Future wishes and constraints from the experiments at the LHC for the Proton-Proton programme

Hosting six different experiments at four different interaction points and widely different requirements for the running conditions, the LHC machine has been faced with a long list of challenges in the first three years of luminosity production (2010-2012, Run 1), many of which were potentially capable of limiting the performance due to instabilities resulting from the extremely high bunch brightness. Nonetheless, LHC met the challenges and performed extremely well at high efficiency and routinely with beam brightness at twice the design, well over one-third of the time in collision for physics, average luminosity lifetimes in excess of 10 h and extremely good background conditions in the experiments. While the experimental running configurations remain largely the same for the future high luminosity proton-proton operational mode, the energy and the luminosity should increase significantly, making a prior assessment of related beam-beam effects extremely important to guarantee high performance. Of particular interest is the need for levelling the luminosity individually in the different experiments. Luminosity control as the more general version of 'levelling' has been at the heart of the success for LHCb, and to a large extent also for ALICE, throughout Run 1. With the increasing energy and potential luminosity, luminosity control may be required by all the experiments at some point in the future as a means of controlling the pileup conditions and trigger rates, but possibly also as a way of optimizing the integrated luminosity. This paper reviews the various motivations and possibilities for controlling the luminosity from the experiments' point of view, and outlines the future running conditions and desiderata for the experiments as they are viewed currently, with the aim of giving guidelines for different options.Comment: 10 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201

Building Integrated Remote Control Systems for Electronics Boards

This paper addresses several aspects of implementing a remote control system for a large number of electronics boards in order to perform remote Field Programmable Gate Array (FPGA) programming, hardware configuration, data register access, and monitoring, as well as interfacing it to an expert system. The paper presents a common strategy for the representation of the boards in the abstraction layer of the control system, and generic communication protocols for the access to the board resources. In addition, an implementation is proposed in which the mapping between the functional parameters and the physical registers of the different boards is represented by descriptors in the board representation such that the translation can be handled automatically by a generic translation manager. Using the Distributed Information Management (DIM) package for the control communication with the boards, and the industry SCADA system PVSS II from ETM, a complete control system has been built for the Timing and Fast Control (TFC) system of the LHCb experiment at CERN. It has been in use during the entire prototyping of the TFC system and the developments of the LHCb sub-detector electronics, and is now installed in the online system of the final experiment

Beam phase and intensity monitor (BPIM) for the LHCb Experiment

The LHC bunch clock is transmitted over kilometres of fibre to the experiments where it is distributed to thousands of front-end electronics boards. In order to ensure that the detector signals are sampled properly, its long-term stability with respect to the bunch arrival times must be monitored with a precision of <100ps. In addition it is important to monitor the trigger conditions by measuring the intensity of each bunch locally in the experiment. For this purpose, we propose a beam phase and intensity acquisition board (BPIM) for the Button Electrode Beam Pick-ups which will be installed on both sides of the LHCb interaction point. The board measures the two quantities per bunch, and processes the information in an onboard FPGA. The information is read-out by the Experiment Control System and is directly fed to the LHCb Timing and Fast Control (TFC) [1]. In the TFC system the information is included in an event data bank but may also be used as a bunch crossing trigger or gate

A 40 MHz Trigger-free Readout Architecture for the LHCb experiment at CERN

LHCb is considering an upgrade towards a full 40 MHz readout. In this paper we investigate possibilities for a new Timing and Fast Control (TFC) system based on completely new technologies, and the consequences for the readout electronics. We define the requirements and propose an architecture allowing partitioning, complete readout control and event management. The backbone is based on bidirectional high-speed optical links using the latest FPGA transceivers. For the Front-End Electronics we advocate exploiting the bidirectional capability of the CERN GigaBit Transceiver to make the Readout Boards the TFC and the Control System interface to the Front-En

The LHCb Timing and Fast Control system

In this paper we describe the LHCb Timing and Fast Control (TFC) system. It is different from that of the other LHC experiments in that it has to support two levels of high-rate triggers. Furthermore, emphasis has been put on partitioning and on locating the TFC mastership in one type of module: the Readout Supervisor. The Readout Supervisor handles all timing, trigger, and control command distribution. It generates auto-triggers as well as controls the trigger rates. Partitioning is handled by a programmable patch panel/switch introduced in the TTC distribution network between a pool of Readout Supervisors and the Front-End electronics. I

Effectiveness of a minimal resource fracture liaison service

Purpose The purpose of this study was to investigate if a 2-year intervention with a minimal resource fracture liaison service (FLS) was associated with increased investigation and medical treatment and if treatment was related to reduced re-fracture risk. Methods The FLS started in 2013 using existing secretaries (without an FLS coordinator) at the emergency department and orthopaedic wards to identify risk patients. All patients older than 50 years of age with a fractured hip, vertebra, shoulder, wrist or pelvis were followed during 2013–2014 (n = 2713) and compared with their historic counterparts in 2011–2012 (n = 2616) at the same hospital. Re-fractures were X-ray verified. A time-dependent adjusted (for age, sex, previous fracture, index fracture type, prevalent treatment, comorbidity and secondary osteoporosis) Cox model was used. Results The minimal resource FLS increased the proportion of DXA-investigated patients after fracture from 7.6 to 39.6 % (p < 0.001) and the treatment rate after fracture from 12.6 to 31.8 %, which is well in line with FLS types using the conventional coordinator model. Treated patients had a 51 % lower risk of any re-fracture than untreated patients (HR 0.49, 95 % CI 0.37–0.65 p < 0.001). Conclusions We found that our minimal resource FLS was effective in increasing investigation and treatment, in line with conventional coordinator-based services, and that treated patients had a 51 % reduced risk of new fractures, indicating that also non-coordinator based fracture liaison services can improve secondary prevention of fractures

Effects of hydrogen bonding on supercooled liquid dynamics and the implications for supercooled water

The supercooled state of bulk water is largely hidden by unavoidable crystallization, which creates an experimentally inaccessible temperature regime - a 'no man's land'. We address this and circumvent the crystallization problem by systematically studying the supercooled dynamics of hydrogen bonded oligomeric liquids (glycols), where water corresponds to the chain-ends alone. This novel approach permits a 'dilution of water' by altering the hydrogen bond concentration via variations in chain length. We observe a dynamic crossover in the temperature dependence of the structural relaxation time for all glycols, consistent with the common behavior of most supercooled liquids. We find that the crossover becomes more pronounced for increasing hydrogen bond concentrations, which leads to the prediction of a marked dynamic transition for water within 'no man's land' at T~220 K. Interestingly, the predicted transition thus takes place at a temperature where a so called 'strong-fragile' transition has previously been suggested. Our results, however, imply that the dynamic transition of supercooled water is analogous to that commonly observed in supercooled liquids. Moreover, we find support also for the existence of a secondary relaxation of water with behavior analogous to that of the secondary relaxation observed for the glycols.Comment: 20 pages, 5 figures; corrected typos, title changed, small clarifying text changes, two labels removed from Fig. 2