1. Advanced Cosmology Bolometer Array Receiver (ACBAR) on Viper Jeff Peterson - CMU –Ravinder Bhatia (Caltech) –Jamie Bock (JPL) –Andrew Lange (Caltech) –Peter Ade (QMWC) –Dale Morgan (CMU) –Matt Newcomb (CMU) –Jeff Peterson (CMU) –Kathy Romer (CMU) ACBAR Team –John Ruhl (UCSB) –Bill Holzapfel (UCB) –Eric Torbet (UCSB) –Jon Goldstein (UCSB) –Marcus Runyan (Caltech) –Chao-Lin Kuo (UCB) The Viper Telescope

2. Acbar Goals CMB Anisotropy –High angular resolution angular power spectrum –Non-gaussianities in the CMB –Measure galactic foregrounds Sunyaev-Zeldovich Effect –Search for clusters to limit  –Kinematic SZ-effect to measure cluster v pec –Study nearby clusters to improve cluster models

3. Frequency Bands Four color, 16 element bolometer array. (150, 220, 275, 350 GHz) => extract foregrounds and SZ 4’ resolution,  1º chop angle on Viper => chop well off clusters SZ Thermal CMB and SZ kinetic

4. Focal Plane Layout Corrugated feeds provide 4’ FWHM on sky.

5. Status Beam pattern at 140GHz and 700 GHz measured Dewar hold time tested Refrigerator design tested Data acquistion tested Viper operational

6. Schedule Install array in cryostat, spring 2000. Test over summer 2000. Deploy November 2000 Winter-over observing in 2001.

7. Viper SZ survey data in 2002, strongly constraining Omega matter.