Vulnerability of CMOS image sensors in Megajoule Class Laser harsh environment.

CMOS image sensors (CIS) are promising candidates as part of optical imagers for the plasma diagnostics devoted to the study of fusion by inertial confinement. However, the harsh radiative environment of Megajoule Class Lasers threatens the performances of these optical sensors. In this paper, the vulnerability of CIS to the transient and mixed pulsed radiation environment associated with such facilities is investigated during an experiment at the OMEGA facility at the Laboratory for Laser Energetics (LLE), Rochester, NY, USA. The transient and permanent effects of the 14 MeV neutron pulse on CIS are presented. The behavior of the tested CIS shows that active pixel sensors (APS) exhibit a better hardness to this harsh environment than a CCD. A first order extrapolation of the reported results to the higher level of radiation expected for Megajoule Class Laser facilities (Laser Megajoule in France or National Ignition Facility in the USA) shows that temporarily saturated pixels due to transient neutron-induced single event effects will be the major issue for the development of radiation-tolerant plasma diagnostic instruments whereas the permanent degradation of the CIS related to displacement damage or total ionizing dose effects could be reduced by applying well known mitigation techniques.

[Neurological outcome of 152 surgical patients with spinal metastasis]. / Evolution neurologique de 152 patients opérés de métastases rachidiennes.

BACKGROUND AND PURPOSE: The aim of this study is to evaluate retrospectively the benefit of the surgical spinal decompression in 152 patients with spinal metastasis. METHODS: Based on clinical notes and GP inquiry, we determined the actuarial survival curve, and assessed the pain level one month post-operatively and the motor, the sensory and sphincter distrurbances three months after surgery. RESULTS: Thoraco-lumbar lesions were usually treated using a posterior approach, with a laminectomy and if necessary an osteosynthesis. Cervical lesions were treated with an anterior approach, i.e. a corporectomy and a methylmetacrylate stabilization. Sixty eight percent of patients (103/152) had pre or postoperative radiotherapy. After the surgical decompression for a spinal metastasis, our study demonstrated an improvement in sensory status (31 % of the patients), in motor ability (56 %), in sphincter function (51 %), and a decrease in the pain intensity in 47 % of the patients. Among 83 patients who could not walk on admission (grade A, B and C of Frankel), 52 % recovered a gait function 3 months post operatively. The best benefit after surgery concerned grade C patients, of which 71 % recovered the gait function. Two percent of the patients had postoperative worsening of their motor strength. No operative mortality was noted, and the postoperative mortality rate was 3 % at 7 days and 9 % at 30 days. The analysis of the actuarial survival curve demonstrated a mean follow up of 3.7 years. The mean survival time was 12 months with 25 % of patients surviving 2 years. CONCLUSION: Surgical decompression is effective in relieving neurological symptoms from spinal metastasis. In our experience a complete motor deficit does not seem to be a good surgical indication because of the lack of postoperative improvement.