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IDR300 Double Monochromator

  • IDR300 integrated monochromator with picoammeter
  • IDR300 integrated monochromator with picoammeter

Composed of two 300mm focal length, triple-grating turret Czerny-Turner monochromators arranged for additive dispersion, the IDR300 has a solenoid-based swing away mirror at the exit of both halves. This provides a single monochromator exit port and two double monochromator exit ports, allowing the specification of up to three system detectors. Grating drive control electronics are located to the base of the unit alongside the signal recovery electronics required to interface the three detectors, including two dual-channel picoammeters and a high voltage power supply for operation of detectors in the photoemissive or photoconductive modes.

The IDR300 is a single unit with a lot of talents, ready for deployment in a number of applications.

Core benefits


  • Two 300mm focal length monochromators in Czerny-Turner mount
  • Triple grating turrets
  • One entrance and three exit ports, all motorised with automated mirror-based selection
  • Integrated drive electronics, two dual-channel picoammeters 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 arranged for additive dispersion
Focal lengthTotal focal length: 600mm
Individual units: 300mm
Grating mountTriple grating turret
Number of gratings1-3
Grating size68 x 84mm
Aperture ratiof/4.1 (at all grating angles)
Number of entrance/ exit ports1/2 or 2/1 on both monochromators


Mechanical resolution drive0.000072°/ step
Slit typeMotorised variable slit
Slit width & height10µm-10mm (W) x 20mm (H)
Filter size25mm diameter

Optical Performance (quoted for 1200 g/mm gratings)

Spectral rangeWithin range 200nm-50µm
Linear dispersion1.35nm/mm
Wavelength accuracy± 0.1nm
Wavelength reproducibility± 0.025nm
Resolution full/reduced slit height0.15/ 0.05nm
Stray light rejection at 2.5 FWHM (single mode)10-4
Stray light rejection at 2.5 FWHM (double mode)10-8
Wavelength acquisition speed2000nm/s


Computer interfaceUSB 2.0
Software controlBenWin+/ SDK

Electrical/ Mechanical

Overall dimensions624L x 375W x 255H mm
Optical height168mm
WeightApprox. 30 kg
Power supplyMains input 110/220V 50/60Hz

487 Dual-Channel Picoammeter Module - Electrical

Channel 1 inputCurrent input to picoammeter
Channel 2 inputCurrent input to picoammeter
Channel 3 inputCurrent input to picoammeter
Channel 4 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 gratingsSee Configurations Tab
Order sorting filtersSee Configurations Tab
Filter wheel252-8 (8-position filter wheel, includes shutter)

Monochromator Configurations

IDR300 Configuration 

Diffraction Gratings

Where a system is to be used over an exceptionally wide spectral range, requiring more than 3 diffraction gratings, interchangeable turrets are employed; the stepping motor in this case drives a platform to which the grating assembly is attached.

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 mNone
3.6-6 µmOS3600
6-10.5 µmOS6000
10.5-21 µmOS10500
> 21µmPlease consult.

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