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Full-Text Articles in Physics

Flux Expulsion In Niobium Superconducting Radio-Frequency Cavities Of Different Purity And Essential Contributions To The Flux Sensitivity, P. Dhakal, Gianluigi Ciovati, Alex Gurevich Jan 2020

Flux Expulsion In Niobium Superconducting Radio-Frequency Cavities Of Different Purity And Essential Contributions To The Flux Sensitivity, P. Dhakal, Gianluigi Ciovati, Alex Gurevich

Physics Faculty Publications

Magnetic flux trapped during the cooldown of superconducting radio-frequency cavities through the transition temperature due to incomplete Meissner state is known to be a significant source of radio-frequency losses. The sensitivity of flux trapping depends on the distribution and the type of defects and impurities which pin vortices, as well as the cooldown dynamics when the cavity transitions from a normal to superconducting state. Here we present the results of measurements of the flux trapping sensitivity on 1.3 GHz elliptical cavities made from large-grain niobium with different purity for different cooldown dynamics and surface treatments. The results show that lower …


Improving Inverse Compton Sources By Avoiding Non-Linearities, B. Terzić, G. A. Krafft, V. Petrillo, I. Drebot, M. Ruijter Jan 2020

Improving Inverse Compton Sources By Avoiding Non-Linearities, B. Terzić, G. A. Krafft, V. Petrillo, I. Drebot, M. Ruijter

Physics Faculty Publications

We present a new, more nuanced understanding of non-linear effects in inverse Compton sources. Deleterious non-linear effects can arise even at low laser intensities, a regime previously viewed as linear. After laying out a survey of non-linear phenomena which degrade the effectiveness of inverse Compton sources, we discuss two powerful techniques designed to avoid these non-linearities. Starting with the known technique of non-linear longitudinal chirping of the laser pulse in the high laser field regime, we show that the simple stretching of the laser pulse, while keeping the energy constant, can significantly increase the spectral density of the scattered radiation …


Developing A High Resolution Zdc For The Eic, J. H. Lee, T. Sako, K. Tanida, M. Murray, Q. Wang, N. Nickel, Y. Yamazaki, Y. Itow, H. Menjo, T. Shibata, C. E. Hyde, V. Baturin, Y. Goto, I. Nakagawa, R. Seidl, K. Kawade, A. Deshpande, B. Schmookler, K. Nakano, T. Chujo, Y. Miyachi Jan 2020

Developing A High Resolution Zdc For The Eic, J. H. Lee, T. Sako, K. Tanida, M. Murray, Q. Wang, N. Nickel, Y. Yamazaki, Y. Itow, H. Menjo, T. Shibata, C. E. Hyde, V. Baturin, Y. Goto, I. Nakagawa, R. Seidl, K. Kawade, A. Deshpande, B. Schmookler, K. Nakano, T. Chujo, Y. Miyachi

Physics Faculty Publications

The Electron Ion Collider offers the opportunity to make un-paralleled multidimen- sional measurements of the spin structure of the proton and nuclei, as well as a study of the onset of partonic saturation at small Bjorken-x [1]. An important requirement of the physics program is the tagging of spectator neutrons and the identification of forward photons. We propose to design and build a Zero Degree Calorimeter, or ZDC, to measure photons and neutrons with excellent energy & position resolution.


Thermal Emittance And Lifetime Of Alkali-Antimonide Photocathodes Grown On Gaas And Molybdenum Substrates Evaluated In A -300 Kv Dc Photogun, Y. Wang, M. A. Mamun, P. Adderley, B. Bullard, J. Grames, J. Hansknecht, C. Hernandez-Garcia, G. A. Krafft, G. Palacios-Serrano, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, S. Wijethunga, J. Yoskowitz, S. Zhang Jan 2020

Thermal Emittance And Lifetime Of Alkali-Antimonide Photocathodes Grown On Gaas And Molybdenum Substrates Evaluated In A -300 Kv Dc Photogun, Y. Wang, M. A. Mamun, P. Adderley, B. Bullard, J. Grames, J. Hansknecht, C. Hernandez-Garcia, G. A. Krafft, G. Palacios-Serrano, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, S. Wijethunga, J. Yoskowitz, S. Zhang

Physics Faculty Publications

CsxKySb photocathodes grown on GaAs and molybdenum substrates were evaluated using a –300 kV dc high voltage photogun and diagnostic beam line. Photocathodes grown on GaAs substrates, with varying antimony layer thickness (estimated range from < 20 nm to > 1 um), yielded similar thermal emittance per rms laser spot size values (~0.4 mm mrad / mm) but very different operating lifetime. Similar thermal emittance was obtained for a photocathode grown on a molybdenum substrate but with markedly improved lifetime. For this photocathode, no decay in quantum efficiency was measured at 4.5 mA average current and with peak current 0.55 A …


High-Luminosity Large Hadron Collider (Hl-Lhc): Technical Design Report, O. Aberle, C. Adorisio, A. Adraktas, M. Ady, J. Albertone, L. Alberty, M. Alcaide Leon, A. Alekou, D. Alesini, B. Almeida Ferreira, P. Alvarez-Lopez, G. Ambrosio, P. Andreu Munoz, M. Anerella, D. Angal-Kalinin, F. Antoniou, G. Apollinari, A. Apollonio, R. Appleby, I. Béjar Alonso, Jean Delayen, I. Zurbano Fernandez, Et Al., I. Béjar Alonso (Ed.), O. Brüning (Ed.), P. Fessia (Ed.), M. Lamont (Ed.), L. Rossi (Ed.), L. Tavian (Ed.), M. Zerlauth (Ed.) Jan 2020

High-Luminosity Large Hadron Collider (Hl-Lhc): Technical Design Report, O. Aberle, C. Adorisio, A. Adraktas, M. Ady, J. Albertone, L. Alberty, M. Alcaide Leon, A. Alekou, D. Alesini, B. Almeida Ferreira, P. Alvarez-Lopez, G. Ambrosio, P. Andreu Munoz, M. Anerella, D. Angal-Kalinin, F. Antoniou, G. Apollinari, A. Apollonio, R. Appleby, I. Béjar Alonso, Jean Delayen, I. Zurbano Fernandez, Et Al., I. Béjar Alonso (Ed.), O. Brüning (Ed.), P. Fessia (Ed.), M. Lamont (Ed.), L. Rossi (Ed.), L. Tavian (Ed.), M. Zerlauth (Ed.)

Physics Faculty Publications

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total number of collisions) by a factor ten. …


Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim Jan 2020

Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim

Physics Faculty Publications

We investigate thermodynamic properties of FeSe under in-plane magnetic fields using torque magnetometry, specific heat, and magnetocaloric measurements. Below the upper critical field Hc2, we observed the field induced anomalies at H1 ∼ 15 T and H2 ∼ 22 T near H ∥ ab and below a characteristic temperature T* ∼ 2 K. The transition magnetic fields H1 and H2 exhibit negligible dependence on both temperature and field orientation. This contrasts to the strong temperature and angle dependence of Hc2, suggesting that these anomalies are attributed to the field induced phase transitions, …