MAGIC-2D simulations of high efficiency hollow beam klystrons

Results from MAGIC-2D simulations of hollow beam, 800 MHz klystrons, with efficiencies on the order of 85% are presented. Such tubes employ the core oscillation method of electron bunching, which allows for most electrons in the beam to be contained within the bunch at the output cavity. By moving towards hollow beam geometries, the bunch at the output cavity presents a favourable phase and spatial profile for energy extraction, and thus, the overall tube efficiency can be maximised

Numerical design of high efficiency klystrons using core oscillation bunching

1-D and 2-D numerical simulations of 800 MHz klystrons with efficiencies approaching 90% are presented. While traditional klystrons employ monotonic electron bunching along their lengths, the core oscillation method allows for an improved bunch shape at the output cavity, facilitating maximum energy extraction. The core oscillation bunching scheme proves an attractive method for attaining high efficiency operation in klystrons, which can be used to reduce the power consumption of future particle accelerators

W-band klystron upconverter driven by pseudospark-sourced electron beam

In this paper, a three-cavity klystron upconverter operating at W-band is presented. It is predicted to generate 40 W when driven by a 30 kV, 0.2 A electron beam. Pseudospark-sourced electron beam after post-acceleration was proposed to be used with the klystron upconverter because it has the advantage of low energy spread, high current density, and no need of any external guiding magnetic field

W-band klystron upconverter driven by pseudospark-sourced electron beam

In this paper, a three-cavity klystron upconverter operating at W-band is presented. It is predicted to generate 40 W when driven by a 30 kV, 0.2 A electron beam. Pseudospark-sourced electron beam after post-acceleration was proposed to be used with the klystron upconverter because it has the advantage of low energy spread, high current density, and no need of any external guiding magnetic field

Analytical and Numerical Simulation of Multipactor within a Helical Resonant Filter

Multipactor analysis of a helical resonant filter has been performed using CST Particle Studio and analytically using a 1-D particle tracking code, based on the Runge-Kutta-Nystrom method. A comparison of results is presented

Particle-in-cell simulation of second and third harmonic cavity klystron

This paper outlines the results obtained from Magic software for the CSM_23 (Core Stabilization Method) klystron. This klystron implements the use of a second and third harmonic klystron to increase the efficiency. From the PIC simulation an efficiency of 78.1% was achieved

MAGIC2-D simulations of high efficiency klystrons using the core oscillation method

Klystrons employing traditional monotonic electron bunching are capable of efficiencies up to ~70%. The use of the core oscillation method (COM) of electron bunching has predicted a significant improvement in efficiency towards 90%. Here, we document refinements on previously presented geometries, with PIC simulations predicting efficiencies up to 85%

A comparative study of cognitive behavioural therapy and shared reading for chronic pain

The case for psychosocial interventions in relation to chronic pain, one of the most common health issues in contemporary healthcare, is well-established as a means of managing the emotional and psychological difficulties experienced by sufferers. Using mixed methods, this study compared a standard therapy for chronic pain, cognitive behavioural therapy (CBT), with a specific literature-based intervention, shared reading (SR) developed by national charity, The Reader. A 5-week CBT group and a 22-week SR group for patients with chronic pain ran in parallel, with CBT group members joining the SR group after the completion of CBT. In addition to self-report measures of positive and negative affect before and after each experience of the intervention, the 10 participants kept twice-daily (12- hourly) pain and emotion diaries. Qualitative data were gathered via literary-linguistic analysis of audio/video�recordings and transcriptions of the CBT and SR sessions and video-assisted individual qualitative interviews with participants. Qualitative evidence indicates SR’s potential as an alternative or long-term follow-up or adjunct to CBT in bringing into conscious awareness areas of emotional pain otherwise passively suffered by patients with chronic pain. In addition, quantitative analysis, albeit of limited pilot data, indicated possible improvements in mood/pain for up to 2 days following SR. Both findings lay the basis for future research involving a larger sample siz

Rationally designed immunogens enable immune focusing following SARS-CoV-2 spike imprinting

Eliciting antibodies to surface-exposed viral glycoproteins can generate protective responses that control and prevent future infections. Targeting conserved sites may reduce the likelihood of viral escape and limit the spread of related viruses with pandemic potential. Here we leverage rational immunogen design to focus humoral responses on conserved epitopes. Using glycan engineering and epitope scaffolding in boosting immunogens, we focus murine serum antibody responses to conserved receptor binding motif (RBM) and receptor binding domain (RBD) epitopes following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike imprinting. Although all engineered immunogens elicit a robust SARS-CoV-2-neutralizing serum response, RBM-focusing immunogens exhibit increased potency against related sarbecoviruses, SARS-CoV, WIV1-CoV, RaTG13-CoV, and SHC014-CoV; structural characterization of representative antibodies defines a conserved epitope. RBM-focused sera confer protection against SARS-CoV-2 challenge. Thus, RBM focusing is a promising strategy to elicit breadth across emerging sarbecoviruses without compromising SARS-CoV-2 protection. These engineering strategies are adaptable to other viral glycoproteins for targeting conserved epitopes