We present a detailed study of the six-dimensional phase space of the electron beam produced by the Cornell Energy Recovery Linac Photoinjector, a high-brightness, high repetition rate (1.3 GHz) DC photoemission source designed to drive a hard x-ray energy recovery linac (ERL). A complete simulation model of the injector has been constructed, verified by measurement, and optimized. Both the horizontal and vertical 2D transverse phase spaces, as well as the time-resolved (sliced) horizontal phase space, were simulated and directly measured at the end of the injector for 19 and 77 pC bunches at roughly 8 MeV. These bunch charges were chosen because they correspond to 25 and 100 mA average current if operating at the full 1.3 GHz repetition rate. The resulting 90% normalized transverse emittances for 19 ð77Þ pC=bunch were 0:23 AE 0:02 ð0:51 AE 0:04Þ m in the horizontal plane, and 0:14 AE 0:01 ð0:29 AE 0:02Þ m in the vertical plane, respectively. These emittances were measured with a corresponding bunch length of 2:1 AE 0:1 ð3:0 AE 0:2Þ ps, respectively. In each case the rms momentum spread was determined to be on the order of 10 À3 . Excellent overall agreement between measurement and simulation has been demonstrated. Using the emittances and bunch length measured at 19 pC=bunch, we estimate the electron beam quality in a 1.3 GHz, 5 GeV hard x-ray ERL to be at least a factor of 20 times better than that of existing storage rings when the rms energy spread of each device is considered. These results represent a milestone for the field of high-brightness, highcurrent photoinjectors.

Dermal and inhalation exposure of the applicator to the insecticide fenavalerate in an apple orchard was measured for risk assessment during treatment. Emulsifiable concentrate (EC) and wettable powder (WP) formulations were sprayed using a speed sprayer (SS) or power sprayer (PS). Dermal patches, gloves, socks, and masks were used to monitor potential dermal exposure to fenavalerate, while personal air samplers with XAD-2 resins were used to monitor potential inhalation exposure. Validation of analytical methods was performed for the instruments' limit of detection, limit of quantitation, reproducibility, linearity of calibration curve, and recovery of fenvelerate from various exposure matrices. The results were encouraging and reasonable for an exposure study. Applicability of XAD-2 resin was evaluated with a trapping efficiency and breakthrough test. During mixing/loading, the amount of dermal exposure ranged from 262.8 μg (EC/SS) to 1652.6 μg (WP/PS) of fenvalerate, corresponding to ~0.0011-0.0066% of the total prepared quantity. In the case of WP, the amount of dermal exposure was 2032.3 μg (0.0081% of the total applied amount) for SS and 1087.9 μg (0.0145%) for PS after application. In the case of EC, the amount of dermal exposure was 3804.6 μg (0.0152%) for SS and 4055.0 μg (0.0541%) for PS after application. The primary body parts subject to exposure were thigh and upper arm for SS, and thigh and hand for PS. The amount of inhalation exposure with WP was 2.2 μg (8.65 × 10⁻⁶% of the total applied amount) for SS and 1.3 g (1.67 × 10⁻⁵%) for PS. The amount of inhalation exposure with EC was 2.5 μg (9.81 × 10⁻⁶%) for SS and 3.7 μg (4.97 × 10⁻⁵%) for PS. The absorbable quantity of exposure and margin of safety (MOS) were calculated for risk assessment. The MOS for all 4 cases was much greater than 1, indicating a low possibility of risk.

The simple irradiation of 355 nm nanosecond laser pulses to SiO2@Pt core–shell nanospheres at fluence of 2.7 mJ cm–2 during the preparation process of hollow platinum nanospheres has been found to enhance the catalytic performances of platinum nanocatalysts on a large scale. Laser irradiation has transformed platinum nanoclusters topped on silica nanospheres into well-defined platinum nanoshells having uniform and smooth surfaces; the thickness of platinum nanoshells has been tuned easily by adjusting the irradiation time only. Laser irradiation increases the catalytic performances of hollow platinum nanospheres in the degradation of rhodamine B in the presence of KBH4 by five times via lowering the energy barrier. The energetically more favorable formation of the activated complexes in the nanocavity surfaces is suggested to reduce the activation energy substantially. The restructuring of surface atoms induced by photothermal annealing during laser irradiation has rendered the metallic surfaces much easier to chemisorb reactants and to facilitate electron relays, enhancing the catalytic performances of platinum nanocatalysts extensively.

The authors report on the growth of Na2KSb bialkali and Na2KSb:Cs3Sb multialkali photocathodes using the vapors generated by evaporating pure metals with effusion cells under vacuum conditions. Details about the ultrahigh vacuum growth system and the used procedures are provided. The new growth system is capable of growing over large areas with uniform photoemission properties using different types of substrates. The measured spectral response curves indicate that high quality photocathodes are produced with peak quantum efficiencies well above 20%. Procedures to obtain multialkali photocathodes with extended sensitivity into the infrared range (well above 800 nm) are described.

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