Cheyne Scoby - Academia.edu (original) (raw)

Papers by Cheyne Scoby

Research paper thumbnail of Modification of ferromagnetism in semiconductors by molecular monolayers

Bulletin of the American Physical Society, Mar 21, 2005

We report that adsorption of monolayers of organic molecules onto ferromagnetic semiconductor het... more We report that adsorption of monolayers of organic molecules onto ferromagnetic semiconductor heterostructures can produce large changes in magnetic properties [1]. The digital-alloy heterostructures studied have 1/2 monolayer MnAs planes embedded in GaAs. We investigate effects on magnetic properties of self-assembly of various organic molecules onto the heterostructure surface. Depending on the molecular structure, the monolayers can either strengthen or suppress ferromagnetism. We attribute this chemical modulation of magnetic properties to electronic changes brought about by molecular binding to the semiconductor surface.

Research paper thumbnail of EMI/EMC, Lightning, Space Environment and SEE Design for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

Virgin Orbit has developed the LauncherOne (L1)two stage LOX/RP-1 launch system, capable of deplo... more Virgin Orbit has developed the LauncherOne (L1)two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO).The company has implemented an EMI/EMC Control Program, tailored from RTCA-DO-160F and MIL-STD-461F.Electromagnetic Compatibility (EMC) for LauncherOne has been verified to Launch Range, EGSE (electrical ground support equipment) and internal launch vehicle (LV) Avionics systems electromagnetic environments, by analysis, and tailored, limited component/unit test, subsystem test and limited system level test. The EMISMs (electromagnetic interference susceptibility margins) for interfaces internal to L1 and between L1-747, have been verified by System qualification test, and are 6dB for noncritical and 20dB for critical interfaces. [10] Reports the test methods used to verify functional performance and margins.

Research paper thumbnail of EMI/EMC, Lightning, and RF Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

Virgin Orbit has developed the LauncherOne (L1) two stage LOX/RP-1 launch system, capable of depl... more Virgin Orbit has developed the LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). The EMI/EMC Control Program has been tailored from RTCA-DO-160F and MIL-STD-461F. Electromagnetic Compatibility (EMC) for LauncherOne has been verified to Launch Range, EGSE (electrical ground support equipment) and internal launch vehicle (LV) Avionics systems electromagnetic environments, by tailored, limited component/unit test, subsystem test and limited system level test. The EMISMs (electromagnetic interference susceptibility margins) for interfaces internal to L1 and between L1-747, have been verified by System qualification test, and are 6dB for noncritical and 20dB for critical interfaces. This paper reports the test results used to verify functional performance and margins.

Research paper thumbnail of Single Event Effects Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

This paper describes the SEE (single event effects) design verification approach and proton beam ... more This paper describes the SEE (single event effects) design verification approach and proton beam verification test results for the Virgin Orbit LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). [9] Describes the EMI/EMC Control Program tailored from RTCA-DO-160F and MIL-STD-461F. [10] Reports the Electromagnetic Compatibility (EMC) verification procedures and results for LauncherOne,.

Research paper thumbnail of Timestamping for Relativistic Electron Diffraction

High brightness ultrashort electron beams have been produced at the UCLA Pegasus photoinjector la... more High brightness ultrashort electron beams have been produced at the UCLA Pegasus photoinjector lab for use in time-resolved electron diffraction applications. Beams have been generated with high enough brightness to obtain single shot diffraction patterns of thin solid targets. These beams contain a few pC at 3.5 MeV in a 200 fs pulse. Pump-probe experiments on thin metal foils have already shown promising results on picosecond time scales*. Current research focuses on materials with processes that are observable on the sub-100 fs scale. To overcome rf jitter and synchronization problems, electro-optic sampling is used as a single shot time-of-arrival diagnostic** to help reconstruct the melting "movie."

Research paper thumbnail of Relativistic electron diffraction at the UCLA Pegasus photoinjector laboratory

Research paper thumbnail of Effect of an ultrafast laser induced plasma on a relativistic electron beam to determine temporal overlap in pump–probe experiments

Ultramicroscopy, 2013

In this paper we report on a simple and robust method to measure the absolute temporal overlap of... more In this paper we report on a simple and robust method to measure the absolute temporal overlap of the laser and the electron beam at the sample based on the effect of a laser induced plasma on the electron beam transverse distribution, successfully extending a similar method from keV to MeV electron beams. By pumping a standard copper TEM grid to form the plasma, we gain timing information independent of the sample under study. In experiments discussed here the optical delay to achieve temporal overlap between the pump electron beam and probe laser can be determined with ~1 ps precision.

Research paper thumbnail of Low-Data Investigation of Higgs Boson Discovery at the LHC

Low-Data Investigation of Higgs Boson Discovery at the LHC

Research paper thumbnail of Molecular enhancement of ferromagnetism in GaAs∕GaMnAs heterostructures

Applied Physics Letters, 2006

The authors investigate effects of chemisorption of polar organic molecules onto ferromagnetic Ga... more The authors investigate effects of chemisorption of polar organic molecules onto ferromagnetic GaAs∕GaMnAs heterostructures. The chemisorbed heterostructures exhibit striking anisotropic enhancement of the magnetization, while GaAs substrates that are physisorbed with the same molecules show no change in magnetic properties. Thus the enhanced magnetism of the chemisorbed heterostructures reflects changes in spin alignment that arise from surface bonding of the organic monolayer.

Research paper thumbnail of Low-Cost Encapsulant for Solar Cells to Mitigate Degradation Effects Due to Energetic Space Environments in a 500Km Sun-Synchronous Orbit

Research paper thumbnail of Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

Research paper thumbnail of Single Event Effects Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE SIPI EMC , 2022

This paper describes the SEE (single event effects) design verification approach and proton beam ... more This paper describes the SEE (single event effects) design verification approach and proton beam verification test results for the Virgin Orbit LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). [9] Describes the EMI/EMC Control Program tailored from RTCA-DO-160F and MIL-STD-461F. [10] Reports the Electromagnetic Compatibility (EMC) verification procedures and results for LauncherOne,.

Research paper thumbnail of Modification of ferromagnetism in semiconductors by molecular monolayers

Bulletin of the American Physical Society, Mar 21, 2005

We report that adsorption of monolayers of organic molecules onto ferromagnetic semiconductor het... more We report that adsorption of monolayers of organic molecules onto ferromagnetic semiconductor heterostructures can produce large changes in magnetic properties [1]. The digital-alloy heterostructures studied have 1/2 monolayer MnAs planes embedded in GaAs. We investigate effects on magnetic properties of self-assembly of various organic molecules onto the heterostructure surface. Depending on the molecular structure, the monolayers can either strengthen or suppress ferromagnetism. We attribute this chemical modulation of magnetic properties to electronic changes brought about by molecular binding to the semiconductor surface.

Research paper thumbnail of EMI/EMC, Lightning, Space Environment and SEE Design for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

Virgin Orbit has developed the LauncherOne (L1)two stage LOX/RP-1 launch system, capable of deplo... more Virgin Orbit has developed the LauncherOne (L1)two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO).The company has implemented an EMI/EMC Control Program, tailored from RTCA-DO-160F and MIL-STD-461F.Electromagnetic Compatibility (EMC) for LauncherOne has been verified to Launch Range, EGSE (electrical ground support equipment) and internal launch vehicle (LV) Avionics systems electromagnetic environments, by analysis, and tailored, limited component/unit test, subsystem test and limited system level test. The EMISMs (electromagnetic interference susceptibility margins) for interfaces internal to L1 and between L1-747, have been verified by System qualification test, and are 6dB for noncritical and 20dB for critical interfaces. [10] Reports the test methods used to verify functional performance and margins.

Research paper thumbnail of EMI/EMC, Lightning, and RF Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

Virgin Orbit has developed the LauncherOne (L1) two stage LOX/RP-1 launch system, capable of depl... more Virgin Orbit has developed the LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). The EMI/EMC Control Program has been tailored from RTCA-DO-160F and MIL-STD-461F. Electromagnetic Compatibility (EMC) for LauncherOne has been verified to Launch Range, EGSE (electrical ground support equipment) and internal launch vehicle (LV) Avionics systems electromagnetic environments, by tailored, limited component/unit test, subsystem test and limited system level test. The EMISMs (electromagnetic interference susceptibility margins) for interfaces internal to L1 and between L1-747, have been verified by System qualification test, and are 6dB for noncritical and 20dB for critical interfaces. This paper reports the test results used to verify functional performance and margins.

Research paper thumbnail of Single Event Effects Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI)

This paper describes the SEE (single event effects) design verification approach and proton beam ... more This paper describes the SEE (single event effects) design verification approach and proton beam verification test results for the Virgin Orbit LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). [9] Describes the EMI/EMC Control Program tailored from RTCA-DO-160F and MIL-STD-461F. [10] Reports the Electromagnetic Compatibility (EMC) verification procedures and results for LauncherOne,.

Research paper thumbnail of Timestamping for Relativistic Electron Diffraction

High brightness ultrashort electron beams have been produced at the UCLA Pegasus photoinjector la... more High brightness ultrashort electron beams have been produced at the UCLA Pegasus photoinjector lab for use in time-resolved electron diffraction applications. Beams have been generated with high enough brightness to obtain single shot diffraction patterns of thin solid targets. These beams contain a few pC at 3.5 MeV in a 200 fs pulse. Pump-probe experiments on thin metal foils have already shown promising results on picosecond time scales*. Current research focuses on materials with processes that are observable on the sub-100 fs scale. To overcome rf jitter and synchronization problems, electro-optic sampling is used as a single shot time-of-arrival diagnostic** to help reconstruct the melting "movie."

Research paper thumbnail of Relativistic electron diffraction at the UCLA Pegasus photoinjector laboratory

Research paper thumbnail of Effect of an ultrafast laser induced plasma on a relativistic electron beam to determine temporal overlap in pump–probe experiments

Ultramicroscopy, 2013

In this paper we report on a simple and robust method to measure the absolute temporal overlap of... more In this paper we report on a simple and robust method to measure the absolute temporal overlap of the laser and the electron beam at the sample based on the effect of a laser induced plasma on the electron beam transverse distribution, successfully extending a similar method from keV to MeV electron beams. By pumping a standard copper TEM grid to form the plasma, we gain timing information independent of the sample under study. In experiments discussed here the optical delay to achieve temporal overlap between the pump electron beam and probe laser can be determined with ~1 ps precision.

Research paper thumbnail of Low-Data Investigation of Higgs Boson Discovery at the LHC

Low-Data Investigation of Higgs Boson Discovery at the LHC

Research paper thumbnail of Molecular enhancement of ferromagnetism in GaAs∕GaMnAs heterostructures

Applied Physics Letters, 2006

The authors investigate effects of chemisorption of polar organic molecules onto ferromagnetic Ga... more The authors investigate effects of chemisorption of polar organic molecules onto ferromagnetic GaAs∕GaMnAs heterostructures. The chemisorbed heterostructures exhibit striking anisotropic enhancement of the magnetization, while GaAs substrates that are physisorbed with the same molecules show no change in magnetic properties. Thus the enhanced magnetism of the chemisorbed heterostructures reflects changes in spin alignment that arise from surface bonding of the organic monolayer.

Research paper thumbnail of Low-Cost Encapsulant for Solar Cells to Mitigate Degradation Effects Due to Energetic Space Environments in a 500Km Sun-Synchronous Orbit

Research paper thumbnail of Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

Research paper thumbnail of Single Event Effects Test Verification for the Virgin Orbit LauncherOne Vehicle

2022 IEEE SIPI EMC , 2022

This paper describes the SEE (single event effects) design verification approach and proton beam ... more This paper describes the SEE (single event effects) design verification approach and proton beam verification test results for the Virgin Orbit LauncherOne (L1) two stage LOX/RP-1 launch system, capable of deploying payloads up to 300kg to 500km Sun Synchronous Orbit (SSO), and deploying payloads up to 500kg to 200km Low Earth Orbit (LEO). [9] Describes the EMI/EMC Control Program tailored from RTCA-DO-160F and MIL-STD-461F. [10] Reports the Electromagnetic Compatibility (EMC) verification procedures and results for LauncherOne,.