PMTs are the most sensitive single channel detector we offer. Here, we show their performance with a Merlin™ Lock-in. The figures represents the performance levels that are fairly typical of our systems. The responsivity and dark current values of PMTs can vary by as much as a factor of 5 each, under identical bias and temperature conditions. Therefore, there may be a few tubes which will not reach these typical results. We offer room temperature end-on and side-on PMTs to cover the 160 to 1100 nm range.
Minimum measurable power levels of photomultiplier tubes, operated by Merlin.
Non-calibrated Detectors
We do not usually calibrate PMTs, since the long term stability is not adequate for this purpose. You can calibrate Merlin™ PMT systems with a standard lamp, or transfer calibration from a Silicon Detectors for Merlin™ Radiometer, provided care is taken in selecting the operating conditions.
Chopping Frequency
Use any chopping frequency between the 8 and 1100 Hz limits of the Merlin Lock-in. The PMTs will comfortably follow any signal within these limits, transimpedance amplifier bandwidth allowing. Let the noise levels and the desired speed of data collection guide your chopping frequency and time constant selections. We find that frequencies equal to 1.5 or 1.75 times the line frequency and 0.3 to 3 second time constants work very well for low light levels.
Detection Systems
We offer two PMT packages for Merlin: an end-on and a side-on system. Each Package Includes:
- 77264 , 77265 End-on or 70683 , 70680 Side-on PMT Housing (Note: 70680 and 77265 are only for customers with 70705 Power Supply)
- 70710 Transimpedance Amplifier
- All necessary interconnecting cables
To Complete the System, Please Order the Following, Separately:
- Photomultiplier Tubes
- Model 70706 Power Supply (or provide your own source of high voltage bias)
- Merlin™ Control Unit
- Optical Chopper
|
Model |
Wavelength Range |
Peak Wavelength |
Cathode * |
Photocathode Size
|
NEP*
(W Hz-1/2) |
Supply Voltage |
| 77341
|
185-870 |
330 nm |
40 mA/W |
8 x 24 mm |
2.8 x 10-16 |
1000 |
| 77343
|
400-1000 |
730 nm |
1.9 mA/W |
8 x 24 mm |
1.2 x 10-13 |
1250 |
| 77348
|
160-900 |
400 nm |
68 mA/W |
8 x 24 mm |
1.2 x 10-16 |
1000 |
| 77360
|
185-850 |
420 nm |
70 mA/W |
8 x 16 mm |
5.0 x 10-16 |
1000 |
| 77346
|
185-850 |
420 nm |
64 mA/W |
25 mm dia. |
6.6 x 10-16 |
1000 |
| 77361
|
400-1100 |
800 nm |
1.9 mA/W |
25 mm dia. |
4.2 x 10-13 |
1250 |
*Typical values at the supply voltage listed.
