X-ray streak camera cathode development and timing accuracy of the 4ω ultraviolet fiducial system at the National Ignition Facility

Y P Opachich; N Palmer; D Homoelle; B Hatch; P Bell; D Bradley; D Kalantar; D Browning; J Zuegel; O Landen

doi:10.1063/1.4732855

X-ray streak camera cathode development and timing accuracy of the 4ω ultraviolet fiducial system at the National Ignition Facility

Rev Sci Instrum. 2012 Oct;83(10):10E123. doi: 10.1063/1.4732855.

Authors

Y P Opachich¹, N Palmer, D Homoelle, B Hatch, P Bell, D Bradley, D Kalantar, D Browning, J Zuegel, O Landen

Affiliation

¹ Lawrence Livermore National Laboratory, Livermore, California 94550, USA. [email protected]

PMID: 23126945
DOI: 10.1063/1.4732855

Abstract

The convergent ablator experiments at the National Ignition Facility (NIF) are designed to measure the peak velocity and remaining ablator mass of an indirectly driven imploding capsule. Such a measurement can be performed using an x-ray source to backlight the capsule and an x-ray streak camera to record the capsule as it implodes. The ultimate goal of this experiment is to achieve an accuracy of 2% in the velocity measurement, which translates to a ±2 ps temporal accuracy over any 300 ps interval for the streak camera. In order to achieve this, a 4ω (263 nm) temporal fiducial system has been implemented for the x-ray streak camera at NIF. Aluminum, titanium, gold, and silver photocathode materials have been tested. Aluminum showed the highest relative quantum efficiency, with five times more peak signal counts per fiducial pulse when compared to Gold. The fiducial pulse data were analyzed to determine the centroiding statistical accuracy for incident laser pulse energies of 1 and 10 nJ, showing an accuracy of ±1.6 ps and ±0.7 ps, respectively.