The optical layout

The set of filters is contained within a removable filter block, so that changing the operating wavelength is an easy operation. The bottom part of the front panel opens, and gives access to the optical bench adjustment, and to the filter block.

The detection cell

The cell is placed on the side of the detector. It is easily removable without any adjustment. A cover protects the user from the laser beam, which crosses the capillary window. The laser beam is shut when the cover is removed, so that the user has access to the cell in complete security (complying to safety regulation IEC 825).

The laser

The laser is a critical choice and depends on the application the scientist has selected. For convenience, this choice of laser should be as broad as possible. The ZETA LIF detector is extremely versatile and allows using laser wavelengths from 325 to 800nm. Moreover, because the laser is not integrated in the detector housing, it can be located in a convenient place for the user, and allows the heat generated to be dissipated quickly. This feature may also provide space savings on the bench.

The laser can be remotely controlled by the detector, to provide maximum safety. Functions available are ON/OFF, stand-by mode, and power control (when the laser provides this feature). An interface printed circuit board is provided for HeCd and Argon ion lasers.

For easy operation, the laser types are pre-programmed in the detector. The user needs only to select the laser through the keyboard. The type of laser, and its wavelength are permanently displayed on the LCD. The laser power has a critical influence on the fluorescence signal. To ensure that adequate power is transmitted to the detection cell, a photodiode is placed inside the optical bench. The detected power is permanently displayed on the LCD screen.

How to change the laser wavelength ?

Changing the laser wavelength on the ZETALIF detector is a very simple operation:
- When necessary, replace the laser by a new one,
- Remove the filter block and replace it by one, corresponding to the selected wavelength,
- Programme the detector, with the new laser characteristics.

Quality of Laser

As a laser has a finite life time, its quality is critical for both the long term performance and the overall running costs. Therefore Picometrics recommends high quality lasers that it has previously tested extensively in its laboratory. Choosing a more powerful laser initially leads to lower running costs, cheaper total cost of ownership, and to less down time.

As an example, the benefits of Spectra Physics Argon Ion lasers are listed here below :

• ENDURA ^TM plasma tube technology provides the longest lifetime Ar-Ion lasers between 5000 hours at 100% operating power and 30000 hours at 30% operating power
• Largest gas reservoir providing more gas to start with and longer life
• High gas fill pressure providing more gas to start with, reduced sputtering erosion rate and longer life
• Crystalline quartz brewster windows ensuring that mode quality is maintained throughout the entire tube life
• Wavelength selective mirrors ensuring lower tube current and longer life
• Protective enclosed mirror mounts to prevent any risk of damage and dirt deposits
• Brazed-on cooling fins providing the most efficient cooling, lower current and longer life
• Optimized bore/throat design to reduce erosion and increase life
• Installation time less than 5 minutes because little to no system realignment is necessary
• Precision beam position alignment making tube replacement cost effective and as easy to change
• Auto-ranging from 90 vac to 265 vac, 47-63 Hz
• Ultra-low optical noise thanks to DC cathode and fan operation
• One third the weight and two thirds the size of any other laser power supply on the market
• High reliability power electronics thanks to surface mount components
• UL and CE certified

ZETALIF Specifications

Measuring ranges RFU
Dynamic range
Sensitivity

0-2,0-20, 0-200
10⁵, linear within 2%
S/N > 10 for a solution of 10 ^-12 M of Rhodamine in a flow cell capillary of 75mm ID with a 488 nm Ar-Ion laser 10 mW.

Noise

< 0.003 RFU flow cell capillary of 75mm ID with a 488 nm Ar-Ion laser 10 mW.

Dimensions and weight
Ambient temperature
Power requirements

247x400x217 mm (wxdxh), 8 kg.
range 10-35 °C.
220-240 V, 0.5 A, 50/60 Hz or 100-120 V, 1 A, 50/60 Hz for the detector
Laser available at the same voltage ratings,
current from 1 to 20A, according to the laser power.

Outputs

Laser


Flow cell capillaries

1 V (unprocessed)
100 mV and 1 V (processed).
Ar-Ion at 488 nm and 514 nm,
He-Cd at 325 nm and 442 nm.
Any other wavelength on request.
I.D. 25, 50,……., 320 mm.