TY - JOUR
T1 - Suspending test masses in terrestrial millihertz gravitational-wave detectors
T2 - A case study with a magnetic assisted torsion pendulum
AU - Thrane, Eric
AU - Anderson, Russell P.
AU - Levin, Yuri
AU - Turner, L. D.
PY - 2017/4/12
Y1 - 2017/4/12
N2 - Current terrestrial gravitational-wave detectors operate at frequencies above 10 Hz. There is strong astrophysical motivation to construct low-frequency gravitational-wave detectors capable of observing 10 mHz-10 Hz signals. While space-based detectors provide one means of achieving this end, one may also consider terretrial detectors. However, there are numerous technological challenges. In particular, it is difficult to isolate test masses so that they are both seismically isolated and freely falling under the influence of gravity at millihertz frequencies. We investigate the challenges of low-frequency suspension in a hypothetical terrestrial detector. As a case study, we consider a magnetically assisted gravitational-wave pendulum intorsion (MAGPI) suspension design. We construct a noise budget to estimate some of the required specifications. In doing so, we identify what are likely to be a number of generic limiting noise sources for terrestrial millihertz gravitational-wave suspension systems (as well as some peculiar to the MAGPI design). We highlight significant experimental challenges in order to argue that the development of millihertz suspensions will be a daunting task. Any system that relies on magnets faces even greater challenges. Entirely mechanical designs such as Zöllner pendulums may provide the best path forward.
AB - Current terrestrial gravitational-wave detectors operate at frequencies above 10 Hz. There is strong astrophysical motivation to construct low-frequency gravitational-wave detectors capable of observing 10 mHz-10 Hz signals. While space-based detectors provide one means of achieving this end, one may also consider terretrial detectors. However, there are numerous technological challenges. In particular, it is difficult to isolate test masses so that they are both seismically isolated and freely falling under the influence of gravity at millihertz frequencies. We investigate the challenges of low-frequency suspension in a hypothetical terrestrial detector. As a case study, we consider a magnetically assisted gravitational-wave pendulum intorsion (MAGPI) suspension design. We construct a noise budget to estimate some of the required specifications. In doing so, we identify what are likely to be a number of generic limiting noise sources for terrestrial millihertz gravitational-wave suspension systems (as well as some peculiar to the MAGPI design). We highlight significant experimental challenges in order to argue that the development of millihertz suspensions will be a daunting task. Any system that relies on magnets faces even greater challenges. Entirely mechanical designs such as Zöllner pendulums may provide the best path forward.
KW - gravitational-wave astronomy
KW - gravitational-wave detectors
KW - millihertz
UR - http://www.scopus.com/inward/record.url?scp=85018949283&partnerID=8YFLogxK
U2 - 10.1088/1361-6382/aa6968
DO - 10.1088/1361-6382/aa6968
M3 - Article
AN - SCOPUS:85018949283
VL - 34
JO - Classical and Quantum Gravity
JF - Classical and Quantum Gravity
SN - 0264-9381
IS - 10
M1 - 105002
ER -