M. Jonas — Page 2 | Searcharxiv

arXiv2015

The Dark Energy Camera

The Dark Energy Camera is a new imager with a 2.2-degree diameter field of view mounted at the prime focus of the Victor M. Blanco 4-meter telescope on Cerro Tololo near La Serena, Chile. The camera was designed and constructed by the Dark Energy Survey Collaboration, and meets or exceeds the stringent requirements designed for the wide-field and supernova surveys for which the collaboration uses it. The camera consists of a five element optical corrector, seven filters, a shutter with a 60 cm aperture, and a CCD focal plane of 250 micron thick fully-depleted CCDs cooled inside a vacuum Dewar. The 570 Mpixel focal plane comprises 62 2kx4k CCDs for imaging and 12 2kx2k CCDs for guiding and focus. The CCDs have 15 microns x15 microns pixels with a plate scale of 0.263 arc sec per pixel. A hexapod system provides state-of-the-art focus and alignment capability. The camera is read out in 20 seconds with 6-9 electrons readout noise. This paper provides a technical description of the camera's engineering, construction, installation, and current status.

astro-ph.IM↗

arXiv2014

The PHENIX Forward Silicon Vertex Detector

A new silicon detector has been developed to provide the PHENIX experiment with precise charged particle tracking at forward and backward rapidity. The Forward Silicon Vertex Tracker (FVTX) was installed in PHENIX prior to the 2012 run period of the Relativistic Heavy Ion Collider (RHIC). The FVTX is composed of two annular endcaps, each with four stations of silicon mini-strip sensors, covering a rapidity range of $1.2<|η|<2.2$ that closely matches the two existing PHENIX muon arms. Each station consists of 48 individual silicon sensors, each of which contains two columns of mini-strips with 75 $μ$m pitch in the radial direction and lengths in the $ϕ$ direction varying from 3.4 mm at the inner radius to 11.5 mm at the outer radius. The FVTX has approximately 0.54 million strips in each endcap. These are read out with FPHX chips, developed in collaboration with Fermilab, which are wire bonded directly to the mini-strips. The maximum strip occupancy reached in central Au-Au collisions is approximately 2.8%. The precision tracking provided by this device makes the identification of muons from secondary vertices away from the primary event vertex possible. The expected distance of closest approach (DCA) resolution of 200 $μ$m or better for particles with a transverse momentum of 5 GeV/$c$ will allow identification of muons from relatively long-lived particles, such as $D$ and $B$ mesons, through their broader DCA distributions.

physics.ins-det↗