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Welcome to the online documentation of the Bridge12 XLP probe for pulsed EPR and ODNP spectroscopy. Bridge12 does not distribute paper manuals with their probes to keep the documentation always up to date. If you have questions, or suggestions for edits please contact us at info@bridge12.com.
The Bridge12 XLP(O) probe is an EPR probe designed for pulsed X-Band (~ 9.5 GHz) EPR spectroscopy based on a loop gap resonator. The probe is optimized for pulsed EPR experiments, which require a large resonator bandwidth and high microwave conversion factors.
This X-Band probe is available in two different configurations:
Both configurations are based on a Loop-Gap Resonator (LGR). When completely overcoupled, the resonator has a large bandwidth, and the high microwave conversion factor guaranties large B1e fields. This makes the XLP resonator the ideal choice for pulsed EPR experiments that require a large excitation bandwidths.
Bridge12 XLP Overview
An overview of the Bridge12 XLP probe is shown in the figure shown above. For low-temperature measurements, the probe can be operated inside a cryostat. The Bridge12 XLP is compatible with commonly used cyrostats, such as the Oxford Instruments cryostat model CF935.
The main features of the probe are:
Optical access to the sample location for e.g. light/laser irradiation is possible in several different ways:
If you like to use an optical fiber to irradiate the sample using the sample holder/stick (option 1), please contact Bridge12 at info@bridge12.com for further information.
The Bridge12 XLP probe has a built-in, calibrated Cernox temperature sensor. The connector is located at the back of the probe. Please use the cable that came with the probe to connect the probe to the temperature controller.
More information about the pin-out can be found in the section Temperature Sensor.
Please make yourself familiar with the instructions below before attempting to install the probe. At no point should you use any force during the installation process. In general, all threads, screws, etc. are imperial size, not metric. Please use the appropriate tools to fasten screws.
Bridge12 XLP Overview
The Bridge12 XLP has a single SMA port to connect the probe to the spectrometer (see figure above). The SMA port is located at the top of the probe. Since the iris coupling is adjusting by moving the coupling loop inside the resonator up and down, we suggest using a flexible SMA cable between the bridge and the probe.
To connect the probe to the spectrometer follow these steps:
Do not use force to tighten the SMA connector. Do not use pliers or regular wrenches to tighten the SMA connection. We recommend using a torque wrench when tightening SMA connections. Torque wrenches for SMA connections are available from DigiKey or Mouser. If you don’t have a torque wrench available please just use your fingers to tighten the connection. Using the wrong tools can lead to permanent damages of the probe.
The BRidge12 XLP probe can except samples up to a maximum OD of 3.0 mm. Vendor links to sample tubes and capillaries can be found on the Cosumables Page.
Please follow the instructions for using the sample stick to mount the EPR sample to the Sample Stick. In general, the distance between the center of the sample and the bottom of the sample holder should be about 1 inch (25.4 mm) (see figure below).
Recommended distance between the center of the sample and the bottom of the sample holder
To insert the sample stick into the probe follow these instructions:
Please keep in mind that these instructions can differ, depending on the type and make of the low-temperature cryostat.
The Bridge12 XLP is a Loop-Gap Resonator (LGR) for pulsed EPR spectroscopy at X-band frequencies (~ 9.6 GHz).
Pulsed Electron Paramagnetic Resonance (EPR) spectroscopy using high-power microwave pulses or arbitrary waveform generated (AWG) broadband pulses require a large resonator bandwidth (low resonator Q) to avoid distortion of the pulse shape.
However, a large resonator bandwidth often comes at the cost of a reduced microwave conversion factor. Loop-Gap Resonators (LGR) are the preferred choice for pulsed EPR experiments since they have large microwave conversion factors and excellent field homogeneity across the length of the sample. This is especially important when using AWG generated broadband pulses.
| Parameter | Value |
|---|---|
| Resonator Frequency (empty) | 9.6 GHz |
| Resonator Frequency (with sample capillary) | 9.5 GHz |
| Microwave Conversion Factor (critically coupled) | > 3.5 G/sqrt(W) |
| Bandwidth (critically coupled) | Q ~ 700 (15 MHz) |
| Microwave Conversion Factor (overcoupled) | > 1 G/sqrt(W) |
| Bandwidth (critically coupled) | Q < 100 (> 100 MHz) |
| Maximum Sample Diameter | 3.0 mm |
| Resonator Height | 10 mm |
| Operating Temperature | 4 K to RT |
The Bridge12 XLO probe is based largely on the design of the XLP probe but has an integrated NMR coil for solution-state Overhauser Dynamic Nuclear Polarization (ODNP) experiments. The XLO probe has similar specifications as the XLP probe (frequency, conversion factor, etc.) but due to the NMR coil the sample access is limited to 1.2 mmm.
In general, the Bridge12 XLP Probe is completely maintenance free.
Please contact Bridge12 at support@bridge12.com if you have any questions or for further information.