We present the Herschel Bright Sources (HerBS) sample, a sample of
bright, high-redshift Herschel sources detected in the 616.4
deg2 Herschel Astrophysical Terahertz Large Area Survey. The
HerBS sample contains 209 galaxies, selected with a 500 μm flux
density greater than 80 mJy and an estimated redshift greater than 2.
The sample consists of a combination of hyperluminous infrared galaxies
and lensed ultraluminous infrared galaxies during the epoch of peak
cosmic star formation. In this paper, we present Submillimetre
Common-User Bolometer Array 2 (SCUBA-2) observations at 850 μm of 189
galaxies of the HerBS sample, 152 of these sources were detected. We fit
a spectral template to the Herschel-Spectral and Photometric Imaging
Receiver (SPIRE) and 850 μm SCUBA-2 flux densities of 22 sources with
spectroscopically determined redshifts, using a two-component modified
blackbody spectrum as a template. We find a cold- and hot-dust
temperature of 21.29_{-1.66}^{+1.35} and 45.80_{-3.48}^{+2.88} K, a
cold-to-hot dust mass ratio of 26.62_{-6.74}^{+5.61} and a β of
1.83_{-0.28}^{+0.14}. The poor quality of the fit suggests that the
sample of galaxies is too diverse to be explained by our simple model.
Comparison of our sample to a galaxy evolution model indicates that the
fraction of lenses are high. Out of the 152 SCUBA-2 detected galaxies,
the model predicts 128.4 ± 2.1 of those galaxies to be lensed
(84.5 per cent). The SPIRE 500 μm flux suggests that out of all 209
HerBS sources, we expect 158.1 ± 1.7 lensed sources, giving a
total lensing fraction of 76 per cent.