arXiv subjects

J. Heefner

Publications and source records attributed to J. Heefner.

5 recordsLinked to original sources

arXiv2016

The Sensitivity of the Advanced LIGO Detectors at the Beginning of Gravitational Wave Astronomy

The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than $10^{-23}/\sqrt{\text{Hz}}$ was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the observable volume in the universe. The average distance at which coalescing binary black hole systems with individual masses of 30 $M_\odot$ could be detected was 1.3 Gpc. Similarly, the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of Universe increased respectively by a factor 69 and 43. These improvements allowed Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914.

astro-ph.IM↗

arXiv2012

Sensors and Actuators for the Advanced LIGO Mirror Suspensions

We have developed, produced and characterised integrated sensors, actuators and the related read-out and drive electronics that will be used for the control of the Advanced LIGO suspensions. The overall system consists of the BOSEMs (displacement sensor with integrated electro-magnetic actuator), the satellite boxes (BOSEM readout and interface electronics) and six different types of coil-driver units. In this paper we present the design of this read-out and control system, we discuss the related performance relevant for the Advanced LIGO suspensions, and we report on the experimental activity finalised at the production of the instruments for the Advanced LIGO detectors.

gr-qc↗

arXiv2001

An Overview of the LIGO Control and Data Acquisition System

The LIGO Control and Data system (CDS) features a tightly coupled and highly integrated control and data acquisition system. Control of the interferometers requires many Multiple Input Multiple Output (MIMO) control loops closed both locally and across the 4-kilometer interferometer arm lengths. In addition to providing the closed loop control, the control systems front end processors act as Data Collection Units (DCU) for the data acquisition system. Data collected by these front ends and the data acquisition system must be collected and time stamped to an accuracy of 1 microsecond and made available to on-line analysis tools such as the Global Diagnostics System (GDS)[1]. Data is also sent to the LIGO Data Analysis System (LDAS)[2] for long-term storage and off-line analysis. Data rates exceed 5 Mbytes per second per interferometer continuous. Connection between the various front end processors and the data acquisition system is achieved using fiber optic reflective memory networks. Both controls and data acquisition systems use VME hardware and VxWorks operating systems. This paper will present an overview of the LIGO CDS and discuss key aspects of its design.

physics.ins-det↗

arXiv2001

The LIGO Interferometer Sensing and Control System

The LIGO Interferometer Sensing and Control System (ISC) is a large and highly distributed Multiple Input Multiple Output (MIMO) control system that is used to control the length and alignment degrees of freedom of the interferometers. The 4 kilometer Fabry-Perot cavity lengths are controlled to better than 10-13 meters (rms) and the angular degrees of freedom are controlled to better than 10-8 radians. This paper will describe the real-time digital servo control systems that have been designed, developed and implemented for the LIGO Length Sensing and Control (LSC) [1] and Alignment Sensing and Control (ASC) [2] systems. In addition, the paper will describe how these controls, along with the suspended optic controls [3], have been integrated into the overall LIGO control and data acquisition system [4].

physics.ins-det↗

arXiv2001

The LIGO Suspended Optic Digital Control System

The original LIGO suspension control system [1] used analog circuitry to implement the closed loop damping required for local control of each the suspended optics. Recent developments in analog to digital converters (ADC), digital to analog converters (DAC), increased processor speed and performance, and the use of reflective memory have made a digital alternative possible. Such a control system would provide additional performance and flexibility that will be required for operation of the interferometers. This paper will describe the real-time digital servo control systems that have been designed, developed and implemented for the LIGO suspended optics. In addition, the paper will describe how the suspension controls have been integrated into the overall LIGO control and data acquisition systems [2].

physics.optics↗