M. D. Niemack, et al., P03 A kilopixel array of TES bolometers for ACT: Development, Testing, and First Light Low Temperature Detectors 12, P03 July 26, 2007 M. D. Niemack, Princeton University Y. Zhao, E. Wollack, R. Thornton, E. R. Switzer, D. S. Swetz, S. T. Staggs, L. Page, O. Stryzak, H. Moseley, T. A. Marriage, M. Limon, J. M. Lau, J. Klein, M. Kaul, N. Jarosik, K. D. Irwin, A. D. Hincks, G. C. Hilton, M. Halpern, J. W. Fowler, R. P. Fisher, R. Dunner, W. B. Doriese, S. R. Dicker, M. J. Devlin, J. Chervenak, B. Burger, E. S. Battistelli, J. Appel, M. Amiri, C. Allen, and A. M. Aboobaker ¼ array

M. D. Niemack, et al., P03 Columbia Haverford U. KwaZulu-Natal Rutgers U. Toronto U. Catolica Cardiff UMass CUNY UBC Cluster (SZ, KSZ X-rays, & optical) Diffuse SZ OV CMB to l~10,000 Lensing Observations: Collaboration: Science: Growth of structure Eqn. of state Neutrino mass Ionization history ACT Atacama Cosmology Telescope Optical X-ray Theory NIST Power spectrum INAOE Princeton NASA/GSFC UPenn U. Pittsburgh wwwphy.princeton.edu/act

M. D. Niemack, et al., P03 Kilopixel Array Overview Detector Parameter Selection Screening and assembly Dark bolometer measurements Optical time constants First light! Current status

M. D. Niemack, et al., P03 Parameter Selection Critical Parameters: Noise level, P sat, f 3dB SQUID noise –Time-domain multiplexing aliasing  select low TES resistance so high current noise dominates SQUID noise Saturation power, P sat –Predicted load at 145 GHz < 2 pW –  saturation power for biasing uniformity and  f 3dB de Korte, et al. (2003)

M. D. Niemack, et al., P03 Pre-screening and Assembly Pre-screen mux chips and shunt chips Assemble components into columns Light Det chip (32 pixels) Shunt chip Nyquist chip Mux chip Assemble columns into array ¼ filled array 8x32 bolometer array thermometer

M. D. Niemack, et al., P03 Array Assembly and Si Coupling Layer Evanescently coupled Si layer matches bolometer impedance to free space …also protects array …currently being tested Light

M. D. Niemack, et al., P03 Pre-Assembly Column Screening Test every pixel –V-phi, T c, I-V, R shunt, noise Repairs –Disconnect oscillating and problematic detectors –Short failed SQUIDs ~90% yield on first ¼ array Dewar Flange 4 He Bath Vacuum Can Vacuum Ports, Electronics 1 m SRDP 4 He Pot 3 He Pot Flex Column (1x32TES) 3 cm

M. D. Niemack, et al., P03 Noise and Nyquist Inductor Selection Compare noise and aliasing estimates pre- and post-Nyquist inductor Find maximum decrease in aliasing after adding inductor, without causing oscillations (R. Dunner & T. Marriage) TES Absorber Si Aliasing Estimate Bolometer Model

M. D. Niemack, et al., P03 Optical time constants – CCam prototype Chopper wheel measurements 3 bolometer types follow trend Consistent f 3dB between 0.25 – 0.75 * R n Drives us to select higher P sat CCam isothermal, no L ACT scans in azimuth 5 o p2p during observations Light

M. D. Niemack, et al., P03 First Light! CCam prototype on ACT Scanning Obs. of Jupiter Caveats: –Mirror alignment –Non-ideal optics –Ladder –Focus Plate scale looks good ~38’/mm

M. D. Niemack, et al., P03 Status & Thanks Completed majority of testing of remaining columns for array Finishing last MBAC receiver tests Testing data acquisition with more CCam observations Aligning mirrors Thank you: Cardiff Univ. for supplying CCam filters A. Dahlen, B. Harrop, T. Essinger-Hileman, K. Martocci, L. Parker, and A. Sederberg for help with detector screening and assembly All other members of the ACT Collaboration