|A millisecond-risetime sub-millimeter light source for lab and in flight bolometer calibration.|
|Ph.Abbon A.Delbart M.Fesquet C.Magneville B.Mazeau J-P.Pansart D.Yvon|
The Olimpo balloon project will use a 120 bolometer camera to observe the sky at $4$ frequencies ($143$, $217$, $385$ and $600\\;GHz$) with a resolution of $3$ to $2$ arc-minute. This paper presents the sub-millimeter calibration \"lamp\" developed for ground testing and in-flight secondary calibration of bolometric detectors. By design, main features of the device are reproductibility and stability of light flux and millisecond rise time. The radiative device will be placed inside the bolometer camera and will illuminate the bolometer array through a hole in the last $2\\;K$ mirror. Operation, readout, and monitoring of the device is ensured by warm electronics. Light output flux and duration is programmable, triggered and monitored from a simple computer $RS232$ interface. It was tested to be reliable in ballooning temperature conditions: from $-80^\\circ C$ to $50^\\circ C$. Design and test\'s results are explained.