First experimental and simulation study on the secondary electron and photoelectron yield of NEG materials (Ti–Zr–V) coating under intense photon irradiation

Recent studies on photoelectron and secondary electron yields of TiN and NEG coatings using the KEKB positron ring

“…An electron current monitor was attached at the bottom of the center pumping port of the test chamber, as in the case of the previous experiment [30,31]. The cross-section of the electron monitor is also illustrated in Fig.…”

“…We have been focusing on a TiN coating and an NEG (Ti-Zr-V) coating and on investigating the effect of their SEYs on the electron cloud formation by using the KEK B-factory (KEKB) positron ring, that is, the low energy ring (LER) [32]. In the previous reports, the test chambers with these surfaces were installed at an arc section in the LER; around this section, the photons of the synchrotron radiation (SR) were directly irradiated with a line density of approximately 6.5 Â 10 14 photons m À1 s À1 mA À1 [30,31]. The number of electrons around the beams was measured using an electron current monitor [30] compared with each other.…”

“…In the previous reports, the test chambers with these surfaces were installed at an arc section in the LER; around this section, the photons of the synchrotron radiation (SR) were directly irradiated with a line density of approximately 6.5 Â 10 14 photons m À1 s À1 mA À1 [30,31]. The number of electrons around the beams was measured using an electron current monitor [30] compared with each other. The measured electron currents of the NEG-coated chamber were almost the same as those of the uncoated copper chamber, except for a small difference in the high beam current region.…”

Experimental observations of in situ secondary electron yield reduction in the PEP-II particle accelerator beam line

“…Note that in the apparatus, the SEY is measured with the use of an electron beam incoming at a 23° angle with respect to the sample surface normal. The SEY of technical surfaces material for accelerator vacuum chamber has been measured in the past at CERN [11,12] at KEK [13,14,15] SLAC [9,16,17] and at other laboratories [18]. 4…”

“…The impact of particles on a metallic surface reduces the surface SEY to low values [9][10][11][12][13][14][15][16][17]. This effect is known as conditioning.…”