Solid-state detector for ICP-OES

Abstract

A new type of solid-state detector has been designed to meet the needs of inductively coupled plasma optical emission spectroscopy (ICP-OES), including high quantum efficiency in the UV, low noise, wide dynamic range, rapid readout, broad spectral coverage, and high spectral resolution. The device is based on buried-channel chargecoupled-device (CCD) technology with unique features for optical emission spectroscopy and is matched to a specific echelle grating optical system described in the companion paper. It measures simultaneously 5.7% of the continuous ICP spectrum from 167 to 782 nm with 224 linear photodetector arrays. These arrays are targeted on three to four primary analytical lines for each of 72 elements and cover over 5000 ICP emission lines. This device provides the combination of high quantum efficiency in the UV, low readout noise typical of CCDs, true random-access readout, and charge blooming control for wide dynamic range. In general, the detector has photometric performance (quantum efficiency, noise, dynamic range) equal to or better than photomultiplier tubes for ICP-OES. The simultaneously measured spectral data can be used to correct for spectral interferences and correlated background noise so that analytical detection limits are photon shot noise limited.

Behaviour of large-area avalanche photodiodes under intense magnetic fields for VUV- visible- and X-ray photon detection

“…Since VUV photons interact within the first atomic layers, the effect of the magnetic field on the photoelectrons and subsequent secondary electrons diffusion may be responsible for increased charge carrier losses to the front electrode with increasing magnetic field. Penetration depths in Si are about 5 nm and 1 mm for 172-and 520-nm photons [22], respectively, and 22 mm for 5.4-keV X-rays [23].…”

Detection of VUV Light with Avalanche Photodiodes

“…This is due to the difference in the average interaction depth of the photons, which is approximately 1 μm for 520-nm photons and approximately 5 nm for 172-nm photons [29]. VUV photons interact mainly within the first atomic layers of the wafer, where the electric field is weaker.…”

High-resolution continuum-source atomic absorption spectrometry: what can we expect?

“…Obviously, such a detector would be expensive, but similar detectors are in use already in echelle spectrometers for ICP OES. [29][30][31] However, the only functional multi-element CS AAS instrument built up until now is that described by Harnly et al 14 back in 1979.…”