prospect for materials to be applied in nuclear medicine devices. Some of them have been developed for the last two decades along the line of rear-earth (RE) garnet (RE//3Al//5O//1//2) oxiorthosilicate (RE//2SiO//5) and perovskite (REAlO//3) crystals doped with Ce ions. Among recently developed oxide materials the lead tungstate scintillator (PWO) becomes the most used scintillation materials in high energy physics experiments due to its application in CMS and ALICE experiments at LHC. In this paper we discuss scintillation properties of some new heavy compounds doped with Ce as well as light yield improvement of PWO crystals to apply them in low energy physics and nuclear medicine. 18 Refs.

Advanced Large Area Plastic Scintillator Project (ALPS): Final Report

International Nuclear Information System (INIS)

Jordan, David V.; Reeder, Paul L.; Todd, Lindsay C.; Warren, Glen A.; McCormick, Kathleen R.; Stephens, Daniel L.; Geelhood, Bruce D.; Alzheimer, James M.; Crowell, Shannon L.; Sliger, William A.

2008-01-01

The advanced Large-Area Plastic Scintillator (ALPS) Project at Pacific Northwest National Laboratory investigated possible technological avenues for substantially advancing the state-of-the-art in gamma-ray detection via large-area plastic scintillators. The three predominant themes of these investigations comprised the following: * Maximizing light collection efficiency from a single large-area sheet of plastic scintillator, and optimizing hardware event trigger definition to retain detection efficiency while exploiting the power of coincidence to suppress single-PMT 'dark current' background; * Utilizing anti-Compton vetoing and supplementary spectral information from a co-located secondary, or 'Back' detector, to both (1) minimize Compton background in the low-energy portion of the 'Front' scintillator's pulse-height spectrum, and (2) sharpen the statistical accuracy of the front detector's low-energy response prediction as implemented in suitable energy-windowing algorithms; and * Investigating alternative materials to enhance the intrinsic gamma-ray detection efficiency of plastic-based sensors

A large liquid scintillator detector for a long baseline neutrino oscillation experiment

International Nuclear Information System (INIS)

Border, P.; Cushman, P.; Heller, K.; Maxam, D.; Nelson, J.K.; Ruddick, K.; Rusack, R.; Schwienhorst, R.; Berg, T.; Chase, T.; Hansen, M.; Bower, C.; Hatcher, R.; Heinz, R.; Miller, L.; Mufson, S.

2001-01-01

We present the concept and design of a liquid scintillator detector for a long-baseline neutrino oscillation experiment. Neutrinos interact in 2.5 cm thick steel plates alternating with 2.0 cm thick planes of liquid scintillator. The scintillator is contained in multicell PVC extrusions containing individual 2 cmx3 cm cells up to 8 m long. Readout of the scintillation light is via wavelength-shifting fibers which transport light to pixellated photodetectors at one end of the cells

Next Generation Neutron Scintillators Based On Semiconductor Nanostructures

International Nuclear Information System (INIS)

Wang, Cai-Lin

2008-01-01

The results reported here successfully demonstrate the technical feasibility of ZnS QDs/ 6 LiF/polymer composites as thermal neutron scintillators. PartTec has obtained stable ZnS QDs with a quantum yield of 17% induced by UV light, and light pulse decay lifetimes of 10-30 ns induced by both UV and neutrons. These lifetime values are much shorter than those of commercial ZnS microparticle and 6 Li-glass scintillators. Clear pulse height peaks induced by neutron irradiation were seen for PartTec's ZnS nanocomposites. By adjusting the concentrations, particle size and degree of dispersion of ZnS QD/ 6 LiF in a PVA matrix, the light absorption and light yield of films at 420-440 nm can be optimized. PartTec's novel scintillators will replace traditional 6 Li-glass and ZnS/ 6 LiF:Ag scintillators if the PL quantum yield can be improved above 30%, and/or increase the transparency of present nanoscintillators. Time and resources inhibited PartTec's total success in Phase I. For example, bulk doping preparations of ZnS QDs with Ag + , Eu 3+ or Ce 3+ QDs was impractical given those constraints, nor did they permit PartTec to measure systematically the change of PL decay lifetimes in different samples. PartTec will pursue these studies in the current proposal, as well as develop a better capping and dopant along with developing brighter and faster ZnS QD scintillators.

Theoretical analysis of stack gas emission velocity measurement by optical scintillation

International Nuclear Information System (INIS)

Yang Yang; Dong Feng-Zhong; Ni Zhi-Bo; Pang Tao; Zeng Zong-Yong; Wu Bian; Zhang Zhi-Rong

2014-01-01

Theoretical analysis for an online measurement of the stack gas flow velocity based on the optical scintillation method with a structure of two parallel optical paths is performed. The causes of optical scintillation in a stack are first introduced. Then, the principle of flow velocity measurement and its mathematical expression based on cross correlation of the optical scintillation are presented. The field test results show that the flow velocity measured by the proposed technique in this article is consistent with the value tested by the Pitot tube. It verifies the effectiveness of this method. Finally, by use of the structure function of logarithmic light intensity fluctuations, the theoretical explanation of optical scintillation spectral characteristic in low frequency is given. The analysis of the optical scintillation spectrum provides the basis for the measurement of the stack gas flow velocity and particle concentration simultaneously. (general)

Cerium doped GSO scintillators and its application to position sensitive detectors

International Nuclear Information System (INIS)

Ishibashi, H.; Shimizu, K.; Susa, K.; Kubota, S.

1989-01-01

The dependence of the light output and the decay times of Ce doped Gd/sub 2/SiO/sub 5/ on Ce concentration is measured. By using the difference in decay times on Ce concentration for GSO(Ce), the combination of different concentration of GSO(Ce) scintillators is shown to be useful as position sensitive detectors. A Ce doped Gd/sub 2/SiO/sub 5/ (GSO(Ce)) single crystal is an excellent scintillator featuring, a large light output, a short decay time and a high absorption coefficient. Further investigation aimed at its implementation to scintillators has been carried out previously. An application of the GSO(Ce) scintillators to the gamma-ray detectors of positron emission computed tomography has also been shown. The authors have investigated the dependence of its scintillation properties on the Ce concentration and its application to position sensitive detectors

Gammastic: towards a pseudo-gamma spectrometry in plastic scintillators

International Nuclear Information System (INIS)

Hamel, Matthieu; Dehe-Pittance, Chrystele; Coulon, Romain; Carrel, Frederick; Pillot, Philippe; Barat, Eric; Dautremer, Thomas; Montagu, Thierry; Normand, Stephane

2013-06-01

War against CBRN-E threats needs to continuously develop sensors with improved detection efficiency. More particularly, this topic concerns the NR controls for homeland security. A first analysis requires indeed a fast gamma spectrometry so as to detect potential special nuclear materials (SNM). To this aim, plastic scintillators could represent the best alternative for the production of large-scale, low-cost radiation portal monitors to be deployed on boarders, tolls, etc. Although they are known to be highly sensitive to gamma rays, due to their poor resolution, information relative to the nature of the SNM is tricky. Thus, only the Compton edge is obtained after interaction, and no information of the photoelectric peak is observed. This project concerns new developments on a possible pseudo-gamma spectrometry performed with plastic scintillators. This project is articulated on a combination of two developments: - The design of new materials most suitable for recovering the photoelectric peak after gamma interaction with the scintillator. This work concerns mainly plastic scintillators loading with heavy elements, such as lead or bismuth. - The analysis of the resulting signal with smart algorithms. This work is thus a pluri-disciplinary work performed at CEA LIST and embeds 4 main disciplines: MCNPX simulations (simulated spectra), chemistry of materials (preparation of various plastic scintillators with different properties), instrumentation (lab experiments) and smart algorithms. Really impressive results were obtained with the unfolding of simulated spectra at various energies (from 241 Am to 60 Co) and an innovative approach was proposed to counter-balance the quenching effect of luminescence by heavy elements in plastic scintillators. (authors)

Growth and scintillation properties of gadolinium and yttrium orthovanadate crystals

International Nuclear Information System (INIS)

Voloshina, O.V.; Baumer, V.N.; Bondar, V.G.; Kurtsev, D.A.; Gorbacheva, T.E.; Zenya, I.M.; Zhukov, A.V.; Sidletskiy, O.Ts.

2012-01-01

Aiming to explore the possibility of using the undoped rare-earth orthovanadates as scintillation materials, we developed the procedure for growth of gadolinium (GdVO 4 ) and yttrium (YVO 4 ) orthovanadate single crystals by Czochralski method, and determined the optimal conditions of their after-growth annealing. Optical, luminescent, and scintillation properties of YVO 4 and GdVO 4 were discussed versus known literature data. Scintillation characteristics of GdVO 4 were determined for the first time.

An integrated photosensor readout for gas proportional scintillation counters

International Nuclear Information System (INIS)

Lopes, J.A.M.; Santos, J.M.F. dos; Conde, C.A.N.

1996-01-01

A xenon gas proportional scintillation counter has been instrumented with a novel photosensor that replaces the photomultiplier tube normally used to detect the VUV secondary scintillation light. In this implementation, the collection grid of a planar gas proportional scintillation counter also functions as a multiwire proportional chamber to amplify and detect the photoelectrons emitted by a reflective CsI photocathode in direct contact with the xenon gas. This integrated concept combines greater simplicity, compactness, and ruggedness (no optical window is used) with low power consumption. An energy resolution of 12% was obtained for 59.6 keV x-rays