IDR150 Double Monochromator

  • IDR150 monochromator with integrated picoammeter and HV supply

Composed of two 150mm focal length Czerny-Turner monochromators arranged for additive dispersion with a stepping motor driven sine bar grating drive, the IDR150 can be configured to include a single or dual exit ports. Grating drive control electronics are located to the base of the unit alongside the signal recovery electronics required to interface up to two detectors, including a dual-channel picoammeter and a high voltage power supply for operation of detectors in the photoemissive or photoconductive modes.

Core benefits


  • Two 150mm focal length monochromators in Czerny-Turner mount
  • Sine bar driven pair of interchangeable, kinematically mounted diffraction gratings
  • One entrance and up to two exit ports, with automated mirror-based selection
  • Integrated drive electronics, dual-channel picoammeter and high voltage power supply
  • Compatible with the full range of sources, detectors and accessories of the Bentham portfolio
  • Fully automated through USB 2.0 interface

Optical Layout

Configuration Pair symmetrical Czerny Turner monochromators, additive dispersion
Focal length - Total focal length: 300mm
- Individual units: 150mm
Grating mount Kinematic
Number of gratings 1 pair
Grating size 33x33mm
Aperture ratio f/4
Number of entrance/exit ports 1 entrance, 1-2 exits
Spectral range Within range 200nm-2400nm


Wavelength scanning By integrated stepping motor and micro-stepping drive electronics
Slit type Fixed, micrometer or motorised variable
Slit width & height 10µm-10mm (W) x 20mm (H)
Filter size - 6 position filter wheel : 25mm diameter
- 8 position filter wheel : 22mm diameter

Optical Performance (quoted for typical 2400 g/mm gratings)

Spectral range 200-600nm
Linear dispersion 5.4nm/mm
Wavelength accuracy ± 0.15nm, ± 0.05nm with software correction
Wavelength reproducibility ± 0.05nm
Resolution full/reduced slit height 0.25/0.1nm
Stray light rejection at 2.5 FWHM 10-8
Wavelength sweep speed 30nm/s

487 Dual-Channel Picoammeter Module - Electrical

Channel 1 input Current input to picoammeter
Channel 2 input Current input to picoammeter
Gain ranges 1010-105 V/A
Maximum current Input 100µA
Frequency response DC to 30Hz
Gain accuracy +1%
Gain stability 200ppm/°C
Output stability 5ppm/°C to 500ppm/°C depending on sensitivity
Linearity < 0.025% departure from linearity from zero to full scale
ADC resolution 4½ digit BCD (0 to 19999) i.e. > 14 bit resolution
ADC integration time 100ms
Auxiliary input range 0- 9.8V
Picoammeter input impedance Virtual earth
Auxiliary input impedance 1 MΩ

415 High Voltage Power Supply Module - Electrical

Output voltage range -350 to -1500V
Maximum current 1.5mA
Temperature stability 100 ppm/°C
Stability to voltage fluctuations 25ppm for 10% change in line voltage
Ripple and noise 100ppm peak-peak

Diffraction Gratings

A range of gratings are available depending on the spectral range of consideration. Diffraction gratings are supplied in pairs, on kinematic mounts to permit easy installation in the IDR150 without compromising the wavelength calibration.

Grating Line density (g/mm) Grating type & Blaze wavelength Maximum wavelength range
GA-T324R0U25 2400 Plane ruled, 250nm blaze 200nm-600nm
GA-T324H0U25 2400 Plane holographic, 250nm blaze 200nm-600nm
GA-T324H0U3 2400 Plane ruled, 300nm blaze 200nm-600nm
GA-T318H0U25 1800 Plane holographic, 250nm blaze 250nm-900nm
GA-T318R0U4 1800 Plane ruled, 400nm blaze 250nm-900nm
GA-T318R0U5 1800 Plane ruled, 500nm blaze 250nm-900nm
GA-T312H0U25 1200 Plane holographic, 250nm blaze 300nm-1.2µm
GA-T312R0U4 1200 Plane ruled, 400nm blaze 300nm-1.2µm
GA-T312R0U5 1200 Plane ruled, 500nm blaze 300nm-1.2µm
GA-T312R0U75 1200 Plane ruled, 750nm blaze 300nm-1.2µm
GA-T312R0U9 1200 Plane ruled, 900nm blaze 300nm-1.2µm
GA-T312R1U0 1200 Plane ruled, 1µm blaze 300nm-1.2µm
GA-T3083R1U2 830 Plane ruled, 1.2µm blaze 600nm-1.8µm
GA-T306R1U0 600 Plane ruled, 1µm blaze 800nm-2.5µm
GA-T306R1U25 600 Plane ruled, 1.25µm blaze 800nm-2.5µm
GA-T306R1U6 600 Plane ruled, 1.6µm blaze 800nm-2.5µm
GA-T306R1U9 600 Plane ruled, 1.9µm blaze 800nm-2.5µm
GA-T306R2U16 600 Plane ruled, 2.16µm blaze 800nm-2.5µm
GA-T304R1U6 400 Plane ruled, 1.6µm blaze 1µm-3µm
GA-T303R3U0 300 Plane ruled, 3µm blaze 1.5µm-5.5µm
GA-T303R4U0 300 Plane ruled, 4µm blaze 1.5µm-5.5µm
GA-T3015R4U0-AU 150 Plane ruled, 4µm blaze. Gold coated. 3µm-10µm
GA-T3015R6U0-AU 150 Plane ruled, 6µm blaze. Gold coated. 3µm-10µm
GA-T301R9U0-AU 100 Plane ruled, 9µm blaze. Gold coated. 4.5µm-16µm
GA-T30075R10U0-AU 75 Plane ruled, 10µm blaze. Gold coated. 6µm-20µm
GA-T30075R12U0-AU 75 Plane ruled, 12µm blaze. Gold coated. 6µm-20µm
GA-T3005R18U0-AU 50 Plane ruled, 18µm blaze. Gold coated. 9µm-30µm
GA-T3005R19U5-AU 50 Plane ruled, 19.5µm blaze. Gold coated. 9µm-30µm


An order sorting filter wheel is located inside the entrance port of the monochromator, fitted with 6 filters selected for the spectral range of use.

When measuring below 400nm, no filters are required as the corresponding wavelength of the subsequent diffraction order is less than 200nm, which is naturally blocked by the atmosphere.

Spectral range Required OS filter
<400 nm Under standard conditions- none required
400-700nm OS400
700-1250nm OS700
1250-2000nm OS1250
2000-3600nm OS2000

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