Hollow Cathode Lamps Overview Atomic absorption spectroscopy (or AAS) in its modern form came from principles developed by Australian physicist Dr. A. Walsh in 1955. Atomic absorption spectroscopy is ideal for analyzing minute quantities of metallic elements because its operating principle and analysis method offer relatively simple measurement with high accuracy. Hamamatsu provides a full line of hollow cathode lamps developed by our discharge tube manufacturing technology accumulated over long years of experience. These lamps provide the sharp, high-purity spectral lines essential for high accuracy measurement. ■Type of hollow cathode lamps ■Applications • Atomic absorption spectrophotometers • Atomic fluorescence spectrophotometers • Multi-element analyzers • Environmental analytical instruments Hollow cathode lamps consist of single-element lamps and multi-element lamps. Single-element lamps are usually superior to multi-element lamps in absorption sensitivity and analytical line radiant intensity. Although multielement lamps offer the advantage of simultaneous determination of multiple elements, their cathode composition must be determined by taking the properties of the metals to combine fully into account, so fabricating cathodes from an optional combination of elements is not possible. Construction As shown in Figure 1, a hollow cathode lamp is constructed with a bulb having a window (4 in Figure 1) made of quartz or UV-transmitting glass or borosilicate glass for spectral line emission, and into which a hollow cylindrical cathode (2 in Figure 1) and a ring-shaped anode (1 in Figure 1) are assembled. Noble gas is also sealed inside at a pressure of several hundred pascals. The cathode is made of a single element or alloy of the element to be analyzed to ensure sharp analytical spectral lines with an absolute minimum of interfering spectral components. Figure 1: Construction of hollow cathode lamp Figure 2: Transmittance of window glass materials hv 100 4 5 7 1 2 6 3 1Anode 2Cathode (hollow cathode) 3Base 4Faceplate (window) 5Bulb 6Stem 7Getter 8Graded glass seal TRANSMITTANCE (%) 80 SYNTHETIC 8 QUARTZ UV-TRANSMITTING GLASS (UV GLASS) 60 40 BOROSILICATE GLASS 20 0 160 200 240 280 320 360 400 440 WAVELENGTH (nm) Operating Principle The hollow cathode lamp is a type of glow discharge tube that uses a hollow cathode to enhance the emission intensity. Compared to parallel plate electrodes, using a hollow cathode increases the current density by more than 10 times and this is accompanied by a significant increase in light intensity and a lower voltage drop in the lamp. This is known as the hollow cathode effect (or hollow effect). When a voltage is applied across the electrodes of a hollow cathode lamp to cause a discharge in the lamp, electrons pass from the interior of the cathode to the cathode-fall region and flow through the negative glow region toward the anode. This causes ionization of the gas within the lamp through inelastic collisions with the gas atoms. Positive ions generated by the gas ionization are accelerated by the electric field and collide with the cathode surface. The kinetic energy of ion impact causes the cathode materials to sputter (or fly) away from the cathode surface in the form of an atomic vapor. This metallic vapor consists primarily of single atoms in the ground state and they are thermally dispersed within the hollow cathode. Meanwhile an electron bunch or cluster is accelerated by the electric field toward the anode. The accelerated electrons collide with the groundstate metallic atoms being diffused and excite the metallic atoms. The excited metallic atoms return to the ground state again in an extremely short transition time of about 10-8 seconds. At this point, monochromatic light characteristic of those atoms is emitted at an energy corresponding to the energy difference between the excited state and the ground state. This transition of electrons occurs not only in the target element for quantitative analysis but also in other elements of the cathode materials, causing a variety of energy transitions to occur. So, in a wide spectral range, many spectral lines of those elements and the filler gas can be observed. Transition metal elements such as Ni, Co and Fe in particular result in an extremely large number of spectral lines. 2 For conventional atomic absorption spectroscopy Lineup of Hollow Cathode Lamps ●L233 series (38 mm diameter): Single-element hollow cathode lamps (66 lamps) 1 Element Maximum Atomic Type No. Analytical Line Operating Current Current (nm) Number (suffix) (mA) (mA) 328.07 * 10 20 47 -47NB 338.28 Ag Silver Al Aluminium 13 -13NB As Arsenic 33 -33NQ Re Rhenium 309.27 * 396.15 193.70 * 197.20 242.80 * 267.59 249.68 * 249.77 553.55 * 10 20 Rh Rhodium 45 -45NB 343.49 * 10 20 10 12 Ru Ruthenium 44 -44NB 349.89 * 20 25 217.58 * 231.15 390.74 391.18 * 196.03 * 10 15 10 15 20 25 251.61 * 288.16 429.67 * 484.17 224.61 * 286.33 460.73 * 10 20 15 20 20 20 10 20 271.47 * 275.83 431.88 432.64 * 214.27 * 10 20 15 15 10 15 364.27 * 365.35 276.78 * 377.57 371.79 * 410.58 306.64 318.40 * 255.14 * 400.87 410.23 * 412.83 346.43 398.79 * 213.86 * 307.59 360.12 * 468.78 240.00 (peak value) 10 20 7 10 10 15 10 20 10 25 15 15 10 10 7 15 20 20 30 35 16 Sb Antimony 51 -51NQ 10 20 Sc Scandium 21 -21NB 10 20 Se Selenium 34 -34NQ 234.86 * 10 20 Si Silicon 14 -14NU 223.06 * 306.77 422.67 * 10 12 Sm Samarium 62 -62NB 10 18 Sn Tin 50 -50NQ -48NQ 228.80 * 5 12 Sr Strontium 38 -38NB 27 -27NU 10 20 Ta Tantalum 73 -73NU Chromium 24 -24NB 10 20 Tb Terbium 65 -65NB Caesium 55 -55NB 240.73 * 346.58 357.87 * 425.44 852.11 * 10 20 Te Tellurium 52 -52NQ Gold 79 -79NQ B Boron 5 -5NQ Ba Barium 56 -56NB Be Beryllium 4 -4NQ Bi Bismuth 83 -83NQ Ca Calcium 20 -20NU Cd Cadmium 48 Co Cobalt Cr Cs Cu Copper 29 -29NB Dy Dysprosium 66 -66NB Er Erbium 68 -68NB Eu Europium 63 -63NB Fe Iron 26 -26NU Ga Gallium 31 -31NU Gd Gadolinium 64 -64NB Ge Germanium 32 -32NU Hf Hafnium 72 -72NU Hg Mercury 80 -80NU Ho Holmium 67 -67NB In Indium 49 -49NB Ir Iridium 77 -77NQ K Potassium 19 -19NB La Lanthanum 57 -57NB Li Lithium 3 -3NB Mg Maximum Atomic Type No. Analytical Line Operating Current Current (nm) Number (suffix) (mA) (mA) 346.05 * 25 20 75 -75NB 346.47 10 Au Lu Element Lutetium Magnesium 71 12 -71NB -12NU Mn Manganese 25 -25NU Mo Molybdenum 42 -42NB Na Sodium 11 -11NB Nb Niobium 41 -41NB Nd Neodymium 60 -60NB Ni Nickel 28 -28NQ Os Osmium 76 -76NU Pb Lead 82 -82NQ Pd Palladium 46 -46NQ Pr Praseodymium 59 -59NB Pt Platinum 78 -78NU Rb Rubidium 37 -37NB 324.75 * 327.40 404.59 * 421.17 400.79 * 415.11 459.40 * 462.72 248.33 * 371.99 287.42 294.36 * 407.87 422.58 * 265.16 * 10 20 Ti Titanium 22 -22NB 15 15 Tl Thallium 81 -81NU 15 15 Tm Thulium 69 -69NB 15 15 V Vanadium 23 -23NB 10 20 W Tungsten 74 -74NU 4 6 Y Yttrium 39 -39NB 12 12 Yb Ytterbium 70 -70NB 10 20 Zn Zinc 30 -30NQ 286.64 * 307.29 253.65 * 20 25 Zr Zirconium 40 -40NB 4 6 D2 Hydrogen 1 -1DQ 410.38 * 416.30 303.94 * 325.61 208.88 * 266.47 766.49 * 769.90 357.44 550.13 * 610.36 670.78 * 328.17 331.21 * 285.21 * 15 20 10 15 20 20 10 15 Na-K 10 20 Ca-Mg 10 20 Si-Al 15 Fe-Ni 18 Sr-Ba 279.48 * 403.08 313.26 * 320.88 589.00 * 589.59 334.91 * 405.89 463.42 492.45 * 232.00 * 341.48 290.90 * 305.86 217.00 * 283.30 244.79 * 247.64 495.13 * 513.34 265.95 * 299.80 780.02 * 794.76 15 10 10 20 10 20 10 15 20 30 15 15 10 20 15 15 10 15 10 20 15 15 10 20 10 20 ●L733 series (38 mm diameter): Multi-element hollow cathode lamps (11 lamps) 1 Element Al-Ca-Mg Ca-Mg-Zn Cu-MoCo-Zn Cd-CuPb-Zn Cu-FeMn-Zn Co-Cr-CuFe-Mn-Ni Sodium Potassium Calcium Magnesium Silicon Aluminium Iron Nickel Strontium Barium Aluminium Calcium Magnesium Calcium Magnesium Zinc Copper Molybdenum Cobalt Zinc Cadmium Copper Lead Zinc Copper Iron Manganese Zinc Cobalt Chromium Copper Iron Manganese Nickel Maximum Atomic Type No. Analytical Line Operating Current Current Number (suffix) (nm) (mA) (mA) 11 589.00 * -201NB Na 15 10 K 766.49 * 19 20 12 14 13 26 28 38 56 13 20 12 20 12 30 29 42 27 30 48 29 82 30 29 26 25 30 27 24 29 26 25 28 422.67 * -202NU Ca Mg 285.21 * Si * -203NU Al 251.61 309.27 * 10 18 10 20 248.33 * -204NQ Fe Ni 232.00 * 460.73 * -205NB Sr Ba 553.55 * 10 20 10 20 -321NU 10 18 10 15 10 15 10 15 8 15 10 20 -322NQ -401NQ -402NQ -405NQ -601NQ Al Ca Mg Ca Mg Zn Cu Mo Co Zn Cd Cu Pb Zn Cu Fe Mn Zn Co Cr Cu Fe Mn Ni 309.27 * 422.67 * 285.21 * 422.67 * 285.21 * 213.86 * 324.75 * 313.26 * 240.73 * 213.86 * 228.80 * 324.75 * 217.00 * 213.86 * 324.75 * 248.33 * 279.48 * 213.86 * 240.73 * 357.87 * 324.75 * 248.33 * 279.48 * 232.00 * Analytical lines marked with an asterisk (*) indicate the maximum absorption wavelength of each element. Since each element has two or more spectral emission lines, select the spectral line that best suits the sample concentration. NOTE: 1The guaranteed lifetime is defined by the product of the operating current and the accumulated operating time and is specified as 5000 mA·hrs except for the guaranteed lifetimes of As, Ga and Hg which are specified as 3000 mA·hrs. Note on the L233 and L733 series current values Pulse-lighting lamp current waveform Peak value Current The operating current and maximum current values listed above are specified as a peak current value. However, instruments using a pulse lighting system may indicate the lamp current value as the mean value. So, when using such an instrument, verify which current value (mean or peak) it indicates and use the specified current value to operate lamps correctly. Mean value Time 3 For atomic absorption spectroscopy using the S-H method background correction Lineup of Giant-pulse Hollow Cathode Lamps ●L2433 series (38 mm diameter): Single-element hollow cathode lamps (46 lamps) Silver 47 -47NB Al Aluminium 13 -13NB As Arsenic 33 -33NQ Au Gold 79 -79NQ B Boron 5 -5NQ Ba Barium 56 -56NB Be Beryllium 4 -4NQ 328.07 * 338.28 309.27 * 396.15 193.70 * 197.20 242.80 * 267.59 249.68 * 249.77 553.55 * 234.86 * Bi Bismuth 83 -83NQ Ca Calcium 20 -20NU Cd Cadmium 48 -48NQ Co Cobalt 27 -27NU Cr Chromium 24 -24NB Cu Copper 29 -29NB Dy Dysprosium 66 -66NB Er Erbium 68 -68NB Eu Europium 63 -63NB Fe Iron 26 -26NU Ga Gallium 31 -31NU Ge Germanium 32 -32NU 2 Hafnium 72 -72NU Hg Mercury 80 -80NU Ho Holmium 67 -67NB K Potassium 19 -19NB La Lanthanum 57 -57NB Li Lithium 3 -3NB Magnesium 12 -12NU Mg Analytical Line (nm) Mn Manganese 25 -25NU Mo Molybdenum 42 -42NB Na Sodium 11 -11NB Ni Nickel 28 -28NQ Pb Lead 82 -82NQ Pd Palladium 46 -46NQ Pt Platinum 78 -78NU Ru Ruthenium 44 -44NB Sb Antimony 51 -51NQ Se Selenium 34 -34NQ Si Silicon 14 -14NU Sm Samarium 62 -62NB Sn Tin 50 -50NQ Sr Strontium 38 -38NB Te Tellurium 52 -52NQ Ti Titanium 22 -22NB V Vanadium 23 -23NB Y Yttrium 39 -39NB Yb Ytterbium 70 -70NB Zn Zinc 30 -30NQ 223.06 * 306.77 422.67 * 228.80 * 240.73 * 346.58 357.87 * 425.44 324.75 * 327.40 404.59 * 421.17 400.79 * 415.11 459.40 * 462.72 248.33 * 371.99 287.42 294.36 * 265.16 * 286.64 * 307.29 253.65 * 410.38 * 416.30 766.49 * 769.90 357.44 550.13 * 610.36 670.78 * 285.21 * 279.48 * 403.08 313.26 * 320.88 589.00 * 589.59 232.00 * 341.48 217.00 * 283.30 244.79 * 247.64 265.95 * 299.80 349.89 * 217.58 * 231.15 196.03 * 251.61 * 288.16 429.67 * 484.17 224.61 * 286.33 460.73 * 214.27 * 364.27 * 365.35 306.64 318.40 * 410.23 * 412.83 346.43 398.79 * 213.86 * 307.59 Low 1 High 1 Accumulated 2 Operating 2 Current Current Lifetime Lifetime (mA) (mA) (mA·ms·h) (h) 10 400 20 000 500 10 600 30 000 500 12 500 7500 150 10 400 20 000 500 10 500 5000 100 15 600 30 000 500 10 600 6000 100 10 300 6000 200 15 600 30 000 500 8 100 5000 500 15 400 20 000 500 10 600 12 000 200 10 500 25 000 500 15 600 6000 100 15 500 5000 100 10 600 6000 100 12 400 20 000 500 4 400 4000 100 20 500 5000 100 20 600 6000 100 12 400 4000 100 10 600 6000 100 10 600 30 000 500 20 600 9000 150 15 500 25 000 500 10 500 25 000 500 10 600 30 000 500 10 600 9000 150 10 600 12 000 200 10 400 20 000 500 10 300 15 000 500 10 300 3000 100 10 300 3000 100 20 600 6000 100 15 500 7500 150 15 300 4500 150 10 500 10 000 200 15 600 6000 100 20 500 25 000 500 10 500 25 000 500 15 400 4000 100 10 600 12 000 200 10 700 7000 100 15 600 6000 100 5 200 2000 100 10 300 15 000 500 Analytical lines marked with an asterisk (*) indicate the maximum absorption wavelength of each element. Since each element has two or more spectral emission lines, select the spectral line that best suits the sample concentration. NOTE: 1Maximum discharge current: Peak current (See the current waveform charts for the low current and high current waveform specifications.) 2 · When lamps are operated at a current less than the maximum discharge current specified for each element: The accumulated lifetime(mA·ms·h) is defined by the operating time including the lamp preheat time multiplied by the product of the low current and its time width or the product of the high current and its time width, whichever is larger. · When lamps are operated at the maximum discharge current specified for each element: The guaranteed lifetime (operating lifetime) is defined by the accumulated operating time including the lamp preheat time. The guaranteed lifetime is specified by either of the above definitions. Note on L2433 series current values ●Low current operation Absorption of the target element occurs when a lamp is operated at a low current. While making sure not to exceed the low current value listed for the lamp, set the current at which the best analytical sensitivity is obtained. Current waveform chart (low current operation) Current Ag Hf 4 Atomic Type No. Number (suffix) 10 ms Min. (100 Hz Max.) 1 ms Max. Low current value Time ●High current operation When a lamp is operated at a high current, a self-reversal effect occurs in the lamp to absorb the background. As in low current operation, set the current while making sure not to exceed the high current value listed for the lamp. Current waveform chart (high current operation) 10 ms Min. (100 Hz Max.) Current Element 0.1 ms Max. High current value Time ●Time width Do not operate the lamps in a state where the time width of the discharge current waveform exceeds the maximum time width shown in the above charts. Lamp Current and Absorption Sensitivity The ideal analytical line profile of the light emitted by a hollow cathode lamp should exhibit no spectral line broadening other than natural broadening. In actual operation, however, the spectral lines are emitted along with a certain broadening. The causes of such broadening include Doppler broadening, self-absorption line width distortion, Lorentz broadening (pressure broadening), Holtzmark broadening (resonance broadening), Zeeman effect broadening, and Stark effect broadening. Among these, Doppler broadening and self-absorption line width distortion are major factors in broadening so that broadening related to other causes is usually small enough to be ignored. Doppler broadening depends on the random thermal motion of the light-emitting atoms, which is affected by the temperature of the gas. Spectral line broadening does not occur as long as the thermal motion of the atoms is within a plane perpendicular to a line connecting the observation point and the light source. However, if the thermal motion of the atoms is parallel to that line (forward and back motion as seen from the observation point), the frequency at the emitted light observation point will increase (shift to shorter wavelength side) during motion toward the observation point and decrease (shift to longer wavelength side) during motion away from the observation point. This phenomenon is the socalled Doppler effect. Light-emitting atoms in a hollow cathode have a random thermal motion that causes the spectral lines to broaden. The width λ0 of this Doppler broadening can be expressed by the following equation: ∆λD=1.67 × λ0 c 2RT Ma where c is the velocity of light, R is the gas constant, T is the absolute temperature of the gas, and Ma is the atomic weight. Self-absorption occurs when there is a temperature gradient within the atomic vapor layer inside the cathode hollow, in other words, it occurs when the atomic vapor within the cathode hollow is flowing out of the hollow. In this state, atoms in the higher-temperature atomic vapor layer within the hollow are more excited than those in the lower-temperature atomic vapor layer outside the hollow, and so cause light emission. When the emitted light passes through the relatively low temperature atomic vapor layer outside the hollow, it is absorbed by the atoms in the ground state. This phenomenon is termed self-absorption and just as with the Doppler effect results in broadening of analytical line width and a loss of absorption sensitivity. As stated above, deterioration in the analytical line profile depends on the lamp current, so care must be taken since increasing the lamp current may cause an excessive increase in atomic vapor. In actual measurement, it is essential to operate the lamp at an optimal current that takes into account both the analytical line output intensity and absorption sensitivity. The self-absorption effect is large for high-vaporization-pressure elements such as Cd (Cadmium) and small for low-vaporization-pressure elements such as Mo (Molybdenum). The typical operating current for the former is usually specified as a low value. Figure 3: Lamp current vs. absorption sensitivity (typical example) ●L233-48NQ (Cd) ●L233-42NB (Mo) 0.6 0.6 ANALYTICAL LINE WAVELENGTH 228.80 nm * ANALYTICAL LINE WAVELENGTH 313.26 nm * 0.5 0.4 1.6 µg/ml 0.3 1.2 µg/ml 0.2 0.8 µg/ml 0.1 RELATIVE ABSORBANCE RELATIVE ABSORBANCE 0.5 140 µg/ml 0.4 0.3 0.2 70 µg/ml 0.1 0 0 0 2 4 6 8 10 LAMP CURRENT (mAdc) 12 14 0 10 20 LAMP CURRENT (mAdc) * Maximum absorption wavelength 5 Spectral Bandwidth (S.B.W.) and Absorption Sensitivity In the vicinity of an analytical line, the presence of other spectral lines from the same element or a different element will cause the absorption sensitivity to drop. (These spectral lines in the vicinity of the analytical line are known as proximity lines.) When these proximity lines are present, the spectral bandwidth (SBW) should be narrowed to reduce the effect of proximity lines by narrowing the slit width of the spectrophotometer. Figure 4: Spectral bandwidth and absorption sensitivity (typical example) SBW 0.08 nm 0.3 ANALYTICAL LINE WAVELENGTH 232.00 nm * RELATIVE ABSORBANCE Ni 341.48 nm Ni 232.00 nm SBW 0.08 nm ●L233-28NQ (Ni) 0.2 4 µg/ml 0.1 2 µg/ml 0 -2 0 +2 -2 0 +2 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 (RADIANT SPECTRA) SPECTRAL BANDWIDTH (nm) * Maximum absorption wavelength Time Stability of Analytical Line Radiant Intensity As described in the section dealing with the emission process of spectral lines, sputtered metal atoms are thermally diffused during repeated inelastic collisions with electrons. In this process, during the period required for the metal atom density to reach equilibrium, the radiant intensity of the analytical lines varies. This variation usually occurs in the direction of increased intensity for 10 to 20 minutes after the lamp has started, although it will vary depending on the element and operating current. After reaching equilibrium, the radiant output intensity at the analytical line wavelength is extremely stable. In high-vapor-pressure element lamps, operation at excessive current levels causes excessively vaporized metal atoms to flow out of the hollow cathode space in the direction of the optical axis. This causes a temperature gradient to occur and might lower the analytical line output intensity due to phenomena such as self-absorption. After a lamp has been left unused for a long period of time, some amount of time may be required for analytical line output intensity to reach initial stabilization, which results from changes in the cathode surface over time and depends on the element (especially alkaline element). Even in such cases, once the lamp is operated, it will light up normally from the next time. Figure 5: Time stability of analytical line output intensity (typical example) RELATIVE ANALYTICAL LINE OUTPUT INTENSITY (%) ●L233-42NB (Mo) 120 100 80 60 LAMP CURRENT: 10 mAdc S.B.W.: 0.16 nm ANALYTICAL LINE: 313.26 nm * AMBIENT TEMPERATURE: 25 °C 40 20 0 0 15 30 45 60 TIME (min) * Maximum absorption wavelength 6 75 90 105 Life The life of a hollow cathode lamp is greatly affected by the operating current. This is due to the increase in the energy of positive ions colliding with the cathode surface which causes violent sputtering. During pulse operation as well, there is no change in the energy of the ions colliding with the cathode surface at each pulse, so lamp life is determined by the peak current and the pulse width (time width). The following phenomena may be observed when a lamp has reached its life end: (1) Discharge does not occur at the hollow cathode and the current does not vary even if the current control knob is changed. The analytical line output is not detectable. (2) Extreme variations occur in analytical line intensity and the lamp current may also vary in some cases. (3) The analytical line intensity weakens significantly and the signal-to-noise ratio deteriorates. The major cause of these phenomena is a drop in gas pressure within the lamp. This drop in gas pressure is caused by the "gas clean-up" phenomenon in which cathode metal atoms sputtered during discharging attracts gases while being scattered and these adhere together to the bulb wall and electrodes at a lower temperature. As the lamp is used, the cathode hollow shape is gradually worn away and deformed by sputtering from the discharge. These characteristics will vary depending upon the element and will exhibit small differences even for lamps of the same element. Dimensional Outlines (Unit: mm) ●L233 / L733 series 2-PIN OCTAL BASE 61.0 ± 1.5 A CATHODE CATHODE ANODE 25.5 ± 1.3 39 MAX. 44.0 MAX. EMISSION POINT 147 ± 3 165 MAX. ●L2433 series 2-PIN OCTAL BASE 61.0 ± 1.5 A Positional tolerance of emission point ±1.5 mm with relative to A CATHODE CATHODE 147 ± 3 165 MAX. 25.5 ± 1.3 ANODE 39 MAX. 44.0 MAX. EMISSION POINT Positional tolerance of emission point ±1.5 mm with relative to A Related Products Deuterium lamps (L2D2 lamps) L2D2 lamps are deuterium lamps developed for spectrophotometry for chemical analysis. These L2D2 lamps offer long service life, high stability, and the high output needed for light sources used in spectrophotometry. L2D2 lamps can also be used for background correction in atomic absorption spectrophotometers. Photomultiplier tubes Among the many light sensors currently available, photomultiplier tubes are the most sensitive and photodetectors with high speed response. Photomultiplier tubes are designed and manufactured to provide stable operation even when detecting changes in weak light or its on/off, or even when the supply voltage is varied. These features make photomultiplier tubes useful as a photodetectors that ensure accurate measurements in atomic absorption spectroscopy. 7 Precautions and Warranty ■Precautions 1. Long-term storage Please note that the lamps should be used shortly after delivery. If the lamps are left unused for a long period of 6 months or more, take the following precautions: · Store the lamps in low humidity and at room temperature in locations where no corrosive gases are present and temperature fluctuations are minimal. · We recommend operating the lamp for approximately 3 hours once every 3 months at half the normal operating current specified for the lamp in order to stabilize the lamp characteristics. 2. Handling · High voltage is supplied to the lamp to start operation. Take precautions to avoid electrical shock. · Ultraviolet rays harmful to the eyes and skin are emitted from the lamp faceplate (window) during operation. Do not look directly at the operating lamp. · Disposal of hollow cathode lamps The cathode of some hollow cathode lamps contains elements that are defined as hazardous substances under waste disposal laws. When disposing of the lamps using such as the cathode, entrust proper disposal to an industrial waste disposal company licensed to perform intermediate treatment and final disposal of hazardous substances. Lamps using a cathode that does not contain the following elements may be disposed of as normal industrial waste (like glass and ceramic waste). Even in such cases, be sure to comply with local regulations to ensure correct disposal. Elements of hazardous substance: As, Be, Cd, Cr, Cs, Cu, Hg, In, K, Na, Ni, Pb, Rb, Se, V, Zn, Na-K · Do not touch the lamp faceplate window with bare hands. Grime from the hands adhering to the faceplate will cause a drop in the analytical line output intensity. If there is grime, wipe the faceplate using gauze or oil-free cotton moistened with high-purity alcohol and wrung out thoroughly. Note that the volatile vaporization of organic solvents will absorb analytical lines of As, Se, etc. So use caution when handling such solvents near the measurement site. · The bulb wall or electrodes of some lamps might appear in a blackened state when delivered. This is caused by the spattering of cathode materials and this condition will differ depending on the particular element. This condition is especially noticeable on lamps with high vapor pressure elements such as As, Se, Cd, Zn, Na and K. This condition occurs during the manufacturing process and does not affect the lamp operating characteristics. · The major analytical lines used in atomic absorption spectroscopy are present in the UV wavelength range from 200 nm to 300 nm. Since mirrors, lenses and other optical components generally have low reflection or transmission efficiency in this wavelength region, alternately fine-adjust the spectrophotometer wavelength dial and the lamp position so that the output meter indicates the maximum while checking the wavelength dial scale to achieve the correct analytical line wavelength. Failure to make this analytical line wavelength adjustment correctly may prevent obtaining high measurement accuracy. · If a high current is passed through the lamp suddenly at the beginning of discharge or the power supply is cut off suddenly during discharge, surge currents or other abnormal currents will flow in the lamp, causing unnecessary lamp deterioration. When lighting the lamp, gradually increase the lamp current to the specified value and when turning off the lamp, also gradually decrease the current to ensure a long lamp life with stable operation. · The maximum current shown on the lamp is the absolute maximum value (which is broadly viewed as the guaranteed current at which no damage is caused to the lamp). In lamps based on elements having high vapor pressure (e.g., Hg, Cd and Zn), the maximum current shown on the lamp is set to a low current value. If this type of lamp is operated at a current higher than this value, the resulting Joule heat might melt the cathode. ■Warranty Warranty period Hamamatsu hollow cathode lamps are warranted for a period of one year after the date of delivery. Warranty coverage The warranty is limited to repair or replacement of defective lamps free of charge. Cases not covered by warranty The warrant shall not apply to the following cases even if within the warranty period. · Lamp operation has exceeded the guaranteed life time. · Lamp failure was caused by incorrect usage that did not meet the product specifications or by careless handling or modifications made by the user. · Lamp failure was caused or induced by unavoidable accidents such as natural disasters. Subject to local technical requirements and regulations, availability of products included in this promotional material may vary. Please consult with our sales office. Information furnished by HAMAMATSU is believed to be reliable. However, no responsibility is assumed for possible inaccuracies or omissions. Specifications are subject to change without notice. No patent rights are granted to any of the circuits described herein. ©2013 Hamamatsu Photonics K.K. HAMAMATSU PHOTONICS K.K. www.hamamatsu.com HAMAMATSU PHOTONICS K.K., Electron Tube Division 314-5, Shimokanzo, Iwata City, Shizuoka Pref., 438-0193, Japan, Telephone: (81)539/62-5248, Fax: (81)539/62-2205 U.S.A.: Hamamatsu Corporation: 360 Foothill Road, P. O. Box 6910, Bridgewater. 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