The Multipoles Factory: An Element of the LHC Control

The measurements performed at CERN on prototypes and first pre-series main dipole magnets confirm the need of an active control of the Large Hadron Collider to compensate the dynamic field changes during the proton beam injection and acceleration. This control requires in turn an accurate forecast of the magnetic field in the accelerator. We plan to predict the field on the basis of two elements: theoretical field models tailored through the accumulated knowledge of the main magnets during series tests, and an on-line measurement system running on few reference magnets tracking the LHC current cycle. Data coming from this "Multipoles Factory" will result from the fusion of the two sources. Based on this system we foresee to deliver calibration information for pre-defined accelerator cycles as well as real time information for the active control. In this paper we report the conceptual design of the system, and we discuss the features and performance of the models that we have developed for the field forecast

Loss and Dynamic Magnetic Field Measurements in LHC Dipoles

Knowledge of AC loss and dynamic magnetic field distortion in the main LHC dipoles is both important for the assessment of the accelerator performance and providing insight into the properties of assembled magnets. We measured the loss due to the current cycling in a few 1-meter long model dipoles, 15-meter long dipole prototypes and pre-series magnets. As expected the loss depends linearly on the rate of the current change. From the slope of this dependence, the contact resistance between the strands of the opposite layers of the cable, Rc, was evaluated for the inner winding of the dipole. We discuss the method to estimate the Rc value in the outer winding. The Rc value has been also derived independently from measurements of the magnetic field. For this, the ramp rate dependent component of the main field as well as of the harmonics has been measured. The main magnetic field measurements were performed using both stationary coils and Hall probes. Rotating coils were used to perform the harmonic measurements

Models of integrated care for young people experiencing medical emergencies related to mental illness: a realist systematic review

Mental illness heightens risk of medical emergencies, emergency hospitalisation, and readmissions. Innovations for integrated medical–psychiatric care within paediatric emergency settings may help adolescents with acute mental disorders to get well quicker and stay well enough to remain out of hospital. We assessed models of integrated acute care for adolescents experiencing medical emergencies related to mental illness (MHR). We conducted a systematic review by searching MEDLINE, PsychINFO, Embase, and Web of Science for quantitative studies within paediatric emergency medicine, internationally. We included populations aged 8–25 years. Our outcomes were length of hospital stay (LOS), emergency hospital admissions, and rehospitalisation. Limits were imposed on dates: 1990 to June 2021. We present a narrative synthesis. This study is registered on PROSPERO: 254,359. 1667 studies were screened, 22 met eligibility, comprising 39,346 patients. Emergency triage innovations reduced admissions between 4 and 16%, including multidisciplinary staffing and training for psychiatric assessment (F(3,42) = 4.6, P < 0.05, N = 682), and telepsychiatry consultations (aOR = 0.41, 95% CI 0.28–0.58; P < 0.001, N = 597). Psychological therapies delivered in emergency departments reduced admissions 8–40%, including psychoeducation (aOR = 0.35, 95% CI 0.17–0.71, P < 0.01, N = 212), risk-reduction counselling for suicide prevention (OR = 2.78, 95% CI 0.55–14.10, N = 348), and telephone follow-up (OR = 0.45, 95% CI 0.33–0.60, P < 0.001, N = 980). Innovations on acute wards reduced readmissions, including guided meal supervision for eating disorders (P = 0.27), therapeutic skills for anxiety disorders, and a dedicated psychiatric crisis unit (22.2 vs 8.5% (P = 0.008). Integrated pathway innovations reduced readmissions between 8 and 37% including family-based therapy (FBT) for eating disorders (X2(1,326) = 8.40, P = 0.004, N = 326), and risk-targeted telephone follow-up or outpatients for all mental disorders (29.5 vs. 5%, P = 0.03, N = 1316). Studies occurred in the USA, Canada, or Australia. Integrated care pathways to psychiatric consultations, psychological therapies, and multidisciplinary follow-up within emergency paediatric services prevented lengthy and repeat hospitalisation for MHR emergencies. Only six of 22 studies adjusted for illness severity and clinical history between before- and after-intervention cohorts and only one reported socio-demographic intervention effects

Objective classification of fabric pilling based on the two-dimensional discrete wavelet transform

A number of methods for automated objective ratings of fabric pilling based on image analysis are described in the literature. The periodic structure of fabrics makes them suitable candidates for frequency domain analysis. We propose a new method of frequency domain analysis based on the two-dimensional discrete wavelet transform to objectively measure pilling intensity in sample images. We present a preliminary evaluation of the proposed method based on analysis of two series of standard pilling evaluation test images. The initial results suggest that the proposed method is feasible, and that the ability of the method to discriminate between levels of pilling intensity depends on the wavelet analysis scale being closely matched to the fabric interyarn pitch. We also present a heuristic method for optimal selection of an analysis wavelet and associated analysis scale. <br /

Persistent and Coupling Current Effects in the LHC Superconducting Dipoles

One of the main issues for the operation of the LHC accelerator at CERN is the field errors generated by persistent and coupling currents in the main dipoles at injection conditions, i.e., 0.54 T dipole field. For this reason we are conducting systematic magnetic field measurements to quantify the above effects and compare them to the expected values from measurement on strands and cables. We discuss the results in terms of DC effects from persistent current magnetization, AC effects with short time constant from strand and cable coupling currents, and long-term decay during constant current excitation. Average and spread of the measured field errors over the population of magnets tested are as expected or smaller. Field decay at injection, and subsequent snap-back, show for the moment the largest variation from magnet to magnet, with weak correlation to parameters that can be controlled during production. For this reason these effects are likely to result in the largest spread of field errors over the whole dipole production

Measurement and Analysis of the Field Quality of LHC Prototype and Pre-series Superconducting Dipoles

We report the main results of the magnetic field measurements performed on the full-size LHC superconducting dipoles tested at CERN since summer 1998. Main field strength and field errors are summarised. We discuss in detail the contributions related to the geometry of the collared coil, the assembled cold mass, cool-down effects, magnetisation of the superconducting cable and saturation effects at high field. Dynamic effects on field harmonics, such as the field decay during injection and field errors during current ramps, are assessed statistically