The Experts below are selected from a list of 6924 Experts worldwide ranked by ideXlab platform
Ruud Visser - One of the best experts on this subject based on the ideXlab platform.
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
The Astrophysical Journal, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate ζ{sub SLR} arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside R ∼> 30 AU for typical disk masses M{sub g} = 0.04 M{sub ☉}. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the interstellar medium. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, ζ{sub CR}, equal to or substantially below that of SLRs (ζ{sub SLR} ∼< 10{sup –18} s{sup –1}). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically Gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate inmore » the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range ζ{sub SLR} ∼ (1-10) × 10{sup –19} s{sup –1}.« less
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
arXiv: Solar and Stellar Astrophysics, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate $\zeta_{\rm{SLR}}$ arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside $R\gtrsim30$ for typical disk masses $M_g=0.04$ M$_\odot$. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the ISM. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, $\zeta_{\rm{CR}}$, equal to or substantially below that of SLRs ($\zeta_{\rm{SLR}}\lesssim10^{-18}$ s$^{-1}$). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate in the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range $\zeta_{\rm{SLR}}\sim(1-10)\times10^{-19}$ s$^{-1}$.
Ilsedore L Cleeves - One of the best experts on this subject based on the ideXlab platform.
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
The Astrophysical Journal, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate ζ{sub SLR} arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside R ∼> 30 AU for typical disk masses M{sub g} = 0.04 M{sub ☉}. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the interstellar medium. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, ζ{sub CR}, equal to or substantially below that of SLRs (ζ{sub SLR} ∼< 10{sup –18} s{sup –1}). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically Gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate inmore » the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range ζ{sub SLR} ∼ (1-10) × 10{sup –19} s{sup –1}.« less
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
arXiv: Solar and Stellar Astrophysics, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate $\zeta_{\rm{SLR}}$ arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside $R\gtrsim30$ for typical disk masses $M_g=0.04$ M$_\odot$. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the ISM. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, $\zeta_{\rm{CR}}$, equal to or substantially below that of SLRs ($\zeta_{\rm{SLR}}\lesssim10^{-18}$ s$^{-1}$). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate in the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range $\zeta_{\rm{SLR}}\sim(1-10)\times10^{-19}$ s$^{-1}$.
Fred C Adams - One of the best experts on this subject based on the ideXlab platform.
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
The Astrophysical Journal, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate ζ{sub SLR} arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside R ∼> 30 AU for typical disk masses M{sub g} = 0.04 M{sub ☉}. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the interstellar medium. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, ζ{sub CR}, equal to or substantially below that of SLRs (ζ{sub SLR} ∼< 10{sup –18} s{sup –1}). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically Gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate inmore » the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range ζ{sub SLR} ∼ (1-10) × 10{sup –19} s{sup –1}.« less
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
arXiv: Solar and Stellar Astrophysics, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate $\zeta_{\rm{SLR}}$ arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside $R\gtrsim30$ for typical disk masses $M_g=0.04$ M$_\odot$. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the ISM. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, $\zeta_{\rm{CR}}$, equal to or substantially below that of SLRs ($\zeta_{\rm{SLR}}\lesssim10^{-18}$ s$^{-1}$). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate in the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range $\zeta_{\rm{SLR}}\sim(1-10)\times10^{-19}$ s$^{-1}$.
Edwin A Bergin - One of the best experts on this subject based on the ideXlab platform.
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
The Astrophysical Journal, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate ζ{sub SLR} arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside R ∼> 30 AU for typical disk masses M{sub g} = 0.04 M{sub ☉}. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the interstellar medium. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, ζ{sub CR}, equal to or substantially below that of SLRs (ζ{sub SLR} ∼< 10{sup –18} s{sup –1}). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically Gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate inmore » the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range ζ{sub SLR} ∼ (1-10) × 10{sup –19} s{sup –1}.« less
-
radionuclide ionization in protoplanetary disks calculations of decay product radiative transfer
arXiv: Solar and Stellar Astrophysics, 2013Co-Authors: Ilsedore L Cleeves, Fred C Adams, Edwin A Bergin, Ruud VisserAbstract:We present simple analytic solutions for the ionization rate $\zeta_{\rm{SLR}}$ arising from the decay of short-lived radionuclides (SLRs) within protoplanetary disks. We solve the radiative transfer problem for the decay products within the disk, and thereby allow for the loss of radiation at low disk surface densities; energy loss becomes important outside $R\gtrsim30$ for typical disk masses $M_g=0.04$ M$_\odot$. Previous studies of chemistry/physics in these disks have neglected the impact of ionization by SLRs, and often consider only cosmic rays (CRs), because of the high CR-rate present in the ISM. However, recent work suggests that the flux of CRs present in the circumstellar environment could be substantially reduced by relatively modest stellar winds, resulting in severely modulated CR ionization rates, $\zeta_{\rm{CR}}$, equal to or substantially below that of SLRs ($\zeta_{\rm{SLR}}\lesssim10^{-18}$ s$^{-1}$). We compute the net Ionizing Particle fluxes and corresponding ionization rates as a function of position within the disk for a variety of disk models. The resulting expressions are especially simple for the case of vertically gaussian disks (frequently assumed in the literature). Finally, we provide a power-law fit to the ionization rate in the midplane as a function of gas disk surface density and time. Depending on location in the disk, the ionization rates by SLRs are typically in the range $\zeta_{\rm{SLR}}\sim(1-10)\times10^{-19}$ s$^{-1}$.
Hidalgo S. - One of the best experts on this subject based on the ideXlab platform.
-
Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications
'Elsevier BV', 2019Co-Authors: Currás E., Carulla M., Centis Vignali M., Duarte-campderros J., Fernández M., Flores D., García A., Gómez G., González J., Hidalgo S.Abstract:Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 mm$^2$ ; and a good timing resolution, around 20–30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP Particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100 % fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 mm 2 ; and a good timing resolution, around 20–30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP Particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100 % fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 $mm^2$; and a good timing resolution, around 20-30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP Particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100${\%}$ fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented
-
Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications
'Elsevier BV', 2019Co-Authors: Currás E., Carulla M., Duarte-campderros J., Fernández M., Flores D., García A., Gómez G., González J., Vignali M. Centis, Hidalgo S.Abstract:Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 $mm^2$; and a good timing resolution, around 20-30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP Particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100${\%}$ fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Comment: Conference Proceedings of VCI2019, 15th Vienna Conference of Instrumentation, February 18-22, 2019, Vienna, Austri
