Precision dosimetry in phototherapy & PDT

PTCal150 from Bentham

Safe and effective phototherapy and photodynamic therapy (PDT) treatment relies on accurate dosimetry. In hospitals and in clinical research, the PTCal150 sets the benchmark for the precise spectral irradiance measurement of all phototherapy and PDT light sources.

Designed with research-grade optical components, the PTCal150 spectroradiometer enables the highest accuracy data on patient exposure, and provides complete confidence in phototherapy radiometer calibration.

  • Double monochromator-based spectroradiometer with precision transmission cosine diffuser
  • Built-in PMT high voltage supply and dual channel, six-decade picoammeter, offering an impressive dynamic range
  • Flexible fire bundle with optional side or end-view entrance optic to conveniently couple light from the transmission diffuser to monochromator
  • Set in a single, robust housing for ease of transport between clinics and laboratories
  • Windows control software (BenWin+) provides full automation via USB 2.0

Further information

Determine warm-up characteristics and gain knowledge of the temporal variation of irradiance to guide the application of phototherapy and PDT.

A compact double monochromator with precision cosine corrected input optic provides excellent stray light performance over a very wide dynamic range, allowing for precise measurement of tungsten filament, LED, metal halide, xenon arc, fluorescent and dichroic sources alongside full-spectrum lamps.

Core benefits

  • High-accuracy spectroradiometry in just a few steps
  • Choice of UV / UV-vis configurations tailored to your phototherapy facilities
  • Alignment-free calibration standards ensure your link to national metrology standards
  • Fully automated measurement process via USB interface

Reported parameters

  • Spectral irradiance 
  • Erythemal irradiance


Entrance optic

Entrance optic type

BenFlect precision transmission diffuser (in-line or right angle configuration)

Aperture diameter





Randomised pure fused silica fibre bundle, from 0.5m long


Monochromator Type

Compact double monochromator, additive dispersion. Czerny-Turner mount.


150mm (each unit)


Fixed, interchangeable


Grating pair, kinematically mounted, 33x33mm

Stray light rejection at 10x FWHM from peak


Optical performance/ configuration

2400 g/mm (UV configuration)

1800 g/mm (UV-Vis configuration)

Spectral range



Typical bandwidth

1, 2 or 5nm

1, 2 or 5nm

Wavelength accuracy

± 0.15nm

± 0.20nm

Wavelength reproducibility

± 0.05nm

± 0.07nm

Detector and detection system

Detector type

S20 photocathode end window photomultiplier tube

Detector High Voltage

-750V (adjustable)

Detector response range


Detector dark current (typ.)


Picoammeter current range

Sub 1pA to 100µA

Picoammeter ADC resolution

> 14 ½ bit

Picoammeter ADC integration time




USB 2.0

Software control

BenWin+ Windows application

Operating System

From Windows 7

Minimum HD/ RAM required

100MB/ 256 MB

Overall dimensions

Approx. 395L x 315W x 250H (mm)


Mains input 110/220V 50/60Hz

Calibration standard (200-300nm)

Lamp type

Deuterium lamp

Nominal lamp power and voltage

30W, 100 V

Operating current

300mA DC

Expected lifetime


Power Supply

PSU_706 deuterium lamp supply

Calibration type and wavelength range

Spectral irraidance at 5.5mm from plane of front face, 200-400nm (2nm steps)

Calibration traceability

Physicalish Technische Bundesanstalt (PTB, Germany)

Calibration standard (250-800nm)

Lamp type

Halogen lamp

Nominal lamp power and voltage

150W, 24 V

Operating current

6.300 A DC

Expected lifetime


Power Supply

PSU_610 current stabilised lamp power supply

Calibration type and wavelength range

Spectral irradiance at 5.5mm from plane of front face, 250-800nm (5nm steps)

Calibration traceability

Physicalish Technische Bundesanstalt (PTB, Germany)


B-PTCal150 Spectroradiometer


Staffan Eriksson
Staffan Eriksson


Quantum Design GmbH

Roddarestigen 3
SE 182 35 Danderyd

Phone:+46 8 41071791
Staffan ErikssonSales Manager
+46 8 410 71791
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