Table 3.

The principal features in our G measurements.

itemsHUST-99/HUST-05HUST-09ongoing experiment
pendulum system:
 shapedumbbellrectangular blockrectangular block
 materialcopper, aluminiumquartzquartz
 coating effect−24.28(4.33) ppm∼2 ppm
 magnetic damper17.54(0.31) ppm∼0.4 ppm
ur of pendulum31 ppm5.07 ppm∼5 ppm
source mass:
 supportingaluminium benchzerodur ringthree-point mount
 materialstainless steelSS316 stainless steelSS316 stainless steel
ur of source mass66 ppm10.68 ppm∼11 ppm
torsion fibre:
 materialtungstenannealed tungstenfused silica, tungsten
Q3.6×1041.7×1035.0×104, 3.0×103
 anelasticity−9 ppm−211.80(18.69) ppm−6.4 ppm, −106 ppm
intrinsic period3484 s535.2 s392 s and 535 s
period change27%0.6%0.3%
ur of Δω275 ppm14.18 ppmexpected less than 15 ppm
background gravityno compensationno compensationcompensation
temperature controlno extra controlno extra controlcopper tube
G(×10−11 m3 kg−1 s−2)6.6699(7)/6.6723(9)6.67349(18)