Hollow cathode lamp is a special form of low-voltage glow discharge sharp line light source commonly used in atomic absorption spectroscopy. During use, hollow cathode lamps may exhibit some abnormal phenomena. The editor has compiled several abnormal phenomena and their handling methods for hollow cathode lamps.

Abnormal phenomenon: cathode glow change (neon lamp changes from orange red pink white light), hydrogen lamp changes from light purple to white. Weakening the emission line may result in background emission at the same time.

Reason: There is impurity gas inside the lamp;

Solution: Reverse discharge the lamp at a current of 10-20mA for a few minutes to half an hour. If it is ineffective, then reverse discharge at 80-150mA to activate the suction agent.

Abnormal phenomenon: The shielding tube emits light. Make the emission weak and unstable.

Reason: The needle shaped crystals or flakes of sputtered gold chips fall off, causing the cathode to be connected to the shielding tube.

Solution: Vibration the lamp housing to disconnect the connection point.

Abnormal phenomenon: anode flashing.

Reason: Uneven discharge on the anode surface;

Solution: Generally does not affect usage; If there is any impact, reverse discharge for half an hour at 1020mA.

Abnormal phenomenon: The outer and rear parts of the cathode emit light. Slightly weaken the transmission line.

Reason: The distance between the shielding tube and the cathode is too large, or there may be impurities in the gas.

Solution: The launch is stable and can still be used. If necessary, reverse the process by pressing 1.

Abnormal phenomenon: Spark like discharge with jumping inside the cathode, no measurement line emission. It cannot be used until normal discharge is restored.

Reason: There are oxides or impurity gases on the surface of the cathode.

Solution: Reverse discharge at 30-50mA, or increase the current stabilizing resistor connected in series with the lamp to 2-10 kiloohms.

Abnormal phenomenon: Decreased sensitivity. Cannot measure normally.

Reason: The lamp has background emission, incorrect wavelength selection, wide passband of the monochromator, clogged injector, insufficient gas, and the burner slit is not below the optical axis.

Solution: Check the background emission of the lamp, observe the color tone of the cathode light, if it is abnormal, handle it the same as l.

Abnormal phenomenon: No light emission. Cannot be used.

Reason: Leakage of lamp head or disconnection of lamp head wiring; The power supply is malfunctioning.

Solution:

First check the power supply with other lamps, then use a high-frequency vacuum leak detector to check. If there is no neon light inside the lamp housing, it is a leak (replace with a new lamp); Neon light indicates wire disconnection.

Abnormal phenomenon: Only emits light outside the cathode mouth. Cannot be used.

Reason: The pressure of inert gas decreases, making it impossible to maintain normal discharge.

Solution: Replace the lamp with a new one.

Abnormal phenomenon: The luminous color tone is normal, but the characteristic line emission is weak or undetectable. Cannot measure normally.

Reason: * After use, the cathode metal is depleted or the photomultiplier tube or amplifier used is not suitable.

Solution: If it cannot be revived, the lamp should be replaced or a suitable photomultiplier tube or amplifier should be selected again.