Our nomenclature for identifying detection assemblies is shown below. For many applications the detector/filter/input optic configuration best suited the measurement is specified in the application package. For example, a detector for making photopic measurements with an IL1700 would be specified as follows: SED033/Y/W. This common combination is listed as the IL1710 Research Photometer.

The SED and SEL type detector housings are made of black anodized aluminum, with female filter threads (1¼-24), a tripod mount (¼-20), and two end mounts (#8-32).

Photo Detectors

Input Optics

Filters

Filters and input optics can dramatically alter a detector's spectral and spatial responsivity.

NOTE: The dynamic ranges given for each detector apply for use with the IL1700

(SED type).

To view the specifications for any detector, click on the detector name.  

The /U following the part numbers below indicates an UNCALIBRATED sensor. Detector kits such as SED033/Y/W include a calibration therefore the /U is not noted in the part number. The SED, SHD and SEL type detector housings are made of black anodized aluminum, with female filter threads (1¼-24), a tripod mount (¼-20), and two end mounts (#8-32). Only these housings allow for filter selection/swapping and only the SED and SEL type housings allow for underwater modification. All underwater modified SED or SEL detectors require the W wide-eye diffuser in addition to any other filters. The SCxxx detectors are in a 112 x 17 x 16 mm wand style housing, The XRxxx are in a 12.5 x 42 mm dia. housing, the SPxxx are in a 121 x 19 mm dia. pen style housing. These three version do not have removable, swappable filters and cannot be made waterproof.
 

HIGH GAIN DETECTORS

SHD033 High Gain Detector
Range: 3 x 10^-13 to 4.5 x 10^-5 W/cm²
Spectrum: 200 to 1050 nm, 750 peak
Size: 69 mm x 42 mm dia.

SHD240 High Gain Solar-Blind Detector
Range: 1 x 10^-12 to 2 x 10^-7 W/cm²
Spectrum: 185 to 320 nm, 240 peak
Size: 101 mm x 42 mm dia.

The SHD033 matches the sensitivity of a PMT using solid state amplification of a silicon photodiode. The proprietary preamp is unique in that it preamplifies the current-chopped junction charge of the cell, providing an 82 dB linear response. Built-in temperature control and leakage shielding minimize noise and dark current. The special Silicon cell has a broad spectral range with excellent sensitivity in the near IR, recovers rapidly from overload (such as direct sunlight) without damage, and maintains its calibration integrity over time.

Since the complex preamplification circuitry is located within the actual detector head, noise is held to a minimum. The remote circuitry requires input voltages automatically provided by the IL1700 and IL1800 Research Radiometers (not available for use with the IL1400A).

The SHD240 uses the same preamplification in conjunction with a Cs-Te solar-blind vacuum phototube with a UV glass window. This high stability device maintains ± 1% sensitivity for ten years. The flat 8 mm diameter cathode provides a large, well defined receiving surface for accurate geometry calculations. The SHD240 contains temperature regulation, for operation from -80°C to +50°C.

Both of the SHD detectors have been designed to operate with the IL1820 Lock-In Radiometer System, for 2 Hz chopped measurement and phased zeroing. This results in a 100:1 improvement in signal to noise.

PM271C Photomultiplier
Detector:
Spectrum: 200 to 675 nm, 390 peak, S^-5
Range: 6 x 10^-14 to 6 x 10^-7 W/cm²
Size: 161 x 50 x 38 mm

PM271D Photomultiplier
Detector:
Spectrum: 200 to 850 nm, 420 peak, S^-20
Range: 3 x 10^-14 to 3 x 10^-7 W/cm²
Size: 161 x 50 x 38 mm

PM271 SERIES PHOTOMULTIPLIERS: Photomultipliers provide high internal current gain by combining the external photoelectric effect (semiconductor photodiodes use the internal photoelectric effect) with low noise secondary electron multiplication. A high voltage regulated supply, such as the IL760D Photomultiplier Power Supply, is required to provide the appropriate cathode, dynode, and anode voltages. The response time for PMT's is typically very fast (<10 nS), and is a function of the dynode voltage.

Photomultipliers typically offer a six decade dynamic range with excellent linearity over most of that range. Although PMT's are relatively immune to thermal "Johnson" noise, the noise equivalent power is limited by dark current, which can be reduced by cooling the photomultiplier. In addition, photomultipliers require more frequent recalibration, as they do not exhibit the long term stability inherent to solid state devices.

  Detectors

The detector itself exhibits a pronounced spectral response. Silicon photodiodes exhibit peak responsivity in the near-IR, decreasing linearly through the visible into the UV. Vacuum photodiodes provide excellent UV response with long wave rejection. "Solar-blind" vacuum photodiodes peak in the deep UV while blocking out both visible and IR light. InGaAs photodiodes offer excellent sensitivity to near IR while blocking long wave Infrared. Thermopiles exhibit sensitivity across the entire spectrum, with an extremely flat response to Infrared from 700 nm to 60 탆. Each detector type has carved a distinct niche in radiometry, providing desirable properties over a particular bandwidth.

The graph below shows the response of some unfiltered detector types. The X axis extends from 150 to 2000 nm. The Y axis extends (logarithmically) from 10^-4 to 10² A*cm²/watt.

 

 

  Detector Types (unfiltered)

  SED(SEL)033

Type: UV Enhanced Silicon Photodiode, Quartz window, 33 mm² area.
Spectrum: 200 to 1100 nm, 950 nm peak
Range: 3 x 10^-12 to 1 x 10^-2 W/cm²
Size: 20 mm x 42 mm diameter

 

  SED(SEL)240 and SED(SEL)220

Type: Solar Blind Vacuum Photodiode (fused silica window available as SED220)
Spectrum: 185 to 320 nm, 240 peak (SED220: 160 to 320 nm, 220 peak)
Range: 5 x 10^-11 to 7 x 10^-5 W/cm²
Size: 53 mm x 42 mm diameter

  XRD(XRL)140 and XRD(XRL)340

Type: Silicon Photodiode with built-in UV filters.
Spectrum: A: 320 to 475 nm, B: 326 to 401 nm
Range: 2 x 10^-9 to 1 W/cm² (XR340 is 1/10 as sensitive)
Size: 13 mm x 42 mm diameter

  SED(SEL)005

Type: GaAsP Photodiode, Quartz window, 5 mm² active area.
Spectrum: 250 to 675 nm, 610 nm peak
Range: 1 x 10^-10 to 2 x 10^-1 W/cm²
Size: 20 mm x 42 mm diameter

  SPD(SPL)024F and SPD(SPL)024Y Integrating Sphere Pen Probe

Type: Silicon Photodiode with filters and sphere built into dedicated probe.
Spectrum: Y Photopic or F Flat
Range: 1 x 10^-9 to 2.0 W/cm²
Size: 121 mm x 19 mm diameter

  SPD(SPL)025F and SPD(SPL)025Y Radiance Pen Probe

Type: Silicon Photodiode with filters and radiance optics built into dedicated probe.
Spectrum: Y Photopic or F Flat
Range: 1 x 10^-9 to 2.0 W/cm²/sr
Size: 121 mm x 19 mm diameter

  SED(SEL)623 and SED(SEL)624

Type: Multi-Junction Thermopile, 4 mm², Quartz window (KBr in SED624).
Spectrum: 200 to 4200 nm, flat above 700 nm (SED624: 0.2 to 40 탆)
Range: 2 x 10^-5 to 1 x 10^-1 W/cm²
Size: 61 mm x 42 mm diameter

  SCD(SCL)110 and SCD(SCL)144

Type: Silicon Photodiode with filters and diffusers built into dedicated probe.
Spectrum: Y Photopic (SCD110) or Bilirubin Blue (SCD144)
Range: 5 x 10^-3 to 1 x 10⁺⁶ lux (SCD144: 1 x 10^-9 to 2.5 W/cm²
Size: 112 x 18 x 18 mm

  SSD(SSL)001 SuperSlim Probe

Type: UV Enhanced Silicon Photodiode, 0.64 mm² area, built in UV filter
Spectrum: A: 260 to 400 nm, 370 peak
Range: 3.9 x 10^-9 to 1.0 W/cm²
Size: 29 x 38 x 2 mm diameter

  SED(SEL)185

Type: Au single metal photocathode 8 mm dia area, quartz window
Spectrum: 160 to 240 nm, 185 peak
Range: 3 x 10^-8 to 4 x 10^-2 W/cm²
Size: 53 mm x 42 mm diameter

  SED(SEL)007

Type: InGaAs with Quartz window.
Spectrum: 850 to 1700 nm, flat
Range: 1.5 x 10^-11 to 3 x 10^-2 W/cm²
Size: 20 mm x 42 mm diameter

Graph of Responsivity vs. Wavelength for Luckiesh Germicidal, ACGIH Actinic, 2 Photoresists, ACGIH Blue Hazard, CIE Scotopic Vision, CIE Photopic Standard Observer, and Silicon Photodiode.

UNDERWATER

DETECTORS

All SED, SEL, and SHD series detectors are available in underwater SUD, SUL, and SHUD versions, respectively. Every underwater detector is pressure tested to 40 meters depth (60 psi). The 'W' quartz diffuser is required to withstand the pressures of underwateruse. Filters are optional, with O-ring seals between all filter rings. Standard SUD detectors come on a 100 foot long, water-blocked cable (Polypropylene reinforced cables up to 600 feet available). The anodized aluminum components provide excellent corrosion resistance to salt water, for all-weather durability.