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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

ConfigurationPair symmetrical Czerny Turner monochromators, additive dispersion
Focal length- Total focal length: 300mm
- Individual units: 150mm
Grating mountKinematic
Number of gratings1 pair
Grating size33x33mm
Aperture ratiof/4
Number of entrance/exit ports1 entrance, 1-2 exits
Spectral rangeWithin range 200nm-2400nm


Wavelength scanningBy integrated stepping motor and micro-stepping drive electronics
Slit typeFixed, micrometer or motorised variable
Slit width & height10µm-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 range200-600nm
Linear dispersion5.4nm/mm
Wavelength accuracy± 0.15nm, ± 0.05nm with software correction
Wavelength reproducibility± 0.05nm
Resolution full/reduced slit height0.25/0.1nm
Stray light rejection at 2.5 FWHM10-8
Wavelength sweep speed30nm/s

487 Dual-Channel Picoammeter Module - Electrical

Channel 1 inputCurrent input to picoammeter
Channel 2 inputCurrent input to picoammeter
Gain ranges1010-105 V/A
Maximum current Input100µA
Frequency responseDC to 30Hz
Gain accuracy+1%
Gain stability200ppm/°C
Output stability5ppm/°C to 500ppm/°C depending on sensitivity
Linearity< 0.025% departure from linearity from zero to full scale
ADC resolution4½ digit BCD (0 to 19999) i.e. > 14 bit resolution
ADC integration time100ms
Auxiliary input range0- 9.8V
Picoammeter input impedanceVirtual earth
Auxiliary input impedance1 MΩ

415 High Voltage Power Supply Module - Electrical

Output voltage range-350 to -1500V
Maximum current1.5mA
Temperature stability100 ppm/°C
Stability to voltage fluctuations25ppm for 10% change in line voltage
Ripple and noise100ppm 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.

GratingLine density (g/mm)Grating type & Blaze wavelengthMaximum wavelength range
GA-T324R0U252400Plane ruled, 250nm blaze200nm-600nm
GA-T324H0U252400Plane holographic, 250nm blaze200nm-600nm
GA-T324H0U32400Plane ruled, 300nm blaze200nm-600nm
GA-T318H0U251800Plane holographic, 250nm blaze250nm-900nm
GA-T318R0U41800Plane ruled, 400nm blaze250nm-900nm
GA-T318R0U51800Plane ruled, 500nm blaze250nm-900nm
GA-T312H0U251200Plane holographic, 250nm blaze300nm-1.2µm
GA-T312R0U41200Plane ruled, 400nm blaze300nm-1.2µm
GA-T312R0U51200Plane ruled, 500nm blaze300nm-1.2µm
GA-T312R0U751200Plane ruled, 750nm blaze300nm-1.2µm
GA-T312R0U91200Plane ruled, 900nm blaze300nm-1.2µm
GA-T312R1U01200Plane ruled, 1µm blaze300nm-1.2µm
GA-T3083R1U2830Plane ruled, 1.2µm blaze600nm-1.8µm
GA-T306R1U0600Plane ruled, 1µm blaze800nm-2.5µm
GA-T306R1U25600Plane ruled, 1.25µm blaze800nm-2.5µm
GA-T306R1U6600Plane ruled, 1.6µm blaze800nm-2.5µm
GA-T306R1U9600Plane ruled, 1.9µm blaze800nm-2.5µm
GA-T306R2U16600Plane ruled, 2.16µm blaze800nm-2.5µm
GA-T304R1U6400Plane ruled, 1.6µm blaze1µm-3µm
GA-T303R3U0300Plane ruled, 3µm blaze1.5µm-5.5µm
GA-T303R4U0300Plane ruled, 4µm blaze1.5µm-5.5µm
GA-T3015R4U0-AU150Plane ruled, 4µm blaze. Gold coated.3µm-10µm
GA-T3015R6U0-AU150Plane ruled, 6µm blaze. Gold coated.3µm-10µm
GA-T301R9U0-AU100Plane ruled, 9µm blaze. Gold coated.4.5µm-16µm
GA-T30075R10U0-AU75Plane ruled, 10µm blaze. Gold coated.6µm-20µm
GA-T30075R12U0-AU75Plane ruled, 12µm blaze. Gold coated.6µm-20µm
GA-T3005R18U0-AU50Plane ruled, 18µm blaze. Gold coated.9µm-30µm
GA-T3005R19U5-AU50Plane 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 rangeRequired OS filter
<400 nmUnder standard conditions- none required

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