HESS, one of the world's best-performing ground-based gamma ray detectors, will soon boast a fifth telescope that will double its potential for making new discoveries. The telescope will be equipped with 

Upper part of the camera (picture from CNRS website)

a camera designed and built by French scientists as part of the HESS joint project, which involves several CNRS laboratories such as IN2P3(1), INSU(2) and CEA-Irfu(3). Enhanced sensitivity provides this new electronic eye with an image twice as sharp as that of the cameras already installed on HESS. It has just been completed and is currently on display at the Ecole Polytechnique. This new camera will considerably increase the overall performance of HESS, which will be renamed HESS-II and will push back the boundaries of the visible, lifting the veil on the mysteries of the most violent phenomena in the Universe.

In order to increase the instrument's sensitivity and reveal some of the mysteries of our Universe, the researchers involved in HESS are developing an even more efficient device, known as HESS-II, which consists in adding a very large central telescope of 28 m in diameter to the existing system. The 596 m2 of this telescope's mirror (compared to 107 m2 for each of the 4 telescopes already in place) will concentrate the light on a camera that has just been built. With a sensitive surface area of 2.15 m in diameter and a granularity(7) twice that of the cameras used at present, it will be able to detect gamma photons one by one with a response time on the nanosecond (10-9 s) scale. This camera is a real eagle's eye and the key component of the fifth telescope. It represents France's main contribution, with IN2P3/CNRS as project manager. The French laboratories, backed up by a network of industrial partners, built on the expertise acquired in developing cameras for the first four telescopes. The new camera still needs to undergo calibration tests before being shipped to Namibia and installed on the fifth telescope, which is expected to be fully operational by 2011.

HESS-II, which is more sensitive and covers a broader energy range, will pave the way for new discoveries and will make it possible to expand the catalogue of high-energy sources in the Universe. More specifically, this new network should help to increase the number of known sources emitting high-energy gamma rays and significantly improve images of celestial objects, such as the remains of supernovae.

Source: CNRS Website