CLIC Waveguide Damped Accelerating Structure Studies

Studies of waveguide damped 30 GHz accelerating structures for multibunching in CLIC are described. Frequency discriminated damping using waveguides with a lowest cutoff frequency above the fundamental but below the higher order modes was considered. The wakefield behavior was investigated using time domain MAFIA computations over up to 20 cells and for frequencies up to 150 GHz. A configuration consisting of four T-cross-sectioned waveguides per cell reduces the transverse wake below 1% at typical CLIC bunch spacings

A 3 GHz photoelectron gun for high beam intensity

For the Compact Linear Collider Test Facility (CTF) at CERN a new rf gun with a laser driven photocathode is under construction. The new rf gun will replace the present 11/2 cell gun and will consist of 21/2 cells accelerating the beam to a momentum of 7.0 MeV/c with an electric field strength of 100 MV/m. The strong space-charge forces at low beam energy caused by the high charge density of the electron bunches are contained by radial and longitudinal rf focusing in the gun. The rf gun under construction has been optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating rf structure and an intermediate solenoid magnet correcting the beam divergence of the 21/2 cell gun. The beam loading of the rf gun, by a train of 48 bunches with 21 nC charge each, causes a strong energy decay accompanied by an increase of the flight time for the bunches with lower energy. These effects can be corrected by slightly shifting the acceleration frequency of the gun. The experimental results obtained with the 11/2 cell gun and booster section presently in operation are reported

Design of a 30 GHz Damped Detuned Accelerating Structure

Within the framework of the SLAC/CERN studies of 30 GHz linear colliders, an attempt has been made to scale as closely as possible the existing X-band NLC damped detuned accelerating structure to 30 GHz. A simple scaling was not possible because of mechanical and RF constraints. The 30 GHz design has 101 cells and a minimum aperture of 3.4 mm. In order to obtain acceptably small values for both the single-bunch transverse wakefield and the long-range multibunch wakefield a relatively large non-linear variation of the iris thickness was introduced in addition to the iris diameter variation. The resulting wakefield has a short-range value of 1290 V/pC/mm/m and a long range value below 10 V/pC/mm/m

A Robust Age Model for the Cryogenian Pocatello Formation of Southeastern Idaho (Northwestern USA) from Tandem in situ and Isotope Dilution U-Pb Dating of Volcanic Tuffs and Epiclastic Detrital Zircons

Tandem in situ and isotope dilution U-Pb analysis of zircons from pyroclastic volcanic rocks and both glacial and non-glacial sedimentary strata of the Pocatello Formation (Idaho, northwestern USA) provides new age constraints on Cryogenian glaciation in the North American Cordillera. Two dacitic tuffs sampled within glacigenic strata of the lower diamictite interval of the Scout Mountain Member yield high-precision chemical abrasion isotope dilution U-Pb zircon eruption and depositional ages of 696.43 ± 0.21 and 695.17 ± 0.20 Ma. When supplemented by a new high-precision detrital zircon maximum depositional age of ≤ 670 Ma for shoreface and offshore sandstones unconformably overlying the lower diamictite, these data are consistent with correlation of the lower diamictite to the early Cryogenian (ca. 717–660 Ma) Sturtian glaciation. These 670–675 Ma zircons persist in beds above the upper diamictite and cap dolostone units, up to and including a purported “reworked fallout tuff,” which we instead conclude provides only a maximum depositional age of ≤ 673 Ma from epiclastic volcanic detritus. Rare detrital zircons as young as 658 Ma provide a maximum depositional age for the upper diamictite and overlying cap dolostone units. This new geochronological framework supports litho- and chemostratigraphic correlations of the lower and upper diamictite intervals of the Scout Mountain Member of the Pocatello Formation with the Sturtian (716–660 Ma) and Marinoan (≤ 650–635 Ma) low-latitude glaciations, respectively. The Pocatello Formation thus contains a more complete record of Cryogenian glaciations than previously postulated

The multidisciplinary, theory-based co-design of a new digital health intervention supporting the care of oesophageal cancer patients

Objective: Oesophageal cancer patients have complex care needs. Cancer clinical nurse specialists play a key role in coordinating their care but often have heavy workloads. Digital health interventions can improve patient care but there are few examples for oesophageal cancer. This paper aims to describe the multidisciplinary co-design process of a digital health intervention to improve the experience of care and reduce unmet needs among patients with oesophageal cancer. Methods: A theory-based, multi-disciplinary, co-design approach was used to inform the developmental process of the digital health intervention. Key user needs were elicited using mixed methodology from systematic reviews, focus groups and interviews and holistic need assessments. Overarching decisions were discussed among a core team of patients, carers, health care professionals including oncologists and cancer clinical nurse specialists, researchers and digital health providers. A series of workshops incorporating a summary of findings of key user needs resulted in the development of a minimum viable product. This was further refined after a pilot study based on feedback from end users. Results: The final digital health intervention consists of a mobile app feature for patients and carers connected to a dashboard with supporting additional features for clinical nurse specialist. It contains a one-way messaging function for clinical nurse specialists to communicate with patients, functions for patients to record weight and holistic need assessment results which could be viewed by their clinical nurse specialists as well as a library of informative articles. Conclusions: The multidisciplinary co-design of a digital health intervention providing support for oesophageal cancer patients and health care professionals has been described. Future studies to establish its impact on patient outcomes are planned

Changing patterns of cancer incidence in the early- and late-HAART periods: the Swiss HIV Cohort Study

BACKGROUND: The advent of highly active antiretroviral therapy (HAART) in 1996 led to a decrease in the incidence of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma (NHL), but not of other cancers, among people with HIV or AIDS (PWHA). It also led to marked increases in their life expectancy. METHODS: We conducted a record-linkage study between the Swiss HIV Cohort Study and nine Swiss cantonal cancer registries. In total, 9429 PWHA provided 20,615, 17,690, and 15,410 person-years in the pre-, early-, and late-HAART periods, respectively. Standardised incidence ratios in PWHA vs the general population, as well as age-standardised, and age-specific incidence rates were computed for different periods. RESULTS: Incidence of KS and NHL decreased by several fold between the pre- and early-HAART periods, and additionally declined from the early- to the late-HAART period. Incidence of cancers of the anus, liver, non-melanomatous skin, and Hodgkin's lymphoma increased in the early- compared with the pre-HAART period, but not during the late-HAART period. The incidence of all non-AIDS-defining cancers (NADCs) combined was similar in all periods, and approximately double that in the general population. CONCLUSIONS: Increases in the incidence of selected NADCs after the introduction of HAART were largely accounted for by the ageing of PWHA

A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a low-energy and ultra-low-emittance electron beam travelling through short-period undulators. It delivers stable hard X-ray FEL radiation at 1-Å wavelength with pulse energies of more than 500 μJ, pulse durations of ~30 fs (root mean square) and spectral bandwidth below the per-mil level. Using special configurations, we have produced pulses shorter than 1 fs and, in a different set-up, broadband radiation with an unprecedented bandwidth of ~2%. The extremely small emittance demonstrated at SwissFEL paves the way for even more compact and affordable hard X-ray FELs, potentially boosting the number of facilities worldwide and thereby expanding the population of the scientific community that has access to X-ray FEL radiation