Remote photonic data recording

Remote photonic data recording*Grant J. Lock wood* William F. Filter, Clinton 0. Landron, David J.Muron, James Chang, and James J. FanningDiagnostics Division, Sandia National Laboratories P.O. Box 5300, Albuquerque, New Mexico 87185and Barry T. NeyerMonsanto Research Corporation MRC-Mound, Miamisburg, Ohio 453^2AbstractWe have successfully recorded analog signtils, using the High-Speed Mult i -Channe 1 DataRecorder (HSMCDR), where the signal source and the recorder were required to bec^2000 m apart. In addition, it was necessary for the system to operate remotely.This photonic data, recording experiment consisted of a HSMCDR, laser diode transmitters and the 2000 m fiber link between them. Of six transmitters, one was used to provide the HSMCDR trigger. Another transmitter sent the trigger waveform to be recorded by the HSMCDR. The remaining four transmitters converted analog electrical data signals into analog photonic signals for transmission to the HSMCDR. Since all signals were coincident, the analog signals were sent over an additional 200 m of fiber to obtain a 1 (Lls delay, necessary to allow for delay from trigger pulse to start of streak. The system bandwidth was about 350 MHz. The HSMCDR performed all its trigger monitoring, shutter control, arming, and data transfer functions under the direction of a computer. To assess system performance, we designed and installed self-diagnostic circuits that recorded key timing signals on a fast strip-chart recorder. Although we were only provided with five data channels, the HSMCDR used is a 20-channel system. We assembled this system in two days and were ready for data recording within one week.We will describe the system and present our results. In addition, a second generation HSMCDR built around a streak camera with a large area photocathode and charge-coupled device (CCD) digital readout will be described. This system will record up to 40 channels of data.IntroductionWe have conducted an experiment using the High-Speed Multi-Channe1 Data Recorder (HSMCDR) at the Nevada Test Site (NTS). The purpose of the experiment was to demonstrate the ability to record analog electric data with the HSMCDR in the NTS environment. Analog electric signals were converted to analog photonic signals using laser diode transmitters (LDTs) located at an underground instrument alcove. The analog photonic signals were transmitted over ^2000 m long fiber-optic cables uphole to a portal recording station and recorded using the HSMCDR.There were several experimental objectives. First was to record five electrical signal channels through LDT interfaces on the HSMCDR. Next was to test surv ivability of the LDTs and HSMCDR in the NTS environment and to learn firsthand NTS instrumentation and diagnostic requirements. Finally, we wished to determine the desirability of the comprehensive integration of photonics in NTS experiments.In the following section the apparatus and procedures are described. The results and data are presented in Section III. Section IV describes a second generation HSMCDR. Our conclusions are presented in Section V.Apparatus and proceduresThe arrangement of the apparatus for this experiment is shown in Figure 1 . There were six LDTs located in an underground instrument alcove. One LDT was used to provide the HSMCDR trigger. The input to the LDT was a positive pulse regenerated from a Compton diode signal. The signal from this LDT was transmitted over a fiber to an avalanche photodiode in the portal recording station. The electric output from the photodiode was used to initiate a series of pulse generator and delay units to gate and trigger the HSMCDR at the