Control of Intra-Bunch Vertical Instabilities at the SPS - Measurements and Technology Demonstration

We present recent measurements demonstrating control of unstable beam motion in single bunch and bunch train configurations at the SPS. The work is motivated by anticipated intensity increases from the LIU and HL-LHC upgrade programs, and has included the development of a GHz bandwidth reconfigurable 4 GS/S signal processor with wideband kickers and associated amplifiers. The system was operated at 3.2GS/s with 16 samples across a 5 ns RF bucket (4.2 ns bunch at injection). The experimental results confirm damping of intra-bunch instabilities in both Q20 and Q26 optics configurations for intensities of 2x10¹¹ P/bunch. Instabilities with growth times of 200 turns are well-controlled from injection, consistent with the achievable gains for the 2 installed stripline kickers with 1 kW broadband power. Measurements from multiple studies in single-bunch and bunch train configurations show achieved damping rates, control of multiple intra-bunch modes, behavior of the system at injection and final damped noise floor. We present an analysis method to study the relative phase of slice motion during a transient to discriminate between TMCI and other types of Head-Tail instabilities

Keronopsamides, a new class of pigments from marine ciliates

New pigments with an unprecedented skeleton, named keronopsamides A–C, were isolated from the marine ciliate Pseudokeronopsis riccii. The structure of the most abundant secondary metabolite, keronopsamide A, was established through extended Nuclear Magnetic Resonance (NMR) analysis and mass spectrometric (MS) data obtained by using electrospray (ESI) and matrix assisted laser desorption (MALDI) ionizations. Structures of the minor analogues (keronopsamide B and C) were inferred from 1H NMR, chemical correlation, and LC-MS measurements. The analysis of NOE dipolar couplings and quantum chemical calculations, carried out by density functional theory (DFT) on the preferred rotamers of keronopsamide A, suggested a fully planar structure with amide bond in anti stereochemistry capable to break down the extended conjugation of the whole π electronic system. Although the presence of a 2-substituted 3,4-dibromo-pyrrole moiety is reminiscent of previously isolated metabolites isolated from a cell extract of Pseudokeronopsis rubra (keronopsins), keronopsamides show a new molecular skeleton formally derived from a peptide-like condensation of a 3-pyrrolepropenoic acid with an unsaturated bromotyramin