In this paper we report on the generation of cold electron beams using a Cs 3 Sb photocathode grown by codeposition of Sb and Cs. By cooling the photocathode to 90 K we demonstrate a significant reduction in the mean transverse energy validating the long-standing speculation that the lattice temperature contributes to limiting the mean transverse energy or intrinsic emittance near the photoemission threshold, opening new frontiers in generating ultrabright beams. At 90 K, we achieve a record low intrinsic emittance of 0.2 μm (rms) per mm of laser spot diameter from an ultrafast (subpicosecond) photocathode with quantum efficiency greater than 7 × 10 −5 using a visible laser wavelength of 690 nm.

Aims:  Isolate and characterize antifungal peptides exhibiting activity against Byssochlamys fulva H25, a spoilage mould associated with juices and beverages. Methods and Results:  A bacterium (H215) isolated from honey showed high antifungal activity against B. fulva H25. The antifungal producer strain was identified as Bacillus subtilis using 16S rDNA sequencing. The antifungal peptide was purified by 20% ammonium sulfate precipitation of the bacterial culture supernatant, followed by Octyl‐Sepharose CL‐4B and reverse phase‐high performance liquid chromatography. The five active fractions were lyophilized and subjected to mass, tandem mass spectrometry and amino acid analysis to deduce their corresponding molecular masses and structural characteristics. The five peaks were determined to be identical to bacillomycin F, varying in the length of the fatty acid chain moiety from C14 to C16. Conclusions:  The broad‐spectrum antifungal activity produced by a bacterium from honey was determined to be due to the production of bacillomycin F. Significance and Impact of the Study:  The antifungal compound produced by a bacterial strain isolated from honey was determined to be stable over a broad pH range and was stable to heat treatments up to 100°C. This is the first report of honey microflora producing bacillomycin F or any antifungal compound.

The intrinsic emittance of electron beams generated from a multi-alkali photocathode operated in a high voltage DC gun is reported. The photocathode showed sensitivity extending to the infrared part of the spectrum up to 830 nm. The measured intrinsic emittances of electron beams generated with light having wavelength longer than 800 nm are approaching the limit imposed by the thermal energy of electrons at room temperature with quantum efficiencies comparable to metallic photocathodes used in operation of modern photoinjectors.

High quantum efficiency alkali antimonide photocathodes have been grown over both stainless steel and glass substrates using sequential evaporation of Sb, K, Rb, and Cs. Quantum efficiencies well above 25% have been measured at 400 nm. A bi-alkali Rb-K-Sb photocathode grown on a stainless steel substrate has been installed in a high voltage DC gun at Cornell University and the intrinsic electron beam emittance was measured at different photon energies.