Microchannel cooling for the LHCb VELO Upgrade I

The LHCb VELO Upgrade I, currently being installed for the 2022 start of LHC Run 3, uses silicon microchannel coolers with internally circulating bi-phase \cotwo for thermal control of hybrid pixel modules operating in vacuum. This is the largest scale application of this technology to date. Production of the microchannel coolers was completed in July 2019 and the assembly into cooling structures was completed in September 2021. This paper describes the R\&D path supporting the microchannel production and assembly and the motivation for the design choices. The microchannel coolers have excellent thermal peformance, low and uniform mass, no thermal expansion mismatch with the ASICs and are radiation hard. The fluidic and thermal performance is presented.Comment: 31 pages, 27 figure

Evaporative CO2_2 microchannel cooling for the LHCb VELO pixel upgrade

The LHCb Vertex Detector (VELO) will be upgraded in 2018 to a lightweight pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the system will be provided by evaporative CO$_2$ circulating in microchannels embedded within thin silicon plates. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs and sensors, the radiation hardness of CO$_2$, and very low contribution to the material budget. Although microchannel cooling is gaining considerable attention for applications related to microelectronics, it is still a novel technology for particle physics experiments, in particular when combined with evaporative CO$_2$ cooling. The R&D effort for LHCb is focused on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures up to 170 bar. Even distribution of the coolant is ensured by means of the use of restrictions implemented before the entrance to a race track like layout of the main cooling channels. The coolant flow and pressure drop have been simulated as well as the thermal performance of the device. This proceeding describes the design and optimization of the cooling system for the VELO upgrade and the latest prototyping results

The VELO optical and power board

The optical and power boards (OPB) are part of the on-detector electronics system for the LHCb Vertex Detector (VELO) and they are used in LHCb upgrade 1 which is installed in the second long LHC shutdown period. The OPBs are assembled printed circuit boards (PCBs) that are located immediately outside of the VELO detector vacuum tank, in custom made mechanical crates. They perform the following main functions: optical-electrical conversion of the high-speed data and control signals that are sent to and from the detector module; DC/DC conversion of the supply voltage that is distributed to the detector module and to the components on the OPB; local slow control of the detector module and the OPB; and monitoring of the temperatures and supplied voltages of on the detector module and the OPB. The OPB operates in an environment with radiation, a magnetic field and limited cooling facilities, which is reflected in the design. This document gives and overview of the VELO electronics system and describes in detail the design of the OPB, providing diagrams to illustrate the functionality and tables to define the connectivity

Reconstruction of charged tracks with Timepix4 ASICs

The spatial and temporal performance of a four-plane system composed of silicon sensors bump-bonded to Timepix4 ASICs is assessed with a 180 GeV/c mixed hadron beam at the CERN SPS and reported in detail. Particle tracks are reconstructed using time-space measurements from the four detector planes, two 100 μm planes perpendicular to the beam and two 300 μm sensors under an angle of 9°. The spatial hit resolution is assessed to be (15.5 ± 0.5) μm and (4.5 ± 0.3) μm for 100 μm and 300 μm thick sensors, respectively. The timestamps from the detectors are also measured with fine precision, yielding time resolutions of (452 ± 10) ps, (420 ± 10) ps, (639 ± 10) ps, (631 ± 10) ps for the two 100 μm and two 300 μm thick sensors respectively. These measurements are combined to a track time resolution of (340 ± 5) ps. The design of the detector system is described together with its data acquisition system, operational infrastructure, and dedicated software.The design of a detector system comprised of four silicon sensors bump-bonded to Timepix4 ASICs is described together with its data acquisition system, operational infrastructure, and dedicated software. The spatial and temporal performance of the system are assessed with a 180 GeV/c mixed hadron beam at the CERN SPS and reported in detail. Particle tracks are reconstructed using time-space measurements from the four detector planes. The spatial hit resolution is assessed to be $(15.5\pm 0.5)$$\mu$m and $(4.5\pm0.3)$$\mu$m for 100 and 300 $\mu$m thick sensors, respectively. The timestamps from the detectors are also measured with fine precision, yielding time resolutions of $(452\pm10)$ ps, $(420\pm10)$ ps, $(639\pm10)$ ps, $(631\pm10)$ ps for the two 100 and two 300 $\mu$m thick sensors respectively. These measurements are combined to a track time resolution of $(340\pm 5)$ ps

Expression of interest for the CODEX-b detector

International audienceThis document presents the physics case and ancillary studies for the proposed CODEX-b long-lived particle (LLP) detector, as well as for a smaller proof-of-concept demonstrator detector, CODEX-$\beta$, to be operated during Run 3 of the LHC. Our development of the CODEX-b physics case synthesizes ‘top-down’ and ‘bottom-up’ theoretical approaches, providing a detailed survey of both minimal and complete models featuring LLPs. Several of these models have not been studied previously, and for some others we amend studies from previous literature: In particular, for gluon and fermion-coupled axion-like particles. We moreover present updated simulations of expected backgrounds in CODEX-b’s actively shielded environment, including the effects of shielding propagation uncertainties, high-energy tails and variation in the shielding design. Initial results are also included from a background measurement and calibration campaign. A design overview is presented for the CODEX-$\beta$ demonstrator detector, which will enable background calibration and detector design studies. Finally, we lay out brief studies of various design drivers of the CODEX-b experiment and potential extensions of the baseline design, including the physics case for a calorimeter element, precision timing, event tagging within LHCb, and precision low-momentum tracking

LHCb VELO Timepix3 Telescope

The LHCb VELO Timepix3 telescope is a silicon pixel tracking system constructed initially to evaluate the performance of LHCb VELO Upgrade prototypes. The telescope consists of eight hybrid pixel silicon sensor planes equipped with the Timepix3 ASIC . The planes provide excellent charge measurement, timestamping and spatial resolution and the system can function at high track rates. This paper describes the construction of the telescope and its data acquisition system and offline reconstruction software. A timing resolution of 350 ps was obtained for reconstructed tracks. A pointing resolution of better than 2\mum was determined for the 180 GeV/c mixed hadron beam at the CERN SPS . The telescope has been shown to operate at a rate of 5 million particles s−1⋅ cm−2 without a loss in efficiency.The LHCb VELO Timepix3 telescope is a silicon pixel tracking system constructed initially to evaluate the performance of LHCb VELO Upgrade prototypes. The telesope consists of eight hybrid pixel silicon sensor planes equipped with the Timepix3 ASIC. The planes provide excellent charge measurement, timestamping and spatial resolution and the system can function at high track rates. This paper describes the construction of the telescope and its data acquisition system and offline reconstruction software. A timing resolution of 350~ps was obtained for reconstructed tracks. A pointing resolution of better than 2~\mum was determined for the 180~GeV/c %\gevc mixed hadron beam at the CERN SPS. The telescope has been shown to operate at a rate of 5 million particles~\unit{s^{-1}\cdot cm^{-2}} without a loss in efficiency

The Road Ahead for CODEX-b

In this Snowmass contribution we present a comprehensive status update on the progress and plans for the proposed CODEX-b detector, intended to search for long-lived particles beyond the Standard Model. We review the physics case for the proposal and present recent progress on optimization strategies for the detector and shielding design, as well as the development of new fast and full simulation frameworks. A summary of the technical design for a smaller demonstrator detector (CODEX-$\beta$) for the upcoming Run~3 of the LHC is also discussed, alongside the road towards realization of the full experiment at the High-Luminosity LHC

The epidemiology of the comorbidity of epilepsy in the general population

*Purpose: To describe the epidemiology of somatic and psychiatric conditions in adults with epilepsy in the community and compare it to that of people without epilepsy.Methods: A cross-sectional population-based study extracting data from the UK General Practice Research Database for the period 1995-1998. Age- and sex-standardized prevalence rates were estimated for selected conditions and groups of conditions (categorized by ICD-9 chapters) in adults with epilepsy registered with primary care physicians. Results were compared with those in adults without epilepsy in the cohort. and prevalence ratios were calculated according to two broad age groups (16-64 and older than 64 years).Results: Conditions common in the general population also were common in adults with epilepsy. Psychiatric disorders occurred twice as often. and the risk of somatic disorders was increased in people with epilepsy, with the exception of muculoskeletal and connective tissue disorders in older adults. The prevalence ratio of neoplasia, excluding intracranial tumors. was not increased in epilepsy. The prevalence ratio of brain tumors was particularly increased in young adults [prevalence ratio(PR). 70.7] and of meningiomas in older adults (PR. 91.9). Neurodegenerative conditions. particularly dementias and Alzheimer' disease (PR. 6.3 and 8. respectively) and Parkinson' disease (PR. 3.2). appeared more frequently in people with epilepsy. Upper gastrointestinal bleed occurred more frequently in epilepsy (PR 4.3). as did cardio- and cerebrovascular disorders, fractures. pneumonia and chronic lung diseases. and diabetes. Eczema. osteoarthritis. and rheumatoid arthritis did not occur more frequently in epilepsy.Conclusions: The prevalence ratio of many common psychiatric and somatic conditions is increased in adults with epilepsy who consult a primary care physician in the U.K. These findings may have implications in the diagnosis and management of epilepsy and coexisting conditions. as well as in health care provision