Paper | Title | Page |
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MOPRI034 | Development of temporal response measurement system for transmission-type spin-polarized photocathodes | 670 |
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Spin polarized electron beam is essential for "International Linear Collider". In Nagoya University, transmission-type spin-polarized photocathodes have been developed, and the quantum efficiency of 0.5 % and the polarization of 90 % were achieved*,**. Recently, we succeeded in making the active layer several times thicker with keeping the spin polarization on the GaAs/GaAsP strain-compensated superlattice photocathode***. Increasing the thickness of the active layer is very advantageous for high quantum efficiency, but might be disadvantageous for pulse response. In order to investigate the pulse response, we have developed a pulse length measurement system by using an RF deflecting cavity. In the measurement, magnetic field induced on the beam axis kicks electron pulse transversely and the pulse length is projected to the transverse plane, which is measured by knife-edge method. The pump laser pulses are provided by a Ti:sapphire laser oscillator. By using a pulse stretcher, the pulse width of the pump laser can be changed in the range between 130 fs and 20 ps. In the poster session, we will describe the details of the measurement system and the most recent experimental results.
* T. Nakanishi, The XXI International LINAC Conference(1998) ** Xiuguang Jin, Japanese Journal of Applied Physics 51 (2012) 108004 *** Xiuguang Jin, Applied Physics Express 6 (2013) 015801 |
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DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI034 | |
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MOPRI057 | Photoemission from III-V Semiconductor Cathodes | 736 |
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Quantum efficiencies (QE) and mean transverse energies (MTE) of GaAs photocathodes grown using various techniques: metal-organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE), and atomic polishing have been compared and found to be identical. GaAs and GaInP based samples grown at Nagoya University were activated and measured in the Cornell ERL photoinjector. These were found to be in agreement with the samples measured at the ERL injector in KEK. | ||
DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI057 | |
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