Contact Us Home Home

Pyroelectric Laser Energy Measuring Heads

Features

 The following range of pyroelectric sensor heads is suitable for direct connection to an oscilloscope or to the LEM 2410 Power and Energy Meter. To give an improved signal size and to improve noise performance, pre-amplifiers can be used. Also available are special heads for high power applications and for VUV (157nm) F2 laser measurements.


Pyroelectric pulsed laser energy detectors with black absorption coating for high sensitivity - Series PEM

HiRep Laser energy detectors designed for high repetition rates - Series PEM HiRep

Pyroelectric pulsed laser energy detectors with metallic absorption coating - Series PEM HR

Pyroelectric pulsed laser energy detectors with ceramic absorption coating for high power densities - Series PEM K

Laser energy detector with integrated pre-amplifier - Series PEM E

VUV laser energy detector for use with F2 lasers - Series PEM VUV


 Pyroelectric sensors can be classified as thermal detectors. They provide wavelength independent conversion of light pulses into voltage pulses. These detectors are built using a coaxial design and are therefore extremely insensitive to electromagnetic interference (eg pulsed gas lasers).

 To satisfy the requirements of different applications, detectors are available with diameters of 4 to 50mm. It is advisable to choose a detector having a slightly larger area than the cross-section of the beam to be measured.

 The detectors have a black absorption coating which possesses uniform absorption over the wavelength range from 185nm to 25µm.

 The comparatively high sensitivity of these detectors is particularly useful. Due to the insensitivity to electromagnetic interference, it permits laser pulse measurements in the mJ range without any additional amplification.

 The maximum pulse repetition rate depends on the internal capacitance of the detector as well as the load resistor. All the detectors can be connected directly to the 1M Ohm input BNC socket of an oscilloscope. A smaller load resistor can be used to obtain the highest pulse repetition rate. Repetition rates of up to 100 Hz are then possible. A 100K Ohm load resistor is included with each head. The sensitivity of the detectors is specified for both 1M Ohm and 100K Ohm load resistors.

 The pyroelectric effect, in general, allows temperature changes to be measured. Thus these detectors are only suitable for detecting pulsed or modulated radiation. There are no limitations as to how narrow pulses can be, as the energy of the pulse is converted into heat flow in the absorption layer. The maximum pulse duration is estimated from the RC time constant (sensor capacitance x load resistance), assuming the thermal time constant (thermal dissipation from the sensor into the heat sink) has no effect. All the sensors offered here can be used to measure pulse widths of up to about 2 ms, so they can be used to measure most of the usual sources of pulsed radiation.

 It is possible to pulse a continuous light source by using an instrument such as an optical chopper if required.



Series PEM Specifications

Type

PEM 4

PEM 8

PEM 11

PEM 21

PEM 34

PEM 45

Active area (mm2)

12.5

50

95

350

900

1590

Measurement range

1 µJ to 20 mJ

2 µJ to 75 mJ

3 µJ to 150 mJ

5 µJ to 500 mJ

15 µJ to 1.4 J

30 µJ to 2 J

Sensitivity, 1 Mohm load (V/J)

500 to 1000

200 to 500

100 to 400

50 to 150

20 to 70

8 to 15

Sensitivity, 100 kohm load (V/J)

130 to 150

50 to 200

50 to 150

30 to 80

10 to 40

4 to 8

Max. repetition rate, 1 Mohm load

80 Hz

40 Hz

40 Hz

25 Hz

25 Hz

25 Hz

Max. repetition rate, 100 kohm load

120 Hz

100 Hz

80 Hz

50 Hz

2 ms

80 Hz

100 Hz

Max. pulse duration

2 ms

Spectral range

0.19 to >25 µm

Max. power density

8 MW/cm² (10 ns pulse)

Max. energy density

0.15 J/cm²

Max. average power

0.15 W/cm²

0.5 W/cm²

Accuracy

5%

Diameter (mm)

30

30

30

39

50

70

Length (mm)

47

47

47

47

47

47

Connector

BNC


Ordering Information

PEM 4

 Pyroelectric sensor head with 4mm active diameter.

PEM 8

 Pyroelectric sensor head with 8mm active diameter.

PEM 11

 Pyroelectric sensor head with 11mm active diameter.

PEM 21

 Pyroelectric sensor head with 21mm active diameter.

PEM 34

 Pyroelectric sensor head with 34mm active diameter.

PEM 45

 Pyroelectric sensor head with 45mm active diameter.


Useful Documents

pdf

PEM Series datasheet - pdf (331K)



Series PEM HiRep

 The following detectors achieve high repetition rates:

Type

PEM 12 HiRep

PEM 24 HiRep

PEM 12 HiRep UV

PEM 24 HiRep UV

Active diameter (mm)

12

24

12

24

Sensitivity (V/J)

20 to 30

20 to 30

35 to 45

35 to 45

Max repetition rate (kHz)

0.75

0.75

2.50

1.20

Max average power (W)

2

5

2

5

Max energy density (mJ/cm2)

80

80

50

50

Max peak power density (MW/cm2)

8

8

5

5

Working range

30 µJ to 100 mJ

30 µJ to 350 mJ

30 µJ to 60 mJ

30 µJ to 250 mJ

Accuracy

± 3%

± 3%

± 3%

± 3%

Dimensions (mm)

40 x 40

55 x 40

40 x 40

55 x 40


Ordering Information

PEM 12 HiRep

 High Repetition sensor head with 12mm active diameter.

PEM 24 HiRep

 High Repetition sensor head with 24mm active diameter.

PEM 12 HiRep UV

 High Repetition sensor head with 12mm active diameter for UV use.

PEM 24 HiRep UV

 High Repetition sensor head with 24mm active diameter for UV use.


Useful Documents

pdf

PEM HiRep Series datasheet - pdf (91K)



Series PEM HR

 The following HR detectors are coated with metallic absorption coating to achieve high repetition rates:

Type

PEM 4 HR

PEM 8 HR

PEM 11 HR

PEM 21 HR

Active diameter (mm)

4

8

11

21

Sensitivity, 1 MOhm load (V/J)

1000 to 1500

700 to 900

400 to 600

150 to 250

Sensitivity, 100 kOhm load (V/J)

900 to 1200

400 to 500

300 to 500

100 to 250

Max. average power density

0.15 W/cm²

Detection threshold

1 µJ

1 µJ

3 µJ

5 µJ

Max. average power

0.15 W/cm²

Accuracy

± 5%

Diameter (mm)

30

30

30

39

Length (mm)

47

47

47

47

Connector

BNC


Ordering Information

PEM 4 HR

 HR sensor head with 4mm active diameter.

PEM 8 HR

 HR sensor head with 8mm active diameter.

PEM 11 HR

 HR sensor head with 11mm active diameter.

PEM 21 HR

 HR sensor head with 21mm active diameter.



Series PEM K

 Pyroelectric pulsed laser energy detectors with ceramic absorption coating for high powers:

Type

PEM 20 K

PEM 45 K

Active diameter (mm)

20

454

Sensitivity, at 1MOhm (V/J)

10 to 15

1.5 to 3.5

Repetition rate, at 1MOhm (Hz)

30

30

Max average power (W)

10

10

Detection threshold, mJ

<1

1

Accuracy

± 5%

± 5%

Connector

BNC

BNC

Diameter (mm)

46

68

Length (mm)

47

53


Ordering Information

PEM 20 K

 High power laser energy detector with 20mm active diameter.

PEM 45 K

 High power laser energy detector with 45mm active diameter.


Useful Documents

pdf

PEM 20 K datasheet - pdf (130K)

pdf

PEM 45 K datasheet - pdf (133K)



Series PEM E

 Pyroelectric pulsed laser energy detector with integrated low noise pre-amplifier to enable measurement of very small laser energies

 Incorporated switch to allow use of the whole dynamic range of the sensor

 Broadband black coating (BC) option for use with different wavelengths

 Metal coating (MC) option for higher repetition rate and sensitivity requirements


Type

PEM 12 E

Active diameter (mm)

12

Sensitivity, switchable (V/J)

~1000/~10000

Repetition rate, (kHz)

1 (black coating)

5 (metal coating)

Max average power (mW)

500

Max energy density (mJ/cm2)

150

Readout

Scope

Outer dimensions (mm)

25 x 25 x 60


Ordering Information

PEM 12 E (BC)

 Laser energy detector with 12mm active diameter and integrated pre-amplifier, with broadband black coating.

PEM 12 E (MC)

 Laser energy detector with 12mm active diameter and integrated pre-amplifier, with metal coating.


Useful Documents

pdf

PEM 12 E datasheet - pdf (103K)



VUV Energy Detectors

 The following energy detectors are designed with higher sensitivity, specially for use at 157 nm:

Type

PEM 10-VUV

PEM 20-VUV

PEM 24-VUV

PEM 30K-VUV

Active diameter (mm)

10

20

24

30

Sensitivity, 1 MOhm load (V/J)

30 to 50

15 to 25

15 to 25

1.5 to 2.5

Max repetition rate, 1 MOhm (Hz)

150

150

150

50

Accuracy

± 5%

Permissible energy density (mJ/cm²)

50

50

50

440

Permissible power density (MW/cm²)

5

5

5

22

Detection threshold

100 µJ

200 µJ

200 µJ

1 mJ

Window material

MgF2

Electrical connector

SMA

BNC

Vacuum connector

KF 16 ND

KF 25 ND

KF 25 ND

KF 40 ND

Diameter (mm)

30

42

42

100

Length (mm)

54

72

72

96


Ordering Information

PEM 10-VUV

 VUV head with 10mm active diameter.

PEM 20-VUV

 VUV head with 20mm active diameter.

PEM 24-VUV

 VUV head with 24mm active diameter.

PEM 30K-VUV

 VUV head with 30mm active diameter.


Useful Documents

pdf

PEM 10 & 20 VUV datasheet - pdf (113K)

pdf

PEM 24 VUV datasheet - pdf (70K)

pdf

PEM 30K VUV datasheet - pdf (91K)


Home | Products | Newsletter | Representatives | Contact | Website Policies
Scitec Instruments Ltd 1999 - 2009. All rights reserved.