Grimm lamp

The Grimm lamp has an abnormal characteristic, the current is selected to be at 40-200 mA and the burning voltage is usually below 1 kV. Both in krypton as well as in neon the burning voltage is higher than in argon, but it also depends on the... 

Because of the low spectral background intensities the limits of detection from the side of the source will be low and for metals will be down to the pg/g range in a classical Grimm lamp [479]. Also elements such as B, P, S, C, As,... can be determined. The plasma is optically thin, but for resonance lines of the matrix elements,... 

Figure 11. The Grimm lamp used in GDOES [99] (1) sample, (2) cathode, (3) O-ring, (4) anode, (5) quartz window, (6), (7) evacuation ports, (8) gas inlet. (9) Teflon insulator.

Technical modification of the Grimm lamp (a hollow-cathode lamp operating in the microwave-boosted mode) has given increased sensitivity compared to the conventional hollow-cathode lamp [1041. Argon line interferences have been removed by introducing a third electrode to modulate the intensities (lO. )). A low-pressure device can be introduced in order to decrease atmospheric contamination of the sample [106]. Fa.st Fourier transform analysis of emitted light has provided increased sensitivity (e.g.. Mo in steel down to 50 ppm [I07 ). 

Little experimental data on the photochemistry of compounds with B—0 bonds have been reported. Boron-hydride/oxygen mixtures are explosive. These explosions can be initiated by photochemical processes. Grimm and Porter have studied the photochemical decomposition of H2B2O3 using a low pressure mercury lamp. The UV spectrum of this compound is illustrated in Fig. 13. The rate of the reaction was increased when mercury was present as a photosensitizer. 

One popular configuration is the Grimm source, which accepts samples in the form of discs. Such sources usually operate at 500-1000 V, 25-100 mA and 1-5 Torr, wiA detection limits of approximately 0.1 ppm. Another configuration is the hollow-cathode lamp in which the sample can be either machined as a hollow cathode, evaporated to dryness (if a solution) or pressed (if a powder) into a hollow cathode made of pure graphite. Typical operating conditions are 200-500 V, 10-100 mA, and 0.1-1.0 Torr, with detection limits in the range 0.1-10 ppm. 

X-ray tube-assisted GD A Grimm-type GD lamp was modifled by incorporating a 15 mm thick PTFE support to insulate the cathode support from the anode body. With this... 

Fig. 25. Spectral-segmented spectrum of a glow discharge [58]. Grimm-type glow discharge lamp with floating restrictor (8 mm diameter) 50 mA, 3.5 torr, 2 kV [42] Plasmaarray spectrometer (LECO) steel sample 217 A (Research Institute, CKD, Prague, Czech Republic).

Fig. 106. Glow discharge lamp according to Grimm, (a) cathode block (b) sample (c) negative glow (d) quartz window (e) insulator (Reprinted with permission from Ref. [232].)...

In the case of a helium discharge sustained in a Grimm-type glow discharge lamp, vapors of halogenated hydrocarbons can be introduced successfully through... 

Steers E. B. M. and Leis F.(1991) Excitation of the spectra of neutral and singly ionized atoms in the Grimm-type discharge lamp with and without supplementary microwave excitation, Spectrochim Acta, Part B 46 527-537. 

Figure 41. Classical Grimm glow discharge lamp [149] a) Cathode body b) Sample c) Negative glow d) Anode body e) PFTE sheath (0,2 mm thick)...

Figure 2 Different glow discharge source configurations (A) coaxial cathode (B) planar diode (C) hollow cathode lamp (D) hollow cathode plume (E) Grimm source. Reprinted from Bogaerts A and Gijbels R (1998) Fundamental aspects and applications of glow discharge spectrometric techniques (Review). Spectrochimica Acta Part BSZ. 1-42, with permission from Eise-vier Science.

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