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Sample records for potent auger emitter

  1. {sup 119}Sb--A potent Auger emitter for targeted radionuclide therapy

    SciTech Connect

    Thisgaard, H.; Jensen, M.

    2008-09-15

    Auger electron emitting radionuclides in cancer therapy offer the opportunity to deliver a high radiation dose to the tumor cells with high radiotoxicity while minimizing toxicity to normal tissue. We have in this study identified the Auger emitter {sup 119}Sb as a potent nuclide for targeted radionuclide therapy based on theoretical dosimetry calculations at a subcellular scale. From these calculations we have determined the cellular S-values for this therapeutic isotope. Moreover, we have demonstrated the possibility of producing this isotope and also the SPECT-analogue {sup 117}Sb for patient-specific dosimetry, by measuring the proton irradiation yields for both isotopes using a low-energy cyclotron. The excellent SPECT imaging properties of the {sup 117}Sb radionuclide have been shown by scanning a Jaszczak SPECT Phantom.

  2. Production and dosimetric aspects of the potent Auger emitter {sup 58m}Co for targeted radionuclide therapy of small tumors

    SciTech Connect

    Thisgaard, H.; Elema, D.R.; Jensen, M.

    2011-08-15

    Purpose: Based on theoretical calculations, the Auger emitter {sup 58m}Co has been identified as a potent nuclide for targeted radionuclide therapy of small tumors. During the production of this isotope, the coproduction of the long-lived ground state {sup 58g}Co is unfortunately unavoidable, as is ingrowth of the ground state following the isomeric decay of {sup 58m}Co. The impact of {sup 58g}Co as a {beta}{sup +}- and {gamma}-emitting impurity should be included in the dosimetric analysis. The purpose of this study was to investigate this critical part of dosimetry based on experimentally determined production yields of {sup 58m}Co and {sup 58g}Co using a low-energy cyclotron. Also, the cellular S-values for {sup 58m}Co have been calculated and are presented here for the first time. Methods: {sup 58m}Co was produced via the {sup 58}Fe(p,n){sup 58m}Co nuclear reaction on highly enriched {sup 58}Fe metal. In addition, radiochemical separations of produced radio-cobalt from {sup nat}Fe target material were performed. The theoretical subcellular dosimetry calculations for {sup 58m}Co and {sup 58g}Co were performed using the MIRD formalism, and the impact of the increasing ground state impurity on the tumor-to-normal-tissue dose ratios (TND) per disintegration as a function of time after end of bombardment (EOB) was calculated. Results: 192 {+-} 8 MBq of {sup 58m}Co was produced in the irradiation corresponding to a production yield of 10.7 MBq/{mu}Ah. The activity of {sup 58g}Co was measured to be 0.85% {+-} 0.04% of the produced {sup 58m}Co activity at EOB. The radio-cobalt yields in the rapid separations were measured to be >97% with no detectable iron contaminations in the cobalt fractions. Due to the unavoidable coproduction and ingrowth of the long-lived ground state {sup 58g}Co, the TND and the potency of the {sup 58m}Co decrease with time after EOB. If a future treatment with a {sup 58m}Co labeled compound is not initiated before, e.g., 21 h after EOB, the

  3. On the equivalent dose for Auger electron emitters.

    PubMed

    Howell, R W; Narra, V R; Sastry, K S; Rao, D V

    1993-04-01

    Radionuclides that emit Auger electrons are widely used in nuclear medicine (e.g., 99mTc, 123I, 201Tl) and biomedical research (e.g., 51Cr, 125I), and they are present in the environment (e.g., 40K, 55Fe). Depending on the subcellular distribution of the radionuclide, the biological effects caused by tissue-incorporated Auger emitters can be as severe as those from high-LET alpha particles. However, the recently adopted recommendations of the International Commission on Radiological Protection (ICRP) provide no guidance with regard to calculating the equivalent dose for these radionuclides. The present work, using spermatogenesis in mouse testis as the experimental model, shows that the lethality of the prolific Auger emitter 125I is linearly dependent on the fraction of the radioactivity in the organ that is bound to DNA. This suggests that the equivalent dose for Auger emitters may have a similar linear dependence. Accordingly, a formalism for calculating the equivalent dose for Auger emitters is advanced within the ICRP framework.

  4. On the Equivalent Dose for Auger Electron Emitters

    PubMed Central

    Howell, Roger W.; Narra, Venkat R.; Sastry, Kandula S. R.; Rao, Dandamudi V.

    2012-01-01

    Radionuclides that emit Auger electrons are widely used in nuclear medicine (e.g., 99mTc, 123I, 201T1) and biomedical research (e.g., 51Cr, 125I), and they are present in the environment (e.g., 40K, 55Fe). Depending on the subcellular distribution of the radionuclide, the biological effects caused by tissue-incorporated Auger emitters can be as severe as those from high-LET α particles. However, the recently adopted recommendations of the International Commission on Radiological Protection (ICRP) provide no guidance with regard to calculating the equivalent dose for these radionuclides. The present work, using spermatogenesis in mouse testis as the experimental model, shows that the lethality of the prolific Auger emitter 125I is linearly dependent on the fraction of the radioactivity in the organ that is bound to DNA. This suggests that the equivalent dose for Auger emitters may have a similar linear dependence. Accordingly, a formalism for calculating the equivalent dose for Auger emitters is advanced within the ICRP framework. PMID:8475256

  5. Dosimetry of Auger emitters: Physical and phenomenological approaches

    SciTech Connect

    Sastry, K.S.R.; Howell, R.W.; Rao, D.V.; Mylavarapu, V.B.; Kassis, A.I.; Adelstein, S.J.; Wright, H.A.; Hamm, R.N.; Turner, J.E.

    1987-01-01

    Recent radiobiological studies have demonstrated that Auger cascades can cause severe biological damage contrary to expectations based on conventional dosimetry. Several determinants govern these effects, including the nature of the Auger electron spectrum; localized energy deposition; cellular geometry; chemical form of the carrier; cellular localization, concentration, and subcellular distribution of the radionuclide. Conventional dosimetry is inadequate in that these considerations are ignored. Our results provide the basis for biophysical approaches toward subcellular dosimetry of Auger emitters in vitro and in vivo. 12 refs., 7 figs., 2 tabs.

  6. A compilation of microdosimetry for uniformly distributed Auger emitters used in medicine.

    PubMed

    Chen, Jing

    2008-12-01

    To provide a compilation of microdosimetric characteristics for 12 Auger emitters commonly used in medicine. Monte Carlo electron track structure simulations are performed for 12 Auger emitters. They are (55)Fe, (67)Ga, (99m)Tc, (111)In, (113m)In, (115m)In, (123)I, (125)I, (193m)Pt, (195m)Pt, (201)Tl, and (203)Pb. Proximity functions of 12 Auger emitters are calculated from the simulated track structures and compared with that of gamma rays from (60)Co. Some of those Auger emitters are highly radiotoxic compared to hard gamma rays from (60)Co. The more electrons per decay and the lower electron energies, the more effective an Auger emitter could be. The high radiotoxicity of Auger emitters is due to correlations of low-energy electrons released from decay processes. If these correlations were disregarded, Auger emitters would not differ significantly from other low linear energy transfer (LET) radiation sources. Even in the case of uniform distribution, some of those Auger emitters are highly radiotoxic compared to hard gamma rays. For Auger emitters to bond to radiosensitive sites in cell nucleus, much higher radiation effectiveness could be expected.

  7. Nuclear Targeting with an Auger Electron Emitter Potentiates the Action of a Widely Used Antineoplastic Drug.

    PubMed

    Imstepf, Sebastian; Pierroz, Vanessa; Raposinho, Paula; Bauwens, Matthias; Felber, Michael; Fox, Thomas; Shapiro, Adam B; Freudenberg, Robert; Fernandes, Célia; Gama, Sofia; Gasser, Gilles; Motthagy, Felix; Santos, Isabel R; Alberto, Roger

    2015-12-16

    We present the combination of the clinically well-proven chemotherapeutic agent, Doxorubicin, and (99m)Tc, an Auger and internal conversion electron emitter, into a dual-action agent for therapy. Chemical conjugation of Doxorubicin to (99m)Tc afforded a construct which autonomously ferries a radioactive payload into the cell nucleus. At this site, damage is exerted by dose deposition from Auger radiation. The (99m)Tc-conjugate exhibited a dose-dependent inhibition of survival in a selected panel of cancer cells and an in vivo study in healthy mice evidenced a biodistribution which is comparable to that of the parent drug. The homologous Rhenium conjugate was found to effectively bind to DNA, inhibited human Topoisomerase II, and exhibited cytotoxicity in vitro. The collective in vitro and in vivo data demonstrate that the presented metallo-conjugates closely mimic native Doxorubicin.

  8. Trifunctional somatostatin-based derivatives designed for targeted radiotherapy using auger electron emitters.

    PubMed

    Ginj, Mihaela; Hinni, Karin; Tschumi, Sibylle; Schulz, Stefan; Maecke, Helmut R

    2005-12-01

    Auger electron-emitting radionuclides have potential for the therapy of small-size cancers because of their high level of cytotoxicity, low-energy, high linear energy transfer, and short-range biologic effectiveness. Biologic effects are critically dependent on the subcellular (and even subnuclear) localization of these radionuclides. Our goals were the design, synthesis, and in vitro preclinical assessment of new trifunctional conjugates of somatostatin that should aim at the nucleus and, therefore, ensure a longer retention time in the cell, a close approximation to the DNA, and the success of Auger electron emitters in targeted radionuclide therapy as well as also improve other targeted therapy strategies. Three trifunctional derivatives of [(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)0,Tyr3]octreotide (DOTA-TOC) bearing the nuclear localization signal (NLS) (of simian virus 40 large-T antigen) PKKKRKV in 3 different positions relative to the somatostatin analog sequence were synthesized using solid and solution phase peptide synthesis. These compounds together with DOTA-TOC and DOTA-NLS derivatives were labeled with 111In and tested for binding affinity, internalization, externalization, and nuclei localization on AR4-2J cells and on human embryonic cells stably transfected with sst2A. The two N-terminal derivatives preserved the sstr2A binding affinity. Their rate of internalization in all tested sstr-expressing cell lines was always superior for the trifunctional derivatives in comparison with the parent compound. A 6-fold increase in cellular retention from the total internalized activity and a 45-fold higher accumulation in the cell nuclei were found for one of the N-terminally modified compounds compared with [111In]-DOTA-TOC. The C-terminal conjugate was inferior in all tests compared with the parent compound. These encouraging results support our hypothesis that an additional NLS sequence to the DOTA-TOC could not only provide a better

  9. Triple targeting of Auger emitters using octreotate conjugated to a DNA-binding ligand and a nuclear localizing signal.

    PubMed

    Violet, John A; Farrugia, Gabriella; Skene, Colin; White, Jonathan; Lobachevsky, Pavel; Martin, Roger

    2016-11-01

    We investigated the effect of incorporation of a nuclear localization signal (NLS) into a conjugate comprising the DNA binding ligand para-iodoHoechst (PIH) and octreotate on its DNA binding and affinity to the somatostatin receptor (SSTR). Confirmation of these properties would support development of similar conjugates labelled with Auger emitters for their potential in Auger endoradiotherapy. We synthesized conjugates of PIH and octreotate (PO) or PIH and NLS (PN) and a conjugate comprising PIH, NLS and octreotate (PNO). DNA-binding characteristics of PIH and conjugates were assessed using synthetic DNA oligonucleotides employing spectrophotometric titration of ligand solutions with DNA. We used membranes from the type 2 SSTR (SSTR2) overexpressing human non-small cell lung cancer cell line A427-7 to investigate the binding affinity of PNO. We demonstrated PN and PNO retain specific high affinity DNA-binding properties observed for PIH, and acquire an additional non-specific binding capacity. No DNA binding was observed for PO. PNO retains its binding affinity for SSTR. The DNA-binding properties of PNO and its affinity for SSTR suggests that it could potentially be used for tumour-specific delivery of PIH labelled with an Auger emitter in SSTR expressing tumours.

  10. Auger effect in yellow light emitters based on InGaN-AlGaN-GaN quantum wells

    NASA Astrophysics Data System (ADS)

    Huong Ngo, Thi; Gil, Bernard; Valvin, Pierre; Damilano, Benjamin; Lekhal, Kaddour; De Mierry, Philippe

    2016-05-01

    The Auger effect and its impact on the internal quantum efficiency (IQE) of yellow light emitters based on silicon-doped InGaN-AlGaN-GaN quantum wells are investigated by power dependence measurement and using an ABC model. Photoluminescence intensity recorded as a function of excitation power density follows a linear dependence up to a threshold P T that depends on the design of the sample. Above this threshold, the variation of the intensity becomes sublinear, which is characteristic of the onset of Auger recombination processes. After extracting the evolution of IQE with pump power from the experimental data, we use a modified ABC modeling that includes the residual n-type doping to estimate the contribution of different recombination channels. We find that the Auger effect dominates in the high-excitation regime. In addition, we find that intercalating an AlGaN-strain-compensating layer reduces not only the coefficient of nonradiative recombination rates but also reduces the onset of Auger recombination.

  11. Internal quantum efficiency and Auger recombination in green, yellow and red InGaN-based light emitters grown along the polar direction

    NASA Astrophysics Data System (ADS)

    Ngo, Thi Huong; Gil, Bernard; Damilano, Benjamin; Lekhal, Kaddour; De Mierry, Philippe

    2017-03-01

    We comparatively study the onset of photo-induced non-radiative intrinsic Auger recombination processes for red, yellow and green light emitting InGaNsbnd GaN hetero-structures grown along the polar orientation. We find a dramatic reduction of the photo excitation densities triggering the domination of Auger effect with increasing emission wavelength; that is to say in concert with the enhancement of the internal electric field in the structure. In long wavelength emitters, the internal electric field is stronger, and hence reducing the impact of the internal electric field is more critical.

  12. Incorporation of iododeoxyuridine in multicellular glioma spheroids: implications for DNA-targeted radiotherapy using Auger electron emitters.

    PubMed Central

    Neshasteh-Riz, A.; Angerson, W. J.; Reeves, J. R.; Smith, G.; Rampling, R.; Mairs, R. J.

    1997-01-01

    A promising new treatment for glioma involves Auger electron emitters such as 125I or 123I conjugated to deoxyuridine (IUdR). However, the presence in tumour deposits of non-proliferating cells with clonogenic potential poses a major limitation to this cycle-specific therapy. We have used multicellular tumour spheroids derived from the human glioma cell line UVW to study [125I]IUdR-targeted radiotherapy in aggregates containing cells in different proliferative states. Autoradiographic identification of labelled cells indicated that nuclear incorporation of [125I]IUdR decreased markedly with increasing size of spheroid. IUdR incorporation was maximal in the surface layer of cells and decreased with depth within spheroids. Radiopharmaceutical uptake corresponded closely to the regions of cell cycling as indicated by staining for the nuclear antigen Ki67. The uptake of drug was enhanced by increasing the duration of incubation from 52 h to 104 h. These observations suggest that significant sparing of non-cycling malignant cells would result from treatment delivered as a single injection of radiolabelled IUdR. To achieve maximal therapeutic effect. IUdR should be administered by multiple injections, by slow release from biodegradable implants or by slow-pump delivery. Images Figure 2 PMID:9052399

  13. Looking for Auger signatures in III-nitride light emitters: A full-band Monte Carlo perspective

    SciTech Connect

    Bertazzi, Francesco Goano, Michele; Zhou, Xiangyu; Calciati, Marco; Ghione, Giovanni; Matsubara, Masahiko; Bellotti, Enrico

    2015-02-09

    Recent experiments of electron emission spectroscopy (EES) on III-nitride light-emitting diodes (LEDs) have shown a correlation between droop onset and hot electron emission at the cesiated surface of the LED p-cap. The observed hot electrons have been interpreted as a direct signature of Auger recombination in the LED active region, as highly energetic Auger-excited electrons would be collected in long-lived satellite valleys of the conduction band so that they would not decay on their journey to the surface across the highly doped p-contact layer. We discuss this interpretation by using a full-band Monte Carlo model based on first-principles electronic structure and lattice dynamics calculations. The results of our analysis suggest that Auger-excited electrons cannot be unambiguously detected in the LED structures used in the EES experiments. Additional experimental and simulative work are necessary to unravel the complex physics of GaN cesiated surfaces.

  14. ET-22CONVECTION-ENHANCED DELIVERY OF THE AUGER-ELECTRON-EMITTER 125I-UdR: A HIGHLY EFFICIENT THERAPY IN AN ORTHOTOPIC GLIOBLASTOMA XENOGRAFT MODEL

    PubMed Central

    Halle, Bo; Thisgaard, Helge; Aaberg-Jessen, Charlotte; Olsen, Birgitte; Dam, Johan; Langkjær, Niels; Munthe, Sune; Någren, Kjell; Høilund-Carlsen, Poul Flemming; Kristensen, Bjarne

    2014-01-01

    BACKGROUND: Glioblastomas (GBMs), the most common and malignant primary brain tumors, always recur after standard treatment. In order to develop more efficient therapies, we tested a novel therapeutic approach using the radioactive Auger-electron-emitter (AEE) [125I]5-Iodo-2'-deoxyuridine (125I-UdR). This drug incorporates into DNA of dividing cells and upon decay emission of Auger-electrons causes clusters of double strand breaks leading to cell death. METHODS: In vitro, cells from two GBM spheroid cultures (T78 & T87) were exposed to either 125I-UdR or 127I-UdR (non-radioactive analogue) and tumor cell viability and migration were measured. In vivo, nude rats were implanted orthotopically with T87 cells and after tumor formation micro infusion pumps were implanted enabling direct intratumoral convection-enhanced delivery (CED). Animals were divided into three groups (I-III). Group I (n = 8) was treated with 127I-UdR by CED, group II (n = 7) with neoadjuvant methotrexate (MTX) + 125I-UdR by CED and group III with neoadjuvant MTX + 125I-UdR by CED and concomitant systemic temozolomide (TMZ). Rats were followed for 180 days post-treatment with repeated [11C]methylaminoisobutyric acid ([11C]MeAIB) positron emission tomography scans and blood sampling. Single photon emission computed tomography/computed tomography (SPECT/CT) scans were performed to evaluate 125I-UdR distribution. Additionally, post-mortem histological examination of brain, liver, kidneys and thyroid gland was performed. RESULTS: In vitro, 125I-UdR significantly decreased GBM cell viability and migration. In group I, no animals (8/8) survived longer than 23 days after treatment start. In group II, 4/7 animals survived the entire observation period of 180 days. In group III, all animals (8/8) survived the entire observation period. SPECT/CT showed a widespread intracerebral distribution of 125I-UdR, while blood samples and post-mortem histology revealed no signs of dose-limiting adverse effects

  15. WE-AB-204-12: Dosimetry at the Sub-Cellular Scale of Auger-Electron Emitter 99m-Tc in a Mouse Single Thyroid Follicle Model

    SciTech Connect

    Taborda, A; Benabdallah, N; Desbree, A

    2015-06-15

    Purpose: To perform a dosimetry study at the sub-cellular scale of Auger-electron emitter 99m-Tc using a mouse single thyroid cellular model to investigate the contribution of the 99m-Tc Auger-electrons to the absorbed dose and possible link to the thyroid stunning in in vivo experiments in mice, recently reported in literature. Methods: The simulation of S-values for Auger-electron emitting radionuclides was performed using both the recent MCNP6 software and the Geant4-DNA extension of the Geant4 toolkit. The dosimetric calculations were validated through comparison with results from literature, using a simple model of a single cell consisting of two concentric spheres of unit density water and for six Auger-electron emitting radionuclides. Furthermore, the S-values were calculated using a single thyroid follicle model for uniformly distributed 123-I and 125-I radionuclides and compared with published S-values. After validation, the simulation of the S-values was performed for the 99m-Tc radionuclide within the several mouse thyroid follicle cellular compartments, considering the radiative and non-radiative transitions of the 99m-Tc radiation spectrum. Results: The calculated S-values using MCNP6 are in good agreement with the results from literature, validating its use for the 99m-Tc S-values calculations. The most significant absorbed dose corresponds to the case where the radionuclide is uniformly distributed in the follicular cell’s nucleus, with a S-value of 7.8 mGy/disintegration, due mainly to the absorbed Auger-electrons. The results show that, at a sub-cellular scale, the emitted X-rays and gamma particles do not contribute significantly to the absorbed dose. Conclusion: In this work, MCNP6 was validated for dosimetric studies at the sub-cellular scale. It was shown that the contribution of the Auger-electrons to the absorbed dose is important at this scale compared to the emitted photons’ contribution and can’t be neglected. The obtained S

  16. Dosimetry at the sub-cellular scale of Auger-electron emitter 99mTc in a mouse single thyroid follicle.

    PubMed

    Taborda, A; Benabdallah, N; Desbrée, A

    2016-02-01

    The Auger-electrons emitted by (99m)Tc have been recently associated with the induction of thyroid stunning in in vivo experiments in mice, making the dosimetry at the sub-cellular level of (99m)Tc a pertinent and pressing subject. The S-values for (99m)Tc were calculated using MCNP6, which was first validated for studies at the sub-cellular scale and for low energies electrons. The calculation was then performed for (99m)Tc within different cellular compartments in a single mouse thyroid follicle model, considering the radiative and non-radiative transitions of the (99m)Tc radiation spectrum. It was shown that the contribution of the (99m)Tc Auger and low energy electrons to the absorbed dose to the follicular cells' nucleus is important, being at least of the same order of magnitude compared to the emitted photons' contribution and cannot be neglected. The results suggest that Auger-electrons emitted by (99m)Tc play a significant role in the occurrence of the thyroid stunning effect in mice.

  17. Study on cell survival, induction of apoptosis and micronucleus formation in SCL-II cells after exposure to the auger electron emitter (99m)Tc.

    PubMed

    Kriehuber, R; Kadenbach, K; Schultz, F; Weiss, D G

    2004-01-01

    To study the biological effectiveness of Auger electrons emitted by (99m)Tc on cell survival, induction of apoptosis and micronucleus (MN) formation in the human squamous cell carcinoma cell line SCL-II and compare the effects observed to those observed after exposure to external 60Co gamma radiation. Cells were either gamma(60Co)-irradiated (0.67 Gy/min) or exposed to (99m)Tc-pertechnetate (0.95-14.3 MBq/ml) for 24 h under cell culture conditions and assayed for cell survival (colony-forming assay), micronucleus formation (cytochalasin B assay) and the frequency of apoptotic cells (fluorescence microscopy). Monte Carlo based dosimetry has been applied to derive the absorbed dose corresponding to the accumulated decays of (99m)Tc under the given geometry. Absorbed doses up to 0.5 Gy could be achieved after 99mTc-exposure leading to no substantial cell killing in this dose range except at one dose point (0.1 Gy) resulting in an relative biological effectiveness (RBE)SF 0.9 of 0.64 when compared to the 60Co reference radiation. MN formation was described best by a linear dose response and was consistently lower after 99mTc exposure when compared to 60Co irradiated cells resulting in an RBE of 0.37. Apoptosis induction was significantly increased after 99mTc exposure at much lower doses (0.1 Gy) when compared to the reference radiation. The (99m)Tc uptake experiments revealed an activity concentration ratio cells vs. medium of 0.07 after 24 h of exposure. No overall increased biological effectiveness due to the emitted Auger electrons of (99m)Tc, applied as sodium-pertechnetate, could be observed in the investigated cell line when compared to acute external gamma radiation. The RBEs in the range of 0.37-0.64 might be well explained by dose rate effects. The significantly increased apoptotic response after (99m)Tc-exposure at very low doses has to be further investigated.

  18. Auger Emitting Radiopharmaceuticals for Cancer Therapy

    NASA Astrophysics Data System (ADS)

    Falzone, Nadia; Cornelissen, Bart; Vallis, Katherine A.

    Radionuclides that emit Auger electrons have been of particular interest as therapeutic agents. This is primarily due to the short range in tissue, controlled linear paths and high linear energy transfer of these particles. Taking into consideration that ionizations are clustered within several cubic nanometers around the point of decay the possibility of incorporating an Auger emitter in close proximity to the cancer cell DNA has immense therapeutic potential thus making nuclear targeted Auger-electron emitters ideal for precise targeting of cancer cells. Furthermore, many Auger-electron emitters also emit γ-radiation, this property makes Auger emitting radionuclides a very attractive option as therapeutic and diagnostic agents in the molecular imaging and management of tumors. The first requirement for the delivery of Auger emitting nuclides is the definition of suitable tumor-selective delivery vehicles to avoid normal tissue toxicity. One of the main challenges of targeted radionuclide therapy remains in matching the physical and chemical characteristics of the radionuclide and targeting moiety with the clinical character of the tumor. Molecules and molecular targets that have been used in the past can be classified according to the carrier molecule used to deliver the Auger-electron-emitting radionuclide. These include (1) antibodies, (2) peptides, (3) small molecules, (4) oligonucleotides and peptide nucleic acids (PNAs), (5) proteins, and (6) nanoparticles. The efficacy of targeted radionuclide therapy depends greatly on the ability to increase intranuclear incorporation of the radiopharmaceutical without compromising toxicity. Several strategies to achieve this goal have been proposed in literature. The possibility of transferring tumor therapy based on the emission of Auger electrons from experimental models to patients has vast therapeutic potential, and remains a field of intense research.

  19. Biophysical aspects of Auger processes. American Association of Physicists in Medicine symposium proceedings No. 8

    SciTech Connect

    Howell, R.W.; Narra, V.R.; Rao, D.V. . Dept. of Radiology); Sastry, K.S.R. . Dept. of Physics and Astronomy)

    1992-01-01

    The 2nd International Symposium on Biophysical Aspects of Auger Processes was held in July 1991, at the University of Massachusetts. This conference provided a forum for state-of-the-art information regarding the basic mechanisms of action by which Auger processes effect biological damage, as well as the nature of the radiosensitive targets in the cell nucleus. In addition, new insight into the radiotoxicity of Auger processes arising from photon activation of atoms situated in the DNA were presented. Novel approaches to implement agents radiolabeled with Auger electron emitters for cancer therapy were discussed. The information is organized into three sections: Biological effects of photon induced Auger processes; biological effects of Auger-electron emitting radionuclides; and therapeutic applications of Auger electron emitters. Individual papers have been processed separately for inclusion in the appropriate data bases.

  20. Differential auger spectrometry

    DOEpatents

    Strongin, Myron; Varma, Matesh Narayan; Anne, Joshi

    1976-06-22

    Differential Auger spectroscopy method for increasing the sensitivity of micro-Auger spectroanalysis of the surfaces of dilute alloys, by alternately periodically switching an electron beam back and forth between an impurity free reference sample and a test sample containing a trace impurity. The Auger electrons from the samples produce representative Auger spectrum signals which cancel to produce an Auger test sample signal corresponding to the amount of the impurity in the test samples.

  1. Nanodosimetry of (125)I Auger electrons.

    PubMed

    Bantsar, Aliaksandr; Pszona, Stanislaw

    2012-12-01

    The nanodosimetric description of the radiation action of Auger electrons on nitrogen targets of nanometric size is presented. Experimental microdosimetry at nanometer scale for Auger electrons has been accomplished with the set-up called Jet Counter. This consists of a pulse-operated valve which injects an expanding nitrogen jet into an interaction chamber where a gaseous sensitive volume of cylindrical shape is created. The ionization cluster size distributions (ICSD) created by Auger electrons emitted by (125)I while crossing a nanometer-sized volume have been measured. The ICSD for the sensitive volumes corresponding to 3 and 12 nm in diameter (in unit density 1 g/cm(3)) irradiated by electrons emitted by a (125)I source were collected and compared with the corresponding Monte Carlo (MC) simulation. The preliminary results of the experiments with Auger electrons of (125)I interacting with a nitrogen jet having nanometric size comparable to a deoxyribonucleic acid (DNA) and nucleosome, showing the discrete spectrum of ICSD with extended cluster size, are described. The presented paper describes for the first time the nanodosimetric experiments with Auger electrons emitted by (125)I. A set of the new descriptors of the radiation quality describing the radiation effect at nanometer level is proposed. The ICSD were determined for the first time for an Auger emitter of (125)I.

  2. Coal-Sizing Auger

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1985-01-01

    Aft end of auger, like forward, face-piercing end, equipped with hard cutting bits such as diamonds. As auger breaks face, pulls broken coal lumps into jaws and forces them into hardened throat section. There, cutting bits chew up lumps: Clearance between throat and auger shaft sets maximum size for coal particles that pass through. Auger motion pushes coal particles into mixing chamber, where paddles combine them with water.

  3. Calculation of equivalent dose for Auger electron emitting radionuclides distributed in human organs.

    PubMed

    Goddu, S M; Howell, R W; Rao, D V

    1996-01-01

    Radionuclides that emit Auger electrons can be extremely radiotoxic depending on the subcellular distribution of the radiochemical. Despite this, ICRP 60 provides no guidance in the calculation of equivalent dose H(T) for Auger electrons. The recent report by the American Association of Physicists in Medicine recommends a radiation weighting factor wR of 20 for stochastic effects caused by Auger electrons, along with a method of calculating the equivalent dose that takes into account the subcellular distribution of the radionuclide. In view of these recommendations, it is important to reevaluate equivalent doses from Auger electron emitters. The mean absorbed dose per unit cumulated activity (S-value) from Auger electrons and other radiations is calculated for ninety Auger-electron-emitting radionuclides distributed in human ovaries, testes and liver. Using these S-values, and the formalism given in the recent AAPM report, the dependence of the organ equivalent doses on subcellular distribution of the Auger electron emitters is examined. The results show an increase in the mean equivalent dose for Auger electron emitters when a significant fraction of the organ activity localizes in the DNA.

  4. Outreach activities within Auger

    NASA Astrophysics Data System (ADS)

    López Ramírez, Rebeca; Snow, Gregory

    2009-04-01

    The scale and scope of the physics studied at the Auger Observatory offer significant opportunities for original outreach work. Education, outreach, and public relations of the Auger collaboration are coordinated in a task of its own whose goals are to encourage and support a wide range of efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. This report focuses on the impact of the collaboration in Mendoza Province, Argentina, as: the Auger Visitor Center in Malargüe that has hosted over 29,000 visitors since 2001, the Auger Celebration and a collaboration-sponsored science fair held on the Observatory campus in November 2005, the opening of the James Cronin School in Malargüe in November 2006, public lectures, school visits, and courses for science teachers.

  5. The effect of dimethyl sulfoxide on the induction of DNA strand breaks in plasmid DNA and colony formation of PC Cl3 mammalian cells by alpha-, beta-, and Auger electron emitters (223)Ra, (188)Re, and (99m)Tc.

    PubMed

    Runge, Roswitha; Oehme, Liane; Kotzerke, Jörg; Freudenberg, Robert

    2016-12-01

    DNA damage occurs as a consequence of both direct and indirect effects of ionizing radiation. The severity of DNA damage depends on the physical characteristics of the radiation quality, e.g., the linear energy transfer (LET). There are still contrary findings regarding direct or indirect interactions of high-LET emitters with DNA. Our aim is to determine DNA damage and the effect on cellular survival induced by (223)Ra compared to (188)Re and (99m)Tc modulated by the radical scavenger dimethyl sulfoxide (DMSO). Radioactive solutions of (223)Ra, (188)Re, or (99m)Tc were added to either plasmid DNA or to PC Cl3 cells in the absence or presence of DMSO. Following irradiation, single strand breaks (SSB) and double strand breaks (DSB) in plasmid DNA were analyzed by gel electrophoresis. To determine the radiosensitivity of the rat thyroid cell line (PC Cl3), survival curves were performed using the colony formation assay. Exposure to 120 Gy of (223)Ra, (188)Re, or (99m)Tc leads to maximal yields of SSB (80 %) in plasmid DNA. Irradiation with 540 Gy (223)Ra and 500 Gy (188)Re or (99m)Tc induced 40, 28, and 64 % linear plasmid conformations, respectively. DMSO prevented the SSB and DSB in a similar way for all radionuclides. However, with the α-emitter (223)Ra, a low level of DSB could not be prevented by DMSO. Irradiation of PC Cl3 cells with (223)Ra, (188)Re, and (99m)Tc pre-incubated with DMSO revealed enhanced survival fractions (SF) in comparison to treatment without DMSO. Protection factors (PF) were calculated using the fitted survival curves. These factors are 1.23 ± 0.04, 1.20 ± 0.19, and 1.34 ± 0.05 for (223)Ra, (188)Re, and (99m)Tc, respectively. For (223)Ra, as well as for (188)Re and (99m)Tc, dose-dependent radiation effects were found applicable for plasmid DNA and PC Cl3 cells. The radioprotection by DMSO was in the same range for high- and low-LET emitter. Overall, the results indicate the contribution of mainly indirect radiation

  6. Selective Emitters

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L. (Inventor)

    1992-01-01

    This invention relates to a small particle selective emitter for converting thermal energy into narrow band radiation with high efficiency. The small particle selective emitter is used in combination with a photovoltaic array to provide a thermal to electrical energy conversion device. An energy conversion apparatus of this type is called a thermo-photovoltaic device. In the first embodiment, small diameter particles of a rare earth oxide are suspended in an inert gas enclosed between concentric cylinders. The rare earth oxides are used because they have the desired property of large emittance in a narrow wavelength band and small emittance outside the band. However, it should be emphasized that it is the smallness of the particles that enhances the radiation property. The small particle selective emitter is surrounded by a photovoltaic array. In an alternate embodiment, the small particle gas mixture is circulated through a thermal energy source. This thermal energy source can be a nuclear reactor, solar receiver, or combustor of a fossil fuel.

  7. Selective emitters

    NASA Astrophysics Data System (ADS)

    Chubb, Donald L.

    1992-01-01

    This invention relates to a small particle selective emitter for converting thermal energy into narrow band radiation with high efficiency. The small particle selective emitter is used in combination with a photovoltaic array to provide a thermal to electrical energy conversion device. An energy conversion apparatus of this type is called a thermo-photovoltaic device. In the first embodiment, small diameter particles of a rare earth oxide are suspended in an inert gas enclosed between concentric cylinders. The rare earth oxides are used because they have the desired property of large emittance in a narrow wavelength band and small emittance outside the band. However, it should be emphasized that it is the smallness of the particles that enhances the radiation property. The small particle selective emitter is surrounded by a photovoltaic array. In an alternate embodiment, the small particle gas mixture is circulated through a thermal energy source. This thermal energy source can be a nuclear reactor, solar receiver, or combustor of a fossil fuel.

  8. Spin-polarized Auger electrons

    NASA Astrophysics Data System (ADS)

    Merz, H.; Semke, J.

    1990-12-01

    The spin polarization of Auger electrons will be discussed within the standard two-step model of the Auger emission process for different situations: target polarized, projectile polarized, targe and projectile unpolarized. In these three cases different interaction mechanisms are responsible for the polarization of the emitted Auger electrons. The present theoretical and experimental situation will be reviewed.

  9. Recombination processes in passivated boron-implanted black silicon emitters

    NASA Astrophysics Data System (ADS)

    von Gastrow, Guillaume; Ortega, Pablo; Alcubilla, Ramon; Husein, Sebastian; Nietzold, Tara; Bertoni, Mariana; Savin, Hele

    2017-05-01

    In this paper, we study the recombination mechanisms in ion-implanted black silicon (bSi) emitters and discuss their advantages over diffused emitters. In the case of diffusion, the large bSi surface area increases emitter doping and consequently Auger recombination compared to a planar surface. The total doping dose is on the contrary independent of the surface area in implanted emitters, and as a result, we show that ion implantation allows control of emitter doping without compromise in the surface aspect ratio. The possibility to control surface doping via implantation anneal becomes highly advantageous in bSi emitters, where surface passivation becomes critical due to the increased surface area. We extract fundamental surface recombination velocities Sn through numerical simulations and obtain the lowest values at the highest anneal temperatures. With these conditions, an excellent emitter saturation current (J0e) is obtained in implanted bSi emitters, reaching 20 fA/cm2 ± 5 fA/cm2 at a sheet resistance of 170 Ω/sq. Finally, we identify the different regimes of recombination in planar and bSi emitters as a function of implantation anneal temperature. Based on experimental data and numerical simulations, we show that surface recombination can be reduced to a negligible contribution in implanted bSi emitters, which explains the low J0e obtained.

  10. The Pierre Auger Observatory

    SciTech Connect

    Hojvat, C.

    1997-03-01

    The Pierre Auger Observatory is an international collaboration for the detailed study of the highest energy cosmic rays. It will operate at two similar sites, one in the northern hemisphere and one in the southern hemisphere. The Observatory is designed to collect a statistically significant data set of events with energies greater than 10{sup 19} eV and with equal exposures for the northern and southern skies.

  11. Vertically reciprocating auger

    NASA Technical Reports Server (NTRS)

    Etheridge, Mark; Morgan, Scott; Fain, Robert; Pearson, Jonathan; Weldi, Kevin; Woodrough, Stephen B., Jr.

    1988-01-01

    The mathematical model and test results developed for the Vertically Reciprocating Auger (VRA) are summarized. The VRA is a device capable of transporting cuttings that result from below surface drilling. It was developed chiefly for the lunar surface, where conventional fluid flushing while drilling would not be practical. The VRA uses only reciprocating motion and transports material through reflections with the surface above. Particles are reflected forward and land ahead of radially placed fences, which prevent the particles from rolling back down the auger. Three input wave forms are considered to drive the auger. A modified sawtooth wave form was chosen for testing, over a modified square wave or sine wave, due to its simplicity and effectiveness. The three-dimensional mathematical model predicted a sand throughput rate of 0.2667 pounds/stroke, while the actual test setup transported 0.075 pounds/stroke. Based on this result, a correction factor of 0.281 is suggested for a modified sawtooth input.

  12. Brownian Emitters

    NASA Astrophysics Data System (ADS)

    Tsekov, Roumen

    2016-06-01

    A Brownian harmonic oscillator, which dissipates energy either by friction or via emission of electromagnetic radiation, is considered. This Brownian emitter is driven by the surrounding thermo-quantum fluctuations, which are theoretically described by the fluctuation-dissipation theorem. It is shown how the Abraham-Lorentz force leads to dependence of the half-width on the peak frequency of the oscillator amplitude spectral density. It is found that for the case of a charged particle moving in vacuum at zero temperature, its root-mean-square velocity fluctuation is a universal constant, equal to roughly 1/18 of the speed of light. The relevant Fokker-Planck and Smoluchowski equations are also derived.

  13. Asymmetrical field emitter

    DOEpatents

    Fleming, James G.; Smith, Bradley K.

    1995-01-01

    Providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure.

  14. Asymmetrical field emitter

    DOEpatents

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  15. Auger recombination in sodium iodide

    NASA Astrophysics Data System (ADS)

    McAllister, Andrew; Kioupakis, Emmanouil; Åberg, Daniel; Schleife, André

    2014-03-01

    Scintillators are an important tool used to detect high energy radiation - both in the interest of national security and in medicine. However, scintillator detectors currently suffer from lower energy resolutions than expected from basic counting statistics. This has been attributed to non-proportional light yield compared to incoming radiation, but the specific mechanism for this non-proportionality has not been identified. Auger recombination is a non-radiative process that could be contributing to the non-proportionality of scintillating materials. Auger recombination comes in two types - direct and phonon-assisted. We have used first-principles calculations to study Auger recombination in sodium iodide, a well characterized scintillating material. Our findings indicate that phonon-assisted Auger recombination is stronger in sodium iodide than direct Auger recombination. Computational resources provided by LLNL and NERSC. Funding provided by NA-22.

  16. Auger North: The Pierre Auger Observatory in the Northern Hemisphere

    SciTech Connect

    Mantsch, Paul M.; /Fermilab

    2009-01-01

    Results from Auger South have settled some fundamental issues about ultra-high energy (UHE) cosmic rays and made clear what is needed now to identify the sources of these particles, to uncover the acceleration process, to establish the particle types, and to test hadronic interaction properties at extreme energies. The cosmic rays above 55 EeV are key. Auger North targets this high energy frontier by increasing the collecting power of the Auger Observatory by a factor of eight for those high energy air showers. Particles above about 40 EeV have been shown to be subject to propagation energy loss, as predicted by Greisen, Zatsepin and Kuzmin (GZK) in 1966. Moreover, it is now evident that there is a detectable flux of particles from extragalactic sources within the GZK sphere. The inhomogeneous distribution of matter in the local universe imprints its anisotropy on the arrival directions of cosmic rays above 55 EeV. The challenge is to collect enough of those arrival directions to identify the class of astrophysical accelerators and measure directly the brightest sources. Auger North will increase the event rate from 25 per year to 200 per year and give the Auger Observatory full sky exposure. The Auger Observatory also has the capability to detect UHE photons and neutrinos from discrete sources or from the decays of GZK pions. With the expanded aperture of Auger North, the detection of GZK photons and neutrinos will provide a complementary perspective of the highest energy phenomena in the contemporary universe. Besides being an observatory for UHE cosmic rays, photons, and neutrinos, the Auger Observatory will serve as a laboratory for the study of hadronic interactions with good statistics over a wide range of center-of-mass energies above what can be reached at the LHC. Auger North will provide statistical power at center-of-mass energies above 250 TeV where the alternative extrapolations of hadronic cross sections diverge. Auger North is ready to go. The

  17. Emittance Theory for Thin Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.; Good, Brian S.

    1994-01-01

    Thin films of high temperature garnet materials such as yttrium aluminum garnet (YAG) doped with rare earths are currently being investigated as selective emitters. This paper presents a radiative transfer analysis of the thin film emitter. From this analysis the emitter efficiency and power density are calculated. Results based on measured extinction coefficients for erbium-YAG and holmium-YAG are presented. These results indicated that emitter efficiencies of 50 percent and power densities of several watts/sq cm are attainable at moderate temperatures (less than 1750 K).

  18. Emittance Theory for Cylindrical Fiber Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1998-01-01

    A fibrous rare earth selective emitter is approximated as an infinitely long cylinder. The spectral emittance, epsilon(lambda), is obtained by solving the radiative transfer equations with appropriate boundary conditions and uniform temperature. For optical depths, Kappa(R) = alpha(lambda)R, where alpha(lambda) is the extinction coefficient and R is the cylinder radius, greater than 1 the spectral emittance is nearly at its maximum value. There is an optimum cylinder radius, R(opt), for maximum emitter efficiency, eta(E). Values for R(opt) are strongly dependent on the number of emission bands of the material. The optimum radius decreases slowly with increasing emitter temperature, while the maximum efficiency and useful radiated power increase rapidly with increasing temperature.

  19. Auger eectron spectroscopy study of the {ZrO }/{W(100) } system at high temperature

    NASA Astrophysics Data System (ADS)

    Lee, S. C.; Irokawa, Y.; Inoue, M.; Shimizu, R.

    1996-09-01

    To study the role of oxygen in the mechanism of lowering the work function in the oxygen-processed {Zr}/{W(100) } system, Auger spectrum shape analysis was performed at high temperature after oxygen processing, according to the conventional treatment for activation processing of a {Zr-O }/{W(100) } thermal field emitter (TFE). For this we prepared O/Zr(≈1/2 ML)/M(100) and O/Zr(≈1 ML/W(100) to examine whether or not the oxygen adsorption on the {Zr}/{W(100) } results in any variation in the Auger spectrum of Zr as a result of the chemical effect caused by ZrO bonding. Auger electron spectroscopy (AES) of these samples reveals a tiny peak near 130 eV, which is thought to represent ZrO bonding. Careful re-examination of the Zr Auger spectra from {ZrO }/{W(100) } at ≈1700 K has led to the conclusion that this tiny peak at 130 eV did appear in the Auger spectrum reported in the previous paper. It has also been found from the analysis of the oxygen Auger spectrum that WO x is partially formed in a W(100) substrate.

  20. Heavily doped transparent-emitter regions in junction solar cells, diodes, and transistors

    NASA Technical Reports Server (NTRS)

    Shibib, M. A.; Lindholm, F. A.; Therez, F.

    1979-01-01

    The paper presents an analytical treatment of transparent-emitter devices, particularly solar cells, that is more complete than previously available treatments. The proposed approach includes the effects of bandgap narrowing, Fermi-Dirac statistics, built-in field due to impurity profile, and a finite surface recombination velocity at the emitter surface. It is demonstrated that the transparent-emitter model can predict experimental values of Voc observed on n(plus)-p thin diffused junction silicon solar cells made on low-resistivity (0.1 ohm-cm) substrates. A test is included for the self-consistent validity of the transparent-emitter model. This test compares the calculated transit time of minority carriers across the emitter with the Auger-impact minority-carrier lifetime within the emitter region.

  1. Heavily doped transparent-emitter regions in junction solar cells, diodes, and transistors

    NASA Technical Reports Server (NTRS)

    Shibib, M. A.; Lindholm, F. A.; Therez, F.

    1979-01-01

    The paper presents an analytical treatment of transparent-emitter devices, particularly solar cells, that is more complete than previously available treatments. The proposed approach includes the effects of bandgap narrowing, Fermi-Dirac statistics, built-in field due to impurity profile, and a finite surface recombination velocity at the emitter surface. It is demonstrated that the transparent-emitter model can predict experimental values of Voc observed on n(plus)-p thin diffused junction silicon solar cells made on low-resistivity (0.1 ohm-cm) substrates. A test is included for the self-consistent validity of the transparent-emitter model. This test compares the calculated transit time of minority carriers across the emitter with the Auger-impact minority-carrier lifetime within the emitter region.

  2. Floating emitter solar cell

    NASA Technical Reports Server (NTRS)

    Chih, Sah (Inventor); Cheng, Li-Jen (Inventor)

    1987-01-01

    A front surface contact floating emitter solar cell transistor is provided in a semiconductor body (n-type), in which floating emitter sections (p-type) are diffused or implanted in the front surface. Between the emitter sections, a further section is diffused or implanted in the front surface, but isolated from the floating emitter sections, for use either as a base contact to the n-type semiconductor body, in which case the section is doped n+, or as a collector for the adjacent emitter sections.

  3. El proyecto AUGER

    NASA Astrophysics Data System (ADS)

    Etchegoyen, A.

    Hace ya más de 30 años en Volcano Ranch, EE.UU., un extenso chubasco cósmico (ECC) fue detectado con energía en exceso de 1020 eV. Desde entonces, observatorios ubicados en Haverah Park del Reino Unido, Yakutsk de Rusia, AGASA de Japón y Dugway de EE.UU. también han observado ECC con energías mayores que 1020 eV. Poco se sabe de dichos rayos, y en particular cuál es la naturaleza del primario, de dónde provienen, y cómo son acelerados, pero su naturaleza ultrarelativista excluye la mayoría de las respuestas dejando sólo algunas plausibles de ser investigadas experimentalmente. Grupos de científicos de 20 países están trabajando con el fin de construir dos arreglos de detectores gigantes, uno en cada hemisferio a lo largo de 3000 km2 c/u. Dichas dimensiones son necesarias debido al flujo estimado de 1 rayo cósmico/centuria/km2/sr. La sede del Observatorio del Sur es la Argentina. El proyecto fue nombrado Pierre Auger en conmemoración del célebre físico francés que detectó por primera vez chubascos cósmicos en 1938. El proyecto focaliza su interés en rayos cósmicos con energías mayores que 1020 eV.

  4. Microdosimetry of the Auger electron emitting 123I radionuclide using Geant4-DNA simulations.

    PubMed

    Fourie, H; Newman, R T; Slabbert, J P

    2015-04-21

    Microdosimetric calculations of the Auger electron emitter (123)I were done in liquid water spheres using the Geant4 toolkit. The electron emission spectrum of (123)I produced by Geant4 is presented. Energy deposition and corresponding S-values were calculated to investigate the influence of the sub-cellular localization of the Auger emitter. It was found that S-values calculated by the Geant4 toolkit are generally lower than the values calculated by other Monte Carlo codes for the (123)I radionuclide. The differences in the compared S-values are mainly due to the different particle emission spectra employed by the respective computational codes and emphasizes the influence of the spectra on dosimetry calculations.

  5. Photonically Engineered Incandescent Emitter

    DOEpatents

    Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.

    2005-03-22

    A photonically engineered incandescence is disclosed. The emitter materials and photonic crystal structure can be chosen to modify or suppress thermal radiation above a cutoff wavelength, causing the emitter to selectively emit in the visible and near-infrared portions of the spectrum. An efficient incandescent lamp is enabled thereby. A method for fabricating a three-dimensional photonic crystal of a structural material, suitable for the incandescent emitter, is also disclosed.

  6. Photonically engineered incandescent emitter

    DOEpatents

    Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.

    2003-08-26

    A photonically engineered incandescence is disclosed. The emitter materials and photonic crystal structure can be chosen to modify or suppress thermal radiation above a cutoff wavelength, causing the emitter to selectively emit in the visible and near-infrared portions of the spectrum. An efficient incandescent lamp is enabled thereby. A method for fabricating a three-dimensional photonic crystal of a structural material, suitable for the incandescent emitter, is also disclosed.

  7. From The Pierre Auger Observatory to AugerPrime

    NASA Astrophysics Data System (ADS)

    Parra, Alejandra; Martínez Bravo, Oscar; Pierre Auger Collaboration

    2017-06-01

    In the present work we report the principal motivation and reasons for the new stage of the Pierre Auger Observatory, AugerPrime. This upgrade has as its principal goal to clarify the origin of the highest energy cosmic rays through improvement in studies of the mass composition. To accomplished this goal, AugerPrime will use air shower universality, which states that extensive air showers can be completely described by three parameters: the primary energy E 0, the atmospheric shower depth of maximum X max, and the number of muons, Nμ . The Auger Collaboration has planned to complement its surface array (SD), based on water-Cherenkov detectors (WCD) with scintillator detectors, calls SSD (Scintillator Surface Detector). These will be placed at the top of each WCD station. The SSD will allow a shower to shower analysis, instead of the statistical analysis that the Observatory has previously done, to determine the mass composition of the primary particle by the electromagnetic to muonic ratio.

  8. AugerPrime: the upgrade of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Sarazin, Frederic; Pierre Auger Collaboration Collaboration

    2017-01-01

    The nature and origin of ultra-high energy cosmic-rays (UHECRs) remain largely a mystery despite a wealth of new information obtained in recent years at the Pierre Auger Observatory and elsewhere. Mass composition studies performed at Auger appear to challenge the historical view that the UHECR primaries (at least for energies greater than 1019 eV) are all protons, and the observation of a GZK-like flux suppression in the cosmic-ray spectrum is counterbalanced by the absence of point source observations and the relatively weak anisotropy of the UHECR sky. In order to resolve this apparent contradiction, the Pierre Auger collaboration is embarking in an upgrade of the Observatory (``AugerPrime'') with the goal of extending the mass composition measurements beyond the observed flux suppression. In this presentation, the science case for the upgrade and its technical realization will be described and discussed especially with regards to the existence of GZK photons and neutrinos. NSF PHY-1506486.

  9. The Pierre Auger Observatory Upgrade

    NASA Astrophysics Data System (ADS)

    Marsella, Giovanni

    2017-03-01

    It is planned to operate the Pierre Auger Observatory until at least the end of 2024. An upgrade of the experiment has been proposed in order to provide additional measurements to allow one to elucidate the mass composition and the origin of the flux suppression at the highest energies, to search for a flux contribution of protons up to the highest energies and to reach a sensitivity to a contribution as small as 10% in the flux suppression region, to study extensive air showers and hadronic multi-particle production. With operation planned until 2024, event statistics will more than double compared with the existing Auger data set, with the critical added advantage that every event will now have mass information. Obtaining additional composition-sensitive information will not only help to better reconstruct the properties of the primary particles at the highest energies, but also improve the measurements in the energy range just above the ankle. Furthermore, measurements with the new detectors will help to reduce systematic uncertainties related to the modelling hadronic showers and to limitations in the reconstruction algorithms. A description of the principal proposed Auger upgrade will be presented. The Auger upgrade promises high-quality future data, and real scope for new physics.

  10. Diamond fiber field emitters

    DOEpatents

    Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

    1996-01-01

    A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

  11. Pulsed hybrid field emitter

    DOEpatents

    Sampayan, S.E.

    1998-03-03

    A hybrid emitter exploits the electric field created by a rapidly depoled ferroelectric material. Combining the emission properties of a planar thin film diamond emitter with a ferroelectric alleviates the present technological problems associated with both types of emitters and provides a robust, extremely long life, high current density cathode of the type required by emerging microwave power generation, accelerator technology and display applications. This new hybrid emitter is easy to fabricate and not susceptible to the same failures which plague microstructure field emitter technology. Local electrode geometries and electric field are determined independently from those for optimum transport and brightness preservation. Due to the large amount of surface charge created on the ferroelectric, the emitted electrons have significant energy, thus eliminating the requirement for specialized phosphors in emissive flat-panel displays. 11 figs.

  12. Pulsed hybrid field emitter

    DOEpatents

    Sampayan, Stephen E.

    1998-01-01

    A hybrid emitter exploits the electric field created by a rapidly depoled ferroelectric material. Combining the emission properties of a planar thin film diamond emitter with a ferroelectric alleviates the present technological problems associated with both types of emitters and provides a robust, extremely long life, high current density cathode of the type required by emerging microwave power generation, accelerator technology and display applications. This new hybrid emitter is easy to fabricate and not susceptible to the same failures which plague microstructure field emitter technology. Local electrode geometries and electric field are determined independently from those for optimum transport and brightness preservation. Due to the large amount of surface charge created on the ferroelectric, the emitted electrons have significant energy, thus eliminating the requirement for specialized phosphors in emissive flat-panel displays.

  13. Auger Radiopharmaceutical Therapy Targeting Prostate-Specific Membrane Antigen

    PubMed Central

    Kiess, Ana P.; Hobbs, Robert; Sgouros, George; Mease, Ronnie C.; Pullambhatla, Mrudula; Shen, Colette J.; Foss, Catherine A.; Pomper, Martin G.

    2015-01-01

    Auger electron emitters such as 125I have a high linear energy transfer and short range of emission (<10 μm), making them suitable for treating micrometastases while sparing normal tissues. We used a highly specific small molecule targeting the prostate-specific membrane antigen (PSMA) to deliver 125I to prostate cancer cells. Methods The PSMA-targeting Auger emitter 2-[3-[1-carboxy-5-(4-125I-iodo-benzoylamino)-pentyl]-ureido]-pentanedioic acid (125I-DCIBzL) was synthesized. DNA damage (via phosphorylated H2A histone family member X staining) and clonogenic survival were tested in PSMA-positive (PSMA+) PC3 PIP and PSMA-negative (PSMA−) PC3 flu human prostate cancer cells after treatment with 125I-DCIBzL. Subcellular drug distribution was assessed with confocal microscopy using a related fluorescent PSMA-targeting compound YC-36. In vivo antitumor efficacy was tested in nude mice bearing PSMA+ PC3 PIP or PSMA− PC3 flu flank xenografts. Animals were administered (intravenously) 111 MBq (3 mCi) of 125I-DCIBzL, 111 MBq (3 mCi) of 125I-NaI, an equivalent amount of nonradiolabeled DCIBzL, or saline. Results After treatment with 125I-DCIBzL, PSMA+ PC3 PIP cells exhibited increased DNA damage and decreased clonogenic survival when compared with PSMA− PC3 flu cells. Confocal microscopy of YC-36 showed drug distribution in the perinuclear area and plasma membrane. Animals bearing PSMA+ PC3 PIP tumors had significant tumor growth delay after treatment with 125I-DCIBzL, with only 1 mouse reaching 5 times the initial tumor volume by 60 d after treatment, compared with a median time to 5 times volume of less than 15 d for PSMA− PC3 flu tumors and all other treatment groups (P = 0.002 by log-rank test). Conclusion PSMA-targeted radiopharmaceutical therapy with the Auger emitter 125I-DCIBzL yielded highly specific antitumor efficacy in vivo, suggesting promise for treatment of prostate cancer micrometastases. PMID:26182968

  14. Auger Radiopharmaceutical Therapy Targeting Prostate-Specific Membrane Antigen.

    PubMed

    Kiess, Ana P; Minn, Il; Chen, Ying; Hobbs, Robert; Sgouros, George; Mease, Ronnie C; Pullambhatla, Mrudula; Shen, Colette J; Foss, Catherine A; Pomper, Martin G

    2015-09-01

    Auger electron emitters such as (125)I have a high linear energy transfer and short range of emission (<10 μm), making them suitable for treating micrometastases while sparing normal tissues. We used a highly specific small molecule targeting the prostate-specific membrane antigen (PSMA) to deliver (125)I to prostate cancer cells. The PSMA-targeting Auger emitter 2-[3-[1-carboxy-5-(4-(125)I-iodo-benzoylamino)-pentyl]-ureido]-pentanedioic acid ((125)I-DCIBzL) was synthesized. DNA damage (via phosphorylated H2A histone family member X staining) and clonogenic survival were tested in PSMA-positive (PSMA+) PC3 PIP and PSMA-negative (PSMA-) PC3 flu human prostate cancer cells after treatment with (125)I-DCIBzL. Subcellular drug distribution was assessed with confocal microscopy using a related fluorescent PSMA-targeting compound YC-36. In vivo antitumor efficacy was tested in nude mice bearing PSMA+ PC3 PIP or PSMA- PC3 flu flank xenografts. Animals were administered (intravenously) 111 MBq (3 mCi) of (125)I-DCIBzL, 111 MBq (3 mCi) of (125)I-NaI, an equivalent amount of nonradiolabeled DCIBzL, or saline. After treatment with (125)I-DCIBzL, PSMA+ PC3 PIP cells exhibited increased DNA damage and decreased clonogenic survival when compared with PSMA- PC3 flu cells. Confocal microscopy of YC-36 showed drug distribution in the perinuclear area and plasma membrane. Animals bearing PSMA+ PC3 PIP tumors had significant tumor growth delay after treatment with (125)I-DCIBzL, with only 1 mouse reaching 5 times the initial tumor volume by 60 d after treatment, compared with a median time to 5 times volume of less than 15 d for PSMA- PC3 flu tumors and all other treatment groups (P = 0.002 by log-rank test). PSMA-targeted radiopharmaceutical therapy with the Auger emitter (125)I-DCIBzL yielded highly specific antitumor efficacy in vivo, suggesting promise for treatment of prostate cancer micrometastases. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

  15. The DIORAMA Neutron Emitter

    SciTech Connect

    Terry, James Russell

    2016-05-05

    Emission of neutrons in a given event is modeled by the DioramaEmitterNeutron object, a subclass of the abstract DioramaEmitterModule object. The GenerateEmission method of this object is the entry point for generation of a neutron population for a given event. Shown in table 1, this method requires a number of parameters to be defined in the event definition.

  16. DIAMOND SECONDARY EMITTER

    SciTech Connect

    BEN-ZVI, I.; RAO, T.; BURRILL, A.; CHANG, X.; GRIMES, J.; RANK, J.; SEGALOV, Z.; SMEDLEY, J.

    2005-10-09

    We present the design and experimental progress on the diamond secondary emitter as an electron source for high average power injectors. The design criteria for average currents up to 1 A and charge up to 20 nC are established. Secondary Electron Yield (SEY) exceeding 200 in transmission mode and 50 in emission mode have been measured. Preliminary results on the design and fabrication of the self contained capsule with primary electron source and secondary electron emitter will also be presented.

  17. Vertical-Screw-Auger Conveyer Feeder

    NASA Technical Reports Server (NTRS)

    Walton, Otis (Inventor); Vollmer, Hubert J. (Inventor)

    2016-01-01

    A conical feeder is attached to a vertically conveying screw auger. The feeder is equipped with scoops and rotated from the surface to force-feed regolith the auger. Additional scoops are possible by adding a cylindrical section above the conical funnel section. Such then allows the unit to collect material from swaths larger in diameter than the enclosing casing pipe of the screw auger. A third element includes a flexible screw auger. All three can be used in combination in microgravity and zero atmosphere environments to drill and recover a wide area of subsurface regolith and entrained volatiles through a single access point on the surface.

  18. Nanoelectrospray Emitter Arrays Providing Inter-Emitter Electric Field Uniformity

    PubMed Central

    Kelly, Ryan T.; Page, Jason S.; Marginean, Ioan; Tang, Keqi; Smith, Richard D.

    2008-01-01

    Arrays of electrospray ionization (ESI) emitters have been reported previously as a means of enhancing ionization efficiency or signal intensity. A key challenge when working with multiple, closely spaced ESI emitters is overcoming the deleterious effects caused by electrical interference among neighboring emitters. Individual emitters can experience different electric fields depending on their relative position in the array, such that it becomes difficult to operate all of the emitters optimally for a given applied potential. In this work, we have developed multi-nanoESI emitters arranged with a circular pattern, which enable the constituent emitters to experience a uniform electric field. The performance of the circular emitter array was compared to a single emitter and to a previously developed linear emitter array, which verified that improved electric field uniformity was achieved with the circular arrangement. The circular arrays were also interfaced with a mass spectrometer via a matching multi-capillary inlet, and the results were compared with those obtained using a single emitter. By minimizing inter-emitter electric field inhomogeneities, much larger arrays having closer emitter spacing should be feasible. PMID:18553942

  19. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, Anthony F.

    1999-01-01

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area.

  20. Positron annihilation induced Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Weiss, Alex; Koymen, A. R.; Mehl, David; Jensen, K. O.; Lei, Chun; Lee, K. H.

    1990-01-01

    Recently, Weiss et al. have demonstrated that it is possible to excite Auger transitions by annihilating core electrons using a low energy (less than 30eV) beam of positrons. This mechanism makes possible a new electron spectroscopy, Positron annihilation induced Auger Electron Spectroscopy (PAES). The probability of exciting an Auger transition is proportional to the overlap of the positron wavefunction with atomic core levels. Since the Auger electron energy provides a signature of the atomic species making the transition, PAES makes it possible to determine the overlap of the positron wavefunction with a particular element. PAES may therefore provide a means of detecting positron-atom complexes. Measurements of PAES intensities from clean and adsorbate covered Cu surfaces are presented which indicate that approx. 5 percent of positrons injected into CU at 25eV produce core annihilations that result in Auger transitions.

  1. Cancer from internal emitters

    SciTech Connect

    Boecker, B.B.; Griffith, W.C. Jr.

    1995-10-01

    Irradiation from internal emitters, or internally deposited radionuclides, is an important component of radiation exposures encountered in the workplace, home, or general environment. Long-term studies of human populations exposed to various internal emitters by different routes of exposure are producing critical information for the protection of workers and members of the general public. The purpose of this report is to examine recent developments and discuss their potential importance for understanding lifetime cancer risks from internal emitters. The major populations of persons being studied for lifetime health effects from internally deposited radionuclides are well known: Lung cancer in underground miners who inhaled Rn progeny, liver cancer from persons injected with the Th-containing radiographic contrast medium Thorotrast, bone cancer from occupational or medical intakes of {sup 226}Ra or medical injections of {sup 224}Ra, and thyroid cancer from exposures to iodine radionuclides in the environment or for medical purposes.

  2. ATHLETE : Double Auger Anchoring Mechanism

    NASA Technical Reports Server (NTRS)

    Shin, Joseph

    2011-01-01

    The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) is a six-limbed robot designed to support surface explorations on Near Earth Objects, the Moon and Mars. ATHLETE can carry large payloads on its top deck and can carry a fully equipped pressurized habitat in low gravity. The robot has wheels on each of its six articulated limbs, allowing it to actively conform to terrain while driving and to walk when driving is impractical. With the use of a tool adapter, ATHLETE limbs can be equipped with end effectors to support various mission objectives. For work on Near Earth Objects and other microgravity environments, an anchoring mechanism is needed to keep the ATHLETE from floating off the surface. My goal for this spring session at JPL was to design and build a counter rotating, double auger, anchoring mechanism. The mechanism mates to the tool adapter and is driven off the wheel motor. The double auger anchoring mechanism will be tested in a regolith simulant that will determine the uplift capacity of the anchoring mechanism.

  3. ATHLETE : Double Auger Anchoring Mechanism

    NASA Technical Reports Server (NTRS)

    Shin, Joseph

    2011-01-01

    The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) is a six-limbed robot designed to support surface explorations on Near Earth Objects, the Moon and Mars. ATHLETE can carry large payloads on its top deck and can carry a fully equipped pressurized habitat in low gravity. The robot has wheels on each of its six articulated limbs, allowing it to actively conform to terrain while driving and to walk when driving is impractical. With the use of a tool adapter, ATHLETE limbs can be equipped with end effectors to support various mission objectives. For work on Near Earth Objects and other microgravity environments, an anchoring mechanism is needed to keep the ATHLETE from floating off the surface. My goal for this spring session at JPL was to design and build a counter rotating, double auger, anchoring mechanism. The mechanism mates to the tool adapter and is driven off the wheel motor. The double auger anchoring mechanism will be tested in a regolith simulant that will determine the uplift capacity of the anchoring mechanism.

  4. RFI emitter location techniques

    NASA Technical Reports Server (NTRS)

    Rao, B. L. J.

    1973-01-01

    The possibility is discussed of using Doppler techniques for determining the location of ground based emitters causing radio frequency interference with low orbiting satellites. An error analysis indicates that it is possible to find the emitter location within an error range of 2 n.mi. The parameters which determine the required satellite receiver characteristic are discussed briefly along with the non-real time signal processing which may by used in obtaining the Doppler curve. Finally, the required characteristics of the satellite antenna are analyzed.

  5. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  6. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  7. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  8. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  9. 30 CFR 77.1500 - Auger mining; planning.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Auger mining; planning. 77.1500 Section 77.1500... MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Auger Mining § 77.1500 Auger mining; planning. Auger mining shall be planned and conducted by the operator to...

  10. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  11. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  12. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  13. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Augers and drill stems. 56.7005 Section 56.7005... Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a moving stem or auger....

  14. Effect of Temperature Gradient on Thick Film Selective Emitter Emittance

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Good, Brian S.; Clark, Eric B.; Chen, Zheng

    1997-01-01

    A temperature gradient across a thick (greater than or equal to .1 mm) film selective emitter will produce a significant reduction in the spectral emittance from the no temperature gradient case. Thick film selective emitters of rare earth doped host materials such as yttrium-aluminum-garnet (YAG) are examples where temperature gradient effects are important. In this paper a model is developed for the spectral emittance assuming a linear temperature gradient across the film. Results of the model indicate that temperature gradients will result in reductions the order of 20% or more in the spectral emittance.

  15. Site-selected Auger electron spectroscopy of N2O.

    PubMed

    Bolognesi, Paola; Coreno, Marcello; Avaldi, Lorenzo; Storchi, Loriano; Tarantelli, Francesco

    2006-08-07

    The N 1s Auger spectra for the two nonequivalent N atoms in N2O have been measured via Auger electron-photoelectron coincidence spectroscopy. The site-selected Auger spectra are compared with the normal Auger spectrum and with accurate theoretical calculations accounting for the effects of the dynamics of the nuclei on the energy and linewidth of the Auger bands. Such effects are found to be crucial factors in determining the different band shapes in the site-selected spectra.

  16. Angular distributions of molecular Auger electrons: The case of C 1s Auger emission in CO

    SciTech Connect

    Semenov, S. K.; Kuznetsov, V. V.; Cherepkov, N. A.; Bolognesi, P.; Feyer, V.; Lahmam-Bennani, A.; Casagrande, M. E. Staicu; Avaldi, L.

    2007-03-15

    The results of a study of the Auger-electron-photoelectron angular correlations in the case of the C 1s ionization of the CO molecule are presented and compared with theoretical calculations in the Hartree-Fock approximation based on the two-step model. The measurements have been performed at two photon energies, 305 and 318 eV, respectively, and at three angles of photoelectron emission relative to the light polarization vector: namely, 0 degree sign , 30 degree sign , and 60 degree sign . A general agreement is found between theory and experiment for the coincidence angular distributions and the relative magnitudes of the Auger-electron-photoelectron angular correlations. However, both experiment and theory show that the Auger-electron-photoelectron angular correlations are not sufficiently sensitive to the details of the Auger-electron wave function to allow a 'complete' Auger experiment in molecules. On the other hand, our calculations demonstrate that the Auger-electron angular distribution measured in the molecular frame is very sensitive to the individual contributions of different partial waves of the Auger electron. Therefore we conclude that the complete experiment for the Auger decay in molecules can be realized only measuring the Auger-electron angular distributions in the molecular frame.

  17. Reappraisal of solid selective emitters

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.

    1990-01-01

    New rare earth oxide emitters show greater efficiency than previous emitters. As a result, based on a simple model the efficiency of these emitters was calculated. Results indicate that the emission band of the selective emitter must be at relatively low energy (less than or equal to .52 eV) to obtain maximum efficiency at moderate emitter temperatures (less than or equal to 1500 K). Thus low bandgap energy PV materials are required to obtain an efficient thermophotovoltaic (TPV) system. Of the 4 specific rare earths (Nd, Ho, Er, Yb) studied Ho has the largest efficiency at moderate temperatures (72 percent at 1500 K). A comparison was made between a selective emitter TPV system and a TPV system that uses a thermal emitter plus a band pass filter to make the thermal emitter behave like a selective emitter. Results of the comparison indicate that only for very optimistic filter and thermal emitter properties will the filter TPV system have a greater efficiency than the selective emitter system.

  18. Rare Earth Garnet Selective Emitter

    NASA Technical Reports Server (NTRS)

    Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

    1994-01-01

    Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approx. = 0.75, sup 4)|(sub 15/2) - (sup 4)|(sub 13/2),for Er-YAG and epsilon(sub lambda) approx. = 0.65, (sup 5)|(sub 7) - (sup 5)|(sub 8) for Ho-YAG) at 1500 K. In addition, low out-of-band spectral emittance, epsilon(sub lambda) less than 0.2, suggest these materials would be excellent candidates for high efficiency selective emitters in thermophotovoltaic (TPV) systems operating at moderate temperatures (1200-1500 K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. Selective emitters in the near IR are of special interest for thermophotovoltaic (TPV) energy conversion. The most promising solid selective emitters for use in a TPV system are rare earth oxides. Early spectral emittance work on rare earth oxides showed strong emission bands in the infrared (0.9 - 3 microns). However, the emittance outside the emission band was also significant and the efficiency of these emitters was low. Recent improvements in efficiency have been made with emitters fabricated from fine (5 - 10 microns) rare earth oxide fibers similar to the Welsbach mantle used in gas lanterns. However, the rare earth garnet emitters are more rugged than the mantle type emitters. A thin film selective emitter on a low emissivity substrate such as gold, platinum etc., is rugged and easily adapted to a wide variety of thermal sources. The garnet structure and its many subgroups have been successfully used as hosts for rare earth ions, introduced as substitutional

  19. Positron annihilation induced Auger electron emission

    SciTech Connect

    Weiss, A.; Jibaly, M.; Lei, Chun; Mehl, D.; Mayer, R.; Lynn, K.G.

    1988-01-01

    We report on measurements of Auger electron emission from Cu and Fe due to core hole excitations produced by the removal of core electrons by matter-antimatter annihilation. Estimates are developed of the probability of positrons annihilating with a 3p electron in these materials. Several important advantages of Positron annihilation induced Auger Electron Spectroscopy (PAES) for surface analysis are suggested. 10 refs., 2 figs.

  20. Auger Recombination in Indium Gallium Nitride: Experimental Evidence

    NASA Astrophysics Data System (ADS)

    Krames, Michael

    2010-03-01

    Progress in InGaN-based light-emitting diode (LED) technology has resulted in white-light emitters with efficiencies far exceeding those of conventional light sources such as tungsten-filament-based incandescence and mercury-vapor based fluorescence. Indeed, by now efficacies exceeding 150 lumens per Watt for InGaN-based phosphor-converted white LEDs are claimed, which represent a 90% energy savings compared to the conventional incandescent (i.e., ``light bulb'') solution. However, these high performance levels are obtained under conditions of very low forward current-density for the InGaN LED and do not represent true operating conditions (nor cost-effective utilization) for the device. In order to reduce the cost (and thus increase market penetration of) solid-state lighting, more lumens per unit of semiconductor area are required which in practice necessitates higher drive current densities. Unfortunately, at these higher driver current densities, the internal quantum efficiency of InGaN-based LEDs is observed to decrease significantly. In the fall of 2007, researchers at the Advanced Laboratories of Philips Lumileds were the first to propose Auger recombination as the root-cause mechanism in InGaN which was behind this ``efficiency droop'' [1]. They further proposed to circumvent the problem by employing InGaN-based active region designs that maintain low carrier density, and demonstrated an LED device design that reaches a maximum quantum efficiency above 200 A/cm2, compared to ˜1-10 A/cm^2 for typical multiple-quantum-well heterostructures [2]. In this talk we will review the experimental evidence for Auger recombination in InGaN, beginning with the early work from 2007 and then considering additional work from more recent efforts to better understand the details behind this loss mechanism. [4pt] [1] Y. C. Shen, G. O. M"uller, S. Watanabe, N. F. Gardner, A. Munkholm, and M. R. Krames, ``Auger recombination in InGaN measured by photoluminescence'', Appl. Phys

  1. Rare earth garnet selective emitter

    NASA Technical Reports Server (NTRS)

    Lowe, Roland A.; Chubb, Donald L.; Farmer, Serene C.; Good, Brian S.

    1994-01-01

    Thin film Ho-YAG and Er-YAG emitters with a platinum substrate exhibit high spectral emittance in the emission band (epsilon(sub lambda) approximately equal to 0.74, ((4)l(sub 15/2)) - ( (4)l(sub13/2)), for Er-YAG and epsilon(sub lambda) approximately equal to 0.65, ((5)l(sub 7))-((5)l(sub 8)) for Ho-YAG) at excellent candidates for high efficiency selective emitters in the thermophotovoltaics (TPV) systems operating at moderate temperatures (1200-1500K). Spectral emittance measurements of the thin films were made (1.2 less than lambda less than 3.0 microns) and compared to the theoretical emittances calculated using measured values of the spectral extinction coefficient. In this paper we present the results for a new class of rare earth ion selective emitters. These emitters are thin sections (less than 1 mm) of yttrium aluminum garnet (YAG) single crystal with a rare earth substitutional impurity. This paper presents normal spectral emittance, epsilon(sub lambda), measurements of holmium (Ho), and erbium (Er) doped YAG thin film selective emitters at 1500 K, and compares those results with the theoretical spectral emittance.

  2. Operations of and Future Plans for the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Performance and operation of the Surface Detectors of the Pierre Auger Observatory; (2) Extension of the Pierre Auger Observatory using high-elevation fluorescence telescopes (HEAT); (3) AMIGA - Auger Muons and Infill for the Ground Array of the Pierre Auger Observatory; (4) Radio detection of Cosmic Rays at the southern Auger Observatory; (5) Hardware Developments for the AMIGA enhancement at the Pierre Auger Observatory; (6) A simulation of the fluorescence detectors of the Pierre Auger Observatory using GEANT 4; (7) Education and Public Outreach at the Pierre Auger Observatory; (8) BATATA: A device to characterize the punch-through observed in underground muon detectors and to operate as a prototype for AMIGA; and (9) Progress with the Northern Part of the Pierre Auger Observatory.

  3. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    DOEpatents

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  4. The LVV Auger line shape of sulfur on copper studied by Auger photoelectron coincidence spectroscopy.

    PubMed

    Di Filippo, G; Trioni, M I; Fratesi, G; Schumann, F O; Wei, Z; Li, C H; Behnke, L; Patil, S; Kirschner, J; Stefani, G

    2015-03-04

    We have studied the line shapes of Cu(0 0 1)-p (2 × 2)S L2VV and L3VV Auger decay by means of Auger photoelectron coincidence spectroscopy. Measuring the LVV Auger spectrum in coincidence with S 2p1/2 and 2p3/2 photoelectrons respectively, we have been able to separate the two overlapping Auger spectra and determine their intrinsic line shapes. The two Auger transitions, though shifted in energy, display an identical line shape whose main features can be qualitatively understood considering a single particle approximation but are better described within a Cini-Sawatzky (CS) approach. Comparison between the experimental and the CS calculated spectra confirms that a substantial part of the Auger lines (∼20%) can be ascribed to decay events accompanied by the excitation of one additional electron-hole pair in the valence band. For the first time, the locality of the Auger process combined with the surface sensitivity of the APECS technique and its ability to separate overlapping structures are used to study Auger transitions taking place at the the surface states of a S/noble-metal interface.

  5. Auger Prime the new stage of the Pierre Auger Observatory, using Universality

    NASA Astrophysics Data System (ADS)

    Parra, Alejandra; Martínez, Oscar; Salazar, Humberto

    2016-10-01

    The Pierre Auger Observatory is currently in an update stage denominated AugerPrime. The Observatory will have scintillator detectors on top of each of the surface stations (WCD). The main goal of AugerPrime is to improve the studies on mass composition for ultra high energy cosmic rays, for this purpose AugerPrime will use Universality. The model will parameterize the signal in four principal components, the objective is an adequate discrimination of the muonic and electromagnetic components. We are interested in the discrimination of these two components using simulations. To do that, we are working with OfflineTrunk (the official software of the Collaboration). Our work is focused on the development of some modules for analysis and study of the signal from AugerPrime.

  6. Amorphous-diamond electron emitter

    DOEpatents

    Falabella, Steven

    2001-01-01

    An electron emitter comprising a textured silicon wafer overcoated with a thin (200 .ANG.) layer of nitrogen-doped, amorphous-diamond (a:D-N), which lowers the field below 20 volts/micrometer have been demonstrated using this emitter compared to uncoated or diamond coated emitters wherein the emission is at fields of nearly 60 volts/micrometer. The silicon/nitrogen-doped, amorphous-diamond (Si/a:D-N) emitter may be produced by overcoating a textured silicon wafer with amorphous-diamond (a:D) in a nitrogen atmosphere using a filtered cathodic-arc system. The enhanced performance of the Si/a:D-N emitter lowers the voltages required to the point where field-emission displays are practical. Thus, this emitter can be used, for example, in flat-panel emission displays (FEDs), and cold-cathode vacuum electronics.

  7. Electrochemical formation of field emitters

    DOEpatents

    Bernhardt, A.F.

    1999-03-16

    Electrochemical formation of field emitters, particularly useful in the fabrication of flat panel displays is disclosed. The fabrication involves field emitting points in a gated field emitter structure. Metal field emitters are formed by electroplating and the shape of the formed emitter is controlled by the potential imposed on the gate as well as on a separate counter electrode. This allows sharp emitters to be formed in a more inexpensive and manufacturable process than vacuum deposition processes used at present. The fabrication process involves etching of the gate metal and the dielectric layer down to the resistor layer, and then electroplating the etched area and forming an electroplated emitter point in the etched area. 12 figs.

  8. Auger recombination and free-carrier absorption in nitrides from first principles

    NASA Astrophysics Data System (ADS)

    Kioupakis, Emmanouil

    2010-03-01

    Solid-state optoelectronic devices in the blue/green part of the visible spectrum, based on group-III-nitride materials and their alloys, have a wide array of applications as well as the potential to replace incandescent and fluorescent light bulbs for general illumination. Progress in nitride light emitters research, however, is hampered by the efficiency droop effect, a severe drop in quantum efficiency at high drive currents that particularly affects devices emitting at longer wavelengths. The efficiency droop has been the subject of extensive research and several mechanisms have been proposed as its origin. One such mechanism is the Auger recombination process, a non-radiative recombination mechanism induced by free carrier scattering via the Coulomb interaction. An additional loss mechanism that affects laser devices in particular is the reabsorption of the generated light by free carriers in the device. We used first-principles calculations to study the direct as well as the indirect Auger recombination and free-carrier absorption processes, mediated by electron-phonon and alloy scattering, and identify their importance in nitride light emitters. Since the various loss processes are hard to decouple experimentally, first-principles calculations are an indispensable tool to investigate the various loss mechanisms in isolation and determine their significance.

  9. Tuneable superradiant thermal emitter assembly

    NASA Astrophysics Data System (ADS)

    Mallawaarachchi, Sudaraka; Premaratne, Malin; Gunapala, Sarath D.; Maini, Philip K.

    2017-04-01

    Superradiance is a signature effect in quantum photonics that explains the collective enhancement of emission power by a factor of N2 when N emitters are placed in subwavelength proximity. Although the effect is inherently transient, successful attempts have been made to sustain it in the steady-state regime. Until recently, the effects of superradiance were not considered to be applicable to thermal emitters due to their intrinsic incoherent nature. Novel nanophotonic thermal emitters display favorable coherent characteristics that enable them to obey principles of superradiance. However, published analytical work on conventional superradiant thermal emitter assemblies shows an anomalous power scaling of 1 /N , and therefore increasing the number of thermal emitters leads to a degeneration of power at resonance. This phenomenon immediately renders the effect of thermal superradiance futile since it cannot outperform noncoupled emitters in the steady-state regime. We propose an alternative assembly of thermal emitters with specific features that improves the power scaling while maintaining the effects of superradiance. In essence, we show that our emitter assembly achieves superior power delivery over conventional noncoupled emitter systems at resonance. Additionally, this assembly has the ability to be tuned to operate at specific resonant frequencies, which is a vital requirement for applications such as photothermal cancer therapy.

  10. Observation of four-electron Auger processes

    NASA Astrophysics Data System (ADS)

    Müller, A.; Borovik, A., Jr.; Buhr, T.; Hellhund, J.; Holste, K.; Kilcoyne, A. L. D.; Klumpp, S.; Martins, M.; Ricz, S.; Viefhaus, J.; Schippers, S.

    2015-09-01

    Multiple ionization of ions subsequent to absorption of a single photon has been studied employing a photon-ion merged-beam setup at the PETRA III synchrotron radiation facility of DESY in Hamburg. Absolute cross sections for single, double and triple ionization of C+ ions were measured with emphasis on specific well defined terms of K-shell excited C+. In particular, the terms C+ (1s2s22p2 2D,2P) were excited from the ground level of C+. Subsequent autoionization processes resulted in the production of C2+, C3+ and C4+ ions. The associated decay mechanisms are single-Auger, double-Auger and triple-Auger decay. The observation of C4+ products arising from C+(1s2s22p2 2D,2P) unambiguously confirmed the existence of triple-Auger decay, i.e., a process in which 4 electrons interact with one another such that one fills the K-shell vacancy and the others are simultaneously ejected. The experiment yields branching ratios for the Auger decay channels as well as individual decay rates for autoionization and radiative stabilization of the C+(1s2s22p2 2D,2P) terms.

  11. Observation of the Auger resonant Raman effect

    SciTech Connect

    Brown, G.S.; Chen, M.H.; Crasemann, B.; Ice, G.E.

    1980-11-01

    Monochromatized synchrotron radiation near the photoionization threshold was used to produce the (2p/sub 3/2/) vacancy state in atomic Xe. Deexcitation of the state through L/sub 3/-M/sub 4/M/sub 5/(/sup 1/G/sub 4/) Auger-electron emission was measured. The 5d spectator-electron Auger satellite was observed. The satellite energy exhibits linear dispersion. The observed width of the /sup 1/G diagram line decreases by approx. 40% when the exciting photon energy reaches the vicinity of the Xe L/sub 3/ binding energy. This radiationless process can thus be construed as the Auger analog of the x-ray resonant Raman effect. The /sup 1/G diagram line is shifted by -+3 eV due to post-collision interaction; this shift varies with excitation energy.

  12. Auger processes in the 21st century

    PubMed Central

    Howell, Roger W.

    2012-01-01

    Purpose The extreme radiotoxicity of Auger electrons and their exquisite capacity to irradiate specific molecular sites has prompted scientists to extensively investigate their radiobiological effects. Their efforts have been punctuated by quadrennial international symposia that have focused on biophysical aspects of Auger processes. The latest meeting, the 6th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes, was held 5–6 July 2007 at Harvard Medical School in Boston, Massachusetts, USA. This article provides a review of the research in this field that was published during the years 2004–2007, the period that has elapsed since the previous meeting. Conclusion The field has advanced considerably. A glimpse of the potential of this unique form of ionizing radiation to contribute to future progress in a variety of fields of study is proffered. PMID:19061120

  13. Auger spectrometry of atoms and molecules

    SciTech Connect

    Krause, M.O.

    1994-09-01

    The author discusses the importance of Auger spectrometry at synchrotron radiation centers. First, he explains how a high energy photon source such as the APS (Advanced Photon Source) could be used to help provide missing spectral information about the shell structure of some elements. The missing data occurs mainly at higher energies in the 1--10 keV ranges as for the K-shells of Z = 30 to 60 elements and the L-shells for Z = 30 to 100 elements. He explains how even though Auger electron spectrometry does not depend on synchrotron radiation it can greatly benefit from this variable photon source as it allows one to select the Auger line group that is most suitable for a specific purpose. Most significantly, a continuous photon source becomes indispensable when one is interested in threshold effects. Lastly, he discusses coherence effects between different inner-shell vacancy states by way of some recent work done at Daresbury.

  14. EMITTANCE COMPENSATION FOR MAGNETIZED BEAMS

    SciTech Connect

    KEWISCH,J.; CHANG, X.

    2007-06-25

    Emittance compensation is a well established technique for minimizing the emittance of an electron beam from a RF photo-cathode gun. Longitudinal slices of a bunch have a small emittance, but due to the longitudinal charge distribution of the bunch and time dependent RF fields they are not focused in the same way, so that the direction of their phase ellipses diverges in phase space and the projected emittance is much larger. Emittance compensation reverses the divergence. At the location where the slopes of the phase ellipses coincide the beam is accelerated, so that the space charge forces are reduced. A recipe for emittance compensation is given in. For magnetized beams (where the angular momentum is non-zero) such emittance compensation is not sufficient because variations in the slice radius lead to variations in the angular speed and therefore to an increase of emittance in the rotating game. We describe a method and tools for a compensation that includes the beam magnetization.

  15. Thin-Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.

    1993-01-01

    Direct conversion of thermal energy into electrical energy using a photovoltaic cell is called thermophotovoltaic energy conversion. One way to make this an efficient process is to have the thermal energy source be an efficient selective emitter of radiation. The emission must be near the band-gap energy of the photovoltaic cell. One possible method to achieve an efficient selective emitter is the use of a thin film of rare-earth oxides. The determination of the efficiency of such an emitter requires analysis of the spectral emittance of the thin film including scattering and reflectance at the vacuum-film and film-substrate interfaces. Emitter efficiencies (power emitted in emission band/total emitted power) in the range 0.35-0.7 are predicted. There is an optimum optical depth to obtain maximum efficiency. High emitter efficiencies are attained only for low (less than 0.05) substrate emittance values, both with and without scattering. The low substrate emittance required for high efficiency limits the choice of substrate materials to highly reflective metals or high-transmission materials such as sapphire.

  16. Latest results from the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Lhenry-Yvon, Isabelle

    2016-07-01

    The Pierre Auger Observatory has been designed to investigate the origin and nature of Ultra High Energy Cosmic Rays (UHECR) with energies from 1017 to 1020 eV. In this paper we will review some of the most recent results obtained from data of the Pierre Auger Observatory, namely the spectrum of cosmic rays, the anisotropies in arrival directions and the studies related to mass composition and to the number of muons measured at the ground. We will also discuss the implication of these results for assembling a consistent description of the composition, origin and propagation of cosmic rays.

  17. Emittance compensation in split photoinjectors

    NASA Astrophysics Data System (ADS)

    Floettmann, Klaus

    2017-01-01

    The compensation of correlated emittance contributions is of primary importance to optimize the performance of high brightness photoinjectors. While only extended numerical simulations can capture the complex beam dynamics of space-charge-dominated beams in sufficient detail to optimize a specific injector layout, simplified models are required to gain a deeper understanding of the involved dynamics, to guide the optimization procedure, and to interpret experimental results. In this paper, a slice envelope model for the emittance compensation process in a split photoinjector is presented. The emittance term is included in the analytical solution of the beam envelope in a drift, which is essential to take the emittance contribution due to a beam size mismatch into account. The appearance of two emittance minima in the drift is explained, and the matching into the booster cavity is discussed. A comparison with simulation results points out effects which are not treated in the envelope model, such as overfocusing and field nonlinearities.

  18. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  19. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  20. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  1. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  2. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  3. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  4. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  5. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  6. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  7. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  8. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  9. 30 CFR 819.17 - Auger mining: Subsidence protection.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Subsidence protection. 819.17 Section 819.17 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.17 Auger mining: Subsidence protection. Auger mining shall be conducted in accordance...

  10. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  11. 30 CFR 819.19 - Auger mining: Backfilling and grading.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Backfilling and grading. 819.19 Section 819.19 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... MINING § 819.19 Auger mining: Backfilling and grading. (a) General. Auger mining shall be conducted...

  12. 30 CFR 77.1501 - Auger mining; inspections.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Auger mining; inspections. 77.1501 Section 77.1501 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... Auger Mining § 77.1501 Auger mining; inspections. (a) The face of all highwalls, to a distance of...

  13. 30 CFR 56.7005 - Augers and drill stems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Augers and drill stems. 56.7005 Section 56.7005... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling § 56.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or...

  14. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  15. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  16. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  17. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Augers and drill stems. 57.7005 Section 57.7005... Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay clear of augers or drill stems that are in motion. Persons shall not pass under or step over a...

  18. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§ 816.41...

  19. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§ 816.41...

  20. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§ 816.41...

  1. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§ 816.41...

  2. 30 CFR 819.15 - Auger mining: Hydrologic balance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Hydrologic balance. 819.15... MINING § 819.15 Auger mining: Hydrologic balance. (a) Auger mining shall be planned and conducted to minimize disturbances of the prevailing hydrologic balance in accordance with the requirements of §§ 816.41...

  3. Highly directional thermal emitter

    DOEpatents

    Ribaudo, Troy; Shaner, Eric A; Davids, Paul; Peters, David W

    2015-03-24

    A highly directional thermal emitter device comprises a two-dimensional periodic array of heavily doped semiconductor structures on a surface of a substrate. The array provides a highly directional thermal emission at a peak wavelength between 3 and 15 microns when the array is heated. For example, highly doped silicon (HDSi) with a plasma frequency in the mid-wave infrared was used to fabricate nearly perfect absorbing two-dimensional gratings structures that function as highly directional thermal radiators. The absorption and emission characteristics of the HDSi devices possessed a high degree of angular dependence for infrared absorption in the 10-12 micron range, while maintaining high reflectivity of solar radiation (.about.64%) at large incidence angles.

  4. Towards graphane field emitters.

    PubMed

    Ding, Shuyi; Cole, Matthew T; Li, Chi; Zhou, Yanhuai; Collins, Clare M; Kang, Moon H; Parmee, Richard J; Lei, Wei; Zhang, Xiaobing; Dai, Qing; Milne, William I; Wang, Baoping

    2015-12-10

    We report on the improved field emission performance of graphene foam (GF) following transient exposure to hydrogen plasma. The enhanced field emission mechanism associated with hydrogenation has been investigated using Fourier transform infrared spectroscopy, plasma spectrophotometry, Raman spectroscopy, and scanning electron microscopy. The observed enhanced electron emissionhas been attributed to an increase in the areal density of lattice defects and the formation of a partially hydrogenated, graphane-like material. The treated GF emitter demonstrated a much reduced macroscopic turn-on field (2.5 V μm(-1)), with an increased maximum current density from 0.21 mA cm(-2) (pristine) to 8.27 mA cm(-2) (treated). The treated GFs vertically orientated protrusions, after plasma etching, effectively increased the local electric field resulting in a 2.2-fold reduction in the turn-on electric field. The observed enhancement is further attributed to hydrogenation and the subsequent formation of a partially hydrogenated structured 2D material, which advantageously shifts the emitter work function. Alongside augmentation of the nominal crystallite size of the graphitic superstructure, surface bound species are believed to play a key role in the enhanced emission. The hydrogen plasma treatment was also noted to increase the emission spatial uniformity, with an approximate four times reduction in the per unit area variation in emission current density. Our findings suggest that plasma treatments, and particularly hydrogen and hydrogen-containing precursors, may provide an efficient, simple, and low cost means of realizing enhanced nanocarbon-based field emission devices via the engineered degradation of the nascent lattice, and adjustment of the surface work function.

  5. Towards graphane field emitters

    PubMed Central

    Ding, Shuyi; Li, Chi; Zhou, Yanhuai; Collins, Clare M.; Kang, Moon H.; Parmee, Richard J.; Zhang, Xiaobing; Milne, William I.; Wang, Baoping

    2015-01-01

    We report on the improved field emission performance of graphene foam (GF) following transient exposure to hydrogen plasma. The enhanced field emission mechanism associated with hydrogenation has been investigated using Fourier transform infrared spectroscopy, plasma spectrophotometry, Raman spectroscopy, and scanning electron microscopy. The observed enhanced electron emissionhas been attributed to an increase in the areal density of lattice defects and the formation of a partially hydrogenated, graphane-like material. The treated GF emitter demonstrated a much reduced macroscopic turn-on field (2.5 V μm–1), with an increased maximum current density from 0.21 mA cm–2 (pristine) to 8.27 mA cm–2 (treated). The treated GFs vertically orientated protrusions, after plasma etching, effectively increased the local electric field resulting in a 2.2-fold reduction in the turn-on electric field. The observed enhancement is further attributed to hydrogenation and the subsequent formation of a partially hydrogenated structured 2D material, which advantageously shifts the emitter work function. Alongside augmentation of the nominal crystallite size of the graphitic superstructure, surface bound species are believed to play a key role in the enhanced emission. The hydrogen plasma treatment was also noted to increase the emission spatial uniformity, with an approximate four times reduction in the per unit area variation in emission current density. Our findings suggest that plasma treatments, and particularly hydrogen and hydrogen-containing precursors, may provide an efficient, simple, and low cost means of realizing enhanced nanocarbon-based field emission devices via the engineered degradation of the nascent lattice, and adjustment of the surface work function. PMID:28066543

  6. Proof of principal for staircase auger chip removal theory

    NASA Technical Reports Server (NTRS)

    Barron, Jeffrey B.; Brewer, Steve; Kerns, Kenneth; Moody, Kyle; Rossi, Richard A.

    1987-01-01

    A proof of principal design of the staircase auger theory is provided for lunar drilling. The drill is designed to drill holes 30 meters deep and 0.1 meters in diameter. The action of the auger is 0.01 meter strokes at a varying number of strokes per second. A detailed analysis of the interaction of the auger and particle was done to optimize the parameters of the auger. This optimum design will allow for proper heat removal and reasonable drilling time. The drill bit is designed to scoop the particles into the auger while efficiently cutting through the moon's surface.

  7. Proof of principal for staircase auger chip removal theory

    NASA Astrophysics Data System (ADS)

    Barron, Jeffrey B.; Brewer, Steve; Kerns, Kenneth; Moody, Kyle; Rossi, Richard A.

    1987-08-01

    A proof of principal design of the staircase auger theory is provided for lunar drilling. The drill is designed to drill holes 30 meters deep and 0.1 meters in diameter. The action of the auger is 0.01 meter strokes at a varying number of strokes per second. A detailed analysis of the interaction of the auger and particle was done to optimize the parameters of the auger. This optimum design will allow for proper heat removal and reasonable drilling time. The drill bit is designed to scoop the particles into the auger while efficiently cutting through the moon's surface.

  8. Pierre Auger--a life in the service of science.

    PubMed

    Persson, L

    1996-01-01

    A short biography of Pierre Auger, the discoverer of the atomic auger electron effect, is given. Professor Auger's outstanding professional career covered physics, nuclear power and space research, organization and administration of research, diplomatic services and pedagogics but also extended into modern biology, humanistic sciences, poetry and arts. Part of a speech in Paris of professor Auger held in 1989 on the theme 'Research and Creativity' at an international symposium on the auger effect is included in this biography as well as one of his poems.

  9. Nuclear Excitation via Auger Transitions (NEAT)

    NASA Astrophysics Data System (ADS)

    Ward, Thomas; Emery, Guy; Rasmussen, John; Karwowski, Hugon; Castaneda, Carlos

    2008-10-01

    Triggering (prompt de-excitation) of isomeric states produced in a process of coupling nuclear excitations to atomic shells via Auger transitions (NEAT) is studied. In this resonant process the nuclear transition energy between the two states must be less than the Auger transition energy. This requires the emitted Auger electron energy and the exact on-resonance nuclear excitation share the Auger transition energy. NEAT is compared to other proposed processes of nuclear excitation produced by x-rays (NEET), by electron capture (NEEC) and bound internal conversion (BIC), all of which suffer from off-resonance nuclear excitation except in those accidental cases where the energies may coincide. Estimates of the total resonance strength will be given for the case of ^182mHf which has been extensively studied theoretically. A second case, ^189Os, where NEAT processes may contribute to the nuclear resonance fluorescence (NRF) of the ground state to the 5.8hr isomeric state will also be examined as a good case for experimental verification of the NEAT process.

  10. Auger Spectroscopy of Hydrogenated Diamond Surfaces

    NASA Technical Reports Server (NTRS)

    Krainsky, I. L.; Asnin, V. M.; Petukhov, A. G.; Foygel, M.

    1997-01-01

    An energy shift and a change of the line shape of the carbon core-valence-valence Auger spectra are observed for diamond surfaces after their exposure to an electron beam, or annealing at temperatures higher then 950 C. The effect is studied for both natural diamond crystals and chemical-vapor-deposited diamond films. A theoretical model is proposed for Auger spectra of hydrogenated diamond surfaces. The observed changes of the carbon Auger line shape are shown to be related to the redistribution of the valence-band local density of states caused by the hydrogen desorption from the surface. One-electron calculation of Auger spectra of diamond surfaces with various hydrogen coverages are presented. They are based on self-consistent wave functions and matrix elements calculated in the framework of the local-density approximation and the self-consistent linear muffin-tin orbital method with static core-hole effects taken into account. The major features of experimental spectra are explained.

  11. 2s photoionization and subsequent Auger cascade in atomic Si

    SciTech Connect

    Partanen, L.; Fritzsche, S.; Jaenkaelae, K.; Huttula, M.; Osmekhin, S.; Aksela, H.; Aksela, S.; Urpelainen, S.

    2010-06-15

    The 2s photoionization and subsequent Auger transition cascade in atomic Si were studied by means of synchrotron-radiation-induced electron spectroscopy. After the 2s photoionization, the core hole states decay predominantly by a two-step Auger transition cascade into the triply ionized [Ne]nl states. The ionization channels of the 2s core-ionized Si{sup +} atoms to Si{sup 3+} ions were observed by measuring the conventional Auger electron spectra of the L{sub 1}-L{sub 2,3}M Coster-Kronig transitions and the L{sub 2,3}M-MMM Auger transitions. The observed L{sub 1}-L{sub 2,3}M and L{sub 2,3}M-MMM Auger spectra were analyzed by means of extensive multiconfiguration Dirac-Fock computations. We found that the electron correlation plays a prominent role in the Auger cascade, especially for the final-step Auger L{sub 2,3}M-MMM spectrum. Additionally, it was seen that the L{sub 2,3}M-MMM Auger spectrum of Si includes more Auger groups than the isoelectronic L{sub 2,3}-MM Auger spectrum of Al. Thus, more information on the intermediate ionic states is obtained if they are produced by Auger cascade rather than by direct photoionization.

  12. Theory and Application of Auger and Photoelectron Diffraction and Holography

    NASA Astrophysics Data System (ADS)

    Chen, Xiang

    This dissertation addresses the theories and applications of three important surface analysis techniques: Auger electron diffraction (AED), x-ray photoelectron diffraction (XPD), and Auger and photoelectron holography. A full multiple-scattering scheme for the calculations of XPD, AED, and Kikuchi electron diffraction pattern from a surface cluster is described. It is used to simulate 64 eV M_{2,3}VV and 913 eV L_3VV AED patterns from Cu(001) surfaces, in order to test assertions in the literature that they are explicable by a classical "blocking" and channeling model. We find that this contention is not valid, and that only a quantum mechanical multiple-scattering calculation is able to simulate these patterns well. The same multiple scattering simulation scheme is also used to investigate the anomalous phenomena of peak shifts off the forward-scattering directions in photo -electron diffraction patterns of Mg KLL (1180 eV) and O 1s (955 eV) from MgO(001) surfaces. These shifts are explained by calculations assuming a short electron mean free path. Similar simulations of XPD from a CoSi_2(111) surface for Co-3p and Si-2p normal emission agree well with experimental diffraction patterns. A filtering process aimed at eliminating the self -interference effect in photoelectron holography is developed. A better reconstructed image from Si-2p XPD from a Si(001) (2 times 1) surface is seen at atomic resolution. A reconstruction algorithm which corrects for the anisotropic emitter waves as well as the anisotropic atomic scattering factors is used for holographic reconstruction from a Co-3p XPD pattern from a CoSi_2 surface. This new algorithm considerably improves the reconstructed image. Finally, a new reconstruction algorithm called "atomic position recovery by iterative optimization of reconstructed intensities" (APRIORI), which takes account of the self-interference terms omitted by the other holographic algorithms, is developed. Tests on a Ni-C-O chain and Si(111

  13. Highly Effective Auger-Electron Therapy in an Orthotopic Glioblastoma Xenograft Model using Convection-Enhanced Delivery

    PubMed Central

    Thisgaard, Helge; Halle, Bo; Aaberg-Jessen, Charlotte; Olsen, Birgitte Brinkmann; Therkelsen, Anne Sofie Nautrup; Dam, Johan Hygum; Langkjær, Niels; Munthe, Sune; Någren, Kjell; Høilund-Carlsen, Poul Flemming; Kristensen, Bjarne Winther

    2016-01-01

    Glioblastoma, the most common and malignant primary brain tumor, always recurs after standard treatment. Therefore, promising new therapeutic approaches are needed. Short-range Auger-electron-emitters carry the ability of causing highly damaging radiation effects in cells. The aim of this study was to test the effect of [125I]5-Iodo-2'-deoxyuridine (125I-UdR, a radioactive Auger-electron-emitting thymidine analogue) Auger-therapy on immature glioblastoma spheroid cultures and orthotopic xenografted glioblastoma-bearing rats, the latter by means of convection-enhanced delivery (CED). Moreover, we aimed to determine if the therapeutic effect could be enhanced when combining 125I-UdR therapy with the currently used first-line chemotherapeutic agent temozolomide. 125I-UdR significantly decreased glioblastoma cell viability and migration in vitro and the cell viability was further decreased by co-treatment with methotrexate and/or temozolomide. Intratumoral CED of methotrexate and 125I-UdR with and without concomitant systemic temozolomide chemotherapy significantly reduced the tumor burden in orthotopically xenografted glioblastoma-bearing nude rats. Thus, 100% (8/8) of the animals survived the entire observation period of 180 days when subjected to the combined Auger-chemotherapy while 57% (4/7) survived after the Auger-therapy alone. No animals (0/8) treated with temozolomide alone survived longer than 50 days. Blood samples and post-mortem histology showed no signs of dose-limiting adverse effects. In conclusion, the multidrug approach consisting of CED of methotrexate and 125I-UdR with concomitant systemic temozolomide was safe and very effective leading to 100% survival in an orthotopic xenograft glioblastoma model. Therefore, this therapeutic strategy may be a promising option for future glioblastoma therapy. PMID:27924163

  14. Diamondoid monolayers as electron emitters

    DOEpatents

    Yang, Wanli; Fabbri, Jason D.; Melosh, Nicholas A.; Hussain, Zahid; Shen, Zhi-Xun

    2013-10-29

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  15. Diamondoid monolayers as electron emitters

    DOEpatents

    Yang, Wanli [El Cerrito, CA; Fabbri, Jason D [San Francisco, CA; Melosh, Nicholas A [Menlo Park, CA; Hussain, Zahid [Orinda, CA; Shen, Zhi-Xun [Stanford, CA

    2012-04-10

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  16. Visible Spectrum Incandescent Selective Emitter

    SciTech Connect

    Sonsight Inc.

    2004-04-30

    The purpose of the work performed was to demonstrate the feasibility of a novel bi-layer selective emitter. Selective emitters are incandescent radiant bodies with emissivities that are substantially larger in a selected part of the radiation spectrum, thereby significantly shifting their radiated spectral distribution from that of a blackbody radiating at the same temperature. The major research objectives involved answering the following questions: (1) What maximum VIS/NIR radiant power and emissivity ratios can be attained at 2650 K? (2) What is the observed emitter body life and how does its performance vary with time? (3) What are the design tradeoffs for a dual heating approach in which both an internally mounted heating coil and electrical resistance self-heating are used? (4) What are the quantitative improvements to be had from utilizing a bi-layer emitter body with a low emissivity inner layer and a partially transmissive outer layer? Two approaches to obtaining selective emissivity were investigated. The first was to utilize large optical scattering within an emitter material with a spectral optical absorption that is much greater within the visible spectrum than that within the NIR. With this approach, an optically thick emitter can radiate almost as if optically thin because essentially, scattering limits the distance below the surface from which significant amounts of internally generated radiation can emerge. The performance of thin emitters was also investigated (for optically thin emitters, spectral emissivity is proportional to spectral absorptivity). These emitters were fabricated from thin mono-layer emitter rods as well as from bi-layer rods with a thin emitter layer mounted on a substrate core. With an initially estimated energy efficiency of almost three times that of standard incandescent bulbs, a number of energy, economic and environmental benefits such as less energy use and cost, reduced CO{sub 2} emissions, and no mercury contamination

  17. Latest results of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Creusot, A.; Pierre Auger Collaboration

    2012-01-01

    The Pierre Auger Observatory measures extensive air showers induced by ultra-high energy cosmic rays using two methods: a sampling of the shower particles at the ground level and the detection of the fluorescence light emitted by the air molecules after the shower crossing. The southern site of the Pierre Auger Observatory is acquiring data since 2004. The first results were published few years ago. This article is dedicated to the presentation of the last results, taking into account the data up to end of March 2009. The energy spectrum, the anisotropies in the arrival directions and the mass composition of the cosmic rays are discussed here as well as the extrapolations of the proton-air cross-section in the hadronic models.

  18. Auger spectroscopy of Magnox pressure vessel steels

    SciTech Connect

    Fisher, S.; Knowles, G.; Lee, B.

    1999-10-01

    Magnox Electric maintains a significant microstructural program in support of its safety case for operation of its stations with steel pressure vessels. An important part of this program is the characterization of grain boundary chemistry using Auger spectroscopy. Mechanical testing and subsequent examination of surveillance material has shown that some Charpy specimens display a proportion of intergranular fracture and Auger work has linked this to the presence of phosphorus on the grain boundaries. A feature of particular interest in the study of the boundaries is the co-segregation of carbon. The measurement of the true levels of phosphorus and carbon segregation is complicated by the presence of carbon contamination. This paper describes the simple approach used to overcome this problem.

  19. Auger electron spectroscopy of lunar samples

    NASA Technical Reports Server (NTRS)

    Grant, R. W.; Housley, R. M.; Szalkowski, F. J.; Marcus, H. L.

    1974-01-01

    Auger spectroscopy has been employed to study the surface composition of a number of grains from the submillimeter lunar fines. Some of the problems associated with using this technique for lunar sample analyses are discussed in terms of relevant physical principles. The use of inert gas sputtering to obtain thickness profiles of surface films is shown to be important in this type of investigation. Four anorthite grains from the Apollo 17 fines have been examined for evidence of vapor-deposited surface coatings of micrometeorite impact origin. The results indicate that the thickness of surface deposits, if they exist at all, are orders of magnitude less than expected. Auger analysis of orange glass balls form the 74220,107 fines have established sulfur-rich surface coatings on the order of 30 A in thickness.

  20. The Pierre Auger Cosmic Ray Observatory

    DOE PAGES

    Aab, Alexander

    2015-07-08

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 1017 eV and study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000 km2 overlooked by 24 air fluorescence telescopes. Additionally, three high elevation fluorescence telescopes overlook a 23.5 km2, 61-detector infilled array with 750 m spacing. The Observatory has been in successful operation since completionmore » in 2008 and has recorded data from an exposure exceeding 40,000 km2 sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory.« less

  1. Recent results from the Pierre Auger Observatory

    SciTech Connect

    Gascón, Alberto; Collaboration: Pierre Auger Collaboration

    2014-07-23

    The Pierre Auger Observatory has been designed to investigate the origin and nature of Ultra High Energy Cosmic Rays (UHECR) using a hybrid detection technique. In this contribution we present some of the most recent results of the observatory, namely the upper-end of the spectrum of cosmic rays, state-of-the-art analyses on mass composition, the measurements of the proton-air cross-section, and the number of muons at ground.

  2. Recent results from the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Gascón, Alberto; Pierre Auger Collaboration

    2014-07-01

    The Pierre Auger Observatory has been designed to investigate the origin and nature of Ultra High Energy Cosmic Rays (UHECR) using a hybrid detection technique. In this contribution we present some of the most recent results of the observatory, namely the upper-end of the spectrum of cosmic rays, state-of-the-art analyses on mass composition, the measurements of the proton-air cross-section, and the number of muons at ground.

  3. Distributed Computing for the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Chudoba, J.

    2015-12-01

    Pierre Auger Observatory operates the largest system of detectors for ultra-high energy cosmic ray measurements. Comparison of theoretical models of interactions with recorded data requires thousands of computing cores for Monte Carlo simulations. Since 2007 distributed resources connected via EGI grid are successfully used. The first and the second versions of production system based on bash scripts and MySQL database were able to submit jobs to all reliable sites supporting Virtual Organization auger. For many years VO auger belongs to top ten of EGI users based on the total used computing time. Migration of the production system to DIRAC interware started in 2014. Pilot jobs improve efficiency of computing jobs and eliminate problems with small and less reliable sites used for the bulk production. The new system has also possibility to use available resources in clouds. Dirac File Catalog replaced LFC for new files, which are organized in datasets defined via metadata. CVMFS is used for software distribution since 2014. In the presentation we give a comparison of the old and the new production system and report the experience on migrating to the new system.

  4. Role of Emission Character in Auger Electron Diffraction

    NASA Astrophysics Data System (ADS)

    Idzerda, Y. U.

    A review of the interpretation of the angle-dependent Auger intensity pattern by both Auger electron diffraction (AED), which is concerned with identifying the nearby atomic structure, and angle-resolved Auger electron spectroscopy (ARAES), which is concerned with identifying the character of the emitted electron source function, is presented. The importance of the emission character of the Auger electron (in terms of its angular momentum, l, and its magnetic quantum number, m) in understanding the generation of the AED and ARAES patterns is described. Understanding of how the various direct and secondary mechanisms for the Auger electron generation can affect the populations of these states can also be used to help identify the multiplet structure within the Auger lineshape as well as elucidate the core hole generation process.

  5. Relativistic Calculations and Measurements of Energies, Auger Rates, and Lifetimes.

    DTIC Science & Technology

    1982-12-01

    Research and Industry, Denton, Texas, 8-10 November 1982. 7. B. Crasemann: "Efectos Relativ’sticos y de QED Sobre las Transiciones Rayos - X y Auger Entre...INNER-SHELL IONIZATION BY PROTONS X -RAY EMISSION BREIT INTERACTION AUGER TRANSITIONS DIRAC-HARTREE-SLATER COMPUTATIONS SYNCHROTRON RADIATION RESONANT...computations, including relativistic and quantum- electrodynamic effects, of atomic energy levels and of x -ray and Auger transitions in atoms with one or

  6. Multielectron spectroscopy: the xenon 4d hole double auger decay.

    PubMed

    Penent, F; Palaudoux, J; Lablanquie, P; Andric, L; Feifel, R; Eland, J H D

    2005-08-19

    A magnetic bottle spectrometer of the type recently developed by Eland et al. [Phys. Rev. Lett. 90, 053003 (2003).] has been implemented for use with synchrotron radiation, allowing multidimensional electron spectroscopy. Its application to the Xe 4d double Auger decay reveals all the energy pathways involved. The dominant path is a cascade process with a rapid (6 fs) ejection of a first Auger electron followed by the slower (>23 fs) emission of a second Auger electron. Weaker processes implying 3 electron processes are also revealed, namely, direct double Auger and associated Rydberg series.

  7. Thermionic converter emitter support arrangement

    DOEpatents

    Allen, Daniel T.

    1990-01-01

    A support is provided for use in a therminonic converter to support an end of an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially as its temperature changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housing, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  8. Thermionic converter emitter support arrangement

    DOEpatents

    Allen, Daniel T.

    1990-01-01

    A support is provided for use in a thermionic converter to support an end an emitter to keep it out of contact with a surrounding collector while allowing the emitter end to move axially at its temperatures changes. The emitter end (34) is supported by a spring structure (44) that includes a pair of Belleville springs, and the spring structure is supported by a support structure (42) fixed to the housing that includes the collector. The support structure is in the form of a sandwich with a small metal spring-engaging element (74) at the front end, a larger metal main support (76) at the rear end that is attached to the housng, and with a ceramic layer (80) between them that is bonded by hot isostatic pressing to the metal element and metal main support. The spring structure can include a loose wafer (120) captured between the Belleville springs.

  9. Strand breakage by decay of DNA-bound (124)I provides a basis for combined PET imaging and Auger endoradiotherapy.

    PubMed

    Lobachevsky, Pavel; Clark, George R; Pytel, Patrycja D; Leung, Brenda; Skene, Colin; Andrau, Laura; White, Jonathan M; Karagiannis, Tom; Cullinane, Carleen; Lee, Boon Q; Stuchbery, Andrew; Kibedi, Tibor; Hicks, Rodney J; Martin, Roger F

    2016-11-01

    Purpose DNA ligands labelled with (125)I induce cytotoxic DNA double-strand breaks (DSB), suggesting a potential for Auger endoradiotherapy. Since the 60-day half-life of (125)I is suboptimal for therapy, we have investigated another Auger-emitter (124)I, with shorter half-life (4.18 days), and the additional feature of positron-emission, enabling positron emission tomography (PET) imaging. The purpose of this study was to compare the two radionuclides on the basis of DNA DSB per decay. Materials and methods Using a (124)I- (or (125)I)-labelled minor groove binding DNA ligand, we investigated DNA breakage using the plasmid DNA assay. Biodistribution of the conjugate of the labelled ligand with transferrin was investigated in nude mice bearing a K562 human lymphoma xenograft. Results The probability of DSB per decay was 0.58 and 0.85 for (124)I and (125)I, respectively, confirming the therapeutic potential of the former. The crystal structure of the ligand DNA complex shows the iodine atom deep within the minor groove, consistent with the high efficiency of induced damage. Biodistribution studies, including PET imaging, showed distinctive results for the conjugate, compared to the free ligand and transferrin, consistent with receptor-mediated delivery of the ligand. Conclusions Conjugation of (124)I-labelled DNA ligands to tumor targeting peptides provides a feasible strategy for Auger endoradiotherapy, with the advantage of monitoring tumor targeting by PET imaging.

  10. Combustion powered thermophotovoltaic emitter system

    SciTech Connect

    McHenry, R.S.

    1995-07-01

    The US Naval Academy (USNA) has recently completed an engineering design project for a high temperature thermophotovoltaic (TPV) photon emitter. The final apparatus was to be portable, completely self contained, and was to incorporate cycle efficiency optimization such as exhaust stream recuperation. Through computer modeling and prototype experimentation, a methane fueled emitter system was designed from structural ceramic materials to fulfill the high temperature requirements necessary for high system efficiency. This paper outlines the engineering design process, discusses obstacles and solutions encountered, and presents the final design.

  11. Emitter location errors in electronic recognition system

    NASA Astrophysics Data System (ADS)

    Matuszewski, Jan; Dikta, Anna

    2017-04-01

    The paper describes some of the problems associated with emitter location calculations. This aspect is the most important part of the series of tasks in the electronic recognition systems. The basic tasks include: detection of emission of electromagnetic signals, tracking (determining the direction of emitter sources), signal analysis in order to classify different emitter types and the identification of the sources of emission of the same type. The paper presents a brief description of the main methods of emitter localization and the basic mathematical formulae for calculating their location. The errors' estimation has been made to determine the emitter location for three different methods and different scenarios of emitters and direction finding (DF) sensors deployment in the electromagnetic environment. The emitter has been established using a special computer program. On the basis of extensive numerical calculations, the evaluation of precise emitter location in the recognition systems for different configuration alignment of bearing devices and emitter was conducted. The calculations which have been made based on the simulated data for different methods of location are presented in the figures and respective tables. The obtained results demonstrate that calculation of the precise emitter location depends on: the number of DF sensors, the distances between emitter and DF sensors, their mutual location in the reconnaissance area and bearing errors. The precise emitter location varies depending on the number of obtained bearings. The higher the number of bearings, the better the accuracy of calculated emitter location in spite of relatively high bearing errors for each DF sensor.

  12. Anomalous Auger intensities for nitrogen explained

    SciTech Connect

    Dawson, P.T.; Chen, Y.

    1995-12-31

    The nitrogen KLL Auger electron intensities from a series of nine interstital nitride films from the Group 4, 5 and 6 elements Ti, V, Cr, Zr, Nb, Mo, Hf, Ta and W, prepared by high temperature reaction with ammonia gas, were found to vary periodically in a manner which could not be interpreted by the usual matrix effects of primary beam back-scattering and inelastic mean free path. In addition to these unexpected trends observed for all nine elements, the extreme members, Ti and W, showed unreasonably anomalous high and low intensities respectively. It is the purpose of this paper to account for these large anomalies. The chemisorption of ground and excited state ammonia on the three low index planes of single crystal tungsten has been investigated. In all cases the extremely low nitrogen KLL Auger electron intensities were no longer observed. The unexpectedly low value previously observed for nitride thin films arises from surface roughness, induced by nucleation and growth of micron-sized nitride particles. Auger electron spectroscopy of nitrogen in titanium is complicated by the total overlap of the nitrogen KLL and titanium LMM peaks at 384 eV. This laboratory has made extensive studies of the titanium-nitrogen system offering a solution to the overlap problem that has become widely accepted as an effective method for nitrogen surface analysis by AES. The procedure involves the assumption that the relative intensity of the 384 and 420 eV Ti peaks does not change on nitriding, and using the observable intensity of the 420 eV peak in the nitride to subtract the Ti contribution from the combined peak at 384 eV. However, the success of this analysis procedure does not require that the relative intensity of the Ti peaks is independent of nitrogen concentration, only that if it varies, it does so linearly. Applying these results to titanium removes the gross anomaly previously reported.

  13. Auger tension leg platform cathodic protection system

    SciTech Connect

    Goolsby, A.D.; Smith, J.D.

    1995-11-01

    In 1986, Shell began investigating corrosion control systems for a generic 3,000 ft. water depth Tension Leg Platform (TLP) type structure to be located in the north-central Gulf of Mexico. In 1987, the 2,850 ft. deep Garden Banks block 426 ``Auger`` location was chosen for the first TLP, and the detailed design process began in earnest. During late 1993 and early 1994, the Auger hull was mated with the other components at its permanent site, and first oil and gas production began April 15, 1994. This paper describes the corrosion control design for the exterior submerged and buried steel surfaces of the 2,850 ft. (869 m) water depth Auger Tension Leg Platform structure. Each major type of component (hull, subsea marine wellhead/guidebase, tendon foundation template, tendon, and production riser) has its own combination of coating system and cathodic protection system designed for a thirty five year lifetime. Cathodic protection (CP) is achieved using a variety of sacrificial anode alloys and geometries (e.g. bracelet, flush-mount, and standoff anodes). Anode and cathode CP design parameters for each component depend upon water depth, and were developed using field test data, laboratory studies, field measurements on existing structures, and available literature information. CP design was performed using design spreadsheets constructed for each component, which optimized anode geometries. Extensive quality assurance efforts were part of the anode procurement process, to ensure performance for the intended life of the corrosion-control systems. Results of early in-service CP surveys of the tendons and guidebases are presented, showing the successful achievement of cathodic protection against seawater corrosion. Corrosion control of one additional system, the eight point lateral mooring system, is not addressed here.

  14. Midwave Infrared (2-6{micro}m) Emitter-Based Chemical Sensor Systems

    SciTech Connect

    Allerman, A.A.; Biefeld, R.M.; Kurtz, S.R.

    1999-02-01

    Long wavelength (2-6 {micro}m) diode emitters are desirable for many applications including monitoring of chemical species in the environment and manufacturing, long wavelength fiber-optic communications, lidar, and JR detector counter-measures. No practical diode lasers are available for any of these applications because the band structure of bulk III-V, II-VI, and IV-VI semiconductor alloys results in large Auger recombination rates at these wavelengths. Experimental and theoretical work at Sandia has resulted in new understanding of the electronic properties of narrow bandgap III-V heterostructures, and we have found methods of reducing the Auger rates in certain InAsSb superlattices and quantum wells. These devices enable us to begin chemical sensing demonstrations of important species such as CO-CO{sub 2} and numerous other compounds. This project will involve developing chemical sensing systems and determining the sensitivity and limitations of these systems. Concurrently, we will improve upon infrared emitters used in these systems.

  15. Shielding in ungated field emitter arrays

    SciTech Connect

    Harris, J. R.; Jensen, K. L.; Shiffler, D. A.; Petillo, J. J.

    2015-05-18

    Cathodes consisting of arrays of high aspect ratio field emitters are of great interest as sources of electron beams for vacuum electronic devices. The desire for high currents and current densities drives the cathode designer towards a denser array, but for ungated emitters, denser arrays also lead to increased shielding, in which the field enhancement factor β of each emitter is reduced due to the presence of the other emitters in the array. To facilitate the study of these arrays, we have developed a method for modeling high aspect ratio emitters using tapered dipole line charges. This method can be used to investigate proximity effects from similar emitters an arbitrary distance away and is much less computationally demanding than competing simulation approaches. Here, we introduce this method and use it to study shielding as a function of array geometry. Emitters with aspect ratios of 10{sup 2}–10{sup 4} are modeled, and the shielding-induced reduction in β is considered as a function of tip-to-tip spacing for emitter pairs and for large arrays with triangular and square unit cells. Shielding is found to be negligible when the emitter spacing is greater than the emitter height for the two-emitter array, or about 2.5 times the emitter height in the large arrays, in agreement with previously published results. Because the onset of shielding occurs at virtually the same emitter spacing in the square and triangular arrays, the triangular array is preferred for its higher emitter density at a given emitter spacing. The primary contribution to shielding in large arrays is found to come from emitters within a distance of three times the unit cell spacing for both square and triangular arrays.

  16. Ultra Low Emittance Light Sources

    SciTech Connect

    Bengtsson,J.

    2008-06-23

    This paper outlines the special issues for reaching sub-nm emittance in a storage ring. Effects of damping wigglers, intra-beam scattering and lifetime issues, dynamic aperture optimization, control of optics, and their interrelations are covered in some detail. The unique choices for the NSLS-II are given as one example.

  17. Auger spectroscopy of fracture surfaces of ceramics

    NASA Technical Reports Server (NTRS)

    Marcus, H. L.; Harris, J. M.; Szalkowski, F. J.

    1974-01-01

    Results of Auger electron spectroscopy (AES) studies of fracture surfaces in a series of ceramic materials, including Al2O3, MgO, and Si3N4, which were formed using different processing techniques. AES on the fractured surface of a lunar sample is also discussed. Scanning electron micrograph fractography is used to relate the surface chemistry to the failure mode. Combined argon ion sputtering and AES studies demonstrate the local variations in chemistry near the fracture surface. The problems associated with doing AES in insulators are also discussed, and the experimental techniques directed toward solving them are described.

  18. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  19. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  20. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  1. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  2. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  3. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  4. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  5. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  6. 30 CFR 819.13 - Auger mining: Coal recovery.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Coal recovery. 819.13 Section 819.13 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  7. 30 CFR 819.11 - Auger mining: General.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: General. 819.11 Section 819.11 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-AUGER MINING §...

  8. Education and public outreach of the Pierre Auger Observatory

    SciTech Connect

    Garcia, B.; Snow, G.

    2005-08-01

    The Auger collaboration's broad mission in education, outreach and public relations is coordinated in a separate task. Its goals are to encourage and support a wide range of outreach efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. This report focuses on recent activities and future initiatives.

  9. 30 CFR 57.7005 - Augers and drill stems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Augers and drill stems. 57.7005 Section 57.7005... SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Surface Only § 57.7005 Augers and drill stems. Drill crews and others shall stay...

  10. Quantitative Auger analysis of Nb-Ge superconducting alloys

    SciTech Connect

    Buitrago, R.H.

    1980-01-01

    The feasibility of using Auger electron analysis for quantitative analysis was investigated by studying Nb/sub 3/Ge thin-film Auger data with different approaches. A method base on elemental standards gave consistent quantitative values with reported Nb-Ge data. Alloy sputter yields were also calculated and results were consistent with those for pure elements.

  11. Experimentally accessible signatures of Auger scattering in graphene

    NASA Astrophysics Data System (ADS)

    Winzer, Torben; Jago, Roland; Malic, Ermin

    2016-12-01

    The gapless and linear electronic band structure of graphene opens up Auger scattering channels bridging the valence and the conduction band and changing the charge carrier density. Here, we reveal experimentally accessible signatures of Auger scattering in optically excited graphene. To be able to focus on signatures of Auger scattering, we apply a low excitation energy, weak pump fluences, and a cryostatic temperature, so that all relevant processes lie energetically below the optical phonon threshold. In this regime, carrier-phonon scattering is strongly suppressed and Coulomb processes govern the carrier dynamics. Depending on the excitation regime, we find an accumulation or depletion of the carrier occupation close to the Dirac point. This reflects well the behavior predicted from Auger-dominated carrier dynamics. Based on this observation, we propose a multicolor pump-probe experiment to uncover the extreme importance of Auger channels for the nonequilibrium dynamics in graphene.

  12. Exploring Protonation and Deprotonation Effects with Auger Electron Spectroscopy.

    PubMed

    Kryzhevoi, Nikolai V; Cederbaum, Lorenz S

    2012-09-20

    Auger electron spectroscopy is demonstrated to be a very efficient tool to probe alterations in local chemical environment due to changes in protonation states. We show that electronic and geometric structure changes induced by protonation or deprotonation are well reflected in Auger spectra through characteristic chemical shifts and spectral shape variations. We also present evidence that Auger spectra are sensitive to relative concentrations of compounds in different protonation states. Special attention is paid to the high kinetic energy spectral regions that exhibit remarkable features resulting from core ICD-like transitions in normal species and Auger transitions in deprotonated fragments. The latter contribution was so far ignored when explaining Auger spectra of species embedded in the environment. This contribution should be reconsidered, taking into account the recently discovered possibility of ultrafast dissociation of core-ionized hydrogen-bonded systems in media.

  13. Molecular frame Auger electron energy spectrum from N2

    NASA Astrophysics Data System (ADS)

    Cryan, J. P.; Glownia, J. M.; Andreasson, J.; Belkacem, A.; Berrah, N.; Blaga, C. I.; Bostedt, C.; Bozek, J.; Cherepkov, N. A.; DiMauro, L. F.; Fang, L.; Gessner, O.; Gühr, M.; Hajdu, J.; Hertlein, M. P.; Hoener, M.; Kornilov, O.; Marangos, J. P.; March, A. M.; McFarland, B. K.; Merdji, H.; Messerschmidt, M.; Petrović, V. S.; Raman, C.; Ray, D.; Reis, D. A.; Semenov, S. K.; Trigo, M.; White, J. L.; White, W.; Young, L.; Bucksbaum, P. H.; Coffee, R. N.

    2012-03-01

    Here we present the first angle-resolved, non-resonant (normal) Auger spectra for impulsively aligned nitrogen molecules. We have measured the angular pattern of Auger electron emission following K-shell photoionization by 1.1 keV photons from the Linac Coherent Light Source (LCLS). Using strong-field-induced molecular alignment to make molecular frame measurements is equally effective for both repulsive and quasi-bound final states. The capability to resolve Auger emission angular distributions in the molecular frame of reference provides a new tool for spectral assignments in congested Auger electron spectra that takes advantage of the symmetries of the final diction states. Based on our experimental results and theoretical predictions, we propose the assignment of the spectral features in the Auger electron spectrum.

  14. Particle physics at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Ebr, Jan

    2014-11-01

    The Pierre Auger Observatory is the largest detector of ultra-high energy cosmic rays (UHECR) in the world. These particles, presumably protons or heavier nuclei of energies up to 1020 eV, initiate extensive air showers which can be detected by sampling the particles that arrive at ground level or observing the fluorescence light generated during the passage of showers through the atmosphere - the Pierre Auger Observatory employs both these techniques. As the center-of-mass energies of the first interactions in the showers can be several orders of magnitude beyond the reach of the LHC, the UHECR provide an unique opportunity to study hadronic interactions. While the uncertainty in modeling these interactions is somewhat degenerate with the unknown composition of the primary beam, interaction models can be tested using data such as the depths of the maxima of the longitudinal development of the showers or their muon content. Particular sensitivity to interaction models is achieved when several observables are combined. Moreover, using careful data selection, proton-air cross section at the c.m.s. energy of 57 TeV per nucleon-nucleon pair can be obtained.

  15. Automatic emittance measurement at the ATF

    SciTech Connect

    Wang, X.J.; Malone, R.; Batchelor, K.; Ben-Zvi, I.

    1993-07-01

    An automatic emittance measurement system to characterize the transverse emittance of the electron beam produced by the BNL photocathode electron gun is described. The system utilize a VAX workstation and a Spiricon beam analyzer. A operator window (created through the Vista control software package) controls the emittance measurement system and the graphic presentation of the results. Quadrupole variation method is used for the ATF automatic emittance measurement system. A simple emittance formula was derived to study the performance of the quadrupole variation method, and compared with the ATF experimental data is also presented.

  16. Carbon nanotubes as field emitter.

    PubMed

    Zou, Rujia; Hu, Junqing; Song, Yuelin; Wang, Na; Chen, Huihui; Chen, Haihua; Wu, Jianghong; Sun, Yangang; Chen, Zhigang

    2010-12-01

    Carbon nanotubes (CNTs) have recently emerged as a promising material of electron field emitters. They exhibit extraordinary field emission properties because of their high electrical conductivity, high aspect ratio "needle like" shape for optimum geometrical field enhancement, and remarkable thermal stability. In this Review, we emphasize the estimation and influencing factors of CNTs' emission properties, and discuss in detail the emission properties of macroscopic CNT cathodes, especially fabricated by transplant methods, and describe recent progress on understanding of CNT field emitters and analyze issues related to applications of CNT based cold cathodes in field emission display (FED). We foresee that CNT-FED will take an important place in display technologies in the near future.

  17. Metal halide perovskite light emitters

    PubMed Central

    Kim, Young-Hoon; Cho, Himchan; Lee, Tae-Woo

    2016-01-01

    Twenty years after layer-type metal halide perovskites were successfully developed, 3D metal halide perovskites (shortly, perovskites) were recently rediscovered and are attracting multidisciplinary interest from physicists, chemists, and material engineers. Perovskites have a crystal structure composed of five atoms per unit cell (ABX3) with cation A positioned at a corner, metal cation B at the center, and halide anion X at the center of six planes and unique optoelectronic properties determined by the crystal structure. Because of very narrow spectra (full width at half-maximum ≤20 nm), which are insensitive to the crystallite/grain/particle dimension and wide wavelength range (400 nm ≤ λ ≤ 780 nm), perovskites are expected to be promising high-color purity light emitters that overcome inherent problems of conventional organic and inorganic quantum dot emitters. Within the last 2 y, perovskites have already demonstrated their great potential in light-emitting diodes by showing high electroluminescence efficiency comparable to those of organic and quantum dot light-emitting diodes. This article reviews the progress of perovskite emitters in two directions of bulk perovskite polycrystalline films and perovskite nanoparticles, describes current challenges, and suggests future research directions for researchers to encourage them to collaborate and to make a synergetic effect in this rapidly emerging multidisciplinary field. PMID:27679844

  18. Alpha particle emitters in medicine

    SciTech Connect

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ({sup 211}At) and natural bismuth-212 ({sup 212}Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ({sup 223}Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs.

  19. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  20. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  1. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  2. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  3. 30 CFR 819.21 - Auger mining: Protection of underground mining.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Auger mining: Protection of underground mining. 819.21 Section 819.21 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-AUGER MINING § 819.21 Auger mining: Protection of underground mining. Auger holes shall not...

  4. 33 CFR 147.813 - Auger Tension Leg Platform safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Auger Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.813 Auger Tension Leg Platform safety zone. (a) Description. The Auger Tension Leg Platform (Auger TLP) is located at position 27°32′45...

  5. 33 CFR 147.813 - Auger Tension Leg Platform safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Auger Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.813 Auger Tension Leg Platform safety zone. (a) Description. The Auger Tension Leg Platform (Auger TLP) is located at position 27°32′45...

  6. 33 CFR 147.813 - Auger Tension Leg Platform safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Auger Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.813 Auger Tension Leg Platform safety zone. (a) Description. The Auger Tension Leg Platform (Auger TLP) is located at position 27°32′45...

  7. 33 CFR 147.813 - Auger Tension Leg Platform safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Auger Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.813 Auger Tension Leg Platform safety zone. (a) Description. The Auger Tension Leg Platform (Auger TLP) is located at position 27°32′45...

  8. 33 CFR 147.813 - Auger Tension Leg Platform safety zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Auger Tension Leg Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.813 Auger Tension Leg Platform safety zone. (a) Description. The Auger Tension Leg Platform (Auger TLP) is located at position 27°32′45...

  9. Soil chip convey of lunar subsurface auger drill

    NASA Astrophysics Data System (ADS)

    Zhao, Deming; Tang, Dewei; Hou, Xuyan; Jiang, Shengyuan; Deng, Zongquan

    2016-05-01

    Celestial body subsurface drilling and sampling is a key aspect of near-earth exploration projects. In these sample return missions, the auger drill system is universally used due to the environment and detector load limits. The common failure that the auger faces is chip chocking, which can raise the torque and cause the drill to stick. This paper builds auger drill models describing chip flow in the auger groove to balance geometric parameters, functional capability, and reliability. The features of chip flow are summarized and verified by a series of discrete element method simulations. In contrast to previous auger design, a convey capability factor is defined to indicate the auger's chip removal capacity, and the role of pitch angle and other parameters is assessed through motion analysis of the lunar soil flow process. The theory is verified by testing the drill penetrating speed limit, which combines drill geometry and motion parameters. This work provides a new method for design and optimization of low speed auger drill systems and research on particle flow with small scale mechanical constraints.

  10. From Auger to AugerPrime: Understanding Ultrahigh-Energy Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Montanet, F.; Pierre Auger Collaboration

    2016-12-01

    Ultrahigh-energy cosmic rays (UHECRs), whose origin is still mysterious, provide a unique probe of the most extreme environments in the universe, of the intergalactic space and of particle physics beyond the reach of terrestrial accelerators. The Pierre Auger Observatory started operating more than a decade ago. Outperforming preceding experiments both in size and in precision, it has boosted forward the field of UHECRs as witnessed by a wealth of results. These include the study of the energy spectrum beyond 1 EeV with its spectral suppression around 40 EeV, of the large-scale anisotropy, of the mass composition, as well as stringent limits on photon and neutrino fluxes. But any harvest of new results also calls for new questions: what is the true nature of the spectral suppression: a propagation effect (so-called Greisen, Zatsepin and Kuz'min or GZK cutoff) or cosmic accelerators running out of steam? What is the composition of UHECRs at the highest energies? In order to answer these questions, the Auger Collaboration is undertaking a major upgrade program of its detectors, the AugerPrime project. The science case and motivations, the technical strategy and the scientific prospects are presented.

  11. Transverse Emittance Reduction with Tapered Foil

    SciTech Connect

    Jiao, Yi; Chao, Alex; Cai, Yunhai; /SLAC

    2011-12-09

    The idea of reducing transverse emittance with tapered energy-loss foil is proposed by J.M. Peterson in 1980s and recently by B. Carlsten. In this paper, we present the physical model of tapered energy-loss foil and analyze the emittance reduction using the concept of eigen emittance. The study shows that, to reduce transverse emittance, one should collimate at least 4% of particles which has either much low energy or large transverse divergence. The multiple coulomb scattering is not trivial, leading to a limited emittance reduction ratio. Small transverse emittances are of essential importance for the accelerator facilities generating free electron lasers, especially in hard X-ray region. The idea of reducing transverse emittance with tapered energy-loss foil is recently proposed by B. Carlsten [1], and can be traced back to J.M. Peterson's work in 1980s [2]. Peterson illustrated that a transverse energy gradient can be produced with a tapered energy-loss foil which in turn leads to transverse emittance reduction, and also analyzed the emittance growth from the associated multiple coulomb scattering. However, what Peterson proposed was rather a conceptual than a practical design. In this paper, we build a more complete physical model of the tapered foil based on Ref. [2], including the analysis of the transverse emittance reduction using the concept of eigen emittance and confirming the results by various numerical simulations. The eigen emittance equals to the projected emittance when there is no cross correlation in beam's second order moments matrix [3]. To calculate the eigen emittances, it requires only to know the beam distribution at the foil exit. Thus, the analysis of emittance reduction and the optics design of the subsequent beam line section can be separated. In addition, we can combine the effects of multiple coulomb scattering and transverse energy gradient together in the beam matrix and analyze their net effect. We find that,when applied to an

  12. In Vitro Assessment of a Peptide Nucleic Acid (PNA) - Peptide Conjugate Labeled With an Auger-Emitting Radionuclide for Prostate Cell Killing

    DTIC Science & Technology

    2005-02-01

    synthesis of a peptide nucleic acid (PNA) that has an Auger-emitter (1-125) incorporated. By design the PNA will bind with mRNA and DNA associated with...bind with cell surface gastrin -releasing peptide receptors and be internalized (3). Binding with mRNA and nuclear DNA specific to the insulin-like...route proposed to prepare 10 is shown in Figure 1 (compounds 1-10). This synthesis began with the preparation of the base-reactive intermediate 5

  13. Latest results from the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Dembinski, Hans P.; Pierre Auger Collaboration

    2012-02-01

    The Pierre Auger Observatory, located in the Province of Mendoza, Argentina, is the World's largest detector for cosmic rays at ultra-high energies. In its seven years of operation it has collected an exposure of more than 20000 km2 sr yr, larger than all previous experiments combined. Its original design, optimized for the energy range 1018 eV to 1020 eV, is currently enhanced to cover energies down to almost 1017 eV. We give an overview of the latest results with a focus on the prospect to study nuclear interactions with cosmic rays and conclude with a brief outlook on developments and extensions of the observatory. Full author list

  14. Electrode surface studies by LEED-Auger

    NASA Technical Reports Server (NTRS)

    Ogrady, W. E.; Woo, M. Y. C.; Hagans, P. L.; Yeager, E.

    1977-01-01

    The role the electronic and geometric structures of the metal surface play in electrochemical surface reactions remains as yet an unknown factor. In order to investigate these surface contributions to electrochemical reactions, a low-energy-electron diffraction (LEED) and an Auger electron spectrometer (AES) have been combined with an electrochemical thin-layer cell. The surface to be studied electrochemically is first characterized by LEED-AES and then transferred into a second chamber where it becomes part of the electrochemical thin-layer cell. Electrochemical reactions are then run on this surface. The sample may then be transferred back to the LEED-AES chamber for further characterization. Data on Pt (111) will be presented.

  15. Auger analysis of silver-glass interfaces

    NASA Astrophysics Data System (ADS)

    Bastasz, R.

    1980-09-01

    Moderate annealing in vacuum of evaporated silver films on float glass (used as mirrors in solar energy concentrators) was found to have little effect on either the composition at the silver/glass interface or the profile of the boundary region. The interface remained free of any contaminants that could be detected by Auger spectroscopy. Limited diffusion of silver with glass components was observed, but the process resulted in only slight broadening of the interface during short annealing treatments and could be described by a diffusion coefficient of less than 1 x 10 to the -15th sq cm/s at 200 C. It is concluded that moderate annealing in the absence of contamination does not significantly alter the characteristics of a silver/glass interface.

  16. The Pierre Auger Observatory progress and first results

    SciTech Connect

    Mantsch, Paul M.

    2005-08-01

    The Pierre Auger Observatory was designed for a high statistics, full sky study of cosmic rays at the highest energies. Energy, direction and composition measurements are intended to illuminate the mysteries of the most energetic particles in nature. The Auger Observatory utilizes a surface array together with air fluorescence telescopes which together provide a powerful instrument for air shower reconstruction. The southern part of the Auger Observatory, now under construction in the Province of Mendoza, Argentina, is well over half finished. Active detectors have been recording events for one and a half years. Preliminary results based on this first data set are presented.

  17. Auger-architectomics: introducing a new nanotechnology to infectious disease.

    PubMed

    Swart, Chantel W; Pohl, Carolina H; Kock, Johan L F

    2014-01-01

    In 2010, we developed a new imaging nanotechnology called Auger-architectomics, to study drug biosensors in nano-detail. We succeeded in applying Auger atom electron physics coupled to scanning electron microscopy (SEM) and Argon-etching to cell structure exploration, thereby exposing a new dimension in structure and element composition architecture. Auger-architectomics was used to expose the fate and effect of drugs on cells. This technology should now be expanded to diseased cells. This paper will outline the development, proof of concept, and application of this imaging nanotechnology. A virtual tour is available at: http://vimeo.com/user6296337 .

  18. Survey of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Dova, T.; Pierre Auger Observatory Collaboration

    The question of the origin and nature of cosmic ray particles with energies exceeding the predicted GZK spectral cutoff is one of the present great challenges of astroparticle physics. The Pierre Auger Observatory (PAO), currently under construction in Province of Mendoza, Argentina, is a broadly based international effort to explore the upper-end of the cosmic ray energy spectrum. The PAO is the first experiment designed to work in a hybrid detection mode. The combination of two complementary detection techniques -water Cerenkov tank arrays overlooked by atmospheric fluorescence detectorsto observe extensive air showers guarantees high-quality and statistically significant data. An updated overview of the science prospects for the PAO is presented. The concept of the experiment as well as the current status is described. 1 Physics motivation for the Pierre Auger Observatory The puzzle set by the existence of cosmic rays with energies above 1020 eV (Lawrence et al., 1991; Hayashida et al., 1994; Bird et al., 1995; Abu-Zayyad et al, 1999), which may be an indication of new physics or exotic particles, is at present one of the hot topics in high energy astroparticle physics. The underlying problem in trying to explain the origin of these extremely high energy cosmic rays (EHECR) is the well-known GZK (Greisen-Zatsepin-Kuzmin) effect: if the cosmic rays are extragalactic in origin, then a sharp cutoff at around several times 1019 eV in the observed spectrum is expected due to energy degradation of the cosmic ray particles through interaction with photons of the microwave background radiation (Greisen, 1965; Zatsepin and Kuzmin, 1966). This process limits the distance of the sources of particles with energies above 1020 eV to less than 100 Mpc from the Earth (Aharonian and Cronin, 1994; Puget et al., 1976; Stecker and Salomon, 1999; Berezinsky, 1970; Protheroe and Biermann, 1996). Since the energy loss mechanism depends on

  19. Current Status of the Pierre Auger Project

    NASA Astrophysics Data System (ADS)

    Etchegoyen, A.

    The Pierre Auger Project aims at building two Observatories in order to study ultra high energy cosmic rays, situated in both northern and southern hemispheres. In 2000 started the construction of the austral observatory. Prior to this, in 1995, the international collaboration was formed encompassing 200 scientists and technicians from institutions in 16 countries. The Auger Project is a basic science enterprise which studies the highest energies known in nature ( 1020 eV) , which are cosmic rays coming from the outer space arriving to the earth surface with at a very reduced flow. This is the reason for constructing a giant observatory spanning an area of 3000 km2 in the department of Malargüe and San Rafael, in the Province of Mendoza. Other distinctive feature, besides the exceptional size of the Observatory, is its hybrid nature: it is constituted by 24 fluorescence detector telescopes .and 1600 surface detectors. As such, it will provide a large number of events with less systematic detection uncertainties. The construction of the Observatory is quite advanced and the buildings at the Central Station in Malargüe city are already operational. So are the telescope buildings at Cerros Los Leones and Coihueco, two telescopes, 32 surface detectors, the telecommunication and data adquisión systems. From the scientific point of view the most important issue was the first detection of an hybrid event (a cosmic ray detected by both telescope and the surface detectors), on January 2002. It confirmed the equipment operates with the design parameters. Twenty hybrid events/month were detected with energies typically below 1019 eV.

  20. Effect Of Auger Recombination In An Ion Track

    NASA Technical Reports Server (NTRS)

    Edmonds, Larry D.

    1993-01-01

    Report presents theoretical calculations of contribution of Auger recombination to depletion of charge carriers from ionization track left by passage of energetic heavy ion through silicon-based electronic device.

  1. The Surface Detector System of the Pierre Auger Observatory

    SciTech Connect

    Allekotte, I.; Barbosa, A.F.; Bauleo, P.; Bonifazi, C.; Civit, B.; Escobar, C.O.; Garcia, B.; Guedes, G.; Gomez Berisso, M.; Harton, J.L.; Healy, M.; /Cuyo U. /Buenos Aires, CONICET /Natl. Tech. U., San Rafael /Campinas State U. /UEFS, Feira de Santana /Bahia U. /BUAP, Puebla /Santiago de Compostela U. /Fermilab /UCLA /Colorado State U.

    2007-11-01

    The Pierre Auger Observatory is designed to study cosmic rays with energies greater than 10{sup 19} eV. Two sites are envisaged for the observatory, one in each hemisphere, for complete sky coverage. The southern site of the Auger Observatory, now approaching completion in Mendoza, Argentina, features an array of 1600 water-Cherenkov surface detector stations covering 3000 km{sup 2}, together with 24 fluorescence telescopes to record the air shower cascades produced by these particles. The two complementary detector techniques together with the large collecting area form a powerful instrument for these studies. Although construction is not yet complete, the Auger Observatory has been taking data stably since January 2004 and the first physics results are being published. In this paper we describe the design features and technical characteristics of the surface detector stations of the Pierre Auger Observatory.

  2. The Auger spectroscopy of pyrimidine and halogen-substituted pyrimidines.

    PubMed

    Storchi, L; Tarantelli, F; Veronesi, S; Bolognesi, P; Fainelli, E; Avaldi, L

    2008-10-21

    The C 1s and N 1s Auger spectra of pyrimidine, 2-chloropyrimidine, and 5-bromopyrimidine have been measured in an electron impact experiment at 1000 eV. In the case of the halogen-substituted pyrimidines, also the Cl 2p and Br 3d Auger spectra have been recorded. We have thoroughly analyzed and interpreted all the Auger spectra recorded here with the aid of accurate Green's function calculations with a large basis set. The spectra are extremely complex with thousands of states contributing and almost no single-state feature even near the double ionization threshold. Besides reproducing and explaining with great detail nearly all the main spectral features observed, the calculations have successfully unraveled the interplay among the different C 1s core hole chemical shifts in each molecule and how this affects some fingerprinting details in the composite C 1s Auger spectra.

  3. Atomic Auger Doppler effects upon emission of fast photoelectrons.

    PubMed

    Simon, Marc; Püttner, Ralph; Marchenko, Tatiana; Guillemin, Renaud; Kushawaha, Rajesh K; Journel, Loïc; Goldsztejn, Gildas; Piancastelli, Maria Novella; Ablett, James M; Rueff, Jean-Pascal; Céolin, Denis

    2014-06-06

    Studies of photoemission processes induced by hard X-rays including production of energetic electrons have become feasible due to recent substantial improvement of instrumentation. Novel dynamical phenomena have become possible to investigate in this new regime. Here we show a significant change in Auger emission following 1s photoionization of neon, which we attribute to the recoil of the Ne ion induced by the emission of a fast photoelectron. Because of the preferential motion of the ionized Ne atoms along two opposite directions, an Auger Doppler shift is revealed, which manifests itself as a gradual broadening and doubling of the Auger spectral features. This Auger Doppler effect should be a general phenomenon in high-energy photoemission of both isolated atoms and molecules, which will have to be taken into account in studies of other recoil effects such as vibrational or rotational recoil in molecules, and may also have consequences in measurements in solids.

  4. EMITTANCE CONTROL FOR VERY SHORT BUNCHES

    SciTech Connect

    Bane, K

    2004-07-20

    Many recent accelerator projects call for the production of high energy bunches of electrons or positrons that are simultaneously short, intense, and have small emittances. Examples of such projects are the Self-Amplified Spontaneous Emission (SASE) FEL's, such as the Linac Coherent Light Source (LCLS). A major challenge is keeping in check forces that increase beam emittances in accelerator components, such as: wakefields of accelerator structures and surface roughness, and coherent synchrotron radiation. We describe such forces and discuss emittance control.

  5. Emittance Growth in the NLCTA First Chicane

    SciTech Connect

    Sun, Yipeng; Adolphsen, Chris; /SLAC

    2011-08-19

    In this paper, the emittance growth in the NLCTA (Next Linear Collider Test Accelerator) first chicane region is evaluated by simulation studies. It is demonstrated that the higher order fields of the chicane dipole magnet and the dipole corrector magnet (which is attached on the quadrupoles) are the main contributions for the emittance growth, especially for the case with a large initial emittance ({gamma}{epsilon}{sub 0} = 5 {micro}m for instance). These simulation results agree with the experimental observations.

  6. Minimum emittance in TBA and MBA lattices

    NASA Astrophysics Data System (ADS)

    Xu, Gang; Peng, Yue-Mei

    2015-03-01

    For reaching a small emittance in a modern light source, triple bend achromats (TBA), theoretical minimum emittance (TME) and even multiple bend achromats (MBA) have been considered. This paper derived the necessary condition for achieving minimum emittance in TBA and MBA theoretically, where the bending angle of inner dipoles has a factor of 31/3 bigger than that of the outer dipoles. Here, we also calculated the conditions attaining the minimum emittance of TBA related to phase advance in some special cases with a pure mathematics method. These results may give some directions on lattice design.

  7. An ESS system for ECRIS Emittance Research

    SciTech Connect

    Cao, Y.; Sun, L.T.; He, W.; Ma, L.; Zhang, Z.M.; Zhao, H.Y.; Zhao, H.W.; Zhang, X.Z.; Guo, X.H.; Ma, B.H.; Li, J.; Wang, H.; Li, J.Y.; Li, X.X.; Feng, Y.C.; Lu, W.

    2005-03-15

    An emittance scanner named Electric-Sweep Scanner had been designed and fabricated in IMP. And it has been set up on the LECR3 beam line for the ion beam quality study. With some development, the ESS system has become a relatively dependable and reliable emittance scanner. Its experiment error is about 10 percent. We have done a lot of experiments of emittance measurement on LECR3 ion source, and have researched the relations between ion beam emittance and the major parameters of ECR ion source. The reliability and accuracy test results are presented in this paper. And the performance analysis is also discussed.

  8. Hybrid emitter all back contact solar cell

    DOEpatents

    Loscutoff, Paul; Rim, Seung

    2016-04-12

    An all back contact solar cell has a hybrid emitter design. The solar cell has a thin dielectric layer formed on a backside surface of a single crystalline silicon substrate. One emitter of the solar cell is made of doped polycrystalline silicon that is formed on the thin dielectric layer. The other emitter of the solar cell is formed in the single crystalline silicon substrate and is made of doped single crystalline silicon. The solar cell includes contact holes that allow metal contacts to connect to corresponding emitters.

  9. Auger decay of 3p-ionized krypton

    SciTech Connect

    Jonauskas, V.; Kucas, S.; Karazija, R.

    2011-11-15

    A theoretical study of Auger cascades during the decay of 3p{sub 1/2} and 3p{sub 3/2} vacancies in krypton has been performed by level-by-level calculations using a wide configuration interaction basis. Auger spectra for all steps of the cascades are presented and are compared with the existing experimental data. Good agreement of our results with the branching ratios of ions measured by a coincidence technique is obtained.

  10. Bone calcium, phosphorus detection by Auger electron spectroscopy.

    PubMed

    Tzaphlidou, Margaret; Berillis, Panagiotis; Matthopoulos, Demetrios

    2005-01-01

    Auger electron spectroscopy was used to detect calcium and phosphorus of cortical bone from rat femoral neck and rear tibia. Spectra were taken from bone pieces as well as from disks prepared from grinded bone material. Experimental conditions were found whereby the samples could be analyzed without conductive coatings. The results of this preliminary investigation demonstrate that Auger electron spectroscopy can be used to study bone mineral elements.

  11. Some performance tests of a microarea AES. [Auger Electron Spectroscopy

    NASA Technical Reports Server (NTRS)

    Todd, G.; Poppa, H.

    1978-01-01

    An Auger electron spectroscopy (AES) system which has a submicron analysis capability is described. The system provides secondary electron imaging, as well as micro- and macro-area AES. The resolution of the secondary electron image of an oxidized Al contact pad on a charge-coupled device chip indicates a primary beam size of about 1000 A. For Auger mapping, a useful resolution of about 4000 A is reported

  12. Chemical regeneration of emitter surface increases thermionic diode life

    NASA Technical Reports Server (NTRS)

    Breiteieser, R.

    1966-01-01

    Chemical regeneration of sublimated emitter electrode increases the operating efficiency and life of thermionic diodes. A gas which forms chemical compounds with the sublimated emitter material is introduced into the space between the emitter and the collector. The compounds migrate to the emitter where they decompose and redeposit the emitter material.

  13. Auger electron intensity variations in oxygen-charged silver

    NASA Technical Reports Server (NTRS)

    Lee, W. S.; Outlaw, R. A.; Hoflund, G. B.; Davidson, M. R.

    1991-01-01

    Auger intensity variations over an oxygen-charged polycrystalline silver surface have been observed by studies of Auger images and line scans of selected adjacent grains which were determined to be the (421) and (221) orientations. The observed contrast (M4.5VV transition) between the grains is produced by the variation in the detected Auger electrons caused by the different directions (interatomic direction) of forward focusing in each grain. The contrast produced by the Ag Auger electrons was found to be strongly dependent on the surface order of the grains, but that of the O Auger electrons was not, presumably because the atoms were randomly distributed throughout the Ag surface or subsurface. The contrast observed between the grains at the lower Auger energies (N1VV and N1N2.3V transitions) appeared to be produced by constructive interference from multiple scattering. The N1N2.3V electrons at 29 eV, for example, gave higher contrast than that of the N1VV transition at 78 eV.

  14. Design of a rotary stepped auger for a lunar environment

    NASA Technical Reports Server (NTRS)

    Dardet, Eduardo; Hart, Derek; Herod, Chris; Homiller, Stephen; Meeks, Mickey; Platt, Kirsten

    1988-01-01

    A lunar outpost will have need for deep drilling operations for both explorative and practical purposes. As in any drilling operation, the cuttings must be cleared from the hole. The hard vacuum of the lunar environment renders conventional flushing methods of cutting removal unfeasible, and requires a new system of removal. A rotary stepped auger (RSA) is a simple mechanical method of removing dry cuttings from a deep hole, and is ideally suited to the lunar environment. The RSA consists of a helical auger with stepped ramps which allow cuttings to slide up the helix, but will prevent them from sliding back down. The auger is driven in a pulsed manner by applying a periodic function of acceleration to the auger shaft. These pulses will compel the cuttings to slide up the auger's helix while the stepped ramps prevent the cuttings from backsliding while the auger accelerates. A mathematical model of the RSA was developed and experimentally evaluated. The math model produced a good baseline design, but the experimental model required some tuning to account for the approximations made in the math model. This design is suited for lunar drilling because it is mechanically simple, integral to the drill string, requires no fluids, is suited to the dry soil, and has relatively low weight and power requirements.

  15. Auger electron intensity variations in oxygen-charged silver

    NASA Technical Reports Server (NTRS)

    Lee, W. S.; Outlaw, R. A.; Hoflund, G. B.; Davidson, M. R.

    1991-01-01

    Auger intensity variations over an oxygen-charged polycrystalline silver surface have been observed by studies of Auger images and line scans of selected adjacent grains which were determined to be the (421) and (221) orientations. The observed contrast (M4.5VV transition) between the grains is produced by the variation in the detected Auger electrons caused by the different directions (interatomic direction) of forward focusing in each grain. The contrast produced by the Ag Auger electrons was found to be strongly dependent on the surface order of the grains, but that of the O Auger electrons was not, presumably because the atoms were randomly distributed throughout the Ag surface or subsurface. The contrast observed between the grains at the lower Auger energies (N1VV and N1N2.3V transitions) appeared to be produced by constructive interference from multiple scattering. The N1N2.3V electrons at 29 eV, for example, gave higher contrast than that of the N1VV transition at 78 eV.

  16. Directional Auger Electron Spectroscopy — Physical Foundations and Applications

    NASA Astrophysics Data System (ADS)

    Mróz, S.

    Experimental data about the dependence of the Auger signal from crystalline samples on the primary beam direction are presented and discussed. It is shown that, for Auger electrons and elastically and inelastically backscattered electrons, maxima of the signal in its dependence on the polar and azimuth angles of the primary beam (in polar and azimuth profiles, respectively) appear when the primary beam is parallel either to one of the close-packed rows of atoms or to one of the densely packed atomic planes in the sample. This indicates that the diffraction of the primary electron beam is responsible for the dependence mentioned above. Mechanisms proposed for simple explanation of this dependence (channeling and forward focusing of primary electrons) are presented and results of their application are discussed. It is shown that both those mechanisms play an important role in the creation of the Auger signal contrast. The possibilities and limitations of the application of polar and azimuth Auger emission profiles in the determination of the surface layer crystalline structure (directional Auger electron spectroscopy — DAES) are presented and discussed. It is shown that the thickness of the investigated surface layer can be decreased up to a few monolayers. Results obtained with DAES are similar to those provided by X-ray photoelectron diffraction (XPD) and Auger electron diffraction (AED), but the DAES experimental equipment is simple and inexpensive and measurements are fast. Finally, experimental systems for DAES are described and examples of DAES applications are presented.

  17. The Pierre Auger Observatory status and the AugerPrime upgrade program

    NASA Astrophysics Data System (ADS)

    Martello, Daniele

    2017-06-01

    The nature and the origin of ultra-high energy cosmic rays (UHECRs), above 1017 eV, are still unknown. The Pierre Auger Observatory with its huge exposure provides us with a large set of high quality data. The analysis of these data has led to major breakthroughs in the last decade, but a coherent interpretation is still missing. To answer the open questions the Observatory has started a major upgrade, with an emphasis on improved mass composition determination using the surface detectors. The latest results and the planned detector upgrade will be presented. The expected performance and the improved physics sensitivity of the Observatory will be discussed.

  18. Localized Irradiation of Cell Membrane by Auger Electrons Is Cytotoxic Through Oxidative Stress-Mediated Nontargeted Effects.

    PubMed

    Paillas, Salomé; Ladjohounlou, Riad; Lozza, Catherine; Pichard, Alexandre; Boudousq, Vincent; Jarlier, Marta; Sevestre, Samuel; Le Blay, Marion; Deshayes, Emmanuel; Sosabowski, Jane; Chardès, Thierry; Navarro-Teulon, Isabelle; Mairs, Robert J; Pouget, Jean-Pierre

    2016-09-10

    We investigated whether radiation-induced nontargeted effects are involved in the cytotoxic effects of anticell surface monoclonal antibodies labeled with Auger electron emitters, such as iodine 125 (monoclonal antibodies labeled with (125)I [(125)I-mAbs]). We showed that the cytotoxicity of (125)I-mAbs targeting the cell membrane of p53(+/+) HCT116 colon cancer cells is mainly due to nontargeted effects. Targeted and nontargeted cytotoxicities were inhibited in vitro following lipid raft disruption with Methyl-β-cyclodextrin (MBCD) or filipin or use of radical oxygen species scavengers. (125)I-mAb efficacy was associated with acid sphingomyelinase activation and modulated through activation of the AKT, extracellular signal-related kinase ½ (ERK1/2), p38 kinase, c-Jun N-terminal kinase (JNK) signaling pathways, and also of phospholipase C-γ (PLC-γ), proline-rich tyrosine kinase 2 (PYK-2), and paxillin, involved in Ca(2+) fluxes. Moreover, the nontargeted response induced by directing 5-[(125)I]iodo-2'-deoxyuridine to the nucleus was comparable to that of (125)I-mAb against cell surface receptors. In vivo, we found that the statistical significance of tumor growth delay induced by (125)I-mAb was removed after MBCD treatment and observed oxidative DNA damage beyond the expected Auger electron range. These results suggest the involvement of nontargeted effects in vivo also. Low-energy Auger electrons, such as those emitted by (125)I, have a short tissue range and are usually targeted to the nucleus to maximize their cytotoxicity. In this study, we show that targeting the cancer cell surface with (125)I-mAbs produces a lipid raft-mediated nontargeted response that compensates for the inferior efficacy of non-nuclear targeting. Our findings describe the mechanisms involved in the efficacy of (125)I-mAbs targeting the cancer cell surface. Antioxid. Redox Signal. 25, 467-484.

  19. The Pierre Auger Observatory offline software

    NASA Astrophysics Data System (ADS)

    Allen, J.; Argirò, S.; Barroso, S. L. C.; Ben Zvi, S. Y.; Cataldi, G.; Ding, M.; Gonzalez, J.; McCauley, T.; Nellen, L.; Paul, T.; Porter, T. A.; Prado, L., Jr.; Roth, M.; Ulrich, R.; Unger, M.; Veberič, D.

    2008-07-01

    The Pierre Auger Observatory aims to discover the nature and origins of the highest energy cosmic rays. The large number of physicists involved in the project and the diversity of simulation and reconstruction tasks pose a challenge for the offline analysis software, not unlike the challenges confronting software for very large high energy physics experiments. Previously we have reported on the design and implementation of a general purpose but relatively lightweight framework which allows collaborators to contribute algorithms and sequencing instructions to build up the variety of applications they require. In this report, we update the status of this work and describe some of the successes and difficulties encountered over the last few years of use. We explain the machinery used to manage user contributions, to organize the abundance of configuration files, to facilitate multi-format file handling, and to provide access to event and time-dependent detector information residing in various data sources. We also describe the testing procedures used to help maintain stability of the code in the face of a large number of contributions. Foundation classes will also be discussed, including a novel geometry package which allows manipulation of abstract geometrical objects independent of coordinate system choice.

  20. Selective Emitter Pumped Rare Earth Laser

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L. (Inventor); Patton, Martin O. (Inventor)

    2001-01-01

    A selective emitter pumped rare earth laser provides an additional type of laser for use in many laser applications. Rare earth doped lasers exist which are pumped with flashtubes or laser diodes. The invention uses a rare earth emitter to transform thermal energy input to a spectral band matching the absorption band of a rare earth in the laser in order to produce lasing.

  1. Emittance growth in rippled solenoidal magnetic fields

    SciTech Connect

    Adler, R.J.

    1987-01-01

    Emittance growth results due to accelerating gaps, and magnetic field gaps in induction accelerators. The analytic technique previously used to study electric field induced emittance growth for immersed source beams is extended to include solenoid fringing field effects in the present work. These results have application to industrial induction accelerators and to high brightness Free Electron Laser drivers. 1 ref., 2 figs.

  2. New methods for image collection and analysis in scanning Auger microscopy

    NASA Astrophysics Data System (ADS)

    Browning, R.

    1985-10-01

    While scanning Auger micrographs are used extensively for illustrating the stoichiometry of complex surfaces and for indicating areas of interest for fine point Auger spectroscopy, there are many problems in the quantification and analysis of Auger images. These problems include multiple contrast mechanisms and the lack of meaningful relationships with other Auger data. Collection of multielemental Auger images allows some new approaches to image analysis and presentation. Information about the distribution and quantity of elemental combinations at a surface are retrievable, and particular combinations of elements can be imaged, such as alloy phases. Results from the precipitate hardened alloy Al-2124 illustrate multispectral Auger imaging.

  3. Negative Ion Beam Extraction and Emittance

    SciTech Connect

    Holmes, Andrew J. T.

    2007-08-10

    The use of magnetic fields to both aid the production of negative ions and suppress the co-extracted electrons causes the emittance and hence the divergence of the negative ion beam to increase significantly due to the plasma non-uniformity from jxB drift. This drift distorts the beam-plasma meniscus and experimental results of the beam emittance are presented, which show that non-uniformity causes the square of the emittance to be proportional to the 2/3 power of the extracted current density. This can cause the divergence of the negative ion beam to be significantly larger than its positive ion counterpart. By comparing results from positive and negative ion beam emittances from the same source, it is also possible to draw conclusions about their vulnerability to magnetic effects. Finally emittances of caesiated and un-caesiated negative ion beams are compared to show how the surface and volume modes of production interact.

  4. Directional emittance surface measurement system and process

    NASA Technical Reports Server (NTRS)

    Puram, Chith K. (Inventor); Daryabeigi, Kamran (Inventor); Wright, Robert (Inventor); Alderfer, David W. (Inventor)

    1994-01-01

    Apparatus and process for measuring the variation of directional emittance of surfaces at various temperatures using a radiometric infrared imaging system. A surface test sample is coated onto a copper target plate provided with selective heating within the desired incremental temperature range to be tested and positioned onto a precision rotator to present selected inclination angles of the sample relative to the fixed positioned and optically aligned infrared imager. A thermal insulator holder maintains the target plate on the precision rotator. A screen display of the temperature obtained by the infrared imager, and inclination readings are provided with computer calculations of directional emittance being performed automatically according to equations provided to convert selected incremental target temperatures and inclination angles to relative target directional emittance values. The directional emittance of flat black lacquer and an epoxy resin measurements obtained are in agreement with the predictions of the electromagnetic theory and with directional emittance data inferred from directional reflectance measurements made on a spectrophotometer.

  5. New approach to obtain boron selective emitters

    SciTech Connect

    Moehlecke, A.; Luque, A.

    1994-12-31

    Selective emitters, used in high efficiency solar cells, need a series of oxidations and photolithographic steps that render the process more expensive. In this paper, a new way to make selective emitters using boron is presented. The main feature of this approach is to save oxide growths and photolithographic processes and it is based on the property of boron doped silicon surfaces to be resistant to anisotropic etchings like the one performed during the texturization. Using this characteristic of boron emitter surfaces, the authors can obtain a highly doped emitter under metal grid and simultaneously a shield to avoid texture on these surfaces. First cells were processed and short wavelength response of p{sup +}nn{sup +} solar cells was enhanced by using lightly doped boron emitters in the uncovered area.

  6. TPV Systems with Solar Powered Tungsten Emitters

    SciTech Connect

    Vlasov, A. S.; Khvostikov, V. P.; Khvostikova, O. A.; Gazaryan, P. Y.; Sorokina, S. V.; Andreev, V. M.

    2007-02-22

    A solar TPV generator development and characterization are presented. A double stage sunlight concentrator ensures 4600x concentration ratio. TPV modules based on tungsten emitters and GaSb cells were designed, fabricated and tested at indoor and outdoor conditions. The performance of tungsten emitter under concentrated solar radiation was analyzed. Emitter temperatures in the range of 1400-2000 K were measured, depending on the emitter size. The light distribution in the module has been characterized, 1x1 cm GaSb TPV cells were fabricated with the use of the Zn-diffusion and LPE technologies. The cell efficiency of 19% under illumination by a tungsten emitter (27% under spectra cut-off at {lambda} > 1820 nm) heated up to 1900-2000 K had been derived from experimentally measured PV parameters. The series connection of PV cells was ensured by the use of BeO ceramics. The possibilities of system performance improvement are discussed.

  7. Emittance measurements of the CLIO electron beam

    NASA Astrophysics Data System (ADS)

    Chaput, R.; Devanz, G.; Joly, P.; Kergosien, B.; Lesrel, J.

    1997-02-01

    We have designed a setup to measure the transverse emittance at the CLIO accelerator exit, based on the "3 gradients" method. The beam transverse size is measured simply by scanning it with a steering coil across a fixed jaw and recording the transmitted current, at various quadrupole strengths. A code then performs a complete calculation of the emittance using the transfer matrix of the quadrupole instead of the usual classical lens approximation. We have studied the influence of various parameters on the emittance: Magnetic field on the e-gun and the peak current. We have also improved a little the emittance by replacing a mismatched pipe between the buncher and accelerating section to avoid wake-field effects; The resulting improvements of the emittance have led to an increase in the FEL emitted power.

  8. Evaluation of Acridine Orange Derivatives as DNA-Targeted Radiopharmaceuticals for Auger Therapy: Influence of the Radionuclide and Distance to DNA

    NASA Astrophysics Data System (ADS)

    Pereira, Edgar; Do Quental, Letícia; Palma, Elisa; Oliveira, Maria Cristina; Mendes, Filipa; Raposinho, Paula; Correia, Isabel; Lavrado, João; di Maria, Salvatore; Belchior, Ana; Vaz, Pedro; Santos, Isabel; Paulo, António

    2017-02-01

    A new family of 99mTc(I)- tricarbonyl complexes and 125I-heteroaromatic compounds bearing an acridine orange (AO) DNA targeting unit was evaluated for Auger therapy. Characterization of the DNA interaction, performed with the non-radioactive Re and 127I congeners, confirmed that all compounds act as DNA intercalators. Both classes of compounds induce double strand breaks (DSB) in plasmid DNA but the extent of DNA damage is strongly dependent on the linker between the Auger emitter (99mTc or 125I) and the AO moiety. The in vitro evaluation was complemented with molecular docking studies and Monte Carlo simulations of the energy deposited at the nanometric scale, which corroborated the experimental data. Two of the tested compounds, 125I-C5 and 99mTc-C3, place the corresponding radionuclide at similar distances to DNA and produce comparable DSB yields in plasmid and cellular DNA. These results provide the first evidence that 99mTc can induce DNA damage with similar efficiency to that of 125I, when both are positioned at comparable distances to the double helix. Furthermore, the high nuclear retention of 99mTc-C3 in tumoral cells suggests that 99mTc-labelled AO derivatives are more promising for the design of Auger-emitting radiopharmaceuticals than the 125I-labelled congeners.

  9. Evaluation of Acridine Orange Derivatives as DNA-Targeted Radiopharmaceuticals for Auger Therapy: Influence of the Radionuclide and Distance to DNA

    PubMed Central

    Pereira, Edgar; do Quental, Letícia; Palma, Elisa; Oliveira, Maria Cristina; Mendes, Filipa; Raposinho, Paula; Correia, Isabel; Lavrado, João; Di Maria, Salvatore; Belchior, Ana; Vaz, Pedro; Santos, Isabel; Paulo, António

    2017-01-01

    A new family of 99mTc(I)- tricarbonyl complexes and 125I-heteroaromatic compounds bearing an acridine orange (AO) DNA targeting unit was evaluated for Auger therapy. Characterization of the DNA interaction, performed with the non-radioactive Re and 127I congeners, confirmed that all compounds act as DNA intercalators. Both classes of compounds induce double strand breaks (DSB) in plasmid DNA but the extent of DNA damage is strongly dependent on the linker between the Auger emitter (99mTc or 125I) and the AO moiety. The in vitro evaluation was complemented with molecular docking studies and Monte Carlo simulations of the energy deposited at the nanometric scale, which corroborated the experimental data. Two of the tested compounds, 125I-C5 and 99mTc-C3, place the corresponding radionuclide at similar distances to DNA and produce comparable DSB yields in plasmid and cellular DNA. These results provide the first evidence that 99mTc can induce DNA damage with similar efficiency to that of 125I, when both are positioned at comparable distances to the double helix. Furthermore, the high nuclear retention of 99mTc-C3 in tumoral cells suggests that 99mTc-labelled AO derivatives are more promising for the design of Auger-emitting radiopharmaceuticals than the 125I-labelled congeners. PMID:28211920

  10. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.

    1987-05-22

    This invention involved a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide in activators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography. 2 figs.

  11. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, Joanna S.; MacGregor, Robert R.; Wolf, Alfred P.; Langstrom, Bengt

    1990-01-01

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  12. Positron emitter labeled enzyme inhibitors

    SciTech Connect

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-04-03

    This invention involves a new strategy for imaging and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography.

  13. Microlensless interdigitated photoconductive terahertz emitters.

    PubMed

    Singh, Abhishek; Prabhu, S S

    2015-01-26

    We report here fabrication of interdigitated photoconductive antenna (iPCA) terahertz (THz) emitters based on plasmonic electrode design. Novel design of this iPCA enables it to work without microlens array focusing, which is otherwise required for photo excitation of selective photoconductive regions to avoid the destructive interference of emitted THz radiation from oppositely biased regions. Benefit of iPCA over single active region PCA is, photo excitation can be done at larger area hence avoiding the saturation effect at higher optical excitation density. The emitted THz radiation power from plasmonic-iPCAs is ~2 times more than the single active region plasmonic PCA at 200 mW optical excitation, which will further increase at higher optical powers. This design is expected to reduce fabrication cost of photoconductive THz sources and detectors.

  14. Low Emittance Electron Beam Studies

    SciTech Connect

    Tikhoplav, Rodion

    2006-01-01

    We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*01 mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.

  15. Calculations of absorbed fractions in small water spheres for low-energy monoenergetic electrons and the Auger-emitting radionuclides (123)Ι and (125)Ι.

    PubMed

    Bousis, Christos; Emfietzoglou, Dimitris; Nikjoo, Hooshang

    2012-12-01

    To calculate the absorbed fraction (AF) of low energy electrons in small tissue-equivalent spherical volumes by Monte Carlo (MC) track structure simulation and assess the influence of phase (liquid water versus density-scaled water vapor) and of the continuous-slowing-down approximation (CSDA) used in semi-analytic calculations. An event-by-event MC code simulating the transport of electrons in both the vapor and liquid phase of water using appropriate electron-water interaction cross sections was used to quantify the energy deposition of low-energy electrons in spherical volumes. Semi-analytic calculations within the CSDA using a convolution integral of the Howell range-energy expressions are also presented for comparison. The AF for spherical volumes of radii from 10-1000 nm are presented for monoenergetic electrons over the energy range 100-10,000 eV and the two Auger-emitting radionuclides (125)I and (123)I. The MC calculated AF for the liquid phase are found to be smaller than those of the (density scaled) gas phase by up to 10-20% for the monoenergetic electrons and 10% for the two Auger-emitters. Differences between the liquid-phase MC results and the semi-analytic CSDA calculations are up to ∼ 55% for the monoenergetic electrons and up to ∼ 35% for the two Auger-emitters. Condensed-phase effects in the inelastic interaction of low-energy electrons with water have a noticeable but relatively small impact on the AF for the energy range and target sizes examined. Depending on the electron energies, the semi-analytic approach may lead to sizeable errors for target sizes with linear dimensions below 1 micron.

  16. Auger recombination in scintillator materials from first principles

    NASA Astrophysics Data System (ADS)

    McAllister, Andrew; Kioupakis, Emmanouil; Åberg, Daniel; Schleife, André

    2015-03-01

    Scintillators convert high energy radiation into lower energy photons which are easier to detect and analyze. One of the uses of these devices is identifying radioactive materials being transported across national borders. However, scintillating materials have a non-proportional light yield in response to incident radiation, which makes this task difficult. One possible cause of the non-proportional light yield is non-radiative Auger recombination. Auger recombination can occur in two ways - direct and phonon-assisted. We have studied both types of Auger recombination from first principles in the common scintillating material sodium iodide. Our results indicate that the phonon-assisted process, assisted primarily by short-range optical phonons, dominates the direct process. The corresponding Auger coefficients are 5 . 6 +/- 0 . 3 ×10-32cm6s-1 for the phonon-assisted process versus 1 . 17 +/- 0 . 01 ×10-33cm6s-1 for the direct process. At higher electronic temperatures the direct Auger recombination rate increases but remains lower than the phonon-assisted rate. This research was supported by the National Science Foundation CAREER award through Grant No. DMR-1254314 and NA-22. Computational Resources provide by LLNL and DOE NERSC Facility.

  17. Education and Outreach for the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Snow, G.

    The scale and scope of the physics studied at the Auger Observatory offer significant opportunities for original outreach work. Education, outreach and public relations of the Auger collaboration are coordinated in a separate task whose goals are to encourage and support a wide range of education and outreach efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. The presentation will focus on the impact of the collaboration in Mendoza Province, Argentina, as: the Auger Visitor Center in Malargüe that has hosted over 25,000 visitors since 2001, the Auger Celebration and a collaboration-sponsored science fair held on the Observatory campus in November 2005, the opening of the James Cronin School in Malargüe in November 2006, public lectures, school visits, and courses for science teachers. As the collaboration prepares its northern hemisphere site proposal, plans for an enhanced outreach program are being developed in parallel and will be described.

  18. Results and Perspectives of the Auger Engineering Radio Array

    NASA Astrophysics Data System (ADS)

    Glaser, Christian

    2017-03-01

    The Auger Engineering Radio Array (AERA) is an extension of the Pierre Auger Cosmic-Ray Observatory. It is used to detect radio emission from extensive air showers with energies beyond 1017 eV in the 30 - 80 MHz frequency band. After three phases of deployment, AERA now consists of more than 150 autonomous radio stations with different spacings, covering an area of about 17km2. It is located at the same site as other Auger low-energy detector extensions enabling combinations with various other measurement techniques. The radio array allows different technical schemes to be explored as well as cross-calibration of our measurements with the established baseline detectors of the Auger Observatory. We report on the most recent technological developments and give an overview of the experimental results obtained with AERA. In particular, we will present the measurement of the radiation energy, i.e., the amount of energy that is emitted by the air shower in the form of radio emission, and its dependence on the cosmic-ray energy by comparing with the measurement of the the well-calibrated Auger surface detector. Furthermore, we outline the relevance of this result for the absolute calibration of the energy scale of cosmic-ray observatories.

  19. Portable infrared reflectometer for evaluating emittance

    NASA Astrophysics Data System (ADS)

    Jaworske, Donald A.; Skowronski, Timothy J.

    2000-01-01

    Optical methods are frequently used to evaluate the emittance of candidate spacecraft thermal control materials. One new optical method utilizes a portable infrared reflectometer capable of obtaining spectral reflectance of an opaque surface in the range of 2 to 25 microns using a Michelson-Type FTIR interferometer. This miniature interferometer collects many infrared spectra over a short period of time. It also allows the size of the instrument to be small such that spectra can be collected in the laboratory or in the field. Infrared spectra are averaged and integrated with respect to the room temperature black body spectrum to yield emittance at 300 K. Integrating with respect to other black body spectra yields emittance values at other temperatures. Absorption bands in the spectra may also be used for chemical species identification. The emittance of several samples was evaluated using this portable infrared reflectometer, an old infrared reflectometer equipped with dual rotating black body cavities, and a bench top thermal vacuum chamber. Samples for evaluation were purposely selected such that a range of emittance values and thermal control material types would be represented, including polished aluminum, Kapton®, silvered Teflon®, and the inorganic paint Z-93-P. Results indicate an excellent linear relationship between the room temperature emittance calculated from infrared spectral data and the emittance obtained from the dual rotating black body cavities and thermal vacuum chamber. The prospect of using the infrared spectral data for chemical species identification will also be discussed. .

  20. The preservation of low emittance flat beams

    SciTech Connect

    Raubenheimer, T.O.

    1993-04-01

    Many future linear collider designs require beams with very small transverse emittances and large emittance ratios {epsilon}{sub x} {much_gt} {epsilon}{sub y}. In this paper, we will discuss issues associated with the preservation of these small emittances during the acceleration of the beams. The primary sources of transverse emittance dilution in a high energy linear accelerator are the transverse wakefields, the dispersive errors, RF deflections, and betatron coupling. We will discuss the estimation of these effects and the calculation of tolerances that will limit the emittance dilution with a high degree of confidence. Since the six-dimensional emittance is conserved and only the projected emittances are increased, these dilutions can be corrected if the beam has not filamented (phase mixed). We discuss methods of correcting the dilutions and easing the tolerances with beam-based alignment and steering techniques, and non-local trajectory bumps. Finally, we discuss another important source of luminosity degradation, namely, pulse-to-pulse jitter.

  1. Diffraction and holography with photoelectrons and Auger electrons: Some new directions

    SciTech Connect

    Fadley, C.S. Lawrence Berkeley Lab., CA )

    1992-06-01

    The current status of photoelectron and Auger-electron diffraction is reviewed, with emphasis on new directions of activity. The use of forward scattering in the study of adsorbed molecules, epitaxial overlayers, and clean surfaces is one of the most developed applications, and one that will become more powerful as higher energy resolution and perhaps spin analysis are used to resolve emitters on the basis of chemical state, position at a surface, or magnetic state. The use of larger data sets spanning a considerable fraction of the solid angle above a surface will also much enhance the structural information available, for example, in the growth of epitaxial layers or nanostructures on surfaces. Detailed fitting of experimental data to theoretical calculations based upon either single scattering or multiple scattering should also provide more rich structural information, including such parameters as substrate interlayer relaxation. Surface phase transitions in which near-surface layers become highly disordered can also be studied, with results that are complementary to those from such techniques as low energy electron diffraction and medium energy ion scattering. Short-range magnetic order also can be probed by somehow resolving the spin of the outgoing electrons, e.g. by using multiplet-split core levels.

  2. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    PubMed Central

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-01-01

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics. PMID:21728281

  3. Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

    SciTech Connect

    Mao, Pan; Wang, Hung-Ta; Yang, Peidong; Wang, Daojing

    2011-06-16

    Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a circular array on a 3-inch silicon chip. The geometry and configuration of the emitters, the dimension and number of the nozzles, and the micropillar arrays embedded in the main channel, can be systematically and precisely controlled during the microfabrication process. Combining electrostatic simulation and experimental testing, we demonstrated that sharpened-end geometry at the stem of the individual multinozzle emitter significantly enhanced the electric fields at its protruding nozzle tips, enabling sequential nanoelectrospray for the high-density emitter array. We showed that electrospray current of the multinozzle emitter at a given total flow rate was approximately proportional to the square root of the number of its spraying-nozzles, suggesting the capability of high MS sensitivity for multinozzle emitters. Using a conventional Z-spray mass spectrometer, we demonstrated reproducible MS detection of peptides and proteins for serial MEA emitters, achieving sensitivity and stability comparable to the commercial capillary emitters. Our robust silicon-based MEA chip opens up the possibility of a fully-integrated microfluidic system for ultrahigh-sensitivity and ultrahigh-throughput proteomics and metabolomics.

  4. Narrowband terahertz emitters using metamaterial films.

    PubMed

    Alves, Fabio; Kearney, Brian; Grbovic, Dragoslav; Karunasiri, Gamani

    2012-09-10

    In this article we report on metamaterial-based narrowband thermal terahertz (THz) emitters with a bandwidth of about 1 THz. Single band emitters designed to radiate in the 4 to 8 THz range were found to emit as high as 36 W/m(2) when operated at 400 °C. Emission into two well-separated THz bands was also demonstrated by using metamaterial structures featuring more complex unit cells. Imaging of heated emitters using a microbolometer camera fitted with THz optics clearly showed the expected higher emissivity from the metamaterial structure compared to low-emissivity of the surrounding aluminum.

  5. Emittance growth due to Tevatron flying wires

    SciTech Connect

    Syphers, M; Eddy, Nathan

    2004-06-01

    During Tevatron injection, Flying Wires have been used to measure the transverse beam size after each transfer from the Main Injector in order to deduce the transverse emittances of the proton and antiproton beams. This amounts to 36 + 9 = 45 flies of each of 3 wire systems, with an individual wire passing through each beam bunch twice during a single ''fly''. below they estimate the emittance growth induced by the interaction of the wires with the particles during these measurements. Changes of emittance from Flying Wire measurements conducted during three recent stores are compared with the estimations.

  6. Thermophotovoltaic emitter material selection and design

    SciTech Connect

    Saxton, P.C.; Moran, A.L.; Harper, M.J.; Lindler, K.W.

    1997-07-01

    Thermophotovoltaics (TPV) is a potentially attractive direct energy conversion technology. It reduces the need for complex machinery with moving parts and maintenance. TPV generators can be run from a variety of heat sources including waste heat for smaller scale operations. The US Naval Academy`s goal was to build a small experimental thermophotovoltaic generator powered by combustion gases from a General Electric T-58 helicopter gas turbine. The design of the generator imposes material limitations that directly affect emitter and structural materials selection. This paper details emitter material goals and requirements, and the methods used to select suitable candidate emitter materials for further testing.

  7. Online clustering algorithms for radar emitter classification.

    PubMed

    Liu, Jun; Lee, Jim P Y; Senior; Li, Lingjie; Luo, Zhi-Quan; Wong, K Max

    2005-08-01

    Radar emitter classification is a special application of data clustering for classifying unknown radar emitters from received radar pulse samples. The main challenges of this task are the high dimensionality of radar pulse samples, small sample group size, and closely located radar pulse clusters. In this paper, two new online clustering algorithms are developed for radar emitter classification: One is model-based using the Minimum Description Length (MDL) criterion and the other is based on competitive learning. Computational complexity is analyzed for each algorithm and then compared. Simulation results show the superior performance of the model-based algorithm over competitive learning in terms of better classification accuracy, flexibility, and stability.

  8. Auger recombination in sodium-iodide scintillators from first principles

    SciTech Connect

    McAllister, Andrew; Åberg, Daniel; Schleife, André; Kioupakis, Emmanouil

    2015-04-06

    Scintillator radiation detectors suffer from low energy resolution that has been attributed to non-linear light yield response to the energy of the incident gamma rays. Auger recombination is a key non-radiative recombination channel that scales with the third power of the excitation density and may play a role in the non-proportionality problem of scintillators. In this work, we study direct and phonon-assisted Auger recombination in NaI using first-principles calculations. Our results show that phonon-assisted Auger recombination, mediated primarily by short-range phonon scattering, dominates at room temperature. We discuss our findings in light of the much larger values obtained by numerical fits to z-scan experiments.

  9. Auger spectroscopy analysis in adhesion, friction and wear studies

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1977-01-01

    The paper reviews the current use of Auger electron spectroscopy in adhesion, friction, wear and lubrication studies. Conventional Auger spectroscopy is adopted to complement LEED studies of the adhesion of metal single crystals. In addition, Auger cylindrical mirror analysis is applied to the study of changes in surface chemistry during dynamic friction and wear experiments on polycrystalline metals and alloys. Important conclusions are that (1) segregation of alloying elements to the surface of metals can alter adhesion behavior; (2) hydrocarbons are adsorbed readily to clean iron surfaces at 23 C; (3) transfer from one surface to another for dissimilar materials in contact can be followed in sliding or rubbing friction studies; and (4) the friction process can enhance surface activity for metals with hydrocarbons.

  10. Multielectron spectroscopy: Auger decays of the krypton 3d hole

    SciTech Connect

    Palaudoux, J.; Lablanquie, P.; Penent, F.; Andric, L.; Ito, K.; Shigemasa, E.; Eland, J. H. D.; Jonauskas, V.; Kucas, S.; Karazija, R.

    2010-10-15

    The emission of one or two Auger electrons, following Kr 3d inner-shell ionization by synchrotron light, has been investigated both experimentally and theoretically. All electrons emitted in the process are detected in coincidence and analyzed in energy thanks to a magnetic-bottle electron time-of-flight spectrometer. In addition, noncoincident high-resolution electron spectra have been measured to characterize the cascade double-Auger paths more fully. Combination of the two experimental approaches and of our calculations allows a full determination of the decay pathways and branching ratios in the case of Kr 3d single- and double-Auger decays. The Kr{sup 3+} threshold is found at 74.197{+-}0.020 eV.

  11. Multimode resonant Auger scattering from the ethene molecule.

    PubMed

    Liu, Ji-Cai; Nicolas, Christophe; Sun, Yu-Ping; Flammini, Roberto; O'Keeffe, Patrick; Avaldi, Lorenzo; Morin, Paul; Kimberg, Victor; Kosugi, Nobuhiro; Gel'mukhanov, Faris; Miron, Catalin

    2011-05-12

    Resonant Auger spectra of ethene molecule have been measured with vibrational resolution at several excitation energies in the region of the C1s(-1)1b(2g)(π*) resonance. The main features observed in the experiment have been assigned and are accurately interpreted on the basis of ab initio multimode calculations. Theory explains the extended vibrational distribution of the resonant Auger spectra and its evolution as a function of the excitation energy by multimode excitation during the scattering process. As a result, the resonant Auger spectra display two qualitatively different spectral features following the Raman and non-Raman dispersion laws, respectively. Calculations show that two observed thresholds of formation of non-Raman spectral bands are related to the "double-edge" structure of the X-ray absorption spectrum.

  12. Mapping the composition of planetary surfaces by Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Lin, R. P.; Gopalan, R.

    1991-01-01

    The feasibility of AES as a remote-sensing technique to map the composition of the sunlit surfaces of planetary bodies without atmospheres is studied. Solar X-rays eject photoelectrons from the planetary surface. The resulting ions relax by emission of fluorescence X-rays or Auger electrons, with energies characteristic of the element which is ionized. The spectrum of Auger electrons and photoelectrons is computed for a variety of elements and for representative lunar rock types illuminated by soft-X-ray line and continuum emission typical of solar long-lived coronal active regions. The Auger electron lines for O, Si, Mg, Al, Fe, and Ca in lunar rocks stand well above the continuum background from photoelectrons and backscattered interplanetary electrons, with typical line-to-continuum ratios from about 20 to over 1000.

  13. Auger spectroscopy analysis in adhesion, friction and wear studies

    NASA Technical Reports Server (NTRS)

    Buckley, D. H.

    1977-01-01

    The paper reviews the current use of Auger electron spectroscopy in adhesion, friction, wear and lubrication studies. Conventional Auger spectroscopy is adopted to complement LEED studies of the adhesion of metal single crystals. In addition, Auger cylindrical mirror analysis is applied to the study of changes in surface chemistry during dynamic friction and wear experiments on polycrystalline metals and alloys. Important conclusions are that (1) segregation of alloying elements to the surface of metals can alter adhesion behavior; (2) hydrocarbons are adsorbed readily to clean iron surfaces at 23 C; (3) transfer from one surface to another for dissimilar materials in contact can be followed in sliding or rubbing friction studies; and (4) the friction process can enhance surface activity for metals with hydrocarbons.

  14. The Pierre Auger Observatory Upgrade - Preliminary Design Report

    SciTech Connect

    Aab, Alexander

    2016-04-12

    The Pierre Auger Observatory has begun a major Upgrade of its already impressive capabilities, with an emphasis on improved mass composition determination using the surface detectors of the Observatory. Known as AugerPrime, the upgrade will include new 4 m2 plastic scintillator detectors on top of all 1660 water-Cherenkov detectors, updated and more flexible surface detector electronics, a large array of buried muon detectors, and an extended duty cycle for operations of the fluorescence detectors. This Preliminary Design Report was produced by the Collaboration in April 2015 as an internal document and information for funding agencies. It outlines the scientific and technical case for AugerPrime. We now release it to the public via the arXiv server. We invite you to review the large number of fundamental results already achieved by the Observatory and our plans for the future.

  15. Auger recombination in sodium-iodide scintillators from first principles

    NASA Astrophysics Data System (ADS)

    McAllister, Andrew; Åberg, Daniel; Schleife, André; Kioupakis, Emmanouil

    2015-04-01

    Scintillator radiation detectors suffer from low energy resolution that has been attributed to non-linear light yield response to the energy of the incident gamma rays. Auger recombination is a key non-radiative recombination channel that scales with the third power of the excitation density and may play a role in the non-proportionality problem of scintillators. In this work, we study direct and phonon-assisted Auger recombination in NaI using first-principles calculations. Our results show that phonon-assisted Auger recombination, mediated primarily by short-range phonon scattering, dominates at room temperature. We discuss our findings in light of the much larger values obtained by numerical fits to z-scan experiments.

  16. Induction of DNA-double-strand breaks by auger electrons from 99mTc complexes with DNA-binding ligands.

    PubMed

    Häfliger, Pascal; Agorastos, Nikos; Spingler, Bernhard; Georgiev, Oleg; Viola, Giampietro; Alberto, Roger

    2005-02-01

    The potential of certain Auger electron emitting nuclides for systemic radiotherapeutic applications has recently gained much attention. In particular, the ability of several nuclides, including 111In, 125I, and 123I, to induce DNA double-strand breaks (dsb), a good indicator of cytotoxicity, has been extensively studied. However, this ability has never previously been shown experimentally for 99mTc, which, besides the well-known gamma radiation that is used for diagnostic applications, also emits an average of 1.1 conversion electrons and 4 Auger or Coster-Kronig electrons per decay. Owing to the short range of Auger electrons, the radionuclide needs to be located very close to the DNA for dsb to occur. We synthesized two cationic 99mTcI-tricarbonyl complexes with pendant DNA binders, pyrene and anthraquinone. The X-ray crystal structures of the two complexes could be elucidated. Linear dichroism and UV/Vis spectroscopy revealed that the complex with pyrene intercalates DNA with a stability constant, K, of 1.1 x 10(6) M(-1), while the analogous complex with anthraquinone interacts with DNA in a groove-binding mode and has an affinity value of K=8.9 x 10(4) M(-1). We showed with phiX174 double-stranded DNA that the corresponding 99mTc complexes induce a significant amount of dsb, whereas non-DNA-binding [TcO4]- and nonradioactive Re compounds did not. These results indicate that the Auger electron emitter 99mTc can induce dsb in DNA when decaying in its direct vicinity and this implies potential for systemic radiotherapy with 99mTc complexes.

  17. Analysis report for 241-BY-104 auger samples

    SciTech Connect

    Beck, M.A.; Bechtold, D.B.; Hey, B.E.

    1992-10-26

    This document details the analytical sample results for two auger samples of the tip 15 cm (6 in.) of tank 241-BY-104 salt cake. The thermal response of tank 241-BY-104 auger samples is generally mild. The level of cyanide and iron, and therefore of ferrocyanide is very low. Evidence of inhomogeneity is present for tank 241-By-104 salt cake. Mass and charge balances were less than ideal. The concentrations found for the major constituents, except chromium, are in line with the expectations.

  18. Thermal swing reactor including a multi-flight auger

    DOEpatents

    Ermanoski, Ivan

    2017-03-07

    A thermal swing reactor including a multi-flight auger and methods for solar thermochemical reactions are disclosed. The reactor includes a multi-flight auger having different helix portions having different pitch. Embodiments of reactors include at least two distinct reactor portions between which there is at least a pressure differential. In embodiments, reactive particles are exchanged between portions during a reaction cycle to thermally reduce the particles at first conditions and oxidize the particles at second conditions to produce chemical work from heat.

  19. Studies of liquid metal surfaces using Auger spectroscopy

    NASA Technical Reports Server (NTRS)

    Hardy, S.; Fine, J.

    1982-01-01

    The surface composition of liquid gallium-tin alloys is studied in an Auger electron spectrometer as a function of bulk composition and temperature. The sessile drop samples are cleaned by argon ion bombardment sputtering of the liquid. This technique produces surfaces that are entirely free of impurities within the sensitivity of the spectrometer and remain so for many days. Tin is found to be strongly adsorbed at the liquid-vacuum interface. Surface concentrations based on Auger measurements are found to be in reasonably good agreement with values calculated from surface tension measurements interpreted in terms of a monolayer depth distribution model for the adsorbed tin.

  20. Nuclear dynamics during the resonant Auger decay of water molecules.

    PubMed

    Eroms, Matthis; Vendrell, Oriol; Jungen, Martin; Meyer, Hans-Dieter; Cederbaum, Lorenz S

    2009-04-21

    The resonant Auger decay of water molecules is investigated. Here, the excitation process, the motion of the nuclei, and the decay of the resonantly excited state take place on the same (femtosecond) time scale. Therefore, a multistep picture is not suitable. Instead, the nuclear wave packet at each instant of time is a result of several competing and interfering contributions. The resonant Auger decay of water is simulated and its dynamics is studied in detail. An analysis of the final vibrational distribution is given. The multiconfiguration time-dependent Hartree method is used to study the intricate multidimensional dynamics. The potential energy surfaces have been calculated using a multireference configuration interaction method.

  1. Studies of liquid metal surfaces using Auger spectroscopy

    NASA Technical Reports Server (NTRS)

    Hardy, S.; Fine, J.

    1982-01-01

    The surface composition of liquid gallium-tin alloys is studied in an Auger electron spectrometer as a function of bulk composition and temperature. The sessile drop samples are cleaned by argon ion bombardment sputtering of the liquid. This technique produces surfaces that are entirely free of impurities within the sensitivity of the spectrometer and remain so for many days. Tin is found to be strongly adsorbed at the liquid-vacuum interface. Surface concentrations based on Auger measurements are found to be in reasonably good agreement with values calculated from surface tension measurements interpreted in terms of a monolayer depth distribution model for the adsorbed tin.

  2. Intrinsic emittance reduction in transmission mode photocathodes

    NASA Astrophysics Data System (ADS)

    Lee, Hyeri; Cultrera, Luca; Bazarov, Ivan

    2016-03-01

    High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describes the photoemission process; however, some photocathode characteristics such as their thickness have not yet been completely exploited to further improve the brightness of the generated electron beams. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto a glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction in the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering during electrons' transit towards the cathode surface. Due to this effect, we predict that thicker photocathode layers will further reduce the intrinsic emittance of electron beams generated by photocathodes operated in transmission mode.

  3. Intrinsic emittance reduction in transmission mode photocathodes

    SciTech Connect

    Lee, Hyeri Cultrera, Luca; Bazarov, Ivan

    2016-03-21

    High quantum efficiency (QE) and low emittance electron beams provided by multi-alkali photocathodes make them of great interest for next generation high brightness photoinjectors. Spicer's three-step model well describes the photoemission process; however, some photocathode characteristics such as their thickness have not yet been completely exploited to further improve the brightness of the generated electron beams. In this work, we report on the emittance and QE of a multi-alkali photocathode grown onto a glass substrate operated in transmission and reflection modes at different photon energies. We observed a 20% reduction in the intrinsic emittance from the reflection to the transmission mode operation. This observation can be explained by inelastic electron-phonon scattering during electrons' transit towards the cathode surface. Due to this effect, we predict that thicker photocathode layers will further reduce the intrinsic emittance of electron beams generated by photocathodes operated in transmission mode.

  4. Beam emittance measurements on multicusp ion sources

    NASA Astrophysics Data System (ADS)

    Sarstedt, M.; Lee, Y.; Leung, K. N.; Perkins, L. T.; Pickard, D. S.; Weber, M.; Williams, M. D.

    1996-03-01

    Multicusp ion sources are used for various applications. Presently, the implementation of this type of ion source is planned for the development of an ion beam lithography machine, which will be used for the projection of sub-0.2 μm patterns onto a wafer substrate. Since, for this application, a very good beam quality and a small ion energy spread are required, emittance measurements have been performed on a multicusp ion source for various source conditions. It is shown that the installation of proper capacitors between the extraction electrodes is necessary to avoid rf pickup, which otherwise leads to a distortion of the beam emittance. The influence of the magnetic filter field on the beam emittance has been investigated, and the beam emittance of a dc filament-discharge plasma has also been compared to that of a rf-generated plasma.

  5. Arc-textured high emittance radiator surfaces

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    1991-01-01

    High emittance radiator surfaces are produced by arc-texturing. This process produces such a surface on a metal by scanning it with a low voltage electric arc from a carbon electrode in an inert environment.

  6. Emitters of N-photon bundles.

    PubMed

    Muñoz, C Sánchez; Del Valle, E; Tudela, A González; Müller, K; Lichtmannecker, S; Kaniber, M; Tejedor, C; Finley, J J; Laussy, F P

    2014-07-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or "bundles" of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications.

  7. Energy efficiency of electron plasma emitters

    SciTech Connect

    Zalesski, V. G.

    2011-12-15

    Electron emission influence from gas-discharge plasma on plasma emitter energy parameters is considered. It is shown, that electron emission from plasma is accompanied by energy contribution redistribution in the gas-discharge from plasma emitter supplies sources-the gas-discharge power supply and the accelerating voltage power supply. Some modes of electron emission as a result can be realized: 'a probe measurements mode,' 'a transitive mode,' and 'a full switching mode.'.

  8. Enhanced Light Emitters Based on Metamaterials

    DTIC Science & Technology

    2015-03-30

    Enhanced Light Emitters based on Metamaterials We report the development of light emitters based on hyperbolic metamaterials . During the 18 month...layer, use of a high refractive index contrast grating to out-couple light from active hyperbolic metamaterials . We also successfully demonstrated for...the first time simultaneous enhancement in spontaneous emission ad light extraction from active metamaterial structures. The views, opinions and/or

  9. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  10. Charge neutrality in heavily doped emitters

    SciTech Connect

    del Alamo, J.A.

    1981-09-01

    The applicability of the quasineutrality approximation to modern emitters of solar cells is analytically reviewed. It is shown that this approximation is fulfilled in more than 80% of the depth of a typical solar-cell emitter, being particularly excellent in the heavily doped regions beneath the surface where most of the heavy doping effects arise. Our conclusions are in conflict with Redfield's recent affirmations.

  11. Alpha-emitters for medical therapy workshop

    SciTech Connect

    Feinendegen, L.E.; McClure, J.J.

    1996-12-31

    A workshop on ``Alpha-Emitters for Medical Therapy`` was held May 30-31, 1996 in Denver Colorado to identify research goals and potential clinical needs for applying alpha-particle emitters and to provide DOE with sufficient information for future planning. The workshop was attended by 36 participants representing radiooncology, nuclear medicine, immunotherapy, radiobiology, molecular biology, biochemistry, radiopharmaceutical chemistry, dosimetry, and physics. This report provides a summary of the key points and recommendations arrived at during the conference.

  12. Tailored emitter, low-resistivity, ion-implanted silicon solar cells

    NASA Technical Reports Server (NTRS)

    Minnucci, J. A.; Kirkpatrick, A. R.; Matthei, K. W.

    1980-01-01

    Open-circuit voltages as high as 0.645 V (AM0, 25 C) have been obtained by a new process developed for low-resistivity silicon. The process utilizes high-dose phosphorus implantation followed by furnace annealing and simultaneous oxide growth. The effect of the thermally grown oxide is a reduction of surface recombination velocity; the oxide also acts as a moderately efficient antireflection (AR) coating. Boron-doped, float-zone silicon with resistivities from 0.1 to 1.0 (omega)(cm) has been processed according to this sequence; results show that the highest open-circuit voltage is obtained with 0.1(omega)(cm) starting material. The effects of Auger recombination and bandgap narrowing caused by high doping concentrations in the n(+)junction region have been investigated by implanting phosphorus over a wide range of dose levels. The effects of emitter-phosphorus concentrations tailored to optimize electric fields in the emitter have also been investigated.

  13. Energy and angular distributions of electrons emitted by direct double auger decay.

    PubMed

    Viefhaus, Jens; Cvejanović, Slobodan; Langer, Burkhard; Lischke, Toralf; Prümper, Georg; Rolles, Daniel; Golovin, Alexander V; Grum-Grzhimailo, Alexei N; Kabachnik, Nikolai M; Becker, Uwe

    2004-02-27

    We have observed the direct L(2,3)MMM double Auger transition after photoionization of the 2p shell of argon by angle-resolved electron-electron coincidence spectroscopy. The process is responsible for about 20% of the observed Auger electron intensity. In contrast to the normal Auger lines, the spectra in double Auger decay show a continuous intensity distribution. The energy and angular distributions of the emitted electrons allow one to obtain information on the electron correlations giving rise to the double Auger process as well as the symmetry of the associated two-electron continuum state.

  14. X-ray excited Auger transitions of Pu compounds

    SciTech Connect

    Nelson, Art J. Grant, William K.; Stanford, Jeff A.; Siekhaus, Wigbert J.; Allen, Patrick G.; McLean, William

    2015-05-15

    X-ray excited Pu core–valence–valence and core–core–valence Auger line-shapes were used in combination with the Pu 4f photoelectron peaks to characterize differences in the oxidation state and local electronic structure for Pu compounds. The evolution of the Pu 4f core-level chemical shift as a function of sputtering depth profiling and hydrogen exposure at ambient temperature was quantified. The combination of the core–valence–valence Auger peak energies with the associated chemical shift of the Pu 4f photoelectron line defines the Auger parameter and results in a reliable method for definitively determining oxidation states independent of binding energy calibration. Results show that PuO{sub 2}, Pu{sub 2}O{sub 3}, PuH{sub 2.7}, and Pu have definitive Auger line-shapes. These data were used to produce a chemical state (Wagner) plot for select plutonium oxides. This Wagner plot allowed us to distinguish between the trivalent hydride and the trivalent oxide, which cannot be differentiated by the Pu 4f binding energy alone.

  15. Removing Single Limbs Using a Rotary Auger Cutter

    Treesearch

    Nels S. Christopherson

    1984-01-01

    An experiment using auger cutters to remove single limbs from six species showed that torque required depends on species and relative cutter rotation direction and that all species require 2 horsepower or less per inch width of cut using 2 1/2-inch-diameter cutters

  16. Ultrafast X-ray Auger probing of photoexcited molecular dynamics

    DOE PAGES

    McFarland, B. K.; Farrell, J. P.; Miyabe, S.; ...

    2014-06-23

    Here, molecules can efficiently and selectively convert light energy into other degrees of freedom. Disentangling the underlying ultrafast motion of electrons and nuclei of the photoexcited molecule presents a challenge to current spectroscopic approaches. Here we explore the photoexcited dynamics of molecules by an interaction with an ultrafast X-ray pulse creating a highly localized core hole that decays via Auger emission. We discover that the Auger spectrum as a function of photoexcitation—X-ray-probe delay contains valuable information about the nuclear and electronic degrees of freedom from an element-specific point of view. For the nucleobase thymine, the oxygen Auger spectrum shifts towardsmore » high kinetic energies, resulting from a particular C–O bond stretch in the ππ* photoexcited state. A subsequent shift of the Auger spectrum towards lower kinetic energies displays the electronic relaxation of the initial photoexcited state within 200 fs. Ab-initio simulations reinforce our interpretation and indicate an electronic decay to the nπ* state.« less

  17. Auger electron spectroscopy of contrast-forming layers on metals

    NASA Technical Reports Server (NTRS)

    Hoffmann, Siegfried; Exner, Hans Eckart

    1988-01-01

    As shown by Auger electron spectroscopy, the layers formed during contrasting metallographic polished Cu and Ni with an apparatus using intense electron bombardment consist of metal sputtered from the Au, Fe, or Pb cathode. This layer takes up oxygen from the residual atmosphere. The mechanism of contrast enhancement is the same as that of vapor-deposited interference layers.

  18. Metastable states in NO2+ probed with Auger spectroscopy.

    PubMed

    Püttner, R; Sekushin, V; Fukuzawa, H; Uhlíková, T; Špirko, V; Asahina, T; Kuze, N; Kato, H; Hoshino, M; Tanaka, H; Thomas, T D; Kukk, E; Tamenori, Y; Kaindl, G; Ueda, K

    2011-11-07

    High-resolution N 1s and O 1s photoelectron spectra (PES) of NO are presented together with spectra of the subsequent Auger decay. The PES are analyzed by taking spin-orbit splitting of the (2)Π ground state into account providing detailed information on equilibrium distances, vibrational energies, and lifetime widths of the core-ionized states. In the Auger electron spectra (AES) transitions to five metastable dicationic final states are observed, with two of them previously unobserved. A Franck-Condon analysis of the vibrational progressions belonging to these transitions provides detailed information on the potential-energy curves of the dicationic final states as well as on the relative Auger rates. The present calculations of the potential-energy curves of NO(2+) agree well with the experimental results and allow an assignment of the two hitherto unresolved Auger transitions to excited states of NO(2+), C(2)Σ(+)and c(4)Π. This journal is © the Owner Societies 2011

  19. Ultrafast X-ray Auger probing of photoexcited molecular dynamics

    SciTech Connect

    McFarland, B. K.; Farrell, J. P.; Miyabe, S.; Tarantelli, F.; Aguilar, A.; Berrah, N.; Bostedt, C.; Bozek, J. D.; Bucksbaum, P. H.; Castagna, J. C.; Coffee, R. N.; Cryan, J. P.; Fang, L.; Feifel, R.; Gaffney, K. J.; Glownia, J. M.; Martinez, T. J.; Mucke, M.; Murphy, B.; Natan, A.; Osipov, T.; Petrović, V. S.; Schorb, S.; Schultz, Th.; Spector, L. S.; Swiggers, M.; Tenney, I.; Wang, S.; White, J. L.; White, W.; Gühr, M.

    2014-06-23

    Here, molecules can efficiently and selectively convert light energy into other degrees of freedom. Disentangling the underlying ultrafast motion of electrons and nuclei of the photoexcited molecule presents a challenge to current spectroscopic approaches. Here we explore the photoexcited dynamics of molecules by an interaction with an ultrafast X-ray pulse creating a highly localized core hole that decays via Auger emission. We discover that the Auger spectrum as a function of photoexcitation—X-ray-probe delay contains valuable information about the nuclear and electronic degrees of freedom from an element-specific point of view. For the nucleobase thymine, the oxygen Auger spectrum shifts towards high kinetic energies, resulting from a particular C–O bond stretch in the ππ* photoexcited state. A subsequent shift of the Auger spectrum towards lower kinetic energies displays the electronic relaxation of the initial photoexcited state within 200 fs. Ab-initio simulations reinforce our interpretation and indicate an electronic decay to the nπ* state.

  20. Auger tension leg platform: Conquering the deepwater Gulf of Mexico

    SciTech Connect

    Bourgeois, T.M.

    1994-12-31

    Conquering the ultra-deepwater Gulf of Mexico (GOM) is among the greatest challenges facing the oil and gas industry today. Explorationists have found significant quantities of hydrocarbons in the ultra-deep GOM. Since Shell Offshore Inc. (Shell) has over one-third of the deepwater GOM acreage under lease today, development of this vast new oil and gas reservoir represents a major opportunity. Shell`s Auger field, located in Garden Banks 426, was discovered in 1987 in 2,860 feet of water. This discovery kicked off a project of mammoth proportions for Shell and the industry. Shell designed and built a Tension Leg Platform (TLP) and related drilling and producing facilities for the major discovery at Prospect Auger. A TLP is a floating structure which is tethered to the seafloor. This $1.2 billion development is located in a world record shattering water depth of 2,860 feet. Integrating the complexities of this floating structure with the challenges of the subsurface makes Auger the most complex project ever undertaken by Shell`s Production Department. The Auger Project, which was conceived in 1989, is now installed within three months of the original target and $100 million under the original estimate. This is a significant success for Shell and the industry in the deepwater GOM as it opens the ultra-deepwater GOM frontier as an energy source to fuel America for decades to come.

  1. Lining material tests for the AUGER PROJECT surface detector

    NASA Astrophysics Data System (ADS)

    Escobar, C. O.; Fauth, A. C.; Guzzo, M. M.; Shibuya, E. H.

    1999-03-01

    We are trying to obtain a suitable material to compose the lining of a water Cerenkov tank for the surface detector. part of a hybrid detector of the Auger Project. Results of tests were compared with DuPont 1073Tyvek TM and obtained a reasonable performance for (PVC+BaSO 4) material.

  2. Suppression of auger recombination in ""giant"" core/shell nanocrystals

    SciTech Connect

    Garcia Santamaria, Florencio; Vela, Javier; Schaller, Richard D; Hollingsworth, Jennifer A; Klimov, Victor I; Chen, Yongfen

    2009-01-01

    Many potential applications of semiconductor nanocrystals are hindered by nonradiative Auger recombination wherein the electron-hole (exciton) recombination energy is transferred to a third charge carrier. This process severely limits the lifetime and bandwidth of optical gain, leads to large nonradiative losses in light emitting diodes and photovoltaic cells, and is believed to be responsible for intermittency ('blinking') of emission from single nanocrystals. The development of nanostructures in which Auger recombination is suppressed has been a longstanding goal in colloidal nanocrystal research. Here, we demonstrate that such suppression is possible using so-called 'giant' nanocrystals that consist of a small CdSe core and a thick CdS shell. These nanostructures exhibit a very long biexciton lifetime ({approx}10 ns) that is likely dominated by radiative decay instead of non-radiative Auger recombination. As a result of suppressed Auger recombination, even high-order multiexcitons exhibit high emission efficiencies, which allows us to demonstrate optical amplification with an extraordinarily large bandwidth (>500 me V) and record low excitation thresholds.

  3. Pristine SiC Candidates: Spectral Imaging and Auger Investigations

    NASA Astrophysics Data System (ADS)

    Croat, T. K.; Lebsack, E.; Bernatowicz, T. J.

    2010-03-01

    We describe a new spectral imaging method to locate pristine SiCs (those prepared without acid dissolution) from within Murchison matrix material. We present images,X-ray and Auger electron spectra from pristine SiCs, which show carbonaceous surface coatings.

  4. Cosmic ray composition studies with the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Boncioli, Denise

    2014-04-01

    The Pierre Auger Observatory in Argentina is the largest cosmic ray detector array ever built. Although the construction was completed in 2008, the Observatory has been taking data continuously since January 2004. Its main goal is to measure ultra high energy cosmic rays (UHECRs, energy above 1018 eV) with unprecedented statistics and precision. Measurements of the energy spectrum, chemical composition (including neutrinos and photons) and arrival directions of UHECRs can provide hints for understanding their origin, propagation and interactions. The fluorescence detector of the Pierre Auger Observatory measures the atmospheric depth, Xmax, where the longitudinal profile of a high energy air shower reaches its maximum. This is sensitive to the nuclear mass composition of the cosmic ray and to the characteristics of the hadronic interactions at very high energy. Due to its hybrid design, the Pierre Auger Observatory also provides independent experimental observables obtained from the surface detector for the study of the shower development. A selection of the Pierre Auger Observatory results on the study of the UHECRs will be presented, focusing on composition results. In particular, the measurements and the different roles of the observables with respect to mass composition will be discussed.

  5. The Pierre Auger Observatory status and latest results

    NASA Astrophysics Data System (ADS)

    Berat, Corinne

    2017-03-01

    The Pierre Auger Observatory, in Argentina, is the present flagship experiment studying ultrahigh-energy cosmic rays (UHECRs). Facing the challenge due to low cosmic-ray flux at the highest energies, the Observatory has been taking data for more than a decade, reaching an exposure of over 50 000 km2 sr yr. The combination of a large surface detector array and fluorescence telescopes provides a substantial improvement in energy calibration and extensive air shower measurements, resulting in data of unprecedented quality. Moreover, the installation of a denser subarray has allowed extending the sensitivity to lower energies. Altogether, this contributes to provide important information on key questions in the UHECR field in the energy range from 0.1 EeV up to 100 EeV. A review of main results from the Pierre Auger Observatory is presented with a particular focus on the energy spectrum measurements, the mass composition studies, the arrival directions analyses, the search for neutral cosmic messengers, and the investigation of high-energy hadronic interactions. Despite this large amount of valuable results, the understanding of the nature of UHECRs and of their origin remains an open science case that the Auger collaboration is planning to address with the AugerPrime project to upgrade the Observatory.

  6. Upflow bioreactor having a septum and an auger and drive assembly

    DOEpatents

    Hansen, Carl S.; Hansen, Conly L.

    2007-11-06

    An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes an auger positioned in the aperture of the septum. The vessel includes an opening in the top for receiving the auger. The auger extends from a drive housing, which is position over the opening and provides a seal around the opening. The drive housing is adjustable relative to the vessel. The position of the auger in the aperture can be adjusted by adjusting the drive housing relative to the vessel. The auger adjustment mechanism allows the auger to be accurately positioned within the aperture. The drive housing can also include a fluid to provide an additional seal around the shaft of the auger.

  7. Studies of Cosmic Ray Composition and Air Shower Structure with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the average depth of shower maximum and its fluctuations with the Pierre Auger Observatory; (2) Study of the nuclear mass composition of UHECR with the surface detectors of the Pierre Auger Observatory; (3) Comparison of data from the Pierre Auger Observatory with predictions from air shower simulations: testing models of hadronic interactions; (4) A Monte Carlo exploration of methods to determine the UHECR composition with the Pierre Auger Observatory; (5) The delay of the start-time measured with the Pierre Auger Observatory for inclined showers and a comparison of its variance with models; (6) UHE neutrino signatures in the surface detector of the Pierre Auger Observatory; and (7) The electromagnetic component of inclined air showers at the Pierre Auger Observatory.

  8. Field-emitter arrays for vacuum microelectronics

    NASA Technical Reports Server (NTRS)

    Spindt, C. A.; Holland, C. E.; Rosengreen, A.; Brodie, Ivor

    1991-01-01

    An ongoing program on microfabricated field-emitter arrays has produced a gated field-emitter tip structure with submicrometer dimensions and techniques for fabricating emitter arrays with tip packaging densities of up to 1.5 x 10 exp 7 tips/sq cm. Arrays have been fabricated over areas varying from a few micrometers up to 13 cm in diameter. Very small overall emitter size, materials selection, and rigorous emitter-tip processing procedures have contributed to reducing the potential required for field emission to tens of volts. Emission current densities of up to 100 A/sq cm have been achieved with small arrays of tips, and 100-mA total emission is commonly produced with arrays 1 mm in diameter containing 10,000 tips. Transconductances of 5.0 micro-S per tip have been demonstrated, indicating that 50 S/sq cm should be achievable with tip densities of 10 exp 7 tips/sq cm. Details of the cathode arrays and a variety of performance characteristics are discussed.

  9. Variable emittance behavior of smart radiative coating

    NASA Astrophysics Data System (ADS)

    Guo, Li; Fan, Desong; Li, Qiang

    2016-02-01

    Smart radiative coating on yttria stabilized zirconia (YSZ) substrate was prepared by the sol-gel La{}1-xSr x MnO3 (x = 0.125, 0.175 and 0.2) nanoparticles and the binder composed of terpineol and ethyl cellulose. The crystallized structure, grain size, chemical compositions, magnetization and the surface morphology were characterized. The thermal radiative properties of coating in the infrared range was evaluated from infrared reflectance spectra at various temperatures. A single perovskite structure is detected in sol-gel nanoparticles with size 200 nm. Magnetization measurement reveals that room temperature phase transition samples can be obtained by appropriate Sr substitution. The influence of surface conditions and sintering temperature on the emittance of coating was observed. For rough coatings with root-mean-square roughness 640 nm (x = 0.125) and 800 nm (x = 0.175) , its emittance increment is 0.24 and 0.26 in in the temperature range of 173-373 K. Increasing sintering temperature to 1673 K, coating emittance variation improves to 0.3 and 0.302 respectively. After mechanical polishing treatment, the emittance increment of coatings are enhanced to 0.31 and 0.3, respectively. The results suggested that the emittance variation can be enhanced by reducing surface roughness and increasing sintering temperature of coating.

  10. Emittance control in Laser Wakefield Accelerator

    NASA Astrophysics Data System (ADS)

    Cheshkov, S.; Tajima, T.; Chiu, C.; Breitling, F.

    2001-05-01

    In this paper we summarize our recent effort and results in theoretical study of the emittance issues of multistaged Laser Wakefield Accelerator (LWFA) in TeV energy range. In such an energy regime the luminosity and therefore the emittance requirements become very stringent and tantamount to the success or failure of such an accelerator. The system of such a machine is very sensitive to jitters due to misalignment between the beam and the wakefield. In particular, the effect of jitters in the presence of a strong focusing wakefield and initial longitudinal phase space spread of the beam leads to severe transverse emittance degradation of the beam. To improve the emittance we introduce several methods: a mitigated wakefield focusing by working with a plasma channel, an approximately synchronous acceleration in a superunit setup, the "horn" model based on exactly synchronous acceleration achieved through plasma density variation and lastly an algorithm based on minimization of the final beam emittance to actively control the stage displacement of such an accelerator.

  11. Integrated photonic crystal selective emitter for thermophotovoltaics

    NASA Astrophysics Data System (ADS)

    Zhou, Zhiguang; Yehia, Omar; Bermel, Peter

    2016-01-01

    Converting blackbody thermal radiation to electricity via thermophotovoltaics (TPV) is inherently inefficient. Photon recycling using cold-side filters offers potentially improved performance but requires extremely close spacing between the thermal emitter and the receiver, namely a high view factor. Here, we propose an alternative approach for thermal energy conversion, the use of an integrated photonic crystal selective emitter (IPSE), which combines two-dimensional photonic crystal selective emitters and filters into a single device. Finite difference time domain and current transport simulations show that IPSEs can significantly suppress sub-bandgap photons. This increases heat-to-electricity conversion for photonic crystal based emitters from 35.2 up to 41.8% at 1573 K for a GaSb photovoltaic (PV) diode with matched bandgaps of 0.7 eV. The physical basis of this enhancement is a shift from a perturbative to a nonperturbative regime, which maximized photon recycling. Furthermore, combining IPSEs with nonconductive optical waveguides eliminates a key difficulty associated with TPV: the need for precise alignment between the hot selective emitter and cool PV diode. The physical effects of both the IPSE and waveguide can be quantified in terms of an extension of the concept of an effective view factor.

  12. Quantitative deconvolution of human thermal infrared emittance.

    PubMed

    Arthur, D T J; Khan, M M

    2013-01-01

    The bioheat transfer models conventionally employed in etiology of human thermal infrared (TIR) emittance rely upon two assumptions; universal graybody emissivity and significant transmission of heat from subsurface tissue layers. In this work, a series of clinical and laboratory experiments were designed and carried out to conclusively evaluate the validity of the two assumptions. Results obtained from the objective analyses of TIR images of human facial and tibial regions demonstrated significant variations in spectral thermophysical properties at different anatomic locations on human body. The limited validity of the two assumptions signifies need for quantitative deconvolution of human TIR emittance in clinical, psychophysiological and critical applications. A novel approach to joint inversion of the bioheat transfer model is also introduced, levering the deterministic temperature-dependency of proton resonance frequency in low-lipid human soft tissue for characterizing the relationship between subsurface 3D tissue temperature profiles and corresponding TIR emittance.

  13. Head erosion with emittance growth in PWFA

    SciTech Connect

    Li, S. Z.; Adli, E.; England, R. J.; Frederico, J.; Gessner, S. J.; Hogan, M. J.; Litos, M. D.; Walz, D. R.; Muggli, P.; An, W.; Clayton, C. E.; Joshi, C.; Lu, W.; Marsh, K. A.; Mori, W.; Vafaei, N.

    2012-12-21

    Head erosion is one of the limiting factors in plasma wakefield acceleration (PWFA). We present a study of head erosion with emittance growth in field-ionized plasma from the PWFA experiments performed at the FACET user facility at SLAC. At FACET, a 20.3 GeV bunch with 1.8 Multiplication-Sign 10{sup 10} electrons is optimized in beam transverse size and combined with a high density lithium plasma for beam-driven plasma wakefield acceleration experiments. A target foil is inserted upstream of the plasma source to increase the bunch emittance through multiple scattering. Its effect on beamplasma interaction is observed with an energy spectrometer after a vertical bend magnet. Results from the first experiments show that increasing the emittance has suppressed vapor field-ionization and plasma wakefields excitation. Plans for the future are presented.

  14. Solid-state single-photon emitters

    NASA Astrophysics Data System (ADS)

    Aharonovich, Igor; Englund, Dirk; Toth, Milos

    2016-10-01

    Single-photon emitters play an important role in many leading quantum technologies. There is still no 'ideal' on-demand single-photon emitter, but a plethora of promising material systems have been developed, and several have transitioned from proof-of-concept to engineering efforts with steadily improving performance. Here, we review recent progress in the race towards true single-photon emitters required for a range of quantum information processing applications. We focus on solid-state systems including quantum dots, defects in solids, two-dimensional hosts and carbon nanotubes, as these are well positioned to benefit from recent breakthroughs in nanofabrication and materials growth techniques. We consider the main challenges and key advantages of each platform, with a focus on scalable on-chip integration and fabrication of identical sources on photonic circuits.

  15. Measurement of transverse emittance and coherence of double-gate field emitter array cathodes

    NASA Astrophysics Data System (ADS)

    Tsujino, Soichiro; Das Kanungo, Prat; Monshipouri, Mahta; Lee, Chiwon; Miller, R. J. Dwayne

    2016-12-01

    Achieving small transverse beam emittance is important for high brightness cathodes for free electron lasers and electron diffraction and imaging experiments. Double-gate field emitter arrays with on-chip focussing electrode, operating with electrical switching or near infrared laser excitation, have been studied as cathodes that are competitive with photocathodes excited by ultraviolet lasers, but the experimental demonstration of the low emittance has been elusive. Here we demonstrate this for a field emitter array with an optimized double-gate structure by directly measuring the beam characteristics. Further we show the successful application of the double-gate field emitter array to observe the low-energy electron beam diffraction from suspended graphene in minimal setup. The observed low emittance and long coherence length are in good agreement with theory. These results demonstrate that our all-metal double-gate field emitters are highly promising for applications that demand extremely low-electron bunch-phase space volume and large transverse coherence.

  16. Measurement of transverse emittance and coherence of double-gate field emitter array cathodes

    PubMed Central

    Tsujino, Soichiro; Das Kanungo, Prat; Monshipouri, Mahta; Lee, Chiwon; Miller, R.J. Dwayne

    2016-01-01

    Achieving small transverse beam emittance is important for high brightness cathodes for free electron lasers and electron diffraction and imaging experiments. Double-gate field emitter arrays with on-chip focussing electrode, operating with electrical switching or near infrared laser excitation, have been studied as cathodes that are competitive with photocathodes excited by ultraviolet lasers, but the experimental demonstration of the low emittance has been elusive. Here we demonstrate this for a field emitter array with an optimized double-gate structure by directly measuring the beam characteristics. Further we show the successful application of the double-gate field emitter array to observe the low-energy electron beam diffraction from suspended graphene in minimal setup. The observed low emittance and long coherence length are in good agreement with theory. These results demonstrate that our all-metal double-gate field emitters are highly promising for applications that demand extremely low-electron bunch-phase space volume and large transverse coherence. PMID:28008918

  17. Current Injection Pumping of Organic Light Emitters

    DTIC Science & Technology

    1989-09-28

    MOT-OOO1AF I Current Injection Pumping of Organic Light Emitters Prepared by DI Jeffrey C. Buchholz E L ri: 8 James P. Stec OCT C "t989 Mary C...Schutte Micro -Optics Technologies, Inc. 8608 University Green #5 Middleton, WI 53562 28 September 1989 D,:?UqflON SA2". N’.’ _ Disuibunon Uanu-ted Contract...Title Report Date Current Injection Pumping of Organic Light Emitters 28 September 1989 Authors Jeffrey C. Buchholz, James P. Stec, Mary C. Schutte

  18. Field emitter technologies for nanovision science

    NASA Astrophysics Data System (ADS)

    Mimura, H.; Neo, Y.; Aoki, T.; Nagao, M.; Yoshida, T.; Kanemaru, S.

    2009-10-01

    We have been investigating an ultra fine field emission display (FED) and an ultra fine CdTe X-ray image sensor for creating nanovision science. For an ultra fine FED with a sub-micron pixel, we have developed a volcano-structured double-gated field emitter arrays with a capability of focusing electron beam without serous reduction in emission current. For an ultra fine X-ray image sensor, we have proposed and demonstrated a novel CdTe X-ray sensor consisting of a CdTe diode and field emitter array.

  19. Coupling single emitters to quantum plasmonic circuits

    NASA Astrophysics Data System (ADS)

    Huck, Alexander; Andersen, Ulrik L.

    2016-09-01

    In recent years, the controlled coupling of single-photon emitters to propagating surface plasmons has been intensely studied, which is fueled by the prospect of a giant photonic nonlinearity on a nanoscaled platform. In this article, we will review the recent progress on coupling single emitters to nanowires towards the construction of a new platform for strong light-matter interaction. The control over such a platform might open new doors for quantum information processing and quantum sensing at the nanoscale and for the study of fundamental physics in the ultrastrong coupling regime.

  20. Heterojunction solar cell with passivated emitter surface

    DOEpatents

    Olson, J.M.; Kurtz, S.R.

    1994-05-31

    A high-efficiency heterojunction solar cell is described wherein a thin emitter layer (preferably Ga[sub 0.52]In[sub 0.48]P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer. 1 fig.

  1. Heterojunction solar cell with passivated emitter surface

    DOEpatents

    Olson, Jerry M.; Kurtz, Sarah R.

    1994-01-01

    A high-efficiency heterojunction solar cell wherein a thin emitter layer (preferably Ga.sub.0.52 In.sub.0.48 P) forms a heterojunction with a GaAs absorber layer. A passivating window layer of defined composition is disposed over the emitter layer. The conversion efficiency of the solar cell is at least 25.7%. The solar cell preferably includes a passivating layer between the substrate and the absorber layer. An anti-reflection coating is preferably disposed over the window layer.

  2. Determination and error analysis of emittance and spectral emittance measurements by remote sensing

    NASA Technical Reports Server (NTRS)

    Dejesusparada, N. (Principal Investigator); Kumar, R.

    1977-01-01

    The author has identified the following significant results. From the theory of remote sensing of surface temperatures, an equation of the upper bound of absolute error of emittance was determined. It showed that the absolute error decreased with an increase in contact temperature, whereas, it increased with an increase in environmental integrated radiant flux density. Change in emittance had little effect on the absolute error. A plot of the difference between temperature and band radiance temperature vs. emittance was provided for the wavelength intervals: 4.5 to 5.5 microns, 8 to 13.5 microns, and 10.2 to 12.5 microns.

  3. Atmospheric aerosol monitoring at the Pierre Auger Observatory

    SciTech Connect

    Cester, R.; Chiosso, M.; Chirin, J.; Clay, R.; Dawson, B.; Fick, B.; Filipcic, A.; Garcia, B.; Grillo, A.; Horvat, M.; Iarlori, M.; Malek, M.; Matthews, J.; Matthews, J.A.J.; Melo, D.; Meyhandan, R.; Mostafa, M.; Mussa, R.; Prouza, M.; Raefert, B.; Rizi, V.

    2005-07-01

    For a ground based cosmic-ray observatory the atmosphere is an integral part of the detector. Air fluorescence detectors (FDs) are particularly sensitive to the presence of aerosols in the atmosphere. These aerosols, consisting mainly of clouds and dust, can strongly affect the propagation of fluorescence and Cherenkov light from cosmic-ray induced extensive air showers. The Pierre Auger Observatory has a comprehensive program to monitor the aerosols within the atmospheric volume of the detector. In this paper the aerosol parameters that affect FD reconstruction will be discussed. The aerosol monitoring systems that have been deployed at the Pierre Auger Observatory will be briefly described along with some measurements from these systems.

  4. Photonic crystal enhancement of auger-suppressed infrared photodetectors

    NASA Astrophysics Data System (ADS)

    Djurić, Zoran; Jakšić, Zoran; Ehrfeld, Wolfgang; Schmidt, Andreas; Matić, Milan; Popović, Mirjana

    2001-04-01

    We examine theoretically and experimentally the possibilities to reach room-temperature background-limited operation of narrow-bandgap compound semiconductor photodetectors in (3-14) micrometer infrared wavelength range. To this purpose we consider the combination of non-equilibrium Auger suppression with photonic crystal enhancement (PCE). This means that Auger generation-recombination processes are suppressed utilizing exclusion, extraction or magnetoconcentration effects or their combination. The residual radiative recombination is removed by immersing the detector active area into a photonic crystal and using the benefits of re-absorption (photon recycling) to effectively increase the radiative lifetime. In this manner the total generation-recombination noise is strongly quenched in sufficiently defect-free device materials. It is concluded that the operation of thus enhanced photonic detectors could even approach signal fluctuation limit.

  5. Some strategies for quantitative scanning Auger electron microscopy

    NASA Technical Reports Server (NTRS)

    Browning, R.; Peacock, D. C.; Prutton, M.

    1985-01-01

    The general applicability of power law forms of the background in electron spectra is pointed out and exploited for background removal from under Auger peaks. This form of B(E) is found to be extremely sensitive to instrumental alignment and to fault-free construction - an observation which can be used to set up analyser configurations in an accurate way. Also, differences between N(E) and B(E) can be used to derive a spectrometer transmission function T(E). The questions of information density in an energy-analysing spatially-resolving instrument are addressed after reliable instrumental characterization has been established. Strategies involving ratio histograms, showing the population distribution of the ratio of a pair of Auger peak heights, composition scatter diagrams and windowed imaging are discussed and illustrated.

  6. Spectrum of energy depositions in the Auger Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Salazar, Humberto

    1999-08-01

    The measured spectrum of energy depositions in a Water Cherenkov Detector (WCD) prototype for the Pierre Auger Observatory is presented. A WCD (area 10 m2 )is located in the Puebla University campus at a depth of 800 g/cm2 (2200 m above sea level). Differential and integral spectra in a wide energy deposition range (0.5 - 150 of vertical equivalent muons) are presented. The problem of the WCD "self calibration" procedure (by rate of the muon events) is discussed. The characteristic change of the slopes of the differential spectrum at the transition from single muon signals to EAS signals is also discussed. The measured energy deposition spectrum at extreme signals is used to estimate the linearity of the response of the WCD PMTs. Key words: Auger array, water Cherenkov detector, extensive air showers

  7. Development of Atmospheric Monitoring System for Auger North

    NASA Astrophysics Data System (ADS)

    Claus, John; Allen, Clint; Botts, Adam; Carande, Bryce; Calhoun, Mike; Emmert, Lucas; Hamilton, Levi; Heid, T. J.; Koop, John; Morgan, Sarah; Robinson, Shay; Sherman, John; Wiencke, Lawrence

    2009-10-01

    The Pierre Auger Northern Fluorescence Detector will measure air-showers over distances of 40 km. Vertical Aerosol profile of the atmosphere at the Pierre Auger Northern site will be measured using the side-scatter method over the 40 km baseline. An atmospheric monitoring telescope (AMT) will use a 3.5 m^2 mirror optimized for UV reflection to focus light from a laser onto a cluster of phototmultiplier tubes. The AMT has been built and final testing and modifications are being carried out before its installation later this year. A remotely programmed, 355 nm YAG laser with a final beam energy of 5 mJ is being used. The automation of the laser and the AMT is controlled via a single board computer (SBC). This talk will present an overview of this R&D program.

  8. Relativistic Radiative and Auger Rates for Fe XXIV

    NASA Technical Reports Server (NTRS)

    Bautista, M. A.; Mendoza, C.; Kallman, T. R.; Palmeri, P.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    As part of a project to compute improved atomic data for the spectral modeling of iron K lines, we report extensive calculations and comparisons of radiative and Auger rates for transitions involving the K-vacancy states in Fe XXIV. By making use of several computational codes, a detailed study is carried out of orbital representation, configuration interaction, relativistic corrections, cancellation effects, and fine tuning. It is shown that a formal treatment of the Breit interaction is essential to render the important magnetic correlations that take part in the decay pathways of this ion. As a result, the accuracy of the present A-values is firmly ranked at better than 10% while that of the Auger rates at only 15%.

  9. Some strategies for quantitative scanning Auger electron microscopy

    NASA Technical Reports Server (NTRS)

    Browning, R.; Peacock, D. C.; Prutton, M.

    1985-01-01

    The general applicability of power law forms of the background in electron spectra is pointed out and exploited for background removal from under Auger peaks. This form of B(E) is found to be extremely sensitive to instrumental alignment and to fault-free construction - an observation which can be used to set up analyser configurations in an accurate way. Also, differences between N(E) and B(E) can be used to derive a spectrometer transmission function T(E). The questions of information density in an energy-analysing spatially-resolving instrument are addressed after reliable instrumental characterization has been established. Strategies involving ratio histograms, showing the population distribution of the ratio of a pair of Auger peak heights, composition scatter diagrams and windowed imaging are discussed and illustrated.

  10. Study of the Auger line shape of polyethylene and diamond

    NASA Technical Reports Server (NTRS)

    Dayan, M.; Pepper, S. V.

    1984-01-01

    The KVV Auger electron line shapes of carbon in polyethylene and diamond have been studied. The spectra were obtained in derivative form by electron beam excitation. They were treated by background subtraction, integration and deconvolution to produce the intrinsic Auger line shape. Electron energy loss spectra provided the response function in the deconvolution procedure. The line shape from polyethylene is compared with spectra from linear alkanes and with a previous spectrum of Kelber et al. Both spectra are compared with the self-convolution of their full valence band densities of states and of their p-projected densities. The experimental spectra could not be understood in terms of existing theories. This is so even when correlation effects are qualitatively taken into account account to the theories of Cini and Sawatzky and Lenselink.

  11. Nitridation of silicon /111/ - Auger and LEED results

    NASA Technical Reports Server (NTRS)

    Delord, J. F.; Schrott, A. G.; Fain, S. C., Jr.

    1980-01-01

    Clean silicon (111) (7x7) surfaces at up to 1050 C have been reacted with nitrogen ions and neutrals produced by a low energy ion gun. The LEED patterns observed are similar to those previously reported for reaction of silicon (111) (7x7) with NH3. The nitrogen KLL peak exhibits no shift or change in shape with nitride growth. At the same time the magnitude of the elemental silicon LVV peak at 92 eV decreases progressively as a new peak at 84 eV increases. The position of both peaks appears to be independent of the degree of nitridation. Since the Auger spectra are free of oxygen and other impurities, these features can be attributed only to silicon, nitrogen, and their reaction products. Characteristic features of the Auger spectra are related to LEED observations and to the growth of microcrystals of Si3N4.

  12. Path-reversed Auger electron and photoelectron diffraction

    SciTech Connect

    Pauli, M. D.; Saldin, D. K.

    2001-08-15

    We propose a method for the computer simulation of Auger electron and photoelectron diffraction patterns by evaluating the amplitude of propagation paths from the detector to the electron-emitting source, justified by Helmholtz's reciprocity principle. The method offers significant computational advantages over previous schemes, and suggests an easy extension to enable the calculation of a structure-perturbation tensor for rapid crystallographic parameter variation.

  13. The Past, Present, and Future of Auger Lineshape Analysis

    DTIC Science & Technology

    1991-01-01

    Availability Codei Avail and/or Dist Special Technical Report No. 55 Wf The Past, Present, And Future of Auger Lineshape Analysis By DAVID E. RAMAKER Prepared...interaction on the 0 atom. Values from 4 to 14 have been reported (see reference Ramhtsc2 for a summary of the theoretical and experimental estimates). The 0...public releas \\ ,, distributibin unlimited ) 4 4. PERFORMING ORGANIZATION REPORT NUMBERCS) S. MONITORING- ORGANIZATION REPOR T NUMBER(S) - Technical

  14. The hybrid performance of the Pierre Auger Observatory

    SciTech Connect

    Mostafa, Miguel, A.; /New Mexico U.

    2005-08-01

    The Pierre Auger Observatory detects ultra-high energy cosmic rays by implementing two complementary air-shower techniques. The combination of a large ground array and fluorescence detectors, known as the hybrid concept, means that a rich variety of measurements can be made on a single shower, providing much improved information over what is possible with either detector alone. In this paper the hybrid reconstruction approach and its performance are described.

  15. Mechanical testing - In situ fracture device for Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Moorhead, R. D.

    1976-01-01

    An in situ fracture device for Auger spectroscopy is described. The device is designed to handle small tensile specimens or small double-cantilever beam specimens and is fully instrumented with load and displacement transducers so that quantitative stress-strain measurements can be made directly. Some initial test results for specimens made from 4130 and 1020 steel are presented. Results indicate that impurity segregation at interfaces other than grain boundary may play a significant role in the mechanism of ductile fracture.

  16. Comment on mesic-atom Auger-rate calculation

    NASA Astrophysics Data System (ADS)

    Altman, A.; Fried, Z.

    1983-07-01

    Auger rates for a mesic atom consisting of a lithium nucleus and two electrons are presented. It is shown that the results are sensitive to the screening of the initial and final state of the ejected electron by the spectator electron. These results are compared to transition rates one would obtain by following the procedure used by Burbridge and de Borde, which neglect screening of one electron by the others. Our results show a 40% reduction in transition rates.

  17. Status and first results of the "Pierre Auger" observatory

    NASA Astrophysics Data System (ADS)

    Arqueros, F.

    The southern Pierre Auger Cosmic Ray Observatory located at Malargue Mendoza Argentina is even before completion the largest cosmic ray detector in operation It consists of a huge surface array for the detection of the air-shower tail and a fluo-rescence detector for the observation of the shower development Since January 2004 the Observatory is collecting data at increasing rate The capabilities of this hybrid detector and the first results will be summarized

  18. A study of emittance growth in the recycler ring

    SciTech Connect

    Krishnaswamy Gounder et al.

    2001-07-20

    We investigate processes contributing to emittance growth in the Fermilab Recycler Ring. In addition to beam-gas multiple scattering, we also examine other external factors such as Main Injector ramping affecting the emittance growth.

  19. Emittance Characteristics of High-Brightness H- Ion Sources

    NASA Astrophysics Data System (ADS)

    Welton, R. F.; Stockli, M. P.; Keller, R.; Thomae, R. W.; Thomason, J.; Sherman, J.; Alessi, J.

    2002-11-01

    A survey of emittance characteristics from high-brightness, H- ion sources has been undertaken. Representative examples of each important type of H- source for accelerator application are investigated: A magnetron surface plasma source (BNL) a multi-cusp-surface-conversion source (LANL) a Penning source (RAL-ISIS) and a multi-cusp-volume source (LBNL). Presently, comparisons between published emittance values from different ion sources are difficult largely because of different definitions used in reported emittances and the use of different data reduction techniques in analyzing data. Although seldom discussed in the literature, rms-emittance values often depend strongly on the method employed to separate real beam from background. In this work, the problem of data reduction along with software developed for emittance analysis is discussed. Raw emittance data, obtained from the above laboratories, is analyzed using a single technique and normalized rms and 90% area-emittance values are determined along with characteristic emittance versus beam fraction curves.

  20. Atmospheric monitoring and model applications at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Keilhauer, Bianca

    2015-03-01

    The Pierre Auger Observatory detects high-energy cosmic rays with energies above ˜1017 eV. It is built as a multi-hybrid detector measuring extensive air showers with different techniques. For the reconstruction of extensive air showers, the atmospheric conditions at the site of the Observatory have to be known quite well. This is particularly true for reconstructions based on data obtained by the fluorescence technique. For these data, not only the weather conditions near ground are relevant, most important are altitude-dependent atmospheric profiles. The Pierre Auger Observatory has set up a dedicated atmospheric monitoring programme at the site in the Mendoza province, Argentina. Beyond this, exploratory studies were performed in Colorado, USA, for possible installations in the northern hemisphere. In recent years, the atmospheric monitoring programme at the Pierre Auger Observatory was supplemented by applying data from atmospheric models. Both GDAS and HYSPLIT are developments by the US weather department NOAA and the data are freely available. GDAS is a global model of the atmospheric state parameters on a 1 degree geographical grid, based on real-time measurements and numeric weather predictions, providing a full altitude-dependent data set every 3 hours. HYSPLIT is a powerful tool to track the movement of air masses at various heights, and with it the aerosols. Combining local measurements of the atmospheric state variables and aerosol scattering with the given model data, advanced studies about atmospheric conditions can be performed and high precision air shower reconstructions are achieved.

  1. Resonant Auger Effect at High X-Ray Intensity

    SciTech Connect

    Rohringer, N; Santra, R

    2008-03-27

    The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

  2. Resonant Auger decay driving intermolecular Coulombic decay in molecular dimers.

    PubMed

    Trinter, F; Schöffler, M S; Kim, H-K; Sturm, F P; Cole, K; Neumann, N; Vredenborg, A; Williams, J; Bocharova, I; Guillemin, R; Simon, M; Belkacem, A; Landers, A L; Weber, Th; Schmidt-Böcking, H; Dörner, R; Jahnke, T

    2014-01-30

    In 1997, it was predicted that an electronically excited atom or molecule placed in a loosely bound chemical system (such as a hydrogen-bonded or van-der-Waals-bonded cluster) could efficiently decay by transferring its excess energy to a neighbouring species that would then emit a low-energy electron. This intermolecular Coulombic decay (ICD) process has since been shown to be a common phenomenon, raising questions about its role in DNA damage induced by ionizing radiation, in which low-energy electrons are known to play an important part. It was recently suggested that ICD can be triggered efficiently and site-selectively by resonantly core-exciting a target atom, which then transforms through Auger decay into an ionic species with sufficiently high excitation energy to permit ICD to occur. Here we show experimentally that resonant Auger decay can indeed trigger ICD in dimers of both molecular nitrogen and carbon monoxide. By using ion and electron momentum spectroscopy to measure simultaneously the charged species created in the resonant-Auger-driven ICD cascade, we find that ICD occurs in less time than the 20 femtoseconds it would take for individual molecules to undergo dissociation. Our experimental confirmation of this process and its efficiency may trigger renewed efforts to develop resonant X-ray excitation schemes for more localized and targeted cancer radiation therapy.

  3. Laser enabled Auger decay in argon atoms and dimers

    NASA Astrophysics Data System (ADS)

    Ranitovic, Predrag; Tong, Xiao-Min; Hogle, Craig W.; Toshima, N.; Murnane, M. M.; Kapteyn, H. C.

    2011-05-01

    In rare-gas atoms, Auger decay in which an inner-valence shell ns hole is filled is normally not energetically allowed. However, in the presence of a strong laser field, a new laser-enabled Auger decay channel can open up to increase the double-ionization yield. This process is efficient at high laser intensities, and an ns hole can be filled within a few femtoseconds of its creation. This novel laser-enabled Auger decay (LEAD) process is of fundamental importance for controlling electron dynamics in atoms, molecules, and materials. We then use LEAD to investigate charge transfer in a Coulomb exploding Ar dimer. We can selectively double-ionize either the Ar dimer (threshold ~ 36 eV) or Ar atoms (threshold ~ 43.5 eV) using combined laser (1.5 eV) and XUV photons (36 eV) in a time-resolved fashion, and then comparing the kinetic energy releases. The Ar dimer can be double ionized when the 3s hole is filled by a 3p electron from either one of the two Ar atoms through LEAD. Theoretical calculation will support data taken using COLTRIMS and HHG.

  4. Auger investigation of annealing processes in MOS technology

    NASA Astrophysics Data System (ADS)

    Jost, S. R.

    Thin oxides of SiO2 on clean Si surfaces were studied by Auger electron spectroscopy to determine the effects of various annealing processes on the Si/SiO2 interface. A defect peak was observed in the Auger spectrum near 83 eV that is theoretically associated with dangling Si bonds at the interface which are caused by lattice mismatch between Si and SiO2. Exposure to hydrogen significantly reduced the magnitude of this Auger peak which corresponds to the reduction in interface-state density in MOS structures following a low temperature forming gas anneal. Subsequent heat treatment in ultrahigh vacuum resulted in the return of the defect peak in the spectrum showing the reversibility of the role of hydrogen in interface state passivation. Nitrogen, argon, and vacuum high temperature anneals were also investigated, and it was found that nitrogen anneals seem to be more effective in the reduction of interface-state density, although a mechanism for its effectiveness could not be determined.

  5. Localized Irradiation of Cell Membrane by Auger Electrons Is Cytotoxic Through Oxidative Stress-Mediated Nontargeted Effects

    PubMed Central

    Paillas, Salomé; Ladjohounlou, Riad; Lozza, Catherine; Pichard, Alexandre; Boudousq, Vincent; Jarlier, Marta; Sevestre, Samuel; Le Blay, Marion; Deshayes, Emmanuel; Sosabowski, Jane; Chardès, Thierry; Navarro-Teulon, Isabelle; Mairs, Robert J.

    2016-01-01

    Abstract Aims: We investigated whether radiation-induced nontargeted effects are involved in the cytotoxic effects of anticell surface monoclonal antibodies labeled with Auger electron emitters, such as iodine 125 (monoclonal antibodies labeled with 125I [125I-mAbs]). Results: We showed that the cytotoxicity of 125I-mAbs targeting the cell membrane of p53+/+ HCT116 colon cancer cells is mainly due to nontargeted effects. Targeted and nontargeted cytotoxicities were inhibited in vitro following lipid raft disruption with Methyl-β-cyclodextrin (MBCD) or filipin or use of radical oxygen species scavengers. 125I-mAb efficacy was associated with acid sphingomyelinase activation and modulated through activation of the AKT, extracellular signal-related kinase ½ (ERK1/2), p38 kinase, c-Jun N-terminal kinase (JNK) signaling pathways, and also of phospholipase C-γ (PLC-γ), proline-rich tyrosine kinase 2 (PYK-2), and paxillin, involved in Ca2+ fluxes. Moreover, the nontargeted response induced by directing 5-[(125)I]iodo-2′-deoxyuridine to the nucleus was comparable to that of 125I-mAb against cell surface receptors. In vivo, we found that the statistical significance of tumor growth delay induced by 125I-mAb was removed after MBCD treatment and observed oxidative DNA damage beyond the expected Auger electron range. These results suggest the involvement of nontargeted effects in vivo also. Innovation: Low-energy Auger electrons, such as those emitted by 125I, have a short tissue range and are usually targeted to the nucleus to maximize their cytotoxicity. In this study, we show that targeting the cancer cell surface with 125I-mAbs produces a lipid raft-mediated nontargeted response that compensates for the inferior efficacy of non-nuclear targeting. Conclusion: Our findings describe the mechanisms involved in the efficacy of 125I-mAbs targeting the cancer cell surface. Antioxid. Redox Signal. 25, 467–484. PMID:27224059

  6. Binary collision model for neon Auger spectra from neon ion bombardment of the aluminum surface

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1986-01-01

    A model is developed to account for the angle-resolved Auger spectra from neon ion bombardment of the aluminum surface recently obtained by Pepper and Aron. The neon is assumed to be excited in a single asymmetric neon-aluminum-collision and scattered back into the vacuum where it emits an Auger electron. The velocity of the Auger electron acquires a Doppler shift by virtue of the emission from a moving source. The dependence of the Auger peak shape and energy on the incident ion energy, angle of incidence and on the angle of Auger electron emission with respect to the surface is presented. Satisfactory agreement with the angle resolved experimental observations is obtained. The dependence of the angle-integrated Auger yield on the incident ion energy and angle of incidence is also obtained and shown to be in satisfactory agreement with available experimental evidence.

  7. Initial-state-selected M N N Auger spectroscopy of atomic rubidium

    NASA Astrophysics Data System (ADS)

    Keskinen, J.; Lablanquie, P.; Penent, F.; Palaudoux, J.; Andric, L.; Cubaynes, D.; Bizau, J.-M.; Huttula, M.; Jänkälä, K.

    2017-04-01

    The M4 ,5N2 ,3N2 ,3 and M4 ,5N1N2 ,3 Auger decay of atomic Rb have been studied by using photoelectron-Auger electron coincidence measurements that enable initial ionic state selected Auger spectroscopy. The Auger spectra in the present study are separated by the total angular momentum j of the 3 d hole and the orbital of the valence electron n ℓ after photoionization. It is shown that the technique allows isolating overlapping features and the study of otherwise unobservable spectral details, from which the presence of shake-down transitions during normal Auger decay is demonstrated experimentally. The technique allows also probing the effects of initial state parity and electron correlation in Auger electron spectroscopy. The observed spectral features are interpreted with theoretical predictions obtained from configuration interaction Dirac-Fock approach.

  8. Normal Auger spectra of iodine in gas phase alkali iodide molecules

    NASA Astrophysics Data System (ADS)

    Hu, Zhengfa; Caló, Antonio; Kukk, Edwin; Aksela, Helena; Aksela, Seppo

    2005-06-01

    Molecular normal Auger electron spectra following the iodine 4d ionization in gas-phase alkali iodides were investigated both experimentally and theoretically. The Auger electron spectra for LiI, NaI and KI were recorded using electron impact, and for RbI by using photo-excitation. These Auger spectra were analyzed in detail and compared to the referenced normal Auger spectra of HI [L. Karlsson, S. Svensson, P. Baltzer, M. Carlsson-Göthe, M.P. Keane, A. Naves de Brito, N. Correia, B. Wannberg, J. Phys. B 22 (1989) 3001]. An energy shift toward higher kinetic energy and a narrowing in linewidth are observed in the Auger spectra series revealing the effect of the changing environment from covalently bonded HI to ionic alkali iodide compounds. The experimental results are also compared with the theoretical ab initio calculations and with the Auger spectra of I -, computed with the multiconfiguration Hartree-Fock (MCHF) method.

  9. Emittance growth rates for displaced beams

    SciTech Connect

    Anderson, O.A. |

    1993-05-01

    Emittance growth rates have been previously analyzed for nonuniform beams in linear channels and for initially uniform mismatched beams in nonlinear channels. These studies were for centered beams. Additional emittance growth can arise in cases where the beam is initially displaced. The purpose of this study is to obtain growth rates for displaced beams. This work differs from studies involving random displacement of electrodes. Our analysis assumes instead that the focusing system is perfectly aligned but that the beam is initially displaced with respect to the equilibrium axis. If the focusing force is slightly nonlinear, we find a gradual transfer of the potential energy of beam displacement into kinetic energy associated with emittance growth. We present explicit results for the emittance growth distance as a function of the nonlinearity of the channel. These results will have practical importance for designers of accelerators and transport systems when setting realistic tolerances for initial beam alignment. These tolerances will depend on the nonlinearity and the length of the system.

  10. Aluminum oxide film thickness and emittance

    SciTech Connect

    Thomas, J.K.; Ondrejcin, R.S.

    1991-11-01

    Aluminum reactor components which are not actively cooled could be subjected to high temperatures due to gamma heating after the core coolant level dropped during the ECS phase of a hypothetical LOCA event. Radiative heat transfer is the dominant heat transfer process in this scenario and therefore the emittance of these components is of interest. Of particular interest are the safety rod thimbles and Mark 60B blanket assemblies; for the K Reactor, these components have been exposed to low temperature (< 55{degrees}C) moderator for about a year. The average moderator temperature was assumed to be 30{degrees}C. The Al oxide film thickness at this temperature, after one year of exposure, is predicted to be 6.4 {mu}m {plus minus} 10%; insensitive to exposure time. Dehydration of the film during the gamma heating accident would result in a film thickness of 6.0 {mu}m {plus minus} 11%. Total hemispherical emittance is predicted to be 0.69 at 96{degrees}C, decreasing to 0.45 at 600{degrees}C. Some phenomena which would tend to yield thicker oxide films in the reactor environment relative to those obtained under experimental conditions were neglected and the predicted film thickness values are therefore conservative. The emittance values predicted for a given film thickness are also conservative. The conservativisms inherent in the predicted emittance are particularly relevant for uncertainty analysis of temperatures generated using these values.

  11. Aluminum oxide film thickness and emittance

    SciTech Connect

    Thomas, J.K.; Ondrejcin, R.S.

    1991-11-01

    Aluminum reactor components which are not actively cooled could be subjected to high temperatures due to gamma heating after the core coolant level dropped during the ECS phase of a hypothetical LOCA event. Radiative heat transfer is the dominant heat transfer process in this scenario and therefore the emittance of these components is of interest. Of particular interest are the safety rod thimbles and Mark 60B blanket assemblies; for the K Reactor, these components have been exposed to low temperature (< 55{degrees}C) moderator for about a year. The average moderator temperature was assumed to be 30{degrees}C. The Al oxide film thickness at this temperature, after one year of exposure, is predicted to be 6.4 {mu}m {plus_minus} 10%; insensitive to exposure time. Dehydration of the film during the gamma heating accident would result in a film thickness of 6.0 {mu}m {plus_minus} 11%. Total hemispherical emittance is predicted to be 0.69 at 96{degrees}C, decreasing to 0.45 at 600{degrees}C. Some phenomena which would tend to yield thicker oxide films in the reactor environment relative to those obtained under experimental conditions were neglected and the predicted film thickness values are therefore conservative. The emittance values predicted for a given film thickness are also conservative. The conservativisms inherent in the predicted emittance are particularly relevant for uncertainty analysis of temperatures generated using these values.

  12. Light modulated electron beam driven radiofrequency emitter

    DOEpatents

    Wilson, M.T.; Tallerico, P.J.

    1979-10-10

    The disclosure relates to a light modulated electron beam-driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

  13. Light modulated switches and radio frequency emitters

    DOEpatents

    Wilson, Mahlon T.; Tallerico, Paul J.

    1982-01-01

    The disclosure relates to a light modulated electron beam driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

  14. Simple-to-prepare multipoint field emitter

    NASA Astrophysics Data System (ADS)

    Sominskii, G. G.; Taradaev, E. P.; Tumareva, T. A.; Mishin, M. V.; Kornishin, S. Yu.

    2015-07-01

    We investigate multitip field emitters prepared by electroerosion treatment of the surface of molybdenum samples. Their characteristics are determined for operation with a protecting activated fullerene coating. Our experiments indicate that such cathodes are promising for high-voltage electron devices operating in technical vacuum.

  15. Emittance growth from electron beam modulation

    SciTech Connect

    Blaskiewicz, M.

    2009-12-01

    In linac ring colliders like MeRHIC and eRHIC a modulation of the electron bunch can lead to a modulation of the beam beam tune shift and steering errors. These modulations can lead to emittance growth. This note presents simple formulas to estimate these effects which generalize some previous results.

  16. Optical transition radiation beam emittance diagnostics

    SciTech Connect

    Fiorito, R.B.; Rule, D.W.

    1994-10-10

    We have developed several analytic and experimental techniques to measure the divergence and emittance of charged particle beams, which employ optical transition radiation (OTR) produced from thin intercepting foils. OTR`s directionality, promptness, linearity, polarization, and the sensitivity of its angular distribution to energy and divergence, can be all exploited to diagnose the spatial distribution, energy, and emittance of a charged particle beam. We describe the techniques we have developed to separately determine the {ital x} and {ital y} emittances of a beam at an {ital x} or {ital y} waist using OTR from a single foil or a two foil OTR interferometer. These methods have proven to be especially valuable for diagnosing low emittance electron beams produced by FEL accelerators, which range in energy from 17 to 110 Mev. However, we have shown that there is no inherent theoretical limit to the utility of these methods for much higher energy lepton or hadron beams. The advantages of OTR methods over those commonly used to diagnose beam properties are described.

  17. Emittance growth from space-charge forces

    SciTech Connect

    Wangler, T.P.

    1991-01-01

    Space-charge-induced emittance growth has become a topic of much recent interest for designing the low-velocity sections of high- intensity, high-brightness accelerators and beam-transport channels. In this paper we review the properties of the space-charge force, and discuss the concepts of matching, space-charge and emittance-dominated beams, and equilibrium beams and their characteristics. This is followed by a survey of some of the work over the past 25 years to identify the mechanisms of this emittance growth in both ion and electron accelerators. We summarize the overall results in terms of four distinct mechanisms whose characteristics we describe. Finally, we show numerical simulation results for the evolution of initial rms-mismatched laminar beams. The examples show that for space-charge dominated beams, the nonlinear space-charge forces produce a highly choatic filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. In the examples we have studied the halo contains only a few percent of the particles, but contributes about half of the emittance growth. 39 refs., 2 figs., 1 tab.

  18. Radiolabeling and in vitro evaluation of (67)Ga-NOTA-modular nanotransporter--a potential Auger electron emitting EGFR-targeted radiotherapeutic.

    PubMed

    Koumarianou, Eftychia; Slastnikova, Tatiana A; Pruszynski, Marek; Rosenkranz, Andrey A; Vaidyanathan, Ganesan; Sobolev, Alexander S; Zalutsky, Michael R

    2014-07-01

    Modular nanotransporters (MNTs) are vehicles designed to transport drugs from the cell surface via receptor-mediated endocytosis and endosomal escape to nucleus. Hence their conjugation to Auger electron emitters, can cause severe cell killing, by nuclear localization. Herein we evaluate the use of MNT as a platform for targeted radiotherapy with (67)Ga. EGF was the targeting ligand on the MNT, and NOTA was selected for its radiolabeling with (67)Ga. In the radiolabeling study we dealt with the precipitation of MNT (pI 5.7) at the labeling pH (4.5-5.5) of (67)Ga. Cellular and nuclei uptake of (67)Ga-NOTA-MNT by the A431 cell line was determined. Its specific cytotoxicity was compared to that of (67)Ga-EDTA, (67)Ga-NOTA-BSA and (67)Ga-NOTA-hEGF, in A431 and U87MGWTT, cell lines, by clonogenic assay. Dosimetry studies were also performed. (67)Ga-NOTA-MNT was produced with 90% yield and specific activity of 25.6mCi/mg. The in vitro kinetics revealed an increased uptake over 24h. 55% of the internalized radioactivity was detected in the nuclei at 1h. The cytotoxicity of (67)Ga-NOTA-MNT on A431 cell line was 17 and 385-fold higher when compared to non-specific (67)Ga-NOTA-BSA and (67)Ga-EDTA. While its cytotoxic potency was 13 and 72-fold higher when compared to (67)Ga-NOTA-hEGF in the A431 and the U87MGWTT cell lines, respectively, validating its nuclear localization. The absorbed dose, for 63% cell killing, was 8Gy, confirming the high specific index of (67)Ga. These results demonstrate the feasibility of using MNT as a platform for single cell kill targeted radiotherapy by Auger electron emitters. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Radiolabeling and in vitro evaluation of 67Ga-NOTA-modular nanotransporter – A potential Auger electron emitting EGFR-targeted radiotherapeutic

    PubMed Central

    Koumarianou, Eftychia; Slastnikova, Tatiana A.; Pruszynski, Marek; Rosenkranz, Andrey A.; Vaidyanathan, Ganesan; Sobolev, Alexander S.; Zalutsky, Michael R.

    2014-01-01

    Introduction Modular nanotransporters (MNTs) are vehicles designed to transport drugs from the cell surface via receptor-mediated endocytosis and endosomal escape to nucleus. Hence their conjugation to Auger electron emitters, can cause severe cell killing, by nuclear localization. Herein we evaluate the use of MNT as a platform for targeted radiotherapy with 67Ga. Methods EGF was the targeting ligand on the MNT, and NOTA was selected for its radiolabeling with 67Ga. In the radiolabeling study we dealt with the precipitation of MNT (pI 5.7) at the labeling pH (4.5–5.5) of 67Ga. Cellular and nuclei uptake of 67Ga-NOTA-MNT by the A431 cell line was determined. Its specific cytotoxicity was compared to that of 67Ga-EDTA, 67Ga-NOTA-BSA and 67Ga-NOTA-hEGF, in A431 and U87MGWTT, cell lines, by clonogenic assay. Dosimetry studies were also performed. Results 67Ga-NOTA-MNT was produced with 90% yield and specific activity of 25.6 mCi/mg. The in vitro kinetics revealed an increased uptake over 24 h. 55% of the internalized radioactivity was detected in the nuclei at 1 h. The cytotoxicity of 67Ga-NOTA-MNT on A431 cell line was 17 and 385-fold higher when compared to non-specific 67Ga-NOTA-BSA and 67Ga-EDTA. While its cytotoxic potency was 13 and 72 – fold higher when compared to 67Ga-NOTA-hEGF in the A431 and the U87MGWTT cell lines, respectively, validating its nuclear localization. The absorbed dose, for 63% cell killing, was 9 Gy, confirms the high specific index of 67Ga. Conclusion These results demonstrate the feasibility of using MNT as a platform for single cell kill targeted radiotherapy by Auger electron emitters. PMID:24776093

  20. Self-powered radiation detector with conductive emitter support

    SciTech Connect

    Bauer, R.F.; Goldstein, N.P.; Playfoot, K.C.

    1981-05-12

    A more reliable self-powered radiation detector structure and method of manufacture is provided by a detector structure in which a relatively ductile centrally disposed conductive emitter wire supports and is in electrical contact with a generally tubular emitter electrode. The detector is fabricated by swaging and the ductile center wire insures that electrical discontinuities of the emitter are minimized.

  1. What is so super about super-emitters? Characterizing methane high emitters from natural gas infrastructure

    NASA Astrophysics Data System (ADS)

    Zavala Araiza, D.; Lyon, D. R.; Alvarez, R.; Harriss, R. C.; Palacios, V.; Hamburg, S.

    2015-12-01

    Methane emissions across the natural gas supply chain are dominated at any one time by a few high-emitters (super-emitters or fat-tail of the distribution), often underrepresented in published datasets used to construct emission inventories. Characterization of high-emitters is essential for improving emission estimates based on atmospheric data (top-down) and emission inventories (bottom-up). The population of high-emitters (e.g. 10-20% of sites that account for 80-90% of the emissions) is temporally and spatially dynamic. As a consequence, it is challenging to design sampling methods and construct estimates that accurately represent their frequency and magnitude of emissions. We present new methods to derive facility-specific emission distribution functions that explicitly integrate the influence of the relatively rare super-emitters. These methods were applied in the Barnett Shale region to construct a custom emission inventory that is then compared to top-down emission estimates for the region. We offer a methodological framework relevant to the design of future sampling campaigns, in which these high-emitters are seamlessly incorporated to representative emissions distributions. This framework can be applied to heterogeneous oil and gas production regions across geographies to obtain accurate regional emission estimates. Additionally, we characterize emissions relative to the fraction of a facility's total methane throughput; an effective metric to identify sites with excess emissions resulting from avoidable operating conditions, such as malfunctioning equipment (defined here as functional super-emitters). This work suggests that identifying functional super-emitters and correcting their avoidable operating conditions would result in significant emission reductions. However, due to their spatiotemporal dynamic behavior, achieving and maintaining uniformly low emissions across the entire population of sites will require mitigation steps (e.g. leak detection

  2. Facet engineering of high power single emitters

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Levi, Moshe; Shamay, Moshe; Tesler, Renana; Rappaport, Noam; Don, Yaroslav; Karni, Yoram; Schnitzer, Itzhak; Sicron, Noam; Shusterman, Sergey

    2011-03-01

    The ever increasing demand for high-power, high-reliability operation of single emitters at 9xx nm wavelengths requires the development of laser diodes with improved facet regions immune to both catastrophic and wear-out failure modes. In our study, we have evaluated several laser facet definition technologies in application to 90 micron aperture single emitters in asymmetric design (In)GaAs/AlGaAs based material emitting at 915, 925 and 980nm. A common epitaxy and emitter design makes for a straightforward comparison of the facet technologies investigated. Our study corroborates a clear trend of increasing difficulty in obtaining reliable laser operation from 980nm down to 915nm. At 980nm, one can employ dielectric facet passivation with a pre-clean cycle delivering a device lifetime in excess of 3,000 hours at increasing current steps. At 925nm, quantum-well intermixing can be used to define non-absorbing mirrors giving good device reliability, albeit with a large efficiency penalty. Vacuum cleaved emitters have delivered excellent reliability at 915nm, and can be expected to perform just as well at 925 and 980nm. Epitaxial regrowth of laser facets is under development and has yet to demonstrate an appreciable reliability improvement. Only a weak correlation between start-of-life catastrophic optical mirror damage (COMD) levels and reliability was established. The optimized facet design has delivered maximum powers in excess of 19 MW/sq.cm (rollover limited) and product-grade 980nm single emitters with a slope efficiency of >1 W/A and a peak efficiency of >60%. The devices have accumulated over 1,500 hours of CW operation at 11W. A fiber-coupled device emits 10W ex-fiber with 47% efficiency.

  3. Astrophysical Sources of Cosmic Rays and Related Measurements with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Correlation of the highest energy cosmic rays with nearby extragalactic objects in Pierre Auger Observatory data; (2) Discriminating potential astrophysical sources of the highest energy cosmic rays with the Pierre Auger Observatory; (3) Intrinsic anisotropy of the UHECR from the Pierre Auger Observatory; (4) Ultra-high energy photon studies with the Pierre Auger Observatory; (5) Limits on the flux of diffuse ultra high energy neutrinos set using the Pierre Auger Observatory; (6) Search for sidereal modulation of the arrival directions of events recorded at the Pierre Auger Observatory; (7) Cosmic Ray Solar Modulation Studies in the Pierre Auger Observatory; (8) Investigation of the Displacement Angle of the Highest Energy Cosmic Rays Caused by the Galactic Magnetic Field; (9) Search for coincidences with astrophysical transients in Pierre Auger Observatory data; and (10) An alternative method for determining the energy of hybrid events at the Pierre Auger Observatory.

  4. The Cosmic Ray Energy Spectrum and Related Measurements with the Pierre Auger Observatory

    SciTech Connect

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the cosmic ray energy spectrum above 10{sup 18} eV with the Pierre Auger Observatory; (2) The cosmic ray flux observed at zenith angles larger than 60 degrees with the Pierre Auger Observatory; (3) Energy calibration of data recorded with the surface detectors of the Pierre Auger Observatory; (4) Exposure of the Hybrid Detector of The Pierre Auger Observatory; and (5) Energy scale derived from Fluorescence Telescopes using Cherenkov Light and Shower Universality.

  5. Triple ionization spectra by coincidence measurements of double Auger decay: The case of OCS.

    PubMed

    Eland, J H D; Hochlaf, M; Linusson, P; Andersson, E; Hedin, L; Feifel, R

    2010-01-07

    By combining multiple electron coincidence detection with ionization by synchrotron radiation, we have obtained resolved spectra of the OCS(3+) ion created through the double Auger effect. The form of the spectra depends critically on the identity of the atom bearing the initial hole. High and intermediate level electron structure calculations lead to an assignment of the resolved spectrum from ionization via the S 2p hole. From the analysis it appears that the double Auger effect from closed shell molecules favors formation of doublet states over quartet states. Molecular field effects in the double Auger effect are similar to those in the single Auger effect in linear molecules.

  6. In situ observation on electron beam induced chemical vapor deposition by Auger electron spectroscopy

    SciTech Connect

    Matsui, S.; Mori, K.

    1987-08-31

    W deposition, using WF/sub 6/ gas source by electron beam induced surface reaction, has been studied by Auger electron spectroscopy. W Auger electron signals have been observed for WF/sub 6/ adlayer by Auger electron spectroscopy. Moreover, initial growth for W deposition has been observed in situ by Auger electron spectroscopy. As a result, it became clear that a growth rate for W deposition is proportional to WF/sub 6/ gas pressure and can be --1 A/min at 2 x 10/sup -7/ Torr.

  7. Relative extent of double and single Auger decay in molecules containing C, N and O atoms.

    PubMed

    Roos, A Hult; Eland, J H D; Andersson, J; Zagorodskikh, S; Singh, R; Squibb, R J; Feifel, R

    2016-09-14

    We show that the proportion of double Auger decay following creation of single 1s core holes in molecules containing C, N and O atoms is greater than usually assumed, amounting to about 10% of single Auger decay in many cases. It varies from molecule to molecule, where the size of the molecule has a positive correlation to the amount of double Auger decay. In neon, examined as a related benchmark, the proportion of double Auger decay is similar to that in methane, and is in the order of 5%.

  8. Normal Auger processes with ultrashort x-ray pulses in neon

    NASA Astrophysics Data System (ADS)

    Sullivan, Raymond; Jia, Junteng; Vázquez-Mayagoitia, Álvaro; Picón, Antonio

    2016-10-01

    Modern x-ray sources enable the production of coherent x-ray pulses with a pulse duration in the same order as the characteristic lifetimes of core-hole states of atoms and molecules. These pulses enable the manipulation of the core-hole population during Auger-decay processes, modifying the line shape of the electron spectra. In this work, we present a theoretical model to study those effects in neon. We identify effects in the Auger-electron-photoelectron coincidence spectrum due to the duration and intensity of the pulses. The normal Auger line shape is recovered in Auger-electron spectra integrated over all photoelectron energies.

  9. Spectral and Total Normal Emittance of Reusable Surface Insulation Materials

    NASA Technical Reports Server (NTRS)

    Kantsios, A. G.; Edwards, S. F.; Dicus, D. L.

    1973-01-01

    Measurements of spectral and total normal emittance have been made on three types of reusable external insulation materials proposed for space shuttles. Emittances were measured in the spectral range 1 to 15 micrometer at temperatures of 800 K and 1100 K using a radiometric measurement technique. Results indicated that the total normal emittance of these materials was less than 0.8 between 800 K and 1300 K. The total normal emittance decreased with increasing temperature. The three ceramic coating candidate materials exhibited a similar spectral emittance distribution.

  10. DEVELOPMENT OF EMITTANCE ANALYSIS SOFTWARE FOR ION BEAM CHARACTERIZATION

    SciTech Connect

    Padilla, M. J.; Liu, Y.

    2007-01-01

    Transverse beam emittance is a crucial property of charged particle beams that describes their angular and spatial spread. It is a fi gure of merit frequently used to determine the quality of ion beams, the compatibility of an ion beam with a given beam transport system, and the ability to suppress neighboring isotopes at on-line mass separator facilities. Generally a high quality beam is characterized by a small emittance. In order to determine and improve the quality of ion beams used at the Holifi eld Radioactive Ion beam Facility (HRIBF) for nuclear physics and nuclear astrophysics research, the emittances of the ion beams are measured at the off-line Ion Source Test Facilities. In this project, emittance analysis software was developed to perform various data processing tasks for noise reduction, to evaluate root-mean-square emittance, Twiss parameters, and area emittance of different beam fractions. The software also provides 2D and 3D graphical views of the emittance data, beam profi les, emittance contours, and RMS. Noise exclusion is essential for accurate determination of beam emittance values. A Self-Consistent, Unbiased Elliptical Exclusion (SCUBEEx) method is employed. Numerical data analysis techniques such as interpolation and nonlinear fi tting are also incorporated into the software. The software will provide a simplifi ed, fast tool for comprehensive emittance analysis. The main functions of the software package have been completed. In preliminary tests with experimental emittance data, the analysis results using the software were shown to be accurate.

  11. EMITTANCE GROWTH IN THE FEL RF-GUN

    SciTech Connect

    Novokhatski, Alexander

    2002-08-20

    A high brightness and low emittance is of crucial importance for the SASE-FEL at the TESLA Test Facility. Therefore a Photo-RF-Gun has been installed as particle source. Numerical simulations with codes like ASTRA [1] and MAFIA [2] show that the space charge dominated processes inside the RF-Gun contribute significantly to the emittance. In this paper we present the results of detailed studies with MAFIA TS2 which clarify the effects resulting in emittance growth for space charge dominated beams. It is shown that the resulting emittance can be minimized by changing the laser parameters like pulse length and spot size on the cathode. Additionally we present the concept of slice emittances which allows a more precise prediction of the real transverse emittance achievable with an emittance compensation scheme.

  12. Edge enhancement control in linear arrays of ungated field emitters

    NASA Astrophysics Data System (ADS)

    Harris, J. R.; Jensen, K. L.; Shiffler, D. A.

    2016-01-01

    In arrays of ungated field emitters, the field enhancement factor of each emitter decreases as the distance between the emitters decreases, an effect known as screening. At the edge of these arrays, emitters experience reduced screening, leading to higher field enhancement factors than emitters at the array center, causing nonuniform emission across the array. Here, we consider this effect in linear arrays of ungated field emitters spaced at distances comparable to their heights, which is the regime that generally maximizes their average current density. A Line Charge Model is used to assess the degree to which these edge effects propagate into the array interior, and to study the impact of varying the height, location, and tip radius of emitters at the ends of an array on the edge enhancement. It is shown that each of these techniques can accomplish this edge enhancement control, but each has advantages and disadvantages that will be discussed.

  13. Integrated compact optical vortex beam emitters.

    PubMed

    Cai, Xinlun; Wang, Jianwei; Strain, Michael J; Johnson-Morris, Benjamin; Zhu, Jiangbo; Sorel, Marc; O'Brien, Jeremy L; Thompson, Mark G; Yu, Siyuan

    2012-10-19

    Emerging applications based on optical beams carrying orbital angular momentum (OAM) will probably require photonic integrated devices and circuits for miniaturization, improved performance, and enhanced functionality. We demonstrate silicon-integrated optical vortex emitters, using angular gratings to extract light confined in whispering gallery modes with high OAM into free-space beams with well-controlled amounts of OAM. The smallest device has a radius of 3.9 micrometers. Experimental characterization confirms the theoretical prediction that the emitted beams carry exactly defined and adjustable OAM. Fabrication of integrated arrays and demonstration of simultaneous emission of multiple identical optical vortices provide the potential for large-scale integration of optical vortex emitters on complementary metal-oxide-semiconductor compatible silicon chips for wide-ranging applications.

  14. Ghost signals in Allison emittance scanners

    SciTech Connect

    Stockli, Martin P.; Leitner, M.; Moehs, D.P.; Keller, R.; Welton, R.F.; /SNS Project, Oak Ridge /Tennessee U.

    2004-12-01

    For over 20 years, Allison scanners have been used to measure emittances of low-energy ion beams. We show that scanning large trajectory angles produces ghost signals caused by the sampled beamlet impacting on an electric deflection plate. The ghost signal strength is proportional to the amount of beam entering the scanner. Depending on the ions, and their velocity, the ghost signals can have the opposite or the same polarity as the main beam signals. The ghost signals cause significant errors in the emittance estimates because they appear at large trajectory angles. These ghost signals often go undetected because they partly overlap with the real signals, are mostly below the 1% level, and often hide in the noise. A simple deflection plate modification is shown to reduce the ghost signal strength by over 99%.

  15. Photonic Crystal Emitters for Thermophotovoltaic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Stelmakh, Veronika; Chan, Walker R.; Ghebrebrhan, Michael; Soljacic, Marin; Joannopoulos, John D.; Celanovic, Ivan

    2015-12-01

    This paper reports the design, fabrication, and characterization of 2D photonic crystal (PhC) thermal emitters for a millimeter-scale hydrocarbon TPV microgenerator as a possible replacement for batteries in portable microelectronics, robotics, etc. In our TPV system, combustion heats a PhC emitter to incandescence and the resulting radiation is converted by a low-bandgap TPV cell. The PhC tailors the photonic density of states to produce spectrally confined thermal emission that matches the bandgap of the TPV cell, enabling high heat-to-electricity conversion efficiency. The work builds on a previously developed fabrication process to produce a square array of cylindrical cavities in a metal substrate. We will present ongoing incremental improvements in the optical and thermo-mechanical properties, the fabrication process, and the system integration, as recently combined with fabrication using novel materials, such as sputtered coatings, to enable a monolithic system.

  16. Computing Eigen-Emittances from Tracking Data

    SciTech Connect

    Alexahin, Y.

    2014-09-18

    In a strongly nonlinear system the particle distribution in the phase space may develop long tails which contribution to the covariance (sigma) matrix should be suppressed for a correct estimate of the beam emittance. A method is offered based on Gaussian approximation of the original particle distribution in the phase space (Klimontovich distribution) which leads to an equation for the sigma matrix which provides efficient suppression of the tails and cannot be obtained by introducing weights. This equation is easily solved by iterations in the multi-dimensional case. It is also shown how the eigen-emittances and coupled optics functions can be retrieved from the sigma matrix in a strongly coupled system. Finally, the developed algorithm is applied to 6D ionization cooling of muons in HFOFO channel.

  17. FIrpic: archetypal blue phosphorescent emitter for electroluminescence.

    PubMed

    Baranoff, Etienne; Curchod, Basile F E

    2015-05-14

    FIrpic is the most investigated bis-cyclometallated iridium complex in particular in the context of organic light emitting diodes (OLEDs) because of its attractive sky-blue emission, high emission efficiency, and suitable energy levels. In this Perspective we review the synthesis, structural characterisations, and key properties of this emitter. We also survey the theoretical studies and summarise a series of selected monochromatic electroluminescent devices using FIrpic as the emitting dopant. Finally we highlight important shortcomings of FIrpic as an emitter for OLEDs. Despite the large body of work dedicated to this material, it is manifest that the understanding of photophysical and electrochemical processes are only broadly understood mainly because of the different environment in which these properties are measured, i.e., isolated molecules in solvent vs. device.

  18. Development of arrayed microcolumns and field emitters

    NASA Astrophysics Data System (ADS)

    Kim, Ho Seob; Bok Lee, Young; Choi, Sung Woong; Kim, Hyung Woo; Kim, Dae-Wook; Ahn, Seung Joon; Oh, Tae Sik; Song, Yoon-Ho; Chon Park, Byong; Jong Lim, Sun

    2017-06-01

    Electron beam devices have been widely used for inspection or lithography processes. The multibeam technology based on arrayed microcolumns has been developed to overcome the low throughput issue. However, the multicolumn system has some drawbacks such as complexity, electron optics, and electron source. The first drawback is the difficulty in multicolumn assembly. In particular, the alignment process of a source lens and a tip requires sophisticated techniques. The second drawback is that the e-beam characteristics of microcolumns constituting the multicolumn differ from column to column. To solve the first drawback, a sub-5-nm-resolution probe beam optic design with a simple structure and a two-dimensional carbon nanotube (2D-CNT) electron emitter instead of the widely used tungsten field emitter tip have been studied.

  19. Front contact solar cell with formed emitter

    DOEpatents

    Cousins, Peter John

    2014-11-04

    A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.

  20. Front contact solar cell with formed emitter

    DOEpatents

    Cousins, Peter John [Menlo Park, CA

    2012-07-17

    A bipolar solar cell includes a backside junction formed by an N-type silicon substrate and a P-type polysilicon emitter formed on the backside of the solar cell. An antireflection layer may be formed on a textured front surface of the silicon substrate. A negative polarity metal contact on the front side of the solar cell makes an electrical connection to the substrate, while a positive polarity metal contact on the backside of the solar cell makes an electrical connection to the polysilicon emitter. An external electrical circuit may be connected to the negative and positive metal contacts to be powered by the solar cell. The positive polarity metal contact may form an infrared reflecting layer with an underlying dielectric layer for increased solar radiation collection.

  1. Is there life after thermal emitters?

    NASA Astrophysics Data System (ADS)

    Malyutenko, V.

    2007-04-01

    In this report, we examine whether photonic IR emitters are able to compete with advanced thermal microemitter technology in testing and stimulating IR sensors, including forward-looking IR missile warning systems, IR search-and-track devices, and missile seekers. We consider fundamentals, technology, and parameters of photonic devices as well as their pros and cons in respect to thermal emitters. In particular, we show that photonic devices can from platform for next generation of multi-spectral and hyper-spectral dynamic scene simulation devices operating inside MWIR and LWIR bands with high spectral output density and able to simulate dynamically cold scenes (without cryogenic cooling) and low observable with very high frame rate.

  2. Reverse Emittance Exchange for Muon Colliders

    SciTech Connect

    V. Ivanov, A. Afanasev, C.M. Ankenbrandt, R.P. Johnson, G.M. Wang, S.A. Bogacz, Y.S. Derbenev

    2009-05-01

    Muon collider luminosity depends on the number of muons in the storage ring and on the transverse size of the beams in collision. Ionization cooling as it is currently envisioned will not cool the beam sizes sufficiently well to provide adequate luminosity without large muon intensities. Six-dimensional cooling schemes will reduce the longitudinal emittance of a muon beam so that smaller high frequency RF cavities can be used for later stages of cooling and for acceleration. However, the bunch length at collision energy is then shorter than needed to match the interaction region beta function. New ideas to shrink transverse beam dimensions by lengthening each bunch will help achieve high luminosity in muon colliders. Analytic expressions for the reverse emittance exchange mechanism were derived, including a new resonant method of beam focusing.

  3. Valorisation of forestry waste by pyrolysis in an auger reactor

    SciTech Connect

    Puy, Neus; Murillo, Ramon; Navarro, Maria V.; Lopez, Jose M.; Rieradevall, Joan; Fowler, G.; Aranguren, Ignacio; Garcia, Tomas; Bartroli, Jordi; Mastral, Ana M.

    2011-06-15

    Pyrolysis of forestry waste has been carried out in an auger reactor to study the influence of operational variables on the reactor performance and the properties of the related products. Pine woodchips were used for the first time as raw material and fed continuously into the reactor. Ten experiments were carried out under inert atmosphere at: (i) different reaction temperature (1073, 973, 873, 823 and 773 K); (ii) different solid residence time (5, 3, 2 and 1.5 min); and (iii) different biomass flow rate (3.9, 4.8 and 6.9 kg/h). Results show that the greatest yields for liquid production (59%) and optimum product characterisation were obtained at the lowest temperature studied (773 K) and applying solid residence times longer than 2 min. Regarding bio-oil properties, GC/MS qualitative identification show that the most abundant compounds are volatile polar compounds, phenols and benzenediols; and very few differences can be observed among the samples regardless of the pyrolysis operating conditions. On the whole, experimental results demonstrate that complete reaction of forest woodchips can be achieved in an auger reactor in most of the experimental conditions tested. Moreover, this study presents the initial steps for the future scaling up of the auger reactor with the aim of converting it into a mobile plant which will be able to remotely process biomass such as energy crops, forestry and agricultural wastes to obtain bio-oil that, in turn, can be used as energy vector to avoid high transport costs.

  4. Valorisation of forestry waste by pyrolysis in an auger reactor.

    PubMed

    Puy, Neus; Murillo, Ramón; Navarro, María V; López, José M; Rieradevall, Joan; Fowler, G; Aranguren, Ignacio; García, Tomás; Bartrolí, Jordi; Mastral, Ana M

    2011-06-01

    Pyrolysis of forestry waste has been carried out in an auger reactor to study the influence of operational variables on the reactor performance and the properties of the related products. Pine woodchips were used for the first time as raw material and fed continuously into the reactor. Ten experiments were carried out under inert atmosphere at: (i) different reaction temperature (1073, 973, 873, 823 and 773 K); (ii) different solid residence time (5, 3, 2 and 1.5 min); and (iii) different biomass flow rate (3.9, 4.8 and 6.9 kg/h). Results show that the greatest yields for liquid production (59%) and optimum product characterisation were obtained at the lowest temperature studied (773 K) and applying solid residence times longer than 2 min. Regarding bio-oil properties, GC/MS qualitative identification show that the most abundant compounds are volatile polar compounds, phenols and benzenediols; and very few differences can be observed among the samples regardless of the pyrolysis operating conditions. On the whole, experimental results demonstrate that complete reaction of forest woodchips can be achieved in an auger reactor in most of the experimental conditions tested. Moreover, this study presents the initial steps for the future scaling up of the auger reactor with the aim of converting it into a mobile plant which will be able to remotely process biomass such as energy crops, forestry and agricultural wastes to obtain bio-oil that, in turn, can be used as energy vector to avoid high transport costs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Interatomic Auger rates for the sodium fluoride crystal

    SciTech Connect

    Green, T.A.; Jennison, D.R.

    1987-10-15

    Interatomic Auger rates for the NaF crystal are calculated for initial 1s, 2s, and 2p holes in the Na/sup +/ ion. The crystal is simulated by a (NaF/sub 6/)/sup 5-/ cluster embedded in a large number of point ions, and the one-electron orbitals are obtained from restricted Hartree-Fock calculations of the initial state. The continuum-electron orbital is obtained from the Coulomb potential for a spherically averaged superposition of atomic charge densities for the initial state, and exchange is treated by the method of Riley and Truhlar. The continuum orbital is orthogonalized to the occupied molecular orbitals. The calculated Na(KLL) rate is about 20% greater than the experimental value. The calculated interatomic Auger widths for the transitions Na(1s)Na(2p)F(2p), Na(2s)Na(2p)F(2p), and Na(2p)F(2p)F(2p)' (following the notation of J. A. D. Matthew and Y. Komninos, Surf. Sci. 53, 716 (1975)) are 0.001 73, 0.641, and 0.153 eV, respectively. For comparison, the width of the Na(KLL) Auger transition is close to 0.26 eV. All three interatomic transitions have been identified by Citrin, Rowe, and Christman. Widths for the transitions Na(1s)Na(2p)F(2p) and Na(2p)F(2p)F(2p)' can be inferred from experimental data. Theory and experiment agree to within 50%. This represents a considerable improvement over previous theoretical treatments.

  6. Interatomic Auger rates for the sodium fluoride crystal

    NASA Astrophysics Data System (ADS)

    Green, T. A.; Jennison, D. R.

    1987-10-01

    Interatomic Auger rates for the NaF crystal are calculated for initial 1s, 2s, and 2p holes in the Na+ ion. The crystal is simulated by a (NaF6)5- cluster embedded in a large number of point ions, and the one-electron orbitals are obtained from restricted Hartree-Fock calculations of the initial state. The continuum-electron orbital is obtained from the Coulomb potential for a spherically averaged superposition of atomic charge densities for the initial state, and exchange is treated by the method of Riley and Truhlar. The continuum orbital is orthogonalized to the occupied molecular orbitals. The calculated Na(KLL) rate is about 20% greater than the experimental value. The calculated interatomic Auger widths for the transitions Na(1s)Na(2p)F(2p), Na(2s)Na(2p)F(2p), and Na(2p)F(2p)F(2p)' [following the notation of J. A. D. Matthew and Y. Komninos, Surf. Sci. 53, 716 (1975)] are 0.001 73, 0.641, and 0.153 eV, respectively. For comparison, the width of the Na(KLL) Auger transition is close to 0.26 eV. All three interatomic transitions have been identified by Citrin, Rowe, and Christman. Widths for the transitions Na(1s)Na(2p)F(2p) and Na(2p)F(2p)F(2p)' can be inferred from experimental data. Theory and experiment agree to within 50%. This represents a considerable improvement over previous theoretical treatments.

  7. RF Emitter Tracking and Intent Assessment

    DTIC Science & Technology

    2013-03-21

    the US Navy. The paper communicated that the Navy requires accurate detecting , locating and tracking of mobile RF emitters. The system design used...x3 are voltage readings taken from different locations in the substation . PA and PB represent the probabilities of a real fault and fake fault...Borghetti, “A Review of Anomaly Detection in Automated Surveillance,” IEEE Transactions on Systems , Man, and Cybernetics, Part C: Applications and Reviews

  8. Controlled emittance blow up in the Tevatron

    SciTech Connect

    Tan, C.Y.; Steimel, J.; /Fermilab

    2009-04-01

    We have designed and commissioned a system which blows up the transverse emittance of the anti-proton beam without affecting the proton beam. It consists of a bandwidth limited noise source centered around the betatron tune, a power amplifier and a directional stripline kicker. The amount of blow up is controlled by the amount of energy delivered to the anti-protons betatron bands.

  9. Complementary methods of transverse emittance measurement

    SciTech Connect

    Zagel, James; Hu, Martin; Jansson, Andreas; Thurman-Keup, Randy; Yan, Ming-Jen; /Fermilab

    2008-05-01

    Several complementary transverse emittance monitors have been developed and used at the Fermilab accelerator complex. These include Ionization profile Monitors (IPM), Flying Wires, Schottky detectors and a Synchrotron Light Monitor (Synchlite). Mechanical scrapers have also been used for calibration purposes. This paper describes the various measurement devices by examining their basic features, calibration requirements, systematic uncertainties, and applications to collider operation. A comparison of results from different kinds of measurements is also presented.

  10. Emittance of a Field Emission Electron Source

    DTIC Science & Technology

    2010-01-05

    mode within the wiggler in order for the laser threshold to be reached. The mode is characterized by a waist radius w and a divergence , the product...the field line red or curved compared to a massive particle trajectory blue or straight. The field lines originate on the surface at s ,zs and...emitter surface s ,zs and along the evalu- ation plane h ,zh. The equivalent sphere characterized by a , is also shown. The red curved line

  11. ALMA deep field in SSA22: Blindly detected CO emitters and [C II] emitter candidates

    NASA Astrophysics Data System (ADS)

    Hayatsu, Natsuki H.; Matsuda, Yuichi; Umehata, Hideki; Yoshida, Naoki; Smail, Ian; Swinbank, A. Mark; Ivison, Rob; Kohno, Kotaro; Tamura, Yoichi; Kubo, Mariko; Iono, Daisuke; Hatsukade, Bunyo; Nakanishi, Kouichiro; Kawabe, Ryohei; Nagao, Tohru; Inoue, Akio K.; Takeuchi, Tsutomu T.; Lee, Minju; Ao, Yiping; Fujimoto, Seiji; Izumi, Takuma; Yamaguchi, Yuki; Ikarashi, Soh; Yamada, Toru

    2017-06-01

    We report the identification of four millimeter line-emitting galaxies with the Atacama Large Milli/submillimeter Array (ALMA) in SSA22 Field (ADF22). We analyze the ALMA 1.1-mm survey data, with an effective survey area of 5 arcmin2, frequency ranges of 253.1-256.8 and 269.1-272.8 GHz, angular resolution of 0{^''.}7 and rms noise of 0.8 mJy beam-1 at 36 km s-1 velocity resolution. We detect four line-emitter candidates with significance levels above 6σ. We identify one of the four sources as a CO(9-8) emitter at z = 3.1 in a member of the proto-cluster known in this field. Another line emitter with an optical counterpart is likely a CO(4-3) emitter at z = 0.7. The other two sources without any millimeter continuum or optical/near-infrared counterpart are likely to be [C II] emitter candidates at z = 6.0 and 6.5. The equivalent widths of the [C II] candidates are consistent with those of confirmed high-redshift [C II] emitters and candidates, and are a factor of 10 times larger than that of the CO(9-8) emitter detected in this search. The [C II] luminosity of the candidates are 4-7 × 108 L⊙. The star formation rates (SFRs) of these sources are estimated to be 10-20 M⊙ yr-1 if we adopt an empirical [C II] luminosity-SFR relation. One of them has a relatively low S/N ratio, but shows features characteristic of emission lines. Assuming that at least one of the two candidates is a [C II] emitter, we derive a lower limit of [C II]-based star formation rate density (SFRD) at z ∼ 6. The resulting value of >10-2 M⊙ yr-1 Mpc-3 is consistent with the dust-uncorrected UV-based SFRD. Future millimeter/submillimeter surveys can be used to detect a number of high-redshift line emitters, with which to study the star formation history in the early universe.

  12. Detection of very inclined showers with the Auger Observatory

    SciTech Connect

    Nellen, Lukas; /Mexico U., ICN

    2005-07-01

    The Pierre Auger Observatory can detect air showers with high efficiency at large zenith angles with both the fluorescence and surface detectors. Since half the available solid angle corresponds to zeniths between 60 and 90 degrees, a large number of inclined events can be expected and are indeed observed. In this paper, we characterize the inclined air showers detected by the Observatory and we present the aperture for inclined showers and an outlook of the results that can be obtained in future studies of the inclined data set.

  13. Resonant Auger for the detection of quadrupolar transitions

    SciTech Connect

    Danger, J.; Le Fevre, P.; Chandesris, D.; Magnan, H.; Jupille, J.; Bourgeois, S.; Eickhoff, T.; Drube, W.

    2003-01-24

    Quadrupolar transitions can play an important role in X-ray absorption spectroscopy, especially when it is used for magnetic measurements, like in X-ray Magnetic Circular Dichroism or Resonant Magnetic Scattering. We show here that resonantly excited Ti KL2,3L2,3 Auger spectra of TiO2 (110) carry a clear signature of quadrupolar transitions from the 1s to localized eg and t2g d-like states. The quadrupolar nature of the observed additional spectator lines are clearly demonstrated by their angular dependence, and their intensity is used to locate and quantify the quadrupolar transitions in the absorption spectrum.

  14. Cutting assembly including expanding wall segments of auger

    DOEpatents

    Treuhaft, Martin B.; Oser, Michael S.

    1983-01-01

    A mining auger comprises a cutting head carried at one end of a tubular shaft and a plurality of wall segments which in a first position thereof are disposed side by side around said shaft and in a second position thereof are disposed oblique to said shaft. A vane projects outwardly from each wall segment. When the wall segments are in their first position, the vanes together form a substantially continuous helical wall. A cutter is mounted on the peripheral edge of each of the vanes. When the wall segments are in their second position, the cutters on the vanes are disposed radially outward from the perimeter of the cutting head.

  15. Observation and Control of Laser-Enabled Auger Decay

    NASA Astrophysics Data System (ADS)

    Iablonskyi, D.; Ueda, K.; Ishikawa, K. L.; Kheifets, A. S.; Carpeggiani, P.; Reduzzi, M.; Ahmadi, H.; Comby, A.; Sansone, G.; Csizmadia, T.; Kuehn, S.; Ovcharenko, E.; Mazza, T.; Meyer, M.; Fischer, A.; Callegari, C.; Plekan, O.; Finetti, P.; Allaria, E.; Ferrari, E.; Roussel, E.; Gauthier, D.; Giannessi, L.; Prince, K. C.

    2017-08-01

    Single-photon laser-enabled Auger decay (spLEAD) is predicted theoretically [B. Cooper and V. Averbukh, Phys. Rev. Lett. 111, 083004 (2013), 10.1103/PhysRevLett.111.083004] and here we report its first experimental observation in neon. Using coherent, bichromatic free-electron laser pulses, we detect the process and coherently control the angular distribution of the emitted electrons by varying the phase difference between the two laser fields. Since spLEAD is highly sensitive to electron correlation, this is a promising method for probing both correlation and ultrafast hole migration in more complex systems.

  16. Performance of the Pierre Auger Observatory Surface Detector

    NASA Astrophysics Data System (ADS)

    Suomijǎrvi, T.

    The surface detector of the Pierre Auger Observatory will consist of 1600 water Cherenkov tanks sampling ground particles of air showers produced by energetic cosmic rays. The construction of the array is nearly completed and a large number of detectors have been operational for more than three years. In this paper the performance of different components of the detectors are discussed. The accuracy of the signal measurement and the trigger stability are presented. The performance of the solar power system and other hardware as well as the water purity and its long-term stability are discussed.

  17. Performance of the Pierre Auger Observatory Surface Detector

    SciTech Connect

    Collaboration, Tiina Suomijarvi for the Pierre Auger

    2007-09-01

    The Surface Detector of the Pierre Auger Observatory will consist of 1600 water Cherenkov tanks sampling ground particles of air showers produced by energetic cosmic rays. The arrival times are obtained from GPS and power is provided by solar panels. The construction of the array is nearly completed and a large number of detectors has been operational for more than three years. In this paper the performance of different components of the detectors are discussed. The accuracy of the signal measurement and the trigger stability are presented. The performance of the solar power system and other hardware, as well as the water purity and its long-term stability are discussed.

  18. Surface detector array for the Pierre Auger observatory

    NASA Astrophysics Data System (ADS)

    Salazar, H.; Garipov, G. K.; Khrenov, B. A.; Martínez, O.; Moreno, E.; Villaseñor, L.; Zepeda, A.

    2001-05-01

    The Pierre Auger international collaboration will install two observatories, one in the southern hemisphere and other in the northern hemisphere. Each observatory will consist of two different subsystem: a surface detector array of about 1600 water Cherenkov detectors (WCD) and a set of fluorescence eyes to measure the longitudinal development of air showers. The large area covered by the surface detectors requires efficient calibration and monitoring methods that can be implemented remotely. We present several complementary methods to calibrate and monitor the performance of the individual surface detector stations. We also present some results of the studies made with a full size prototype tank in Puebla, Mexico and in Malargue, Argentina. .

  19. 27. MASCOT BRICK AUGER AND No 1 COMBINATION CUTTING TABLE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. MASCOT BRICK AUGER AND No 1 COMBINATION CUTTING TABLE MANUFACTURED BY THE AMERICAN CLAY MACHINERY CO. OF BUCYRUS, OHIO. IT WAS PURCHASED IN 1903. AND USED AT THE FIRST MORAVIAN POTTERY AND TILE WORKS BEFORE BEING MOVED TO ITS PRESENT LOCATION IN 1912. IT IS USED TO SCREEN STONES FROM RAW CLAY AND INCORPORATE WATER TO A PROPER WORKING CONSISTENCY. IT IS NOW POWERED BY AN ELECTRIC MOTOR INSTALLED IN 1990. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  20. Observatorio Pierre Auger: motivación y estado actual

    NASA Astrophysics Data System (ADS)

    Rovero, A. C.; Etchegoyen, A.; García, B.

    The Pierre Auger Observatory is aiming to understand the origin, nature and acceleration mechanisms of the most energetic cosmic rays (E>10 E18 eV). It will consist of one hybrid detector in each hemisphere, giving a total acceptance of 14200 km2 sr. The southern observatory is being constructed in Malargue, Mendoza, Argentina, and will be finished in 2006. No final statement can be made so far about any feature in the most energetic part of the spectrum. However, good candidate events were observed to have a primary energy of about 10 E20 eV.

  1. Surface segregation in titanium as monitored by Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Khan, I. H.

    1973-01-01

    Investigation of the surface diffusion and segregation of bulk impurities in titanium single crystals under well-defined and controlled experimental conditions. It is shown that an atomically clean titanium single-crystal surface can be obtained by argon ion bombardment within the temperature range from 700 to 800 C. It is demonstrated by Auger electron spectroscopy that, if such clean surfaces are subjected to thermal treatment, bulk impurities, especially sulfur, diffuse out to the crystal surface, and that the rate of surface segregation increases with increasing temperature.

  2. Auger spectroscopy of HCl interaction with Al at low pressures

    NASA Technical Reports Server (NTRS)

    Lassiter, W. S.

    1975-01-01

    The purpose of the present study was to determine some adsorption characteristics of HCl with partially clean polycrystalline Al by Auger electron spectroscopy. The adsorption was found to exhibit a Freundlich-type behavior pattern in which the number of molecules adsorbed varied with HCl pressure linearly on a log-log plot. Assuming that the adsorption behaves according to the Clausius-Clapeyron equation, the isosteric heat of adsorption increases with coverage at low pressures, appearing to approach a constant value of 4-5 kcal/mole.

  3. Surface segregation in titanium as monitored by Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Khan, I. H.

    1973-01-01

    Investigation of the surface diffusion and segregation of bulk impurities in titanium single crystals under well-defined and controlled experimental conditions. It is shown that an atomically clean titanium single-crystal surface can be obtained by argon ion bombardment within the temperature range from 700 to 800 C. It is demonstrated by Auger electron spectroscopy that, if such clean surfaces are subjected to thermal treatment, bulk impurities, especially sulfur, diffuse out to the crystal surface, and that the rate of surface segregation increases with increasing temperature.

  4. IFIN - HH contribution at the Pierre Auger observatory

    NASA Astrophysics Data System (ADS)

    Brancus, I. M.; Saftoiu, A.

    2017-06-01

    Since 2000, in collaboration with KIT, Germany, the research of Astroparticle Physics has developed in IFIN-HH Bucharest. Romanian researchers participated in large international experiments, KASCADE Grande and LOPES, for investigating cosmic rays. New experimental devices have been built in IFIN-HH Bucharest for measuring the cosmic ray muons. Based on the experience and results gained over that time, Romanian researchers became part of the Pierre Auger Collaboration, the largest complex experiment for the investigation of Extensive Air Showers. The contribution of IFIN-HH is focused on the studies of cosmic rays using radio antennae and the measuring of cosmic muons using detectors based on new technology.

  5. Aperture calculation of the Pierre Auger Observatory surface detector

    SciTech Connect

    Allard, D.; Allekotte, I.; Armengaud, E.; Aublin, J.; Bertou, Xavier; Chou, A.; Ghia, P.L.; Gomez Berisso, M.; Hamilton, J.C.; Lhenry-Yvon, I.; Medina, C.; Navarra, G.; Parizot, E.; Tripathi, A.

    2005-08-01

    We determine the instantaneous aperture and integrated exposure of the surface detector of the Pierre Auger Observatory, taking into account the trigger efficiency as a function of the energy, arrival direction (with zenith angle lower than 60 degrees) and nature of the primary cosmic-ray. We make use of the so-called Lateral Trigger Probability function (or LTP) associated with an extensive air shower, which summarizes all the relevant information about the physics of the shower, the water tank Cherenkov detector, and the triggers.

  6. High Spatial Resolution Auger Spectroscopy and Nucleation and Growth Studies of SILVER/SILICON(100)

    NASA Astrophysics Data System (ADS)

    Luo, Frank C. H.

    1990-01-01

    The ability to analyse the composition of a sample at high spatial resolution using Auger Electron Spectroscopy is very desirable for both industrial and academic research. The spatial resolution of the traditional Auger instrument is typically limited by the incident beam size to the range of 0.1-1 mum. This dissertation reports the efforts of construction, testing and utilizing a new Auger spectrometer with a nanometer incident probe in a scanning transmission electron microscopy (STEM). In order to use the 100 keV electron beam of the STEM for the Auger experiment, a low energy electron beam deflection system was designed and constructed. The testing of such deflection system and the spectrometer, both in a test chamber with different hardware configuration and in the microscope, was very extensive. Both Auger spectra and images can be obtained in the microscope with excellent energy resolution in a relatively short time. Quantitative analysis of the data showed a spatial resolution of less than 10 nm was achieved with a good collection efficiency. More quantitative work was carried on the Silver/Silicon(100) system as the application of the Auger instrument. Nucleation and growth phenomena of Ag on Si at both room and elevated temperatures was studied with the microscope operating both in Auger and scanning electron microscopy (SEM) mode. Suggestions for the further improvement of the Auger instrument and the Ag/Si(100) case study are made.

  7. Emissivity Tuned Emitter for RTPV Power Sources

    SciTech Connect

    Carl M. Stoots; Robert C. O'Brien; Troy M. Howe

    2012-03-01

    Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heat to electricity and are inherently inefficient ({approx} 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size

  8. Identification of Auger electron heating and inverse Auger effect in experiments irradiating solids with XUV free electron laser radiation at intensities larger than 1016 W/cm2

    NASA Astrophysics Data System (ADS)

    Rosmej, Frank B.; Petitdemange, Frédérick; Galtier, E.

    2011-09-01

    We present simulations that allow studying Auger heating and the subsequent evolution of the radiation emission of near solid density matter. Particular emphasize is paid to the multi-charge state inverse Auger-effect in dense plasmas which is proposed to explain the target emission when the conduction band at solid density becomes more atomic like as energy is transferred from the electrons to the ions. Simulations are discussed along with the first available experimental data.

  9. Auger analysis of films formed on metals in sliding contact with halogenated polymers

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1974-01-01

    The use of Auger electron spectroscopy (AES) to search for transferred polymer must contend with the fact that there has been no published work on Auger analysis of polymers. Since this is a new area for AES, the Auger spectra of polymers and of halogenated polymers in particular is discussed. It is shown that the Auger spectra of halogenated polymers have certain characteristics that permit an assessment of whether a polymeric transfer film has been established by sliding contact. The discussion is general and the concepts should be useful in considering the Auger analysis of any polymer. The polymers chosen for this study are the halogenated polymers polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polychlorotrifluorethylene (PCTFE).

  10. Angular correlation between photoelectrons and auger electrons from K-shell ionization of neon.

    PubMed

    Landers, A L; Robicheaux, F; Jahnke, T; Schöffler, M; Osipov, T; Titze, J; Lee, S Y; Adaniya, H; Hertlein, M; Ranitovic, P; Bocharova, I; Akoury, D; Bhandary, A; Weber, Th; Prior, M H; Cocke, C L; Dörner, R; Belkacem, A

    2009-06-05

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  11. Angular Correlation between Photoelectrons and Auger Electrons from K-Shell Ionization of Neon

    SciTech Connect

    Landers, A. L.; Robicheaux, F.; Bhandary, A.; Jahnke, T.; Schoeffler, M.; Titze, J.; Akoury, D.; Doerner, R.; Osipov, T.; Lee, S. Y.; Adaniya, H.; Hertlein, M.; Weber, Th.; Prior, M. H.; Belkacem, A.; Ranitovic, P.; Bocharova, I.; Cocke, C. L.

    2009-06-05

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  12. Angular Correlation between Photoelectrons and Auger Electrons from K-Shell Ionization of Neon

    NASA Astrophysics Data System (ADS)

    Landers, A. L.; Robicheaux, F.; Jahnke, T.; Schöffler, M.; Osipov, T.; Titze, J.; Lee, S. Y.; Adaniya, H.; Hertlein, M.; Ranitovic, P.; Bocharova, I.; Akoury, D.; Bhandary, A.; Weber, Th.; Prior, M. H.; Cocke, C. L.; Dörner, R.; Belkacem, A.

    2009-06-01

    We have used cold target recoil ion momentum spectroscopy to study the continuum correlation between the photoelectron of core-photoionized neon and the subsequent Auger electron. We observe a strong angular correlation between the two electrons. Classical trajectory Monte Carlo calculations agree quite well with the photoelectron energy distribution that is shifted due to the potential change associated with Auger decay. However, a striking discrepancy results in the distribution of the relative angle between Auger and photoelectron. The classical model predicts a shift in photoelectron flux away from the Auger emission direction, and the data strikingly reveal that the flux is lost rather than diverted, indicating that the two-step interpretation of photoionization followed by Auger emission is insufficient to fully describe the core-photoionization process.

  13. Time-domain ab initio study of Auger and phonon-assisted auger processes in a semiconductor quantum dot.

    PubMed

    Hyeon-Deuk, Kim; Prezhdo, Oleg V

    2011-04-13

    We developed time-domain ab initio simulation of Auger phenomena, including multiple exciton generation (MEG) and recombination (MER). It is the first approach describing phonon-assisted processes and early dynamics. MEG starts below the electronic threshold, strongly accelerating with energy. Ligands are particularly important to phonon-assisted MEG, which therefore can be probed with infrared spectroscopy. Short-time gaussian component gives 5-10% of MEG, justifying rate theories that assume exponential dynamics. MER is preceded by electron-phonon relaxation to low energies.

  14. Wavelength locking of single emitters and multi-emitter modules: simulation and experiments

    NASA Astrophysics Data System (ADS)

    Yanson, Dan; Rappaport, Noam; Peleg, Ophir; Berk, Yuri; Dahan, Nir; Klumel, Genady; Baskin, Ilya; Levy, Moshe

    2016-03-01

    Wavelength-stabilized high-brightness single emitters are commonly used in fiber-coupled laser diode modules for pumping Yb-doped lasers at 976 nm, and Nd-doped ones at 808 nm. We investigate the spectral behavior of single emitters under wavelength-selective feedback from a volume Bragg (or hologram) grating (VBG) in a multi-emitter module. By integrating a full VBG model as a multi-layer thin film structure with commercial raytracing software, we simulated wavelength locking conditions as a function of beam divergence and angular alignment tolerances. Good correlation between the simulated VBG feedback strength and experimentally measured locking ranges, in both VBG misalignment angle and laser temperature, is demonstrated. The challenges of assembling multi-emitter modules based on beam-stacked optical architectures are specifically addressed, where the wavelength locking conditions must be achieved simultaneously with high fiber coupling efficiency for each emitter in the module. It is shown that angular misorientation between fast and slow-axis collimating optics can have a dramatic effect on the spectral and power performance of the module. We report the development of our NEON-S wavelength-stabilized fiber laser pump module, which uses a VBG to provide wavelength-selective optical feedback in the collimated portion of the beam. Powered by our purpose-developed high-brightness single emitters, the module delivers 47 W output at 11 A from an 0.15 NA fiber and a 0.3 nm linewidth at 976 nm. Preliminary wavelength-locking results at 808 nm are also presented.

  15. The Mexican participation at the Pierre Auger Observatory: Recent results

    NASA Astrophysics Data System (ADS)

    Román, S.; Alcaráz, F.; Cantoral, E.; Castro, J.; Cordero, A.; Fernández, A.; López, R.; Pacheco, C.; Rubín, M.; Salazar, H.; Valdés, J.; Vargas, M.; Villaseñor, L.; Zepeda, A.

    1998-02-01

    In this work we present the participations of the Mexican group at development of the Pierre Auger Observatory. We have been working in both parts of the hybrid proposed for the Auger detector, the fluorescence and the surface detectors. In the part of fluorescence, we have analyzed the resolution of the Hi-Res optical design of the fluorescence detector observatory. We have found a heterogeneus image resolution. We propose to use a lensless Schmidt camera (with spherical image surface) to duplicate the field of view to 30×30 degrees and simultaneously guarantee a resolution of one degree over of the whole field of view. By the Surface Detector, a water Čerenkov detector (WCD) prototype of reduced dimensions (cylinder 1.54 diameter filled with purified water up to 1.20 m high) is used to obtain preliminary experimental results that validate the concept of remote calibration and monitoring of WCDs. We use muons that stop and decay inside the WCD and, in a complementary way, muons that croos the WCD. We used a moun telescope trigger in order to study the charge distribution of vertical muons, their pulse amplitude decay and the Cerenkov light attenuation length of those secondary cosmic muons we include the bacteria population content for the four months of operation to validate the monitoring method.

  16. Ultrahigh Energy Neutrinos at the Pierre Auger Observatory

    DOE PAGES

    Abreu, P.; Aglietta, M.; Ahlers, M.; ...

    2013-01-01

    The observation of ultrahigh energy neutrinos (UHE ν s) has become a priority in experimental astroparticle physics. UHE ν s can be detected with a variety of techniques. In particular, neutrinos can interact in the atmosphere (downward-going ν ) or in the Earth crust (Earth-skimming ν ), producing air showers that can be observed with arrays of detectors at the ground. With the surface detector array of the Pierre Auger Observatory we can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after havingmore » traversed a large amount of atmosphere). In this work we review the procedure and criteria established to search for UHE ν s in the data collected with the ground array of the Pierre Auger Observatory. This includes Earth-skimming as well as downward-going neutrinos. No neutrino candidates have been found, which allows us to place competitive limits to the diffuse flux of UHE ν s in the EeV range and above.« less

  17. The Central Raman Laser Facility at the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    medina, C.; Mayotte, E.; Wiencke, L. R.; Rizi, V.; Grillo, A.

    2013-12-01

    We describe the newly upgraded Central Raman Laser Facility (CRLF) located close to the center of the Piere Auger observatory (PAO) in Argentina. The CRLF features a Raman Lidar receiver, a 335 nm wavelength solid state laser, a robotic beam energy calibration system, and a weather station, all powered by solar energy and operated autonomously using a single board computer. The system optics are arranged to direct the laser beam into the atmosphere in steered and vertical modes with adjustable polarization settings,and it is measured in a bi-static configuration by the 4 fluorescence stations of the Pierre Auger observatory. Additionally the system optics can be easily switched to provide a fixed vertical beam that is measured by a Raman Lidar receiver in mono-static configuration,allowing an independent measurement of the aerosol optical depth τ(z,t) and other properties of the atmosphere. A description of the CLRF's installation, hardware and software integration, initial operations and examples of data collected, will also be presented.

  18. The offline software framework of the Pierre Auger Observatory

    SciTech Connect

    Argiro, S.; Barroso, S.L.C.; Dagoret-Campagne, S.; Gonzalez, Javier G.; Nellen, L.; Paul, T.; Porter, T.; Prado, L., Jr.; Roth, M.; Ulrich, R.; Veberic, D.

    2005-08-01

    The Pierre Auger Observatory is designed to unveil the nature and origin of the highest energy cosmic rays through the analysis of extensive air showers. The large and geographically dispersed collaboration of physicists and the wide-ranging collection of simulation and reconstruction tasks pose some special challenges for the offline analysis software. They have designed and implemented a general purpose framework which allows Auger collaborators to contribute algorithms and configuration instructions to build up the variety of applications they require. The framework includes machinery to manage these user codes, to organize the abundance of user-contributed configuration files, to facilitate multi-format file handling, and to provide access to event and time-dependent detector information residing in many data sources. A number of utilities are also provided, including a novel geometry package allowing manipulation of abstract geometrical objects independent of coordinate system choice. The framework is implemented in C++ and takes advantage of object oriented design and common open source tools, while keeping the user-side simple enough for C++ novices to learn in a reasonable time. The distribution system incorporates unit and acceptance testing in order to support rapid development of both the core framework and the contributed user codes.

  19. Delay modeling of bipolar ECL/EFL (Emitter-Coupled Logic/Emitter-Follower-Logic) circuits

    NASA Astrophysics Data System (ADS)

    Yang, Andrew T.

    1986-08-01

    This report deals with the development of a delay-time model for timing simulation of large circuits consisting of Bipolar ECL(Emitter-Coupled Logic) and EFL (Emitter-Follower-Logic) networks. This model can provide adequate information on the performance of the circuits with a minimum expenditure of computation time. This goal is achieved by the use of proper circuit transient models on which analytical delay expressions can be derived with accurate results. The delay-model developed in this report is general enough to handle complex digital circuits with multiple inputs or/and multiple levels. The important effects of input slew rate are also included in the model.

  20. Rare Earth Doped Yttrium Aluminum Garnet (YAG) Selective Emitters

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Pal, AnnaMarie T.; Patton, Martin O.; Jenkins, Phillip P.

    1999-01-01

    As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study presents a spectral emittance model for films and cylinders of rare earth doped yttrium aluminum garnets. Good agreement between experimental and theoretical film spectral emittances was found for erbium and holmium aluminum garnets. Spectral emittances of films are sensitive to temperature differences across the film. For operating conditions of interest, the film emitter experiences a linear temperature variation whereas the cylinder emitter has a more advantageous uniform temperature. Emitter efficiency is also a sensitive function of temperature. For holminum aluminum garnet film the efficiency is 0.35 at 1446K but only 0.27 at 1270 K.

  1. The Quantum Efficiency and Thermal Emittance of Metal Photocathodes

    SciTech Connect

    Dowell, David H.; Schmerge, John F.; /SLAC

    2009-03-04

    Modern electron beams have demonstrated the brilliance needed to drive free electron lasers at x-ray wavelengths, with the principle improvements occurring since the invention of the photocathode gun. The state-of-the-art normalized emittance electron beams are now becoming limited by the thermal emittance of the cathode. In both DC and RF photocathode guns, details of the cathode emission physics strongly influence the quantum efficiency and the thermal emittance. Therefore improving cathode performance is essential to increasing the brightness of beams. It is especially important to understand the fundamentals of cathode quantum efficiency and thermal emittance. This paper investigates the relationship between the quantum efficiency and the thermal emittance of metal cathodes using the Fermi-Dirac model for the electron distribution. We derive the thermal emittance and its relationship to the quantum efficiency, and compare our results to those of others.

  2. Emittance measurements of Space Shuttle orbiter reinforced carbon-carbon

    NASA Technical Reports Server (NTRS)

    Caram, Jose M.; Bouslog, Stanley A.; Cunnington, George R., Jr.

    1992-01-01

    The spectral and total normal emittance of the Reinforced Carbon-Carbon (RCC) used on Space Shuttle nose cap and wing leading edges has been measured at room temperature and at surface temperatures of 1200 to 2100 K. These measurements were made on virgin and two flown RCC samples. Room temperature directional emittance data were also obtained and were used to determine the total hemispherical emittance of RCC as a function of temperature. Results of the total normal emittance for the virgin samples showed good agreement with the current RCC emittance design curve; however, the data from the flown samples showed an increase in the emittance at high temperature possibly due to exposure from flight environments.

  3. Characterization of radiant emitters used in food processing.

    PubMed

    Lloyd, B J; Farkas, B E; Keener, K M

    2003-01-01

    Radiant emissions from short, medium, and long wavelength thermal radiant emitter systems typically used for food processing applications were quantified. Measurements included heat flux intensity, emitter surface temperature, and spectral wavelength distribution. Heat flux measurements were found highly dependent on the incident angle and the distance from the emitter facing. The maximum flux measured was 5.4 W/cm2. Emitter surface temperature measurements showed that short wavelength radiant systems had the highest surface temperature and greatest thermal efficiency. The emitter spectral distributions showed that radiant emitter systems had large amounts of far infrared energy emission greater than 3 microm when compared to theoretical blackbody curves. The longer wavelength energy would likely cause increased surface heating for most high moisture content food materials.

  4. Plasmonic superradiance of two emitters near a metal nanorod

    NASA Astrophysics Data System (ADS)

    Protsenko, I. E.; Uskov, A. V.; Chen, Xue-Wen; Xu, Hongxing

    2017-06-01

    Quantum emitters, such as quantum dots or dye molecules, pumped and situated close to plasmonic nanostructures resonantly excite surface plasmon-polaritons (SPPs). Excitation efficiency increases with the number of emitters because the SPP field synchronizes dipole oscillations of emitters, in analogy with superradiance (SR) in free space. Using a fully quantum mechanical model for two emitters coupled to a single metal nanorod, we predict that plasmonic SR increases the SPP generation yield of a single emitter by up to 15%. Such ‘plasmonic SR’ enhancement of SPP generation is stationary and takes place even at strong dissipation, dephasing and under incoherent pumping. Solid-state quantum emitters with blinking behaviors may be used to demonstrate plasmonic SR. Plasmonic SR may be useful for excitation of non-radiative SPP modes in plasmonic waveguides and lowering the threshold of plasmonic nanolasers.

  5. Active spacecraft potential control: An ion emitter experiment. [Cluster mission

    NASA Technical Reports Server (NTRS)

    Riedler, W.; Goldstein, R.; Hamelin, M.; Maehlum, B. N.; Troim, J.; Olsen, R. C.; Pedersen, A.; Grard, R. J. L.; Schmidt, R.; Rudenauer, F.

    1988-01-01

    The cluster spacecraft are instrumented with ion emitters for charge neutralization. The emitters produce indium ions at 6 keV. The ion current is adjusted in a feedback loop with instruments measuring the spacecraft potential. The system is based on the evaporation of indium in the apex field of a needle. The design of the active spacecraft potential control instruments, and the ion emitters is presented.

  6. Separation of temperature and emittance in remotely sensed radiance measurements

    NASA Technical Reports Server (NTRS)

    Kahle, Anne B.; Alley, Ronald E.

    1992-01-01

    The remote determination of surface temperature and surface spectral emittance by use of airborne or satellite-borne thermal infrared instruments is not straightforward. The radiance measured is a function of surface temperature, the unknown surface spectral emittance, and absorption and emission in the intervening atmosphere. With a single measurement, the solution for temperature and spectral emittance is undedetermined. This article reviews two of the early approximate methods which have been fairly widely used to approach this problem.

  7. Thermal emittance measurements of a cesium potassium antimonide photocathode

    NASA Astrophysics Data System (ADS)

    Bazarov, Ivan; Cultrera, Luca; Bartnik, Adam; Dunham, Bruce; Karkare, Siddharth; Li, Yulin; Liu, Xianghong; Maxson, Jared; Roussel, William

    2011-05-01

    Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented. The emittance is obtained with a solenoid scan technique using a high voltage dc photoemission gun. The thermal emittance is 0.56±0.03 mm mrad/mm(rms) at 532 nm wavelength. The results are compared with a simple photoemission model and found to be in a good agreement.

  8. Sub-nm emittance lattice design for CANDLE storage ring

    NASA Astrophysics Data System (ADS)

    Sargsyan, A.; Zanyan, G.; Sahakyan, V.; Tsakanov, V.

    2016-10-01

    The most effective way to increase the brilliance of synchrotron light sources is the reduction of beam emittance. Following the recent developments in low emittance lattice design, a new sub-nm emittance lattice based on implementation of multi-band achromat concept and application of longitudinal gradient bending magnets was developed for CANDLE storage ring. The paper presents the main design considerations, linear and non-linear beam dynamics aspects of the new lattice proposed.

  9. Emittance calculations for the Stanford Linear Collider injector

    SciTech Connect

    Sheppard, J.C.; Clendenin, J.E.; Helm, R.H.; Lee, M.J.; Miller, R.H.; Blocker, C.A.

    1983-03-01

    A series of measurements have been performed to determine the emittance of the high intensity, single bunch beam that is to be injected into the Stanford Linear Collider. On-line computer programs were used to control the Linac for the purpose of data acquisition and to fit the data to a model in order to deduce the beam emittance. This paper will describe the method of emittance calculation and present some of the measurement results.

  10. Environmental awareness for sensor and emitter employment

    NASA Astrophysics Data System (ADS)

    Yamamoto, Kenneth K.; Wilson, D. Keith

    2010-04-01

    Environmental Awareness for Sensor and Emitter Employment (EASEE) is a flexible, object-oriented software design for predicting environmental effects on the performance of battlefield sensors and detectability of signal emitters. Its decision-support framework facilitates many sensor and emitter modalities and can be incorporated into battlespace command and control (C2) systems. Other potential applications include immersive simulation, force-on-force simulation, and virtual prototyping of sensor systems and signal-processing algorithms. By identifying and encoding common characteristics of Army problems involving multimodal signal transmission and sensing into a flexible software architecture in the Java programming language, EASEE seeks to provide an application interface enabling rapid integration of diverse signal-generation, propagation, and sensor models that can be implemented in many client-server environments. Its explicit probabilistic modeling of signals, systematic consideration of many complex environmental and mission-related factors affecting signal generation and propagation, and computation of statistical metrics characterizing sensor performance facilitate a highly flexible approach to signal modeling and simulation. EASEE aims to integrate many disparate statistical formulations for modeling and processing many types of signals, including infrared, acoustic, seismic, radiofrequency, and chemical/biological. EASEE includes objects for representing sensor data, inferences for target detection and/or direction, signal transmission and processing, and state information (such as time and place). Various transmission and processing objects are further grouped into platform objects, which fuse data to make various probabilistic predictions of interest. Objects representing atmospheric and terrain environments with varying degrees of fidelity enable modeling of signal generation and propagation in diverse and complex environments.

  11. Infrared spectral normal emittance/emissivity comparison

    NASA Astrophysics Data System (ADS)

    Hanssen, L.; Wilthan, B.; Filtz, J.-R.; Hameury, J.; Girard, F.; Battuello, M.; Ishii, J.; Hollandt, J.; Monte, C.

    2016-01-01

    The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory comparisons (including thermal conductivity and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical Quantities (TG-ThQ). The objective of this collaborative work is to strengthen the major operative National Measurement Institutes' infrared spectral emittance scales and consequently the consistency of radiative properties measurements carried out worldwide. The comparison has been performed over a spectral range of 2 μm to 14 μm, and a temperature range from 23 °C to 800 °C. Artefacts included in the comparison are potential standards: oxidized Inconel, boron nitride, and silicon carbide. The measurement instrumentation and techniques used for emittance scales are unique for each NMI, including the temperature ranges covered as well as the artefact sizes required. For example, all three common types of spectral instruments are represented: dispersive grating monochromator, Fourier transform and filter-based spectrometers. More than 2000 data points (combinations of material, wavelength and temperature) were compared. Ninety-eight percent (98%) of the data points were in agreement, with differences to weighted mean values less than the expanded uncertainties calculated from the individual NMI uncertainties and uncertainties related to the comparison process. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  12. Energy levels, Auger branching ratios, and radiative rates of the core-excited states of B-like carbon

    SciTech Connect

    Sun Yan; Gou Bingcong; Chen Feng

    2011-09-28

    Energy levels, Auger branching ratios, and radiative rates of the core-excited states of B-like carbon are calculated by the saddle-point variation and saddle-point complex-rotation methods. Relativistic and mass polarization corrections are included using first-order perturbation theory. Calculated Auger channel energies and branching ratios are used to identify high-resolution Auger spectrum in the 300-keV C{sup +}{yields} CH{sub 4} collision experiment. It is found that Auger decay of these five-electron core-excited states gives significant contributions to Auger spectrum in the range of 238-280 eV.

  13. Emittance and energy control in the NLC main linacs

    SciTech Connect

    Adolphsen, C.; Bane, K.L.F.; Kubo, K.; Raubenheimer, T.; Ruth, R.D.; Thompson, K.A.; Zimmermann, F.

    1995-06-01

    The authors discuss tolerances and correction schemes needed to control single- and multi-bunch emittance in the NLC main linacs. Specifications and design of emittance diagnostic stations will be presented. Trajectory correction schemes appropriate to simultaneously controlling the emittance of a multibunch train and the emittance of individual bunches within the train will be discussed. The authors discuss control of bunch-to-bunch energy spread using a ramped RF pulse generated by phase-modulating the SLED-II input. Tolerances on ions, wake fields, quadrupole alignment, and accelerating structure alignment will be given.

  14. Analysis of Slice Transverse Emittance Evolution ina Photocathode RF Gun

    SciTech Connect

    Huang, Z.; Ding, Y.; Qiang, J.; /LBL, Berkeley

    2007-10-17

    The slice transverse emittance of an electron beam is of critical significance for an x-ray FEL. In a photocathode RF gun, the slice transverse emittance is not only determined by the emission process, but also influenced strongly by the non-linear space charge effect. In this paper, we study the slice transverse emittance evolution in a photocathode RF gun using a simple model that includes effects of RF acceleration, focusing, and space charge force. The results are compared with IMPACT-T space charge simulations and may be used to understand the development of the slice emittance in an RF gun.

  15. Theoretical study of transverse-longitudinal emittance coupling

    SciTech Connect

    Qin, H; Davidson, R C; Chung, M; Barnard, J J; Wang, T F

    2011-04-14

    The effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions is investigated using the generalized Courant-Snyder theory for coupled lattices. Recently, the concept and technique of transverse-longitudinal emittance coupling have been proposed for applications in the Linac Coherent Light Source and other free-electron lasers to reduce the transverse emittance of the electron beam. Such techniques can also be applied to the driver beams for the heavy ion fusion and beam-driven high energy density physics, where the transverse emittance budget is typically tighter than the longitudinal emittance. The proposed methods consist of one or several coupling components which completely swap the emittances of one of the transverse directions and the longitudinal direction at the exit of the coupling components. The complete emittance exchange is realized in one pass through the coupling components. In the present study, we investigate the effect of a weakly coupled periodic lattice in terms of achieving emittance exchange between the transverse and longitudinal directions. A weak coupling component is introduced at every focusing lattice, and we would like to determine if such a lattice can realize the function of emittance exchange.

  16. Efficient low-temperature thermophotovoltaic emitters from metallic photonic crystals.

    PubMed

    Nagpal, Prashant; Han, Sang Eon; Stein, Andreas; Norris, David J

    2008-10-01

    We examine the use of metallic photonic crystals as thermophotovoltaic emitters. We coat silica woodpile structures, created using direct laser writing, with tungsten or molybdenum. Optical reflectivity and thermal emission measurements near 650 degrees C demonstrate that the resulting structures should provide efficient emitters at relatively low temperatures. When matched to InGaAsSb photocells, our structures should generate over ten times more power than solid emitters while having an optical-to-electrical conversion efficiency above 32%. At such low temperatures, these emitters have promise not only in solar energy but also in harnessing geothermal and industrial waste heat.

  17. Injection of large transverse emittance EBIS beams in booster

    SciTech Connect

    Gardner, C.

    2011-10-10

    During the commissioning of EBIS beams in Booster in November 2010 and in April, May and June 2011, it was found that the transverse emittances of the EBIS beams just upstream of Booster were much larger than expected. Beam emittances of 11{pi} mm milliradians had been expected, but numbers 3 to 4 times larger were measured. Here and throughout this note the beam emittance, {pi}{epsilon}{sub 0}, is taken to be the area of the smallest ellipse that contains 95% of the beam. We call this smallest ellipse the beam ellipse. If the beam distribution is gaussian, the rms emittance of the distribution is very nearly one sixth the area of the beam ellipse. The normalized rms emittance is the rms emittance times the relativistic factor {beta}{gamma} = 0.06564. This amounts to 0.12{pi} mm milliradians for the 11{pi} mm milliradian beam ellipse. In [1] we modeled the injection and turn-by-turn evolution of an 11{pi} mm milliradian beam ellipse in the horizontal plane in Booster. It was shown that with the present injection system, up to 4 turns of this beam could be injected and stored in Booster without loss. In the present note we extend this analysis to the injection of larger emittance beams. We consider only the emittance in the horizontal plane. Emittance in the vertical plane and the effects of dispersion are treated in [2].

  18. Multi-channel polarized thermal emitter

    DOEpatents

    Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P

    2013-07-16

    A multi-channel polarized thermal emitter (PTE) is presented. The multi-channel PTE can emit polarized thermal radiation without using a polarizer at normal emergence. The multi-channel PTE consists of two layers of metallic gratings on a monolithic and homogeneous metallic plate. It can be fabricated by a low-cost soft lithography technique called two-polymer microtransfer molding. The spectral positions of the mid-infrared (MIR) radiation peaks can be tuned by changing the periodicity of the gratings and the spectral separation between peaks are tuned by changing the mutual angle between the orientations of the two gratings.

  19. High efficiency quasi-monochromatic infrared emitter

    NASA Astrophysics Data System (ADS)

    Brucoli, Giovanni; Bouchon, Patrick; Haïdar, Riad; Besbes, Mondher; Benisty, Henri; Greffet, Jean-Jacques

    2014-02-01

    Incandescent radiation sources are widely used as mid-infrared emitters owing to the lack of alternative for compact and low cost sources. A drawback of miniature hot systems such as membranes is their low efficiency, e.g., for battery powered systems. For targeted narrow-band applications such as gas spectroscopy, the efficiency is even lower. In this paper, we introduce design rules valid for very generic membranes demonstrating that their energy efficiency for use as incandescent infrared sources can be increased by two orders of magnitude.

  20. High efficiency quasi-monochromatic infrared emitter

    SciTech Connect

    Brucoli, Giovanni; Besbes, Mondher; Benisty, Henri Greffet, Jean-Jacques; Bouchon, Patrick; Haïdar, Riad

    2014-02-24

    Incandescent radiation sources are widely used as mid-infrared emitters owing to the lack of alternative for compact and low cost sources. A drawback of miniature hot systems such as membranes is their low efficiency, e.g., for battery powered systems. For targeted narrow-band applications such as gas spectroscopy, the efficiency is even lower. In this paper, we introduce design rules valid for very generic membranes demonstrating that their energy efficiency for use as incandescent infrared sources can be increased by two orders of magnitude.

  1. Multiple emitter location and signal parameter estimation

    NASA Astrophysics Data System (ADS)

    Schmidt, R. O.

    1986-03-01

    Multiple signal classification (MUSIC) techniques involved in determining the parameters of multiple wavefronts arriving at an antenna array are discussed. A MUSIC algorithm is described, which provides asymptotically unbiased estimates of (1) the number of signals, (2) directions of arrival (or emitter locations), (3) strengths and cross correlations among the incident waveforms, and (4) the strength of noise/interference. The example of the use of the algorithm as a multiple frequency estimator operating on time series is examined. Comparisons of this method with methods based on maximum likelihood and maximum entropy, as well as conventional beamforming, are presented.

  2. Emittance growth from transient coherent synchrotron radiation

    SciTech Connect

    Bohn, C.L.; Li, R.; Bisognano, J.J.

    1996-10-01

    If the energies of individual particles in a bunch change as the bunch traverses a bending system, even if it is achromatic, betatron oscillations can be excited. Consequently, the transverse emittance of the bunch will grow as it moves downstream. Short bunches may be particularly susceptible to emission of coherent synchrotron radiation which can act back on the particles to change their energies and trajectories. Because a bend spans a well-defined length and angle, the bunch-excited wakefield and its effect back on the bunch are inherently transient. We outline a recently developed theory of this effect and apply it to example bending systems.

  3. Monitoring airborne alpha-emitter contamination

    SciTech Connect

    Kerr, P.L.; Koster, J.E.; Conaway, J.G.; Bounds, J.A.; Whitley, C.W.; Steadman, P.A.

    1998-02-01

    Facilities that may produce airborne alpha emitter contamination require a continuous air monitoring (CAM) system. However, these traditional CAMs have difficulty in environments with large quantities of non-radioactive particulates such as dust and salt. Los Alamos has developed an airborne plutonium sensor (APS) for the REBOUND experiment at the Nevada Test Site which detects alpha contamination directly in the air, and so is less vulnerable to the problems associated with counting activity on a filter. In addition, radon compensation is built into the detector by the use of two measurement chambers.

  4. Ultrafast Molecular Three-Electron Collective Auger Decay

    NASA Astrophysics Data System (ADS)

    Feifel, Raimund

    2016-06-01

    A new class of many-electron Auger transitions in atoms was initially proposed over 40 years ago, but the first tentative evidence for its real existence was only adduced by Lee et al. in 1993, on the basis of the resonant Auger spectrum of Kr. Using a multi-electron coincidence technique with synchrotron radiation, we unambiguously showed very recently that the transition suggested by Lee et al. in Kr really does take place, but with a rather small branching ratio. Related inter-atomic three-electron transitions in rare gas clusters were recently predicted by Averbukh and Kolorenc and demonstrated by Ouchi et al.. From consideration of the energy levels involved it seems that the basic three-electron process could occur in molecules too, wherever a double inner-valence shell vacancy lies at a higher energy than the molecular triple ionisation onset. Experiments on CH_3F reveal for the first time the existence of this new decay pathway there, and calculations show that despite its three-electron nature, its effective oscillator strength is orders of magnitudes higher than in atoms, allowing an efficient competition with both molecular dissociation and two-electron decay channels on the ultrafast time scale. The dramatic enhancement of the molecular three-electron Auger transition can be explained in terms of a partial breakdown of the molecular orbital picture of ionisation. We predict that the collective decay pathway will be significant in a wide variety of heteroatomic molecules ionised by extreme UV and soft X-rays, particularly at Free-Electron-Lasers where double inner-shell vacancies can be created efficiently by two-photon transitions. G.N. Ogurtsov et al., Sov. Phys. Tech. Phys. 15, 1656 (1971) and V.V. Afrosimov et al., JETP Lett. 21, 249 (1975). I. Lee, R. Wehlitz, U. Becker and M. Ya. Amusia, J. Phys. B: At. Mol. Opt. Phys. 26, L41 (1993). J.H.D. Eland, R.J. Squibb, M. Mucke, S. Zagorodskikh, P. Linusson, and R. Feifel, New J. Phys. 17, 122001 (2015). V

  5. Effect of Auger Recombination on Lasing in Heterostructured Quantum Dots with Engineered Core/Shell Interfaces.

    PubMed

    Park, Young-Shin; Bae, Wan Ki; Baker, Thomas; Lim, Jaehoon; Klimov, Victor I

    2015-11-11

    Nanocrystal quantum dots (QDs) are attractive materials for applications as laser media because of their bright, size-tunable emission and the flexibility afforded by colloidal synthesis. Nonradiative Auger recombination, however, hampers optical amplification in QDs by rapidly depleting the population of gain-active multiexciton states. In order to elucidate the role of Auger recombination in QD lasing and isolate its influence from other factors that might affect optical gain, we study two types of CdSe/CdS core/shell QDs with the same core radii and the same total sizes but different properties of the core/shell interface ("sharp" vs "smooth"). These samples exhibit distinctly different biexciton Auger lifetimes but are otherwise virtually identical. The suppression of Auger recombination in the sample with a smooth (alloyed) interface results in a notable improvement in the optical gain performance manifested in the reduction of the threshold for amplified spontaneous emission and the ability to produce dual-color lasing involving both the band-edge (1S) and the higher-energy (1P) electronic states. We develop a model, which explicitly accounts for the multiexciton nature of optical gain in QDs, and use it to analyze the competition between stimulated emission from multiexcitons and their decay via Auger recombination. These studies re-emphasize the importance of Auger recombination control for the realization of real-life QD-based lasing technologies and offer practical strategies for suppression of Auger recombination via "interface engineering" in core/shell structures.

  6. Dynamics of Intraband and Interband Auger Processes in Colloidal Core-Shell Quantum Dots.

    PubMed

    Rabouw, Freddy T; Vaxenburg, Roman; Bakulin, Artem A; van Dijk-Moes, Relinde J A; Bakker, Huib J; Rodina, Anna; Lifshitz, Efrat; L Efros, Alexander; Koenderink, A Femius; Vanmaekelbergh, Daniël

    2015-10-27

    Conventional colloidal quantum dots (QDs) suffer from rapid energy losses by nonradiative (Auger) processes, leading to sub-ns lifetimes in all excited states but the lowest-energy single exciton. Suppression of interband Auger decay, such as biexciton Auger recombination, has been achieved with the design of heterostructured core-shell QDs. Auger-like processes are also believed to be responsible for rapid intraband hot-electron cooling in QDs. However, the simultaneous effect of shell growth on interband Auger recombination and intraband hot-electron cooling has not been addressed. Here we investigate how the growth of a CdS shell affects these two relaxation processes in CdSe/CdS core-shell QDs. Using a combination of ultrafast pump-push-probe spectroscopy on the QD ensemble and analysis of the photon statistics from single QDs, we find that Auger losses in the biexciton state are suppressed with increasing shell thickness, while hot-electron cooling remains unaffected. Calculations conducted within an eight-band k·p model confirm the experimental dependence of the biexciton Auger decay on the shell thickness, and provide insights into the factors determining the cooling rate of hot carriers.

  7. Barium depletion in hollow cathode emitters

    NASA Astrophysics Data System (ADS)

    Polk, James E.; Mikellides, Ioannis G.; Capece, Angela M.; Katz, Ira

    2016-01-01

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al2O3 source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values.

  8. Barium depletion in hollow cathode emitters

    SciTech Connect

    Polk, James E. Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

    2016-01-14

    Dispenser hollow cathodes rely on a consumable supply of Ba released by BaO-CaO-Al{sub 2}O{sub 3} source material in the pores of a tungsten matrix to maintain a low work function surface. The examination of cathode emitters from long duration tests shows deposits of tungsten at the downstream end that appear to block the flow of Ba from the interior. In addition, a numerical model of Ba transport in the cathode plasma indicates that the Ba partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant Ba-producing reaction, and it was postulated previously that this would suppress Ba loss in the upstream part of the emitter. New measurements of the Ba depletion depth from a cathode insert operated for 8200 h reveal that Ba loss is confined to a narrow region near the downstream end, confirming this hypothesis. The Ba transport model was modified to predict the depletion depth with time. A comparison of the calculated and measured depletion depths gives excellent qualitative agreement, and quantitative agreement was obtained assuming an insert temperature 70 °C lower than measured beginning-of-life values.

  9. Micro-electrospray with stainless steel emitters.

    PubMed

    Shui, Wenqing; Yu, Yanling; Xu, Xuejiao; Huang, Zhenyu; Xu, Guobing; Yang, Pengyuan

    2003-01-01

    The physical processes underlying micro-electrospray (micro-ES) performance were investigated using a stainless steel (SS) emitter with a blunt tip. Sheathless micro-ES could be generated at a blunt SS tip without any tapering or sanding if ESI conditions were optimized. The Taylor cone was found to shrink around the inner diameter of the SS tubing, which permitted a low flow rate of 150 nL/min for sheathless microspray on the blunt tip (100 microm i.d. x 400 microm o.d.). It is believed that the wettability and/or hydrophobicity of SS tips are responsible for their micro-ES performance. The outlet orifice was further nipped to reduce the size of the spray cone and limit the flow rate to 50-150 nL/min, resulting in peptide detection down to attomole quantities consumed per spectrum. The SS emitter was also integrated into a polymethylmethacrylate microchip and demonstrated satisfactory performance in the analysis and identification of a myoglobin digest.

  10. Emittance measurements from the LLUMC proton accelerator

    NASA Astrophysics Data System (ADS)

    Coutrakon, G.; Gillespie, G. H.; Hubbard, J.; Sanders, E.

    2005-12-01

    A new method of calculating beam emittances at the extraction point of a particle accelerator is presented. The technique uses the optimization programs NPSOL and MINOS developed at Stanford University in order to determine the initial values of beam size, divergence and correlation parameters (i.e. beam sigma matrix, σij) that best fit measured beam parameters. These σij elements are then used to compute the Twiss parameters α, β, and the phase space area, ε, of the beam at the extraction point. Beam size measurements in X and Y throughout the transport line were input to the optimizer along with the magnetic elements of bends, quads, and drifts. The σij parameters were optimized at the accelerator's extraction point by finding the best agreement between these measured beam sizes and those predicted by TRANSPORT. This expands upon a previous study in which a "trial and error" technique was used instead of the optimizer software, and which yielded similar results. The Particle Beam Optics Laboratory (PBO Lab™) program used for this paper integrates particle beam optics and other codes into a single intuitive graphically-based computing environment. This new software provides a seamless interface between the NPSOL and MINOS optimizer and TRANSPORT calculations. The results of these emittance searches are presented here for the eight clinical energies between 70 and 250 MeV currently being used at LLUMC.

  11. Muon Emittance Exchange with a Potato Slicer

    SciTech Connect

    Summers, D. J.; Hart, T. L.; Acosta, J. G.; Cremaldi, L. M.; Oliveros, S. J.; Perera, L. P.; Neuffer, D. V.

    2015-04-15

    We propose a novel scheme for final muon ionization cooling with quadrupole doublets followed by emittance exchange in vacuum to achieve the small beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low beta region occupied by a dense, low Z absorber. After final cooling, normalized transverse, longitudinal, and angular momentum emittances of 0.100, 2.5, and 0.200 mm-rad are exchanged into 0.025, 70, and 0.0 mm-rad. A skew quadrupole triplet transforms a round muon bunch with modest angular momentum into a flat bunch with no angular momentum. Thin electrostatic septa efficiently slice the flat bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 µs, one quarter of a synchrotron oscillation period. A linear long wavelength RF bucket gives each bunch a different energy causing the bunches to drift in the ring until they merge into one bunch and can be captured in a short wavelength RF bucket with a 13% muon decay loss and a packing fraction as high as 87 %.

  12. Calibration of the surface array of the Pierre Auger Observatory

    SciTech Connect

    Aglietta, M.; Allison, P.S.; Arneodo, F.; Barnhill, D.; Bauleo, P.; Beatty, J.J.; Bertou, Xavier; Bonifazi, C.; Busca, N.; Creusot, A.; Dornic, D.; Etchegoyen, A.; Filevitch, A.; Ghia, P.L.; Grunfeld, C.M.; Lhenry-Yvon, I.; Medina, M.C.; Moreno, E.; Navarra, G.; Nitz, D.; Ohnuki, T.

    2005-08-01

    The ground array of the Pierre Auger Observatory consists of 1600 water Cherenkov detectors, deployed over 3000 km{sup 2}. The remoteness and large number of detectors required a simple, automatic remote calibration procedure. The primary physics calibration is based on the average charge deposited by a vertical and central throughgoing muon, determined with good precision at the detector via a novel rate-based technique and later with higher precision via charge histograms. This value is named the vertical-equivalent muon (VEM). The VEM and the other parameters needed to maintain this calibration over the full energy range and to assess the quality of the detector are measured every minute. This allows an accurate determination of the energy deposited in each detector when an atmospheric cosmic ray shower occurs.

  13. Molecular and cellular radiobiological effects of Auger emitting radionuclides

    PubMed Central

    Kassis, Amin I.

    2011-01-01

    Although the general radiobiologic principles underlying external beam therapy and radionuclide therapy are similar, significant differences in the biophysical and radiobiologic effects from the two types of radiation continue to accumulate. Here, I will address the unique features that distinguish the molecular and cellular radiobiological effects of Auger electron-emitting radionuclides consequent to (1) the physical characteristics of the decaying atom and its subcellular localisation, (2) DNA topology and (3) the bystander effect. Based on these experimental findings, I postulate that the ability of track structural simulations as primary tools in modelling DNA damage and cellular survival at the molecular level would be greatly enhanced when these contributions are factored in. PMID:21106639

  14. Status and perspectives of the Pierre Auger cosmic ray observatory

    NASA Astrophysics Data System (ADS)

    Argirò, Stefano

    The problem of the origin of Ultra High Energy Cosmic Rays, that is those with an energy of the Primary above 1019 eV, is a challenging one. The expected flux at those energies is around 1/yr/km2, thus requiring an unprecedented size of the detector in order to achieve consistent statistics. The Pierre Auger Observatory will be the largest cosmic ray detector ever built, consisting of two sites, one for each hemisphere, equipped with 1600 water Cherenkov detectors and four fluorescence detectors, covering each 3000 km 2. The combination of the two techniques, referred to as the hybrid technique, results in unprecedented accuracy in the reconstruction of the air showers. The concept has been validated with an Engineering Array of 32 water tanks and two fluorescence telescopes, during which the apparatus demonstrated very good performances. This paper will summarize the features of the data, the reconstruction methods and the strategy toward completion of the full Observatory.

  15. An Auger electron spectroscopy study of surface-preparation contaminants

    NASA Technical Reports Server (NTRS)

    Wu, D.; Stephens, R. M.; Outlaw, R. A.; Hopson, P.

    1990-01-01

    There are many cleaning techniques that are presently being employed for surface preparation of materials that are subsequently exposed to ultrahigh vacuum (UHV). Unfortunately, there are virtually no comparative measurements which establish the residual contaminant level of each method. In this report, eleven different cleaning methods, ranging from only detergent cleaning to electrochemical polishing, were applied to identical samples of 347 stainless steel. Two surface conditions, a standard machined surface and a mechanically polished surface, were studied. Auger electron spectroscopy (AES) within a UHV environment was then used to detect the types of contaminants and the magnitudes found on the sample surfaces. It was found that the electrochemical polishing gave the least contaminated surface of all metals studied and that mechanically polished surfaces were significantly cleaner than the as-machined surfaces for any given cleaning method. Furthermore, it was also found that the residual contaminations left by methanol, ethanol, isopropyl alcohol, acetone, and freon finishing rinses are almost the same.

  16. Use of Auger spectroscopy in the evaluation of thermionic cathodes

    NASA Technical Reports Server (NTRS)

    Forman, R.

    1977-01-01

    Auger spectroscopy has been used to evaluate the properties of 'good' and 'poor' impregnated tungsten cathodes used in high-power microwave wave tubes. The results were interpreted to analyze failure modes in cathodes removed from TWT's because of poor emission characteristics. Most of the poor cathodes evaluated in this program were obtained from fabricated electron guns that had been employed and discarded from the 200-W TWT tubes developed for the Communication Technology Satellite program. The results of these measurements have shown there are at least two types of failure modes that one observes with poor cathodes. They are (1) chemical contamination of the cathode surface and (2) low partial layer barium coverage of the cathode surface.

  17. Photo-Auger-ionization and charge-state distribution

    NASA Astrophysics Data System (ADS)

    Omar, Gaber; Hahn, Yukap

    1991-07-01

    The radiative and Auger emissions in cascade (RAC) model constructed earlier [G. Omar and Y. Hahn, Phys. Rev. A (to be published)] is applied to the calculation of the final-charge-state distribution in the decay of Ar+(1s¯) with an initial 1s hole created by synchrotron irradiation. Experimental data of Church et al. [Phys. Rev. A 36, 2487 (1987)] are reasonably well reproduced, including the observed asymmetry in the final-state charge distribution. In addition to Ar+(1s¯), we have also considered the decay of the initial states Ar+(2s¯), Ar+(2p¯), and Ar(1s¯,4p). The higher charge states are underestimated by the RAC model, presumably due to the neglect of correlated multielectron processes in the present calculation.

  18. Measurements of TYVEK reflective properties for the Pierre Auger Project

    SciTech Connect

    Gichaba, Justus Ogwoka; /Mississippi U.

    1998-08-01

    The authors have measured the spectrum and diffuse reflection of various samples of Tyvek, a material to be used to line the inner walls of the Pierre Auger Observatory water crenkov tanks. These measurements were carried out with a Lambda 18 UV/VIS spectrometer over a wavelength range from 200 nm to 700 nm. The angular dependence of this scattering was a gaussian. They have also carried the measurements with the PASCO OS-8020 to find the reflectivity of Tyvek samples versus Incident and Reflected angles. The reflected angles range from -90{sup o} to -90{sup o}. Finally, information from these measurements was used to simulate Cosmic rays events in a Water Cerenkov detector.

  19. EUSO angular resolution based on Pierre Auger Observatory reconstruction methodology

    NASA Astrophysics Data System (ADS)

    Painter, William

    2015-04-01

    Ultra high energy cosmic rays (UHECRs) are astro-particles with energies above 1018 eV and are a readily detected phenomena. Their origin is yet undetermined due to the exceedingly low flux, 1 particle per km2 per century at 1020 eV. The proposed Extreme Universe Space Observatory (EUSO) utilizes the bottom 20 km of the atmosphere as a detection volume resulting in a detection area of nearly 150 , 000 km2 in nadir mode. We have developed an UHECR angular reconstruction algorithm based on the methodology developed at the Pierre Auger Observatory. This algorithm shows improved angular resolution over previous EUSO methods and has been applied to simulated showers over the expected energy and zenith angle ranges. William Painter with Dr. Fred Sarazin.

  20. The fluorescence detector of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez-Muñiz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anzalone, A.; Aramo, C.; Arganda, E.; Argirò, S.; Arisaka, K.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avila, G.; Bacher, A.; Bäcker, T.; Badagnani, D.; Barber, K. B.; Barbosa, A. F.; Barbosa, H. J. M.; Barenthien, N.; Barroso, S. L. C.; Baughman, B.; Bauleo, P.; Beatty, J. J.; Beau, T.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bernardini, P.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Bleve, C.; Blümer, H.; Boháčová, M.; Bollmann, E.; Bolz, H.; Bonifazi, C.; Bonino, R.; Borodai, N.; Bracci, F.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Camin, D.; Caramete, L.; Caruso, R.; Carvalho, W.; Castellina, A.; Castro, J.; Catalano, O.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Chye, J.; Clark, P. D. J.; Clay, R. W.; Colombo, E.; Conceição, R.; Connolly, B.; Contreras, F.; Coppens, J.; Cordero, A.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J. W.; Cuautle, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Daudo, F.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; Di Giulio, C.; Diaz, J. C.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dornic, D.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; DuVernois, M. A.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrer, F.; Ferrero, A.; Fick, B.; Filevich, A.; Filipčič, A.; Fleck, I.; Fliescher, S.; Fonte, R.; Fracchiolla, C. E.; Fraenkel, E. D.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Garrido, X.; Geenen, H.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Gibbs, K.; Giller, M.; Gitto, J.; Glass, H.; Goggin, L. M.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gomez Vitale, P. F.; Gonçalves, P.; Gonçalves do Amaral, M.; Gonzalez, D.; Gonzalez, J. G.; Góra, D.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grassi, V.; Grebe, S.; Grigat, M.; Grillo, A. F.; Grygar, J.; Guardincerri, Y.; Guardone, N.; Guerard, C.; Guarino, F.; Gumbsheimer, R.; Guedes, G. P.; Gutiérrez, J.; Hague, J. D.; Halenka, V.; Hansen, P.; Harari, D.; Harmsma, S.; Hartmann, S.; Harton, J. L.; Haungs, A.; Healy, M. D.; Hebbeker, T.; Hebrero, G.; Heck, D.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hofman, G.; Hörandel, J. R.; Horneffer, A.; Horvat, M.; Hrabovský, M.; Hucker, H.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kasper, P.; Kégl, B.; Keilhauer, B.; Kemp, E.; Kern, H.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D.-H.; Kopmann, A.; Krieger, A.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Lee, J.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Leuthold, M.; Lhenry-Yvon, I.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Malek, M.; Mandat, D.; Mantsch, P.; Marchetto, F.; Mariazzi, A. G.; Maris, I. C.; Marquez Falcon, H. R.; Martello, D.; Martineau, O.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; McNeil, R. R.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meyhandan, R.; Micheletti, M. I.; Miele, G.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Morris, C.; Mostafá, M.; Moura, C. A.; Mucchi, M.; Mueller, S.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nerling, F.; Newman-Holmes, C.; Newton, D.; Nhung, P. T.; Nicotra, D.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Ortolani, F.; Oßwald, B.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Parente, G.; Parizot, E.; Parlati, S.; Pastor, S.; Patel, M.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Peķala, J.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Pichel, A.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pinto, T.; Pirronello, V.; Pisanti, O.; Platino, M.; Pochon, J.; Ponce, V. H.; Pontz, M.; Pouryamout, J.; Prado, L., Jr.; Privitera, P.; Prouza, M.; Quel, E. J.; Raia, G.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Redondo, A.; Reis, H. C.; Reucroft, S.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Rivière, C.; Rizi, V.; Robledo, C.; Roberts, M. D.; Rodriguez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sánchez, F.; Santander, M.; Santo, C. E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schleif, G.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schroeder, F.; Schulte, S.; Schüssler, F.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Sequieros, G.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; SmiaŁkowski, A.; Šmída, R.; Smith, A. G. K.; Smith, B. E.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Tamashiro, A.; Tamburro, A.; Tarutina, T.; Taşcău, O.; Tcaciuc, R.; Tcherniakhovski, D.; Thao, N. T.; Thomas, D.; Ticona, R.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Tomé, B.; Tonachini, A.; Torres, I.; Trapani, P.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tuci, V.; Tueros, M.; Tusi, E.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van den Berg, A. M.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Velarde, A.; Venters, T.; Verzi, V.; Videla, M.; Villaseñor, L.; Vitali, G.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Westerhoff, S.; Whelan, B. J.; Wild, N.; Wiebusch, C.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Wileman, C.; Winnick, M. G.; Wörner, G.; Wu, H.; Wundheiler, B.; Yamamoto, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.; Pierre Auger Collaboration

    2010-08-01

    The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.

  1. Final report for tank 241-BX-112, auger samples 95-Aug-047 and 95-Aug-048

    SciTech Connect

    Conner, J.M.

    1996-02-29

    This document serves as the final report for Tank 241-BX-112. The auger samples were taken on Nov. 16 and 17, 1995. The report is broken into 2 parts; the nd part consists of the original 45-day safety screening report (including the DSC and TGA raw data). Prior to auger sampling, the vapor space of tank BX-112 was screened for flammability issues; the vapor space was found to be far below the lower explosive limit. The auger samples were taken to fully satisfy the DQO.

  2. Generation of pure spin currents via Auger recombination in quantum wells with Rashba splitting

    SciTech Connect

    Afanasiev, A. N. Greshnov, A. A. Greshnov, A. A.

    2015-10-15

    We propose a nonoptical mechanism for generating spin current via Auger recombination in semiconductor quantum wells (QWs) with spin–orbit splitting associated with structural QW asymmetry. It is shown that Auger recombination in narrow-bandgap semiconductors makes it possible to produce spin currents that exceed those that are obtained in the case of intraband as well as interband optical excitation. Analysis shows that the interference term in the expression for the Auger-recombination rate is responsible for the generation of spin currents.

  3. Ultrafast and band-selective Auger recombination in InGaN quantum wells

    SciTech Connect

    Williams, Kristopher W.; Monahan, Nicholas R.; Zhu, X.-Y. E-mail: mhcrawf@sandia.gov; Koleske, Daniel D.; Crawford, Mary H. E-mail: mhcrawf@sandia.gov

    2016-04-04

    In InGaN quantum well based light-emitting diodes, Auger recombination is believed to limit the quantum efficiency at high injection currents. Here, we report the direct observation of carrier loss from Auger recombination on a sub-picosecond timescale in a single InGaN quantum well using time-resolved photoemission. Selective excitations of different valence sub-bands reveal that the Auger rate constant decreases by two orders of magnitude as the effective hole mass decreases, confirming the critical role of momentum conservation.

  4. Chemical effects of F KVV Auger spectra induced by photon impact

    NASA Astrophysics Data System (ADS)

    Uda, M.; Maeda, K.; Koyama, A.; Sasa, Y.

    1984-03-01

    F KVV Auger emissions were measured with NaF, MgF2, A1F3, and Teflon [(CF2)n], which were induced by photoionization. Chemical effects were reflected in line broadening and change in intensity ratios of the spectra emitted from singly and doubly ionized initial states, |K1L0> and |K1L1>. Reduction in Auger peak intensities which originated from |K1L1> is in the order of the covalencies of the fluorides or the natural widths of F L shells. This is caused by the refilling of a F L-shell vacancy by one of the ligand electrons prior to Auger emission.

  5. Identifying clouds over the Pierre Auger Observatory using infrared satellite data

    NASA Astrophysics Data System (ADS)

    Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Baughman, B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buroker, L.; Burton, R. E.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fliescher, S.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Jansen, S.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Peķala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Pfendner, C.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Ponce, V. H.; Pontz, M.; Porcelli, A.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovánek, P.; Schröder, F. G.; Schulz, J.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Tcaciuc, R.; Thao, N. T.; Thomas, D.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano Garcia, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

    2013-12-01

    We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ˜2.4 km by ˜5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

  6. Auger electron intensity variations in oxygen-exposed large grain polycrystalline silver

    NASA Technical Reports Server (NTRS)

    Lee, W. S.; Outlaw, R. A.; Hoflund, G. B.; Davidson, M. R.

    1989-01-01

    Auger electron spectroscopic studies of the grains in oxygen-charged polycrystal-line silver show significant intensity variations as a function of crystallographic orientation. These intensity variations were observed by studies of the Auger images and line scans of the different grains (randomly selected) for each silver transition energy. The results can be attributed to the diffraction of the ejected Auger electrons and interpreted by corresponding changes in the electron mean-free path for inelastic scattering and by oxygen atom accumulation in the subsurface. The subsurface (second layer) octahedral sites increased in size because of surface relaxation and serve as a stable reservoir for the dissolved oxygen.

  7. Auger electron spectroscopy at high spatial resolution and nA primary beam currents

    NASA Technical Reports Server (NTRS)

    Todd, G.; Poppa, H.; Moorhead, D.; Bales, M.

    1975-01-01

    An experimental Auger microprobe system is described which incorporates a field-emission electron gun and total beam currents in the nanoampere range. The distinguishing characteristics of this system include a large multistation UHV specimen chamber, pulse counting and fully digital Auger signal-processing techniques, and digital referencing methods to eliminate the effects of beam instabilities. Some preliminary results obtained with this system are described, and it is concluded that field-emission electron sources can be used for high-resolution Auger electron spectroscopy with primary-beam spots of less than 100 nm and beam currents of the order of 1 nA.

  8. Analysis of 3d photoionization and subsequent Auger decay of atomic germanium

    SciTech Connect

    Jaenkaelae, K.; Anin, D.; Huttula, S.-M.; Heinaesmaeki, S.; Huttula, M.; Urpelainen, S.

    2011-11-15

    Experimental and theoretical study of the 3d photoionization and subsequent Auger decay of initially neutral atomic germanium is presented. The features of the high-resolution photoelectron and Auger electron spectra are interpreted with the aid of multiconfiguration calculations. The binding energies and relative cross sections of the 3d ionized fine-structure states of Ge are given. The complete M{sub 4,5}NN Auger electron spectrum to doubly ionized final states of the Ge ion is interpreted and discussed.

  9. Ratioed scatter diagrams - An erotetic method for phase identification on complex surfaces using scanning Auger microscopy

    NASA Technical Reports Server (NTRS)

    Browning, R.

    1984-01-01

    By ratioing multiple Auger intensities and plotting a two-dimensional occupational scatter diagram while digitally scanning across an area, the number and elemental association of surface phases can be determined. This can prove a useful tool in scanning Auger microscopic analysis of complex materials. The technique is illustrated by results from an anomalous region on the reaction zone of a SiC/Ti-6Al-4V metal matrix composite material. The anomalous region is shown to be a single phase associated with sulphur and phosphorus impurities. Imaging of a selected phase from the ratioed scatter diagram is possible and may be a useful technique for presenting multiple scanning Auger images.

  10. 45-Day deliverable for Tank 241-BX-105 Auger samples, risers 2 and 6

    SciTech Connect

    Bell, K.E.

    1994-11-16

    Two auger samples from single-shell tank 241-BX-105 (BX-105) were extruded, broken down, and analyzed for DSC, TGA, and total alpha as prescribed. Analytical results were tracked and reported using the laboratory information management system known as LabCore. This is the final report for the fiscal year 1995 BX-105 auger sample characterization effort. Included are copies of the differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA) scans as requested. Also included is a copy of any immediate notification documentation, chain of custody forms, the hot cell work plan, extruded segment [auger] description sheets, and total alpha data.

  11. K-shell Auger lifetime variation in doubly ionized Ne and first row hydrides

    SciTech Connect

    Kolorenc, Premysl; Averbukh, Vitali

    2011-10-07

    We consider 1s Auger decay in doubly (core-core and core-valence) ionized Ne and in the isoelectronic first row element hydrides. We show theoretically that the presence of the spectator inner valence vacancy leads to Auger lifetime variation of up to about a factor of 2, relative to the Auger lifetimes in the singly ionized species. The origin of this effect is traced to spin selection rules. Implications on the modelling of the radiation damage in strong x-ray fields are discussed.

  12. Incident-beam effects in electron-stimulated Auger-electron diffraction

    NASA Astrophysics Data System (ADS)

    Gao, Y.; Cao, Jianming

    1991-04-01

    We have examined incident-beam effects in electron-stimulated Auger-electron diffraction (AED) on a cleaved GaAs(110) surface. The results indicate that incident-beam diffraction is significant in an AED experiment, and that the dissipative nature of the incident beam in contributing to the Auger process must be accounted for. We have developed a qualitative model that describes the trend of the polar-angle dependence of the Auger intensity for both the incident and exit beams. In calculating the diffraction features, we used a zeroth-order approximation to simulate the dissipation of the incident beam, which is found to adequately describe the experimental data.

  13. Identifying clouds over the Pierre Auger Observatory using infrared satellite data

    SciTech Connect

    Abreu, Pedro; et al.,

    2013-12-01

    We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km^2 of the Pierre Auger Observatory twice per hour with a spatial resolution of ~2.4 km by ~5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories.

  14. A new technique for Auger analysis of surface species subject to electron-induced desorption

    NASA Technical Reports Server (NTRS)

    Pepper, S. V.

    1973-01-01

    A method is presented to observe surface species subject to electron-induced desorption by Auger electron spectroscopy. The surface to be examined is moved under the electron beam at constant velocity, establishing a time independent condition and eliminating the time response of the electron spectrometer as a limiting factor. The dependence of the Auger signal on the surface velocity, incident electron current, beam diameter, and desorption cross section are analyzed. The method is illustrated by the Auger analysis of PTFE, in which the fluorine is removed by electron induced desorption.

  15. Compact Rare Earth Emitter Hollow Cathode

    NASA Technical Reports Server (NTRS)

    Watkins, Ronald; Goebel, Dan; Hofer, Richard

    2010-01-01

    A compact, high-current, hollow cathode utilizing a lanthanum hexaboride (LaB6) thermionic electron emitter has been developed for use with high-power Hall thrusters and ion thrusters. LaB6 cathodes are being investigated due to their long life, high current capabilities, and less stringent xenon purity and handling requirements compared to conventional barium oxide (BaO) dispenser cathodes. The new cathode features a much smaller diameter than previously developed versions that permit it to be mounted on axis of a Hall thruster ( internally mounted ), as opposed to the conventional side-mount position external to the outer magnetic circuit ("externally mounted"). The cathode has also been reconfigured to be capable of surviving vibrational loads during launch and is designed to solve the significant heater and materials compatibility problems associated with the use of this emitter material. This has been accomplished in a compact design with the capability of high-emission current (10 to 60 A). The compact, high-current design has a keeper diameter that allows the cathode to be mounted on the centerline of a 6- kW Hall thruster, inside the iron core of the inner electromagnetic coil. Although designed for electric propulsion thrusters in spacecraft station- keeping, orbit transfer, and interplanetary applications, the LaB6 cathodes are applicable to the plasma processing industry in applications such as optical coatings and semiconductor processing where reactive gases are used. Where current electrical propulsion thrusters with BaO emitters have limited life and need extremely clean propellant feed systems at a significant cost, these LaB6 cathodes can run on the crudest-grade xenon propellant available without impact. Moreover, in a laboratory environment, LaB6 cathodes reduce testing costs because they do not require extended conditioning periods under hard vacuum. Alternative rare earth emitters, such as cerium hexaboride (CeB6) can be used in this

  16. Group-III Nitride Field Emitters

    NASA Technical Reports Server (NTRS)

    Bensaoula, Abdelhak; Berishev, Igor

    2008-01-01

    Field-emission devices (cold cathodes) having low electron affinities can be fabricated through lattice-mismatched epitaxial growth of nitrides of elements from group III of the periodic table. Field emission of electrons from solid surfaces is typically utilized in vacuum microelectronic devices, including some display devices. The present field-emission devices and the method of fabricating them were developed to satisfy needs to reduce the cost of fabricating field emitters, make them compatible with established techniques for deposition of and on silicon, and enable monolithic integration of field emitters with silicon-based driving circuitry. In fabricating a device of this type, one deposits a nitride of one or more group-III elements on a substrate of (111) silicon or other suitable material. One example of a suitable deposition process is chemical vapor deposition in a reactor that contains plasma generated by use of electron cyclotron resonance. Under properly chosen growth conditions, the large mismatch between the crystal lattices of the substrate and the nitride causes strains to accumulate in the growing nitride film, such that the associated stresses cause the film to crack. The cracks lie in planes parallel to the direction of growth, so that the growing nitride film becomes divided into microscopic growing single-crystal columns. The outer ends of the fully-grown columns can serve as field-emission tips. By virtue of their chemical compositions and crystalline structures, the columns have low work functions and high electrical conductivities, both of which are desirable for field emission of electrons. From examination of transmission electron micrographs of a prototype device, the average column width was determined to be about 100 nm and the sharpness of the tips was determined to be characterized by a dimension somewhat less than 100 nm. The areal density of the columns was found to about 5 x 10(exp 9)/sq cm . about 4 to 5 orders of magnitude

  17. K-shell auger decay of atomic oxygen

    SciTech Connect

    Stolte, W.C.; Lu, Y.; Samson, J.A.R.

    1997-04-01

    The aim of the present research is to understand the interaction between the ejected photoelectron and Auger electron produced by the Auger decay of a 1s hole in atomic oxygen, and to understand the influence this interaction has on the shape of the ionization cross sections. To accomplish this the authors have measured the relative ion yields (ion/photon) in the vicinity of the oxygen K-shell (525 - 533 eV) for O{sup +} and O{sup 2+}. The measurements were performed at the ALS on beamline, 6.3.2. The atomic oxygen was produced by passing molecular oxygen through a microwave-driven discharge. A Rydberg analysis of the two series leading to the [1s]2s{sup 2}2p{sup 4}({sup 4}P) and [1s]2s{sup 2}2p{sup 4}({sup 2}P) limits were obtained. This analysis shows some differences to the recently published results by Menzel et al. The energy position of the main 1s{sup 1}2s{sup 2}2p{sup 5}({sup 3}P) resonance differs by approximately 1 eV from the authors value, all members of the ({sup 2}P)np series differ by 0.3 eV, but the members of the ({sup 4}P)np series agree. The molecular resonance at 530.5 eV and those between 539 eV and 543 eV, measured with the microwave discharge off show identical results in both experiments.

  18. Auger analysis of the PbS-Si heterojunction

    NASA Astrophysics Data System (ADS)

    Elabd, H.; Steckl, A. J.

    1980-05-01

    The chemical structure of the solution-grown PbS-Si hetero-junction was studied by Auger Electron Spectroscopy. Auger depth profiles indicate a PbS film of uniform composition. No major contaminants were observed in the bulk of the PbS film. At the PbS-Si interface the only impurity observed was an oxygen peak, corresponding to approximately 1% atomic concentration. Heating the growth solution enhances the chemical reaction and deposition rates without altering the profiles of the elements at the interface. Similar oxygen peaks were detected at the Au-PbS interface and at the interface between consecutive PbS films. The interface oxygen concentration in the PbS-Si (100) structure is roughly twice that present in the PbS-Si (111) structure. Heat treatment in air increased the interface and surface oxygen concentration by a factor of 2 to 5. The same treatment in N2} ambient had only a slight effect on the surface oxygen concentration but enhanced the interface oxygen concentration. The oxygen at the Au-PbS interface showed similar sensitivity to heat treatment. Oxygen content at the interface of HJs formed on unpolished Si was double that in HJs formed on polished Si. The relative intensity of the S to Pb peaks in the bulk of the PbS film compares closely with that measured on the cleaved surface of natural single crystal galena. The Pb: S peak ratio was roughly constant throughout the PbS film and at the PbS-Si interface. Fe and Cl contaminants were observed at the surface of the PbS film, along with significant changes in the Pb:S ratio. The simultaneous detection of Pb, S and Si near the interface is attributed to the presence of surface irregularity caused by a secondary PbS macrostructure consisting of isolated chain-like clusters.

  19. Emittance growth due to negative-mass instability above transition

    SciTech Connect

    Ng, King-Yuen

    1994-08-01

    Due to space-charge effect, there is a growth of bunch emittance across transition as a result of negative-mass instability. The models of growth at cutoff frequency and growth from high-frequency Schottky noise are reviewed. The difficulties of performing reliable simulations are discussed. An intuitive self-bunching model for estimating emittance growth is presented.

  20. Emittance growth due to dipole ripple and sextupole

    SciTech Connect

    Shih, H.J.; Ellison, J.A.; Syphers, M.J.; Newberger, B.S.

    1993-05-01

    Ripple in the power supplies for storage ring magnets can have adverse effects on the circulating beams: orbit distortion and emittance growth from dipole ripple, tune modulation and dynamic aperture reduction from quadrupole ripple, etc. In this paper, we study the effects of ripple in the horizontal bending field of the SSC in the presence of nonlinearity, in particular, the growth in beam emittance.

  1. Close proximity electrostatic effect from small clusters of emitters

    NASA Astrophysics Data System (ADS)

    Dall’Agnol, Fernando F.; de Assis, Thiago A.

    2017-10-01

    Using a numerical simulation based on the finite-element technique, this work investigates the field emission properties from clusters of a few emitters at close proximity, by analyzing the properties of the maximum local field enhancement factor (γm ) and the corresponding emission current. At short distances between the emitters, we show the existence of a nonintuitive behavior, which consists of the increasing of γm as the distance c between the emitters decreases. Here we investigate this phenomenon for clusters with 2, 3, 4 and 7 identical emitters and study the influence of the proximity effect in the emission current, considering the role of the aspect ratio of the individual emitters. Importantly, our results show that peripheral emitters with high aspect-ratios in large clusters can, in principle, significantly increase the emitted current as a consequence only of the close proximity electrostatic effect (CPEE). This phenomenon can be seen as a physical mechanism to produce self-oscillations of individual emitters. We discuss new insights for understanding the nature of self-oscillations in emitters based on the CPEE, including applications to nanometric oscillators.

  2. Surface Coatings for Low Emittance in the Thermal Surveillance Band

    DTIC Science & Technology

    1984-08-01

    transparent but conducting coatings on glass [4] and (3) the solar energy industry , where surface coatings are required for solar collectors which...increase in coating emittance [10]. 0 Research into low emittance paint is mainly carried out in the solar energy industry [11, 12] and can be

  3. Spectral beam combining of multi-single emitters

    NASA Astrophysics Data System (ADS)

    Wang, Baohua; Guo, Weirong; Guo, Zhijie; Xu, Dan; Zhu, Jing; Zhang, Qiang; Yang, Thomas; Chen, Xiaohua

    2016-03-01

    Spectral beam combination expands the output power while keeps the beam quality of the combined beam almost the same as that of a single emitter. Spectral beam combination has been successfully achieved for high power fiber lasers, diode laser arrays and diode laser stacks. We have recently achieved the spectral beam combination of multiple single emitter diode lasers. Spatial beam combination and beam transformation are employed before beams from 25 single emitter diode lasers can be spectrally combined. An average output power about 220W, a spectral bandwidth less than 9 nm (95% energy), a beam quality similar to that of a single emitter and electro-optical conversion efficiency over 46% are achieved. In this paper, Rigorous Coupled Wave analysis is used to numerically evaluate the influence of emitter width, emitter pitch and focal length of transform lens on diffraction efficiency of the grating and spectral bandwidth. To assess the chance of catastrophic optical mirror damage (COMD), the optical power in the internal cavity of a free running emitter and the optical power in the grating external cavity of a wavelength locked emitter are theoretically analyzed. Advantages and disadvantages of spectral beam combination are concluded.

  4. Experimental Results of a Single Emittance Compensation Solenoidal Magnet

    NASA Astrophysics Data System (ADS)

    Palmer, D. T.; Wang, X. J.; Ben-Zvi, I.; Miller, R. H.; Skaritka, J.

    1997-05-01

    A new iron dominated single emittance compensation solenoidal magnet was designed to be integrated with the BNL/SLAC/UCLA 1.6 cell S-Band Photocathode RF Gun. This emittance compensated photoinjector is now in operation at the Brookhaven Accelerator Test Facility. It has produced a 300 pC electron bunches with a normalized rms transverse emittance of ɛ_n,rms = 0.7 π mm mrad. POISSON field maps were used with PARMELA to optimize the emittance compensation solenoidal magnet design. Magnetic field measurements show that at the cathode plane Bz <= 10 gauss for a peak magnetic field of B_z,max = 3 KG. Which is in agreement with POISSON simulation. A single emittance compensation solenoidal magnet will produces a initial angular momentum of the electron bunch that manifests itself in a initial magnetic emittance term that cannot be eliminated. This magnetic emittance ɛ_mag,n,rms scales as 0.01 π mm mrad per gauss at the cathode. Which is in agreement with PARMELA simulations. Experimental beam dynamics results are presented that show spot size and emittance as a function of cathode magnetic field. These results are compared to theory and simulations.

  5. Sharpening of field emitter tips using high-energy ions

    DOEpatents

    Musket, Ronald G.

    1999-11-30

    A process for sharpening arrays of field emitter tips of field emission cathodes, such as found in field-emission, flat-panel video displays. The process uses sputtering by high-energy (more than 30 keV) ions incident along or near the longitudinal axis of the field emitter to sharpen the emitter with a taper from the tip or top of the emitter down to the shank of the emitter. The process is particularly applicable to sharpening tips of emitters having cylindrical or similar (e.g., pyramidal) symmetry. The process will sharpen tips down to radii of less than 12 nm with an included angle of about 20 degrees. Because the ions are incident along or near the longitudinal axis of each emitter, the tips of gated arrays can be sharpened by high-energy ion beams rastered over the arrays using standard ion implantation equipment. While the process is particularly applicable for sharpening of arrays of field emitters in field-emission flat-panel displays, it can be effectively utilized in the fabrication of other vacuum microelectronic devices that rely on field emission of electrons.

  6. Microfabricated emitter array for an ionic liquid electrospray thruster

    NASA Astrophysics Data System (ADS)

    Nakagawa, Kaito; Tsuchiya, Toshiyuki; Takao, Yoshinori

    2017-06-01

    We have fabricated needle-shaped emitters on a Si wafer by a MEMS process, and measured the voltage-current characteristics and the frequency dependence of a bipolar pulse voltage for ionic liquid electrospray thrusters, which can be mounted on nanosatellites ( ≲ 10 kg). Although the extracted current did not increase with increasing number of emitters, probably owing to the lack of uniformity of the emitters fabricated, we have demonstrated that the emitted current depends on the gap distance between the emitter and the extractor grid electrode, and low frequencies of the bipolar pulse voltage are desirable for thruster operation. Moreover, the Bosch process is required for fabricating a reservoir of ionic liquid, which prevents undesirable electrical short circuits, and the minimum emitter pitch to prevent loss of ion beams to the extractor is estimated to be about 400 µm.

  7. Power flow from a dipole emitter near an optical antenna.

    PubMed

    Huang, Kevin C Y; Jun, Young Chul; Seo, Min-Kyo; Brongersma, Mark L

    2011-09-26

    Current methods to calculate the emission enhancement of a quantum emitter coupled to an optical antenna of arbitrary geometry rely on analyzing the total Poynting vector power flow out of the emitter or the dyadic Green functions from full-field numerical simulations. Unfortunately, these methods do not provide information regarding the nature of the dominant energy decay pathways. We present a new approach that allows for a rigorous separation, quantification, and visualization of the emitter output power flow captured by an antenna and the subsequent reradiation power flow to the far field. Such analysis reveals unprecedented details of the emitter/antenna coupling mechanisms and thus opens up new design strategies for strongly interacting emitter/antenna systems used in sensing, active plasmonics and metamaterials, and quantum optics.

  8. Transit time and charge storage measurements in heavily doped emitters

    NASA Technical Reports Server (NTRS)

    Neugroschel, A.; Park, J. S.; Hwang, B. Y.

    1986-01-01

    A first direct measurement of the minority-carrier transit time in a transparent heavily doped emitter layer is reported. The value was obtained by a high-frequency conductance method recently developed and used for low-doped Si. The transit time coupled with the steady-state current enables the determination of the quasi-static charge stored in the emitter and the quasi-static emitter capacitance. Using a transport model, from the measured transit time, the value for the minority-carrier diffusion coefficient and mobility is estimated. The measurements were done using a heavily doped emitter of the Si p(+)-n-p bipolar transistor. The new result indicates that the position-averaged minority-carrier diffusion coefficients may be much smaller than the corresponding majority-carrier values for emitters having a concentration ranging from about 3 x 10 to the 19th per cu cm to 10 to the 20th per cu cm.

  9. Radiative performance of rare earth garnet thin film selective emitters

    SciTech Connect

    Lowe, R.A.; Chubb, D.L.; Good, B.S.

    1994-08-01

    In this paper the authors present the first emitter efficiency results for the thin film 40 percent Er-1.5 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) and 25 percent Ho YAG selective emitter at 1500 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns). Emitter efficiency and power density are significantly improved with the addition of multiple rare earth dopants. Predicted efficiency results are presented for an optimized (equal power density in the Er, (4)I[sub 15/2]-(4)I[sub 13/2] at 1.5 microns, and Ho, (5)I[sub 7]-(5)I[sub 8] at 2.0 micron emission bands) Er-Ho YAG thin film selective emitter.

  10. Transit time and charge storage measurements in heavily doped emitters

    NASA Technical Reports Server (NTRS)

    Neugroschel, A.; Park, J. S.; Hwang, B. Y.

    1986-01-01

    A first direct measurement of the minority-carrier transit time in a transparent heavily doped emitter layer is reported. The value was obtained by a high-frequency conductance method recently developed and used for low-doped Si. The transit time coupled with the steady-state current enables the determination of the quasi-static charge stored in the emitter and the quasi-static emitter capacitance. Using a transport model, from the measured transit time, the value for the minority-carrier diffusion coefficient and mobility is estimated. The measurements were done using a heavily doped emitter of the Si p(+)-n-p bipolar transistor. The new result indicates that the position-averaged minority-carrier diffusion coefficients may be much smaller than the corresponding majority-carrier values for emitters having a concentration ranging from about 3 x 10 to the 19th per cu cm to 10 to the 20th per cu cm.

  11. Evaluations of carbon nanotube field emitters for electron microscopy

    NASA Astrophysics Data System (ADS)

    Nakahara, Hitoshi; Kusano, Yoshikazu; Kono, Takumi; Saito, Yahachi

    2009-11-01

    Brightness of carbon nanotube (CNT) emitters was already reported elsewhere. However, brightness of electron emitter is affected by a virtual source size of the emitter, which strongly depends on electron optical configuration around the emitter. In this work, I- V characteristics and brightness of a CNT emitter are measured under a practical field emission electron gun (e-gun) configuration to investigate availability of CNT for electron microscopy. As a result, it is obtained that an emission area of MWNT is smaller than its tip surface area, and the emission area corresponds to a five-membered-ring with 2nd nearest six-membered-rings on the MWNT cap surface. Reduced brightness of MWNT is measured as at least 2.6×109 A/m 2 sr V. It is concluded that even a thick MWNT has enough brightness under a practical e-gun electrode configuration and suitable for electron microscopy.

  12. Radiative Performance of Rare Earth Garnet Thin Film Selective Emitters

    NASA Technical Reports Server (NTRS)

    Lowe, Roland A.; Chubb, Donald L.; Good, Brian S.

    1994-01-01

    In this paper we present the first emitter efficiency results for the thin film 40 percent Er-1.5 percent Ho YAG (Yttrium Aluminum Garnet, Y3Al5O12) and 25 percent Ho YAG selective emitter at 1500 K with a platinum substrate. Spectral emittance and emissive power measurements were made (1.2 less than lambda less than 3.2 microns). Emitter efficiency and power density are significantly improved with the addition of multiple rare earth dopants. Predicted efficiency results are presented for an optimized (equal power density in the Er, (4)I(sub 15/2)-(4)I(sub 13/2) at 1.5 microns, and Ho, (5)I(sub 7)-(5)I(sub 8) at 2.0 micron emission bands) Er-Ho YAG thin film selective emitter.

  13. GTF Transverse and Longitudinal Emittance Data Analysis Technique

    SciTech Connect

    Not Available

    2010-12-07

    The SSRL Gun Test Facility (GTF) was built to develop a high brightness electron injector for the LCLS and has been operational since 1996. Measurements at the GTF include quadrupole scan transverse emittance measurements and linac phase scan longitudinal emittance measurements. Typically the beam size is measured on a screen as a function of a quadrupole current or linac phase and the beam matrix is then fit to the measured data. Often the emittance which is the final result of the measurement is the only number reported. However, the method used to reduce the data to the final emittance value can have a significant effect on the result. This paper describes in painful detail the methods used to analyze the transverse and longitudinal emittance data collected at the GTF.

  14. Comment on 'Hunting long-lived gluinos at the Pierre Auger Observatory'

    SciTech Connect

    Kopenkin, V.; Fujimoto, Y.; Sinzi, T.

    2008-06-15

    A Comment on the article by Anchordoqui et al. 'Hunting long-lived gluinos at the Pierre Auger Observatory' [L. A. Anchordoqui, A. Delgado, C. A. Garcia Canal, and S. J. Sciutto, Phys. Rev. D 77, 023009 (2008)].

  15. Insight on hole-hole interaction and magnetic order from dichroic auger-photoelectron coincidence spectra.

    PubMed

    Cini, M; Perfetto, E; Gotter, R; Offi, F; Ruocco, A; Stefani, G

    2011-11-18

    The absence of sharp structures in the Auger line shapes of partially filled bands has severely limited the use of electron spectroscopy in magnetic crystals and other correlated materials. By a novel interplay of experimental and theoretical techniques we achieve a combined understanding of the photoelectron, Auger, and Auger-photoelectron coincidence spectra (APECS) of the antiferromagnetic CoO. A recently discovered dichroic effect in angle resolved (DEAR) APECS reveals a complex pattern in the Auger line shape, which is here explained in detail, labeling the final states by their total spin. Since the dichroic effect exists in the antiferromagnetic state but vanishes at the Néel temperature, the DEAR-APECS technique detects the phase transition from its local effects, thus providing a unique tool to observe and understand magnetic correlations where the usual methods are not applicable.

  16. Auger electron angular distribution of double core-hole states in the molecular reference frame.

    PubMed

    Cryan, James P; Glownia, J M; Andreasson, J; Belkacem, A; Berrah, N; Blaga, C I; Bostedt, C; Bozek, J; Buth, C; DiMauro, L F; Fang, L; Gessner, O; Guehr, M; Hajdu, J; Hertlein, M P; Hoener, M; Kornilov, O; Marangos, J P; March, A M; McFarland, B K; Merdji, H; Petrović, V S; Raman, C; Ray, D; Reis, D; Tarantelli, F; Trigo, M; White, J L; White, W; Young, L; Bucksbaum, P H; Coffee, R N

    2010-08-20

    The Linac Coherent Light Source free electron laser is a source of high brightness x rays, 2×10(11) photons in a ∼5 fs pulse, that can be focused to produce double core vacancies through rapid sequential ionization. This enables double core vacancy Auger electron spectroscopy, an entirely new way to study femtosecond chemical dynamics with Auger electrons that probe the local valence structure of molecules near a specific atomic core. Using 1.1 keV photons for sequential x-ray ionization of impulsively aligned molecular nitrogen, we observed a rich single-site double core vacancy Auger electron spectrum near 413 eV, in good agreement with ab initio calculations, and we measured the corresponding Auger electron angle dependence in the molecular frame.

  17. A local chemical environment effect in site-specific Auger spectra of ethyl trifluoroacetate.

    PubMed

    Iwayama, H; Sisourat, N; Lablanquie, P; Penent, F; Palaudoux, J; Andric, L; Eland, J H D; Bučar, K; Žitnik, M; Velkov, Y; Hikosaka, Y; Nakano, M; Shigemasa, E

    2013-01-14

    We have investigated a local chemical environment effect on Auger spectra of ethyl trifluoroacetate (C(4)H(5)F(3)O(2)), using multi-electron coincidence spectroscopy and high-resolution electron spectroscopy. Site-specific KVV Auger spectra for each carbon atom, and for the fluorine and oxygen atoms are presented. The extent of hole localization in the final dicationic states was investigated with the help of theoretical calculations based on a two-hole population analysis. The Auger spectra have been simulated using a statistical approach. It is found that all Auger decays populate mainly localized dicationic states, with the two holes located either on the same fluorine atom or on adjacent fluorine atoms. While the decay of the F 1s hole populates exclusively the former states, the latter class of states is also populated by the decay of the C and O 1s holes.

  18. Auger Electron Angular Distribution of Double Core-Hole States in the Molecular Reference Frame

    NASA Astrophysics Data System (ADS)

    Cryan, James P.; Glownia, J. M.; Andreasson, J.; Belkacem, A.; Berrah, N.; Blaga, C. I.; Bostedt, C.; Bozek, J.; Buth, C.; Dimauro, L. F.; Fang, L.; Gessner, O.; Guehr, M.; Hajdu, J.; Hertlein, M. P.; Hoener, M.; Kornilov, O.; Marangos, J. P.; March, A. M.; McFarland, B. K.; Merdji, H.; Petrović, V. S.; Raman, C.; Ray, D.; Reis, D.; Tarantelli, F.; Trigo, M.; White, J. L.; White, W.; Young, L.; Bucksbaum, P. H.; Coffee, R. N.

    2010-08-01

    The Linac Coherent Light Source free electron laser is a source of high brightness x rays, 2×1011 photons in a ˜5fs pulse, that can be focused to produce double core vacancies through rapid sequential ionization. This enables double core vacancy Auger electron spectroscopy, an entirely new way to study femtosecond chemical dynamics with Auger electrons that probe the local valence structure of molecules near a specific atomic core. Using 1.1 keV photons for sequential x-ray ionization of impulsively aligned molecular nitrogen, we observed a rich single-site double core vacancy Auger electron spectrum near 413 eV, in good agreement with ab initio calculations, and we measured the corresponding Auger electron angle dependence in the molecular frame.

  19. Low-energy Auger electron diffraction: influence of multiple scattering and angular momentum

    NASA Astrophysics Data System (ADS)

    Chassé, A.; Niebergall, L.; Kucherenko, Yu.

    2002-04-01

    The angular dependence of Auger electrons excited from single-crystal surfaces is treated theoretically within a multiple-scattering cluster model taking into account the full Auger transition matrix elements. In particular the model has been used to discuss the influence of multiple scattering and angular momentum of the Auger electron wave on Auger electron diffraction (AED) patterns in the region of low kinetic energies. Theoretical results of AED patterns are shown and discussed in detail for Cu(0 0 1) and Ni(0 0 1) surfaces, respectively. Even though Cu and Ni are very similar in their electronic and scattering properties recently strong differences have been found in AED patterns measured in the low-energy region. It is shown that the differences may be caused to superposition of different electron diffraction effects in an energy-integrated experiment. A good agreement between available experimental and theoretical results has been achieved.

  20. Auger electron diffraction in thin CoO films on Au(1 1 1)

    NASA Astrophysics Data System (ADS)

    Chassé, A.; Niebergall, L.; Heiler, M.; Neddermeyer, H.; Schindler, K.-M.

    The local structure of thin CoO films grown on a single crystal Au(1 1 1) surface has been studied by Auger electron diffraction (AED). Therefore, the angular dependence of the Auger electron intensity of Co-LMM and O-KLL Auger electrons was recorded in the total half-space above the film. Such 2 π-scans immediately reflect the symmetry of the surface and the local structure of the film. The experimental data are compared to multiple-scattering cluster calculations, where both the influence of multiple-scattering effects and effects of Auger transition matrix elements have been investigated. We have found that the AED patterns of a CoO film in forward-scattering conditions do not always provide straightforward information on the local structure of the film, whereas the multiple-scattering approximation applied gives very good agreement between experimental and theoretical results.

  1. Experimental and theoretical study of the double-core-hole hypersatellite Auger spectrum of Ne

    NASA Astrophysics Data System (ADS)

    Goldsztejn, G.; Püttner, R.; Journel, L.; Guillemin, R.; Travnikova, O.; Cunha de Miranda, B.; Ismail, I.; Carniato, S.; Selles, P.; Céolin, D.; Lago, A. F.; Feifel, R.; Lablanquie, P.; Penent, F.; Piancastelli, M. N.; Simon, M.; Marchenko, T.

    2017-07-01

    We present the hypersatellite Auger spectrum of neon which contains the decay transitions of the K-2, K-2V , K-2L-1 , K-2L-1V , and K-1L-1V states. The Auger decays of these types of core-hole states show different line shapes and linewidths which can be distinguished due to the high experimental resolution available for the present experiments. The individual Auger transitions are assigned based on various approaches. Complementary calculations are performed to assign the K-2L-1→K-1L-3 and the K-2L-1V →K-1L-3V Auger transitions. Based on the obtained results we were able to derive the ratio for the double to single ionization yield.

  2. Theory and measurements of emittance preservation in plasma wakefield acceleration

    SciTech Connect

    Frederico, Joel

    2016-12-01

    In this dissertation, we examine the preservation and measurement of emittance in the plasma wakefield acceleration blowout regime. Plasma wakefield acceleration (PWFA) is a revolutionary approach to accelerating charged particles that has been demonstrated to have the potential for gradients orders of magnitude greater than traditional approaches. The application of PWFA to the design of a linear collider will make new high energy physics research possible, but the design parameters must first be shown to be competitive with traditional methods. Emittance preservation is necessary in the design of a linear collider in order to maximize luminosity. We examine the conditions necessary for circular symmetry in the PWFA blowout regime, and demonstrate that current proposals meet these bounds. We also present an application of beam lamentation which describes the process of beam parameter and emittance matching. We show that the emittance growth saturates as a consequence of energy spread in the beam. The initial beam parameters determine the amount of emittance growth, while the contribution of energy spread is negligible. We also present a model for ion motion in the presence of a beam that is much more dense than the plasma. By combining the model of ion motion and emittance growth, we find the emittance growth due to ion motion is minimal in the case of marginal ion motion. In addition, we present a simulation that validates the ion motion model, which is under further development to examine emittance growth of both marginal and pronounced ion motion. Finally, we present a proof-of-concept of an emittance measurement which may enable the analysis of emittance preservation in future PWFA experiments.

  3. Powerful ultrawideband rf emitters: status and challenges

    NASA Astrophysics Data System (ADS)

    Agee, Forrest J.; Scholfield, David W.; Prather, William D.; Burger, Jeffrey W.

    1995-09-01

    Ultra-wideband emitters are of interest for a variety of potential applications that range from radar transmitters to communications applications. This technology is of current interest to the USAF Phillips Laboratory where theoretical and experimental efforts have been underway for a number of years. Research into the production of ultra-wideband sources at the Phillips Laboratory has been accomplished along several different technology lines. The approaches include three main thrusts: 1) very powerful hydrogen spark gap pulsers, 2) compact hydrogen gas switches in conjunction with high gain ultra-wideband antennas and, 3) solid state switched array antennas. This paper reviews the progress-to-date along these lines and identifies some pacing research obastacles that limit further improvements.

  4. Odd-odd deformed proton emitters.

    PubMed

    Ferreira, L S; Maglione, E

    2001-02-26

    Proton decay from odd-odd deformed nuclei is a long-standing unsolved problem. We present for the first time an exact solution using single particle Nilsson resonances. The lifetime is found to depend strongly on the single particle level occupied by the unpaired neutron, allowing a clear assignment of its Nilsson level. The emitters 112Cs, 140Ho, 150Lu, and 150Lu(m) are considered. The agreement with the experimental data is very good with deformations 0.1

  5. Plasma treatment for producing electron emitters

    DOEpatents

    Coates, Don Mayo; Walter, Kevin Carl

    2001-01-01

    Plasma treatment for producing carbonaceous field emission electron emitters is disclosed. A plasma of ions is generated in a closed chamber and used to surround the exposed surface of a carbonaceous material. A voltage is applied to an electrode that is in contact with the carbonaceous material. This voltage has a negative potential relative to a second electrode in the chamber and serves to accelerate the ions toward the carbonaceous material and provide an ion energy sufficient to etch the exposed surface of the carbonaceous material but not sufficient to result in the implantation of the ions within the carbonaceous material. Preferably, the ions used are those of an inert gas or an inert gas with a small amount of added nitrogen.

  6. Gamma emitters in Hong Kong water

    SciTech Connect

    Shun-Yin, L.; Chung-Keung, M.; Wai-Kwok, N.; Shiu-Chun, A. )

    1990-01-01

    Radioactivity in water originates from natural and artificial sources. The development of a nuclear powerplant near Hong Kong necessitates that attention be given to formulating techniques to assess the possible resultant environmental radioactive contamination. Water samples collected from various sites in Hong Kong in the spring and summer of 1987, representing seawater, river water, reservoir water, drinking water, and underground water were studied through gamma-ray spectral analysis. Only gamma emitters in the U238 and Th232 series and K40 were detected. No fission product was detected with specific activity above 0.1 Bq/kg. The data could be the baseline for future monitoring of the radioactivity released from a nuclear plant being built at a 50-km distance from Hong Kong. The variation of detected specific activities may be due to geological differences and the effect of plants. 1 ref., 3 tabs.

  7. New strongly deformed proton emitter: 117La

    NASA Astrophysics Data System (ADS)

    Soramel, F.; Guglielmetti, A.; Stroe, L.; Müller, L.; Bonetti, R.; Poli, G. L.; Malerba, F.; Bianchi, E.; Andrighetto, A.; Guo, J. Y.; Li, Z. C.; Maglione, E.; Scarlassara, F.; Signorini, C.; Liu, Z. H.; Ruan, M.; Ivaşcu, M.; Broude, C.; Bednarczyk, P.; Ferreira, L. S.

    2001-03-01

    The decay by proton emission of the 117La nucleus has been studied via the 310 MeV 58Ni+64Zn reaction. The nucleus has two levels that decay to the ground state of 116Ba with Ep=783(6) keV (T1/2=22(5) ms] and Ep=933(10) keV [T1/2=10(5) ms]. Calculations performed for a deformed proton emitter reproduce quite well the experimental results confirming that 117La is strongly deformed (β2~0.3). Spin and parity of the two p-decaying levels have been determined as well: 3/2+ for the ground state and 9/2+ for the Ex=151(12) keV excited state.

  8. Lyman Alpha Emitters and Galaxy Formation Scenarios

    NASA Astrophysics Data System (ADS)

    Malhotra, S.; Kovac, K.; Somerville, R.; Moustakas, L.; Rhoads, J. E.

    2002-12-01

    The Large Area Lyman Alpha (LALA) survey has successfully identified the population of young Lyman-alpha emitting galaxies predicted about 35 years ago. High equivalent widths of the Lyman-alpha line in these sources suggest that they are a very young (age < 107 years), metal poor, population of stars at redshifts 4.5 and 5.7, making them very interesting objects to study in the context of galaxy formation scenarios. We have begun to do exactly this using the correlation function of LALA galaxies. While the strong correlation function indicates massive halos, the volume density of Lyman-alpha sources and the faint continuum levels indicate low-mass stellar systems. This discrepancy can be resolved by postulating multiple emitters in a single halo.

  9. Magnetic field emission gun with zirconiated emitter.

    PubMed

    Troyon, M

    1989-03-01

    A magnetic-field-superimposed field emission gun with low aberrations and equipped with a zirconiated tungsten emitter has been developed for applications where very stable high probe currents are required. It has been tested on a conventional electron microscope at 10 kV and on an electron beam testing system at 1 kV. Probe current i = 250 nA in a probe size d = 0.4 micron is obtained at 10 kV; at 1 kV the resolution is 0.1 micron with i = 5 nA, and 0.4 micron with i = 30 nA. For these probe currents, the spatial broadening effect due to electron-electron interactions in the beam is the preponderant factor limiting the probe size.

  10. Overcoming Auger recombination in nanocrystal quantum dot laser using spontaneous emission enhancement.

    PubMed

    Gupta, Shilpi; Waks, Edo

    2014-02-10

    We propose a method to overcome Auger recombination in nanocrystal quantum dot lasers using cavity-enhanced spontaneous emission. We derive a numerical model for a laser composed of nanocrystal quantum dots coupled to optical nanocavities with small mode-volume. Using this model, we demonstrate that spontaneous emission enhancement of the biexciton transition lowers the lasing threshold by reducing the effect of Auger recombination. We analyze a photonic crystal nanobeam cavity laser as a realistic device structure that implements the proposed approach.

  11. Auger contributions to electron impact ionization of Li-like ions

    NASA Astrophysics Data System (ADS)

    Hahn, Yukap

    1980-07-01

    Electron impact ionization by a two-step process of inner-shell excitation followed by an Auger emission is estimated for the Li-like Oxygen and Fe ions. Result for the O 5+ is in good agreement with a recent experiment by Crandall et al. for incident energies above the twice of threshold energy. The Auger cross section is very much reduced in the case of Fe 23+ because of a large fluorescence yield.

  12. 4f photoionization and subsequent Auger decay in atomic Pb: Relativistic effects

    SciTech Connect

    Patanen, M.; Kantia, T.; Heinaesmaeki, S.; Aksela, S.; Aksela, H.; Urpelainen, S.

    2011-05-15

    High-resolution 4f photoelectron and subsequent Auger-electron spectra have been measured from free Pb atoms using synchrotron radiation. The fine structure of the spectra has been investigated theoretically by calculating the energies and intensities for 4f photoionization and Auger decay processes using the multiconfigurational Dirac-Fock approach. The role of the relativistic effects in the ground and singly and doubly ionized states has been studied on the basis of computed results and their comparison with experiment.

  13. Detectability of a Direct Sequence Emitter within a Network of Direct Sequence Emitters,

    DTIC Science & Technology

    1988-01-01

    interception over 1/R propagation paths requires very large, ground-based antennas in order to achieve a usable intercept Signal-to- Noise Ratio (SNR). On...the other hand, free space, 1/R 2 propagation paths provide intercept receivers with signal power levels well above tne thermal noise power even when...large enough to resolve individual emitters are too large to put on aircraft as required to achieve the necessary free space propagation. Hence, the

  14. Determination and error analysis of emittance and spectral emittance measurements by remote sensing. [of leaves, soil and plant canopies

    NASA Technical Reports Server (NTRS)

    Kumar, R.

    1977-01-01

    Theoretical and experimental determinations of the emittance of soils and leaves are reviewed, and an error analysis of emittance and spectral emittance measurements is developed as an aid to remote sensing applications. In particular, an equation for the upper bound of the absolute error in an emittance determination is derived. The absolute error is found to decrease with an increase in contact temperature and to increase with an increase in environmental integrated radiant flux density. The difference between temperature and band radiance temperature is plotted as a function of emittance for the wavelength intervals 4.5 to 5.5 microns, 8 to 13.5 microns and 10.2 to 12.5 microns.

  15. Installation of observation wells on hazardous waste sites in Kansas using a hollow-stem auger

    USGS Publications Warehouse

    Perry, C.A.; Hart, R.J.

    1985-01-01

    Noncontaminating procedures were used during the hollow-stem auger installation of 12 observation wells on three hazardous waste sites in Kansas. Special precautions were taken to ensure that water samples were representative of the ground water in the aquifer and were not subjected to contamination from the land surface or cross contamination from within borehole. Precautions included thorough cleaning of the hollow-stem auger and casing, keeping drill cuttings from falling back into the borehole while drilling, and not adding water to the borehole. These procedures were designed to prevent contamination of the ground water during well installation. Because of the use of water during well installation could contaminate the aquifer or dilute contaminants already present in the aquifer, two methods of well installation that did not introduce outside water to the borehole were used. The first method involved using a slotted 3/4 -inch coupling that was attached to the bit plate of the hollow-stem auger, allowing formation water to enter the auger, thereby preventing sand-plug formation. This method proved to be adequate, except when drilling through clay layers, which tended to clog the slotted coupling. The second method involved screened well swab that allowed only formation water to enter the hollow-stem auger and prevented sand from plugging the hollow-stem auger when the bit plate was removed.

  16. Ramsey interferometry for resonant Auger decay through core-excited states

    NASA Astrophysics Data System (ADS)

    Chatterjee, Souvik; Nakajima, Takashi

    2016-08-01

    We theoretically investigate the electron dynamics in Ne atoms involving core-excited states through the Ramsey scheme with a pair of time-delayed x-ray pulses. Irradiation of Ne atoms by the ˜1 femtosecond x-ray pulse simultaneously populates two core-excited states, and an identical but time-delayed x-ray pulse probes the dynamics of the core-excited electron wave packet which is subject to the resonant Auger decay. The energy-integrated total Auger electron yield and energy-resolved Auger electron spectra in the time domain show periodic structures due to the temporal evolution of the wave packet, from which we can obtain the counterpart in the frequency domain through the Fourier transformation. The Auger electron energy spectra in the time as well as frequency domains show the interference patterns between the two Auger electron wave packets released into the continuum from the superposition of two core-excited states at different times. These spectra are important to clarify the individual contribution of the different Auger decay channels upon core excitation by the x-ray pulse.

  17. Energies, radiative and Auger transitions of the core-excited states for the boron atom

    NASA Astrophysics Data System (ADS)

    Chen, Chao; Sun, Yan; Cong Gou, Bing

    2014-09-01

    Energies, radiative and Auger transitions of the 1s vacancy resonances 1s2s22p2, 1s2s22p3p, 1s2s2p3, 1s2p4, and 1s2p33p, 4L (L=S, P, D) for the neutral boron atom are calculated using the saddle-point variation and saddle-point complex-rotation methods. Large-scale wave functions are used to obtain reliable results. Relativistic and mass polarization corrections are included by the first-order perturbation theory. The calculated term energies, x-ray wavelengths, and Auger electron energies for these core-excited states are compared with available theoretical and experimental results. Auger electron energies and branching ratios are used to identify high-resolution B Auger spectrum produced in 300 keV B+ on CH4 collision experiment. It is found that the Auger decay of core-excited states of the boron atom gives significant contributions to Auger spectrum in the range of 165-210 eV, and many previously unknown line identifications are presented.

  18. Physical electrostatics of small field emitter arrays/clusters

    NASA Astrophysics Data System (ADS)

    Forbes, Richard G.

    2016-08-01

    This paper aims to improve qualitative understanding of electrostatic influences on apex field enhancement factors (AFEFs) for small field emitter arrays/clusters. Using the "floating sphere at emitter-plate potential" (FSEPP) model, it re-examines the electrostatics and mathematics of three simple systems of identical post-like emitters. For the isolated emitter, various approaches are noted. An adequate approximation is to consider only the effects of sphere charges and (for significantly separated emitters) image charges. For the 2-emitter system, formulas are found for charge-transfer ("charge-blunting") effects and neighbor-field effects, for widely spaced and for "sufficiently closely spaced" emitters. Mutual charge-blunting is always the dominant effect, with a related (negative) fractional AFEF-change δtwo. For sufficiently small emitter spacing c, |δtwo| varies approximately as 1/c; for large spacing, |δtwo| decreases as 1/c3. In a 3-emitter equispaced linear array, differential charge-blunting and differential neighbor-field effects occur, but differential charge-blunting effects are dominant, and cause the "exposed" outer emitters to have higher AFEF (γ0) than the central emitter (γ1). Formulas are found for the exposure ratio Ξ = γ0/γ1, for large and for sufficiently small separations. The FSEPP model for an isolated emitter has accuracy around 30%. Line-charge models (LCMs) are an alternative, but an apparent difficulty with recent LCM implementations is identified. Better descriptions of array electrostatics may involve developing good fitting equations for AFEFs derived from accurate numerical solution of Laplace's equation, perhaps with equation form(s) guided qualitatively by FSEPP-model results. In existing fitting formulas, the AFEF-reduction decreases exponentially as c increases, which is different from the FSEPP-model formulas. This discrepancy needs to be investigated, using systematic Laplace-based simulations and appropriate results

  19. A MEMS-based infrared emitter array for combat identification

    NASA Astrophysics Data System (ADS)

    San, Haisheng; Chen, Xuyuan; Xu, Peng; Li, Fangqiang; Cheng, Meiying

    2008-04-01

    The silicon-based MEMS (MEMS: microelectromechanical systems) Infrared (IR) emitter arrays of 1x2, 2x2 and 3x3 elements are presented. The MEMS infrared emitters were fabricated on silicon-on-insulator (SOI) wafer. The resistively heated poly-silicon membrane fabricated by using deep reactive ion etching (DRIE) process on backside of SOI wafer make a low thermal mass structure, thus this IR-emitter can be modulated at high frequency. A heavily boron doping technology enable the supporting silicon layer to absorb the infrared radiation. As a result, the self-heating effect will reduce the power loss. By using the SOI wafer, the fabrication processes are simplified, and the production costs are decreased. In experiment, the surface temperature distribution of IR emitter arrays were measured by thermal imaging system, and the optical spectrum and modulation characteristics were measured by spectroradiometer. The measured results show that the IR emitter arrays exhibit a strong emission in middle infrared range, and the modulation frequency at 0.5 modulation depth is about 30Hz. The emitter arrays are expected to improve performance by using suspended membrane and sealed package structure. It is expected that the IR emitter arrays can be used for increasing the visible intensity and distance in the application of infrared Combat Identification.

  20. Emittance growth mechanisms for laser-accelerated proton beams.

    PubMed

    Kemp, Andreas J; Fuchs, J; Sentoku, Y; Sotnikov, V; Bakeman, M; Antici, P; Cowan, T E

    2007-05-01

    In recent experiments the transverse normalized rms emittance of laser-accelerated MeV ion beams was found to be < 0.002 mm mrad, which is at least 100 times smaller than the emittance of thermal ion sources used in accelerators [T. E. Cowan, Phys. Rev. Lett. 92, 204801 (2004)]. We investigate the origin for the low emittance of laser-accelerated proton beams by studying several candidates for emittance-growth mechanisms. As our main tools, we use analytical models and one- and two-dimensional particle-in-cell simulations that have been modified to include binary collisions between particles. We find that the dominant source of emittance is filamentation of the laser-generated hot electron jets that drive the ion acceleration. Cold electron-ion collisions that occur before ions are accelerated contribute less than ten percent of the final emittance. Our results are in qualitative agreement with the experiment, for which we present a refined analysis relating emittance to temperature, a better representative of the fundamental beam physics.