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73 results on '"Piller, C."'

1. Negative ion radio frequency surface plasma source with solenoidal magnetic field

Author

Dudnikov, V., Johnson, R. P., Han, B., Kang, Y., Murray, S., Pennisi, T., Piller, C., Stinson, C., Stockli, M., Welton, R., and Dudnikova, G.

Subjects
Physics - Plasma Physics
Abstract

Pulsed and CW operation of negative ion radio frequency surface plasma source with a solenoidal magnetic field is described. Dependences of a beam current on RF power, extraction voltage, solenoid magnetic field, gas flow are presented. Compact design of RF SPS is presented., Comment: arXiv admin note: text overlap with arXiv:1808.02829

Published
2018
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2. RF Positive Ion Source with Solenoidal Magnetic Field

Author

Dudnikov, V., Johnson, R. P., Han, B., Kang, Y., Murray, S., Pennisi, T., Piller, C., Stinson, C., Stockli, M., Welton, R., and Dudnikova, G.

Subjects
Physics - Plasma Physics
Abstract

A positive ion source with RF discharge in solenoidal magnetic field is described. In this paper we present an overview of positive ion production in saddle antenna (helicon discharge) radio frequency (SA RF) ion sources. The efficiency of H+ ion production in recently developed RF sources with solenoidal antennas was improved to 2.9 mA/kW. About 24 kW of RF power is typically needed for 70 mA beam current production from a 7 mm emission aperture. This efficiency is relatively low because in the RF discharge with a solenoidal antenna, the plasma is generated near the coil and diffuses to the axis creating a nearly uniform plasma density distribution in all cross sections of the discharge chamber, when the plasma flow is necessary only near an emission aperture. The efficiency of the extracted ion generation was improved significantly by using a saddle antenna with solenoidal magnetic field. In the RF discharge with the saddle antenna the plasma is generated near the axis and the magnetic field suppress the plasma diffusion from the axis, creating a peaked plasma density distribution on the emission aperture. With the SA the efficiency of positive ion generation in the plasma has been improved up to ~100 mA/cm2 per kW of RF power at 13.56 MHz. Continuous wave (CW) operation of the RF source has been tested on the small ORNL SNS test stand. The general design of the CW RF source is based on the pulsed version. A compact design of ion source is presented. Some modifications were made to improve the cooling and to simplify the design. Features of SA RF discharges and ion generation are discussed.

Published
2018

5. The Spallation Neutron Source accelerator system design

Author

Henderson, S., Abraham, W., Aleksandrov, A., Allen, C., Alonso, J., Anderson, D., Arenius, D., Arthur, T., Assadi, S., Ayers, J., Bach, P., Badea, V., Battle, R., Beebe-Wang, J., Bergmann, B., Bernardin, J., Bhatia, T., Billen, J., Birke, T., Bjorklund, E., Blaskiewicz, M., Blind, B., Blokland, W., Bookwalter, V., Borovina, D., Bowling, S., Bradley, J., Brantley, C., Brennan, J., Brodowski, J., Brown, S., Brown, R., Bruce, D., Bultman, N., Cameron, P., Campisi, I., Casagrande, F., Catalan-Lasheras, N., Champion, M., Chen, Z., Cheng, D., Cho, Y., Christensen, K., Chu, C., Cleaves, J., Connolly, R., Cote, T., Cousineau, S., Crandall, K., Creel, J., Crofford, M., Cull, P., Cutler, R., Dabney, R., Dalesio, L., Daly, E., Damm, R., Danilov, V., Davino, D., Davis, K., Dawson, C., Day, L., Deibele, C., Delayen, J., DeLong, J., Demello, A., DeVan, W., Digennaro, R., Dixon, K., Dodson, G., Doleans, M., Doolittle, L., Doss, J., Drury, M., Elliot, T., Ellis, S., Error, J., Fazekas, J., Fedotov, A., Feng, P., Fischer, J., Fox, W., Fuja, R., Funk, W., Galambos, J., Ganni, V., Garnett, R., Geng, X., Gentzlinger, R., Giannella, M., Gibson, P., Gillis, R., Gioia, J., Gordon, J., Gough, R., Greer, J., Gregory, W., Gribble, R., Grice, W., Gurd, D., Gurd, P., Guthrie, A., Hahn, H., Hardek, T., Hardekopf, R., Harrison, J., Hatfield, D., He, P., Hechler, M., Heistermann, F., Helus, S., Hiatt, T., Hicks, S., Hill, J., Hoff, L., Hoff, M., Hogan, J., Holding, M., Holik, P., Holmes, J., Holtkamp, N., Hovater, C., Howell, M., Hseuh, H., Huhn, A., Hunter, T., Ilg, T., Jackson, J., Jain, A., Jason, A., Jeon, D., Johnson, G., Jones, A., Joseph, S., Justice, A., Kang, Y., Kasemir, K., Keller, R., Kersevan, R., Kerstiens, D., Kesselman, M., Kim, S., Kneisel, P., Kravchuk, L., Kuneli, T., Kurennoy, S., Kustom, R., Kwon, S., Ladd, P., Lambiase, R., Lee, Y.Y., Leitner, M., Leung, K.-N., Lewis, S., Liaw, C., Lionberger, C., Lo, C.C., Long, C., Ludewig, H., Ludvig, J., Luft, P., Lynch, M., Ma, H., MacGill, R., Macha, K., Madre, B., Mahler, G., Mahoney, K., Maines, J., Mammosser, J., Mann, T., Marneris, I., Marroquin, P., Martineau, R., Matsumoto, K., McCarthy, M., McChesney, C., McGahern, W., McGehee, P., Meng, W., Merz, B., Meyer, R., Jr., Meyer, R., Sr., Miller, B., Mitchell, R., Mize, J., Monroy, M., Munro, J., Murdoch, G., Musson, J., Nath, S., Nelson, R., O׳Hara, J., Olsen, D., Oren, W., Oshatz, D., Owens, T., Pai, C., Papaphilippou, I., Patterson, N., Patterson, J., Pearson, C., Pelaia, T., Pieck, M., Piller, C., Plawski, T., Plum, M., Pogge, J., Power, J., Powers, T., Preble, J., Prokop, M., Pruyn, J., Purcell, D., Rank, J., Raparia, D., Ratti, A., Reass, W., Reece, K., Rees, D., Regan, A., Regis, M., Reijonen, J., Rej, D., Richards, D., Richied, D., Rode, C., Rodriguez, W., Rodriguez, M., Rohlev, A., Rose, C., Roseberry, T., Jr., Rowton, L., Roybal, W., Rust, K., Salazer, G., Sandberg, J., Saunders, J., Schenkel, T., Schneider, W., Schrage, D., Schubert, J., Severino, F., Shafer, R., Shea, T., Shishlo, A., Shoaee, H., Sibley, C., Sims, J., Smee, S., Smith, J., Smith, K., Spitz, R., Staples, J., Stein, P., Stettler, M., Stirbet, M., Stockli, M., Stone, W., Stout, D., Stovall, J., Strelo, W., Strong, H., Sundelin, R., Syversrud, D., Szajbler, M., Takeda, H., Tallerico, P., Tang, J., Tanke, E., Tepikian, S., Thomae, R., Thompson, D., Thomson, D., Thuot, M., Treml, C., Tsoupas, N., Tuozzolo, J., Tuzel, W., Vassioutchenko, A., Virostek, S., Wallig, J., Wanderer, P., Wang, Y., Wang, J.G., Wangler, T., Warren, D., Wei, J., Weiss, D., Welton, R., Weng, J., Weng, W-T., Wezensky, M., White, M., Whitlatch, T., Williams, D., Williams, E., Wilson, K., Wiseman, M., Wood, R., Wright, P., Wu, A., Ybarrolaza, N., Young, K., Young, L., Yourd, R., Zachoszcz, A., Zaltsman, A., Zhang, S., Zhang, W., Zhang, Y., and Zhukov, A.

Published
2014
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7. H− ion source research and development at the Oak Ridge National Laboratory.

Author

Welton, R. F., Stockli, M. P., Han, B. X., Murray, S. N., Pennisi, T. R., Stinson, C., Aleksandrov, A., Piller, C., Kang, Y., and Tarvainen, O.

Subjects
ION sources, GOVERNMENT laboratories, PLASMA torch, NEUTRON beams, RESEARCH & development, SMALL-angle neutron scattering
Abstract

The U.S. Spallation Neutron Source (SNS) is a state-of-the-art neutron scattering facility delivering the world's most intense pulsed neutron beams to a wide array of instruments which are used to conduct investigations in many fields of science and engineering. Neutrons are produced by spallation of liquid Hg due to bombardment of short (∼1µs), intense (∼35 A) pulses of protons delivered at 60 Hz from a storage ring which is fed by a high-intensity, 1 GeV H− LINAC. This facility has operated almost continuously since 2006, with ion source performance increasing over those years, and currently providing 50-60 mA of H− ions with a duty-factor of 6% for maintenance-free runs of ∼120 days with near 100% availability. Ion source research and development at ORNL has played a key role in enabling and supporting these achievements: this report provides some historical highlights of this effort, describes our current ion source testing facilities, discusses the goals of the program and finally provides a snapshot of some of our ongoing R&D activities. In particular, we have recently simplified and improved the reliability of the plasma ignition gun for the external antenna ion source which is discussed in detail. [ABSTRACT FROM AUTHOR]

Published
2021
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10. PROCESSO DE NEGOCIAÇÃO E TRANSFERÊNCIA DE TECNOLOGIA EM UMA INSTITUIÇÃO MULTICAMPI: CASO DO IFBA

Author

Bruno Araujo Oliveira, Vivian Patricia Suzart, Wagna Piller C. Santos, and Anete Santos Santos

Subjects
Physics, parcerias, transferência tecnológica, General Medicine, Humanities, negociação, contratos
Abstract

A transferencia de tecnologia e um processo pelo qual apos o desenvolvimento de um produto ou processo cientifico e tecnologico, o que chamamos de Propriedade Intelectual, por meio de pesquisas, em um ambiente apropriado, principalmente, academico, seu resultado e transferido, atraves de acordos, parcerias e negociacoes, para analisar a melhor proposta, a fim de ser aprimorado o seu desenvolvimento e colocado no mercado, com isso contribuindo com o avanco economico do pais, alimentando a competitividade comercial. Esse processo a cada dia tem se firmado no cenario tecnologico de maneira muito contundente e segura, tendo em vista a apropriacao do bem intangivel e a necessidade de salvaguardar direitos inerentes ao bem intangivel. Geralmente, essas transacoes sao firmadas atraves de contratos, que externa um acordo de vontade celebrada entre partes. Em uma Instituicao multicampi nao e diferente, todo processo de transferencia de tecnologia e centralizada e acompanhada por um departamento especifico, de inovacao e transferencia tecnologica.

Published
2015

14. Saddle antenna radio frequency ion sources

Author

Dudnikov, V., primary, Johnson, R., additional, Murray, S., additional, Pennisi, T., additional, Santana, M., additional, Piller, C., additional, Stockli, M., additional, Welton, R., additional, Breitschopf, J., additional, and Dudnikova, G., additional

Published
2016
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16. Ion extraction from a saddle antenna RF surface plasma source

Author

Dudnikov, V., primary, Johnson, R. P., additional, Han, B., additional, Murray, S., additional, Pennisi, T., additional, Piller, C., additional, Santana, M., additional, Stockli, M., additional, Welton, R., additional, Breitschopf, J., additional, and Dudnikova, G., additional

Published
2015
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17. Recent Performance and Ignition Tests of the Pulsed SNS H- Source for 1-MW Neutron Production.

Author

Stockli, Martin P., Han, B. X., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., and Welton, R. F.

Subjects
NEUTRON multiplicity, ION beams, ELECTRIC fields, PLASMA gases, ELECTRIC potential
Abstract

After acquiring several reliable spare targets, SNS ramped the beam power from 850 kW to 1.4 MW, which required an increase in H- beam pulse length from 0.88 to 1.0 ms at 60 Hz. This increase initially produced slow 2-MHz power ramp-ups and, after several weeks of uninterrupted operation, it produced plasma outages every time the pulse length was raised above ~0.95 ms. Similar outages were previously observed towards the end of long service cycles, which were believed to indicate that the breakdown voltage of the high purity hydrogen started to exceed the induced electric fields. In 2011 the RF was reconfigured to start with 10 cycles of 1.96 MHz, which yielded the shortest H- beam rise times and apparently eliminated those plasma outages. The new, pulse-length dependent outages were eliminated by increasing the initial frequency to 1.985 MHz. However, careful frequency studies are unable to justify this frequency. In addition, the paper discusses the issues and solutions for the electron-dump voltage, which starts to sag and become unstable after several weeks of high current operation. [ABSTRACT FROM AUTHOR]

Published
2015
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18. Recent performance of and plasma outage studies with the SNS H- source.

Author

Stockli, M. P., Han, B., Murray, S. N., Pennisi, T. R., Piller, C., Santana, M., and Welton, R.

Subjects
SPALLATION (Nuclear physics), NEUTRON sources, DIRECTIONAL antennas, RADIO frequency, PLASMA gases
Abstract

Spallation Neutron Source ramps to higher power levels that can be sustained with high availability. The goal is 1.4MWdespite a compromised radio frequency quadrupole (RFQ), which requires higher radio frequency power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ~55-kW 2-MHz plasma pulses reflecting ~90% of the continuous ~300 W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly detuned 13-MHz match. Lowering the H2 gas also increased the H- beam current to ~55 mA and increased the RFQ transmission by ~7% (relative). [ABSTRACT FROM AUTHOR]

Published
2016
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19. Characterization of the CW starter plasma RF matching network for operating the SNS H- ion source with lower H2 flows.

Author

Han, B. X., Stockli, M. P., Kang, Y., Piller, C., Jr., S. N. Murray,, Pennisi, T. R., Santana, M., and Welton, R. F.

Subjects
RADIO frequency discharges, SPALLATION (Nuclear physics), NEUTRON sources, NUCLEAR physics instruments, QUADRUPOLE mass analyzers
Abstract

The Spallation Neutron Source H- ion source is operated with a pulsed 2-MHz RF (50-60 kW) to produce the 1-ms long, ~50 mA H- beams at 60 Hz. A continuous low power (~300 W) 13.56-MHz RF plasma, which is initially ignited with a H2 pressure bump, serves as starter plasma for the pulsed high power 2-MHz RF discharges. To reduce the risk of plasma outages at lower H2 flow rates which is desired for improved performance of the following radio frequency quadrupole, the 13.56-MHz RF matching network was characterized over a broad range of its two tuning capacitors. The H-α line intensity of the 13.56-MHz RF plasma and the reflected power of the 13.56-MHz RF were mapped against the capacitor settings. Optimal tunes for the maximum H-α intensity are consistent with the optimal tunes for minimum reflected power. Low limits of the H2 flow rate not causing plasma outages were explored within the range of the map. A tune region that allows lower H2 flow rate has been identified, which differs from the optimal tune for global minimum reflected power that was mostly used in the past. [ABSTRACT FROM AUTHOR]

Published
2016
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20. Firm misled investors on Alzheimer's drug, SEC charges.

Author

Piller C

Subjects
Humans, Investments, United States, Alzheimer Disease drug therapy, Alzheimer Disease economics, Drug Industry economics, Spiro Compounds economics, Scientific Misconduct
Abstract

Agency fines Cassava Sciences $40 million for touting flawed research on simufilam.

Published
2024
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21. Picture imperfect.

Author

Piller C

Abstract

Did a top NIH official, neuroscientist Eliezer Masliah, doctor influential Alzheimer's and Parkinson's studies for decades?

Published
2024
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22. Challenged papers underpin several drugs.

Author

Piller C

Subjects
Humans, National Institute on Aging (U.S.), Neuroprotective Agents therapeutic use, Clinical Trials as Topic, Scientific Misconduct, Antiparkinson Agents therapeutic use, Drug Industry
Published
2024
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25. 'Damning' FDA inspection report undermines Alzheimer's drug.

Author

Piller C

Subjects
Humans, United States, Clinical Trials as Topic, Alzheimer Disease drug therapy, Scientific Misconduct, Spiro Compounds therapeutic use, United States Food and Drug Administration
Abstract

Inspectors faulted analyses of clinical trial samples by Hoau-Yan Wang for drug developer Cassava Sciences.

Published
2024
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26. Brain games?

Author

Piller C

Subjects
Humans, Brain, Clinical Trials as Topic, National Institutes of Health (U.S.), Alzheimer Disease therapy, Stroke therapy, Whistleblowing, Scientific Misconduct
Abstract

Whistleblowers and former lab members suggest a star neuroscientist routinely manipulated data, compromising a planned NIH stroke trial and key Alzheimer's research.

Published
2023
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28. Report on trial death stokes Alzheimer's drug fears.

Author

Piller C

Subjects
Humans, Autopsy, Clinical Trials as Topic, Fear, United States Food and Drug Administration, Female, Aged, Alzheimer Disease drug therapy, Alzheimer Disease mortality, Amyloid beta-Peptides immunology, Antibodies, Monoclonal, Humanized adverse effects, Antibodies, Monoclonal, Humanized therapeutic use, Brain pathology
Abstract

Amyloid-clearing antibody lecanemab faces key FDA hearing in June.

Published
2023
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29. Alzheimer's drug stirs excitement-and concerns.

Author

Couzin-Frankel J and Piller C

Subjects
Humans, Randomized Controlled Trials as Topic, Alzheimer Disease drug therapy, Alzheimer Disease genetics, Apolipoprotein E4 genetics, Antibodies, Monoclonal, Humanized therapeutic use
Abstract

Antibody slows cognitive decline, but deaths, brain bleeds, and swelling mar results.

Published
2022
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32. Blots on a field?

Author

Piller C

Subjects
Humans, Alzheimer Disease drug therapy, Alzheimer Disease metabolism, Amyloid beta-Peptides chemistry, Amyloid beta-Peptides metabolism, Blotting, Western, Scientific Misconduct
Abstract

A neuroscience image sleuth finds signs of fabrication in scores of Alzheimer's articles, threatening a reigning theory of the disease.

Published
2022
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35. Failure to protect?

Author

Piller C

Subjects
Adolescent, Black or African American, Asthma complications, Child, Clinical Trial Protocols as Topic, Comparative Effectiveness Research, Dietary Supplements, Ethics Committees, Research, Humans, Informed Consent, Placebos, Standard of Care, Symptom Flare Up, Vitamin D Deficiency complications, Vitamin D Deficiency drug therapy, Vitamins administration & dosage, Asthma drug therapy, Randomized Controlled Trials as Topic ethics, Vitamin D administration & dosage
Published
2021
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38. How CDC foundered.

Author

Piller C

Subjects
Politics, Trust, United States, COVID-19, Centers for Disease Control and Prevention, U.S.
Published
2020
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39. Undermining CDC.

Author

Piller C

Subjects
Federal Government, Politics, Trust, United States, COVID-19 epidemiology, COVID-19 prevention & control, Centers for Disease Control and Prevention, U.S.
Published
2020
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41. Official inaction.

Author

Piller C

Subjects
Humans, Informed Consent ethics, United States, Clinical Trials as Topic ethics, Medical Errors ethics, United States Food and Drug Administration ethics
Published
2020
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42. Data secrecy may cripple U.S. attempts to slow pandemic.

Author

Piller C

Subjects
COVID-19, California epidemiology, Coronavirus Infections prevention & control, Disclosure, Humans, Pandemics prevention & control, Pneumonia, Viral prevention & control, Coronavirus Infections epidemiology, Information Dissemination, Pneumonia, Viral epidemiology
Published
2020
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44. Gaming the system.

Author

Piller C

Subjects
National Institutes of Health (U.S.), United States, Clinical Trials as Topic ethics, Clinical Trials as Topic organization & administration, Mandatory Reporting
Published
2020
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46. Upgrading the LANSCE accelerator with a SNS RF-driven H - ion source.

Author

Stockli MP, Han B, Clemmer M, Cousineau SM, Justice A, Kang YW, Murray SN Jr, Pennisi TR, Piller C, Stinson CM, Welton RF, Draganic IN, Batygin YK, Garnett RW, Kleinjan D, Medina JL, Montross JP, Rouleau G, and Dudnikov V

Abstract

The LANSCE accelerator is currently powered by a filament-driven, biased converter-type H - ion source that operates at 10%, the highest plasma duty factor for this type of source, using only ∼2.2 SCCM of H 2 . The ion source needs to be replaced every 4 weeks, which takes up to 4 days. The measured negative beam current of 12-16 mA falls below the desired 24 mA acceptance of the LANCSE accelerator. The SNS (Spallation Neutron Source) RF-driven, H - ion source injects ∼50 mA of H - beam into the SNS accelerator at 60 Hz with a 6% duty factor and an availability of >99.5% but requires ∼30 SCCM of H 2 . Up to 7 A h of H - have been produced during the 14-weeks-long source service cycles, which is unprecedented for small emittance, high-current, pulsed H - ion sources. The emittance of the SNS source is slightly smaller than the emittance of the LANSCE source. The SNS source also features unrivaled low Cs consumption and can be installed and started up in <12 h. LANSCE and SNS are working toward the use of SNS H - ion sources on the LANSCE accelerator because they could (a) fill the LANSCE accelerator to its capacity, (b) decrease the source replacement time by a factor of up to 7, and (c) increase source lifetime by a factor of about 4. This paper discusses some of the challenges that emerge when trying to match a different H - source into an existing injector with significantly different characteristics and operating regimes.

Published
2020
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47. Double dip.

Author

Piller C

Subjects
Drug Industry economics, Education, Medical economics, United States, National Institutes of Health (U.S.) economics, Physicians economics, Research Personnel economics, Training Support
Published
2019
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