Neutron penumbral imaging of inertial confinement fusion targets at Phébusa)

Abstract

First 14 MeV neutron images of imploded microballoons have been obtained at the Phébus laser facility at CEL-V in 1992 [Garconnet et al. Laser Part Beams 11, 3 (1994)]. The sizes of the neutron source have been measured by using a coded-aperture imaging system and a scintillator array as a detector. The threshold of the experimental setup was typically 2×1010 neutrons/shot. 600–800 μm source sizes in direct drive experiments have been measured with a 130 μm two-point resolution. In 1993 we improved the sensitivity of the camera by increasing the light collection efficiency. It can now work at a neutron yield as small as a few 108. Thanks to this improvement some images in indirect drive experiments have been recorded in the range 3×108–5×109 with a 56 μm two-point resolution. Wiener filter, homomorphic Wiener filter, and Nugent’s ‘‘comb filter’’ methods have been used and compared to deconvolve the penumbral images. Design of the camera and numerical method performances will be discussed.

Obtaining point spread function of penumbral encoding aperture with “expectation maximization” algorithm based on matched source-image pair experiment

“…The remaining part of the system is set to vacuum. A parallel version of MCNP was used on a workstation at the School of Nuclear Science and Technology, Xi'an Jiaotong University that took about 20 h. 34 The MC program makes 10 8 samples per operation with appropriate bias solid angle to approximate to the actual yield, and the relative error is less than 1.5%. The two-dimensional ͑2D͒ system PSF, calculated by MC model, and is shown in Fig.…”

A new reconstruction method based on classical molecular dynamics of neutron penumbral imaging in ICF

“…Before presenting our CMD reconstruction method, we will briefly introduce the general principle of penumbral imaging [4,8], and then focus on the CMD reconstruction method in Section 3.…”

D 3 He -proton emission imaging for inertial-confinement-fusion experiments (invited)

“…In practice, noise is con- trolled by usng a Wiener filter approach to modify the ideal deconvolution filter in such a way as to reduce noise amplification near the singularities while minimizing distortion to real structural information in the data. This direct reconstruction approach has been used for DT neutrons [11][12][13][14][15][16][17][18][19] and for 3-MeV DD protons. 36,37 Another direct reconstruction algorithm that works in frequency space 21 has been applied to DT neutrons.…”