Studies of linear and nonlinear photoelectric emission for advanced accelerator applications

Photoemission from diamond and fullerene films for advanced accelerator applications

“…In this experiment the electric field at the cathode surface was around The observed QE for the one-photon process on copper at 217 nm is 1.3 to 1.6 + lop3, compared to a one-photon QE of about 1 .O . 10@ observed at 266 nm under the same conditions [34]. Note that the ratio of these two QE's (130-160) is in very good agreement with the ratio expected from (2) (136.5)…”

“…With its large work function, diamond requires a laser wavelength shorter than 225 nm to generate a one-photon process necessary for the RF gun stability. Conversely, by using a high-order multiphoton process, electron pulses shorter in duration than the laser pulse could be obtained, in principle, using a diamond cathode which can tolerate a high photon flux before damage [34].…”

The laser assisted field electron emission from carbon nanostructure

“…The electronic sources based on laser assisted electron emission have found applications in different fields of science and technology including particle accelerators [1], free electron lasers [2], and modern photovoltaic systems [3]. The laser assisted electron emission has opened a way towards the time resolved electron microscopy [4,5] because electrical gating and source control enable time resolution down to picoseconds, while using optical control enables creation of electron pulses with duration down to tens of femtoseconds [6].…”

Integral design of a laser wakefield accelerator with external bunch injectioon

“…Based on the experimental results from Brogle et.al. in reference [104], we estimated that an electron bunch with a charge of about 5 pC would be generated with such a pulse. To avoid any disturbance of the bunch due to any asymmetry of the accelerating field that would occur with off-axis propagation in the linac, it is required that the laser pulse hits the center of the cathode.…”

“…In particular there is no need to use a third-harmonic generator to convert the infra-red pulses to the ultra-violet. Although three-photon absorption is generally considered weaker than single-photon absorption, here it is sufficiently strong to provide the required bunches of low charge (∼5-10 pC) without laser ablation of the cathode surface [104]. After pre-acceleration inside the linac, the bunch is transported to the channel via a compression section, consisting of two subsequent 45…”