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| d2:spectroscopy_module_212 [2014/12/03 00:23] – [Inputs, Outputs, and Controls] Michael Radunsky | d2:spectroscopy_module_212 [2023/04/18 16:31] (current) – external edit 127.0.0.1 |
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| =====Description===== | =====Description===== |
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| The D2-212 saturated absorption spectroscopy module provides error signals derived from saturated absorption spectroscopy of atomic rubidium, cesium, or potassium. It contains a vapor cell, internal temperature controller, balanced photodetectors, and optics. Temperature control stabilizes the number density of atoms in the cell.The photodiode output is shot-noise limited out to greater than 5 MHz for photocurrents of 100 μA and above. The high bandwidth of the feedback enables tight solid locking that is immune to vibrations and shock. The D2-212 is powered by a cable that plugs into the power connectors on any D2 series electronics module or into an ICE-PB1 board, depending on which system you purchased. | The D2-212 saturated absorption spectroscopy module provides error signals derived from saturated absorption spectroscopy of atomic rubidium, cesium, or potassium. It contains a vapor cell, internal temperature controller, a single photodetector, and optics. Temperature control stabilizes the number density of atoms in the cell.The photodiode output is shot-noise limited out to greater than 5 MHz for photocurrents of 100 μA and above. The high bandwidth of the feedback enables tight solid locking that is immune to vibrations and shock. The D2-212 is powered by a cable that plugs into the power connectors on any D2 series electronics module or into an ICE-PB1 board, depending on which system you purchased. |
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| | =====Purchase Includes===== |
| | * D2-212 Spectroscopy Module |
| | * VPN00463 SMA cable (6ft) |
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| ===== Absolute Maximum Ratings ===== | ===== Absolute Maximum Ratings ===== |
| =====Inputs, Outputs, and Controls===== | =====Inputs, Outputs, and Controls===== |
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| <imgcaption front|>{{ :d2:d2-212:frontlegend.jpg?nolink |D2-212 Connectors}}</imgcaption> | <imgcaption front|>{{ :d2:d2-212:frontview-labeled-for-manual.jpg?nolink |D2-212 Connectors}}</imgcaption> |
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| **Input Connector**** (****6-pin circular)** | **Input Connector**** (****6-pin circular)** |
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| Power from the D2-series power bus or other power supply are made through a 6-pin circular connector ([[http://www.digikey.com/product-detail/en/HR10A-7R-6SB(73)/HR1608-ND/1095466?WT.srch=1&WT.medium=cpc&WT.mc_id=IQ59989287-VQ2-g-VQ6-40609413915-VQ15-1t1-VQ16-c|Hirose HR10A-7R-6SB]]) shown in <imgref front>. The pin definitions (pin numbers are marked on the connectors) are listed below. | Power from the D2-005 Power Supply, ICE-PB1 Power Buss, or other power supply are made through a Hirose 6-pin circular connector ([[http://www.digikey.com/product-detail/en/HR10A-7TR-6SA/HR357-ND/510211|HR10A-7TR-6SA]]) shown in <imgref front> and <imgref hirose_pinout>. The pin definitions (pin numbers are marked on the connectors) are listed in <tabref connector>. |
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| <WRAP center round box 500px> | <imgcaption hirose_pinout|Pin numbering on female Hirose 6-pin connector>{{ :d2:d2-160:hirose-connector.png?200 }}</imgcaption> |
| ^ Pin ^ Input Voltage ^ Max Current Draw ^ Notes ^ | |
| | 1 | +5V | 1.5A | | | <WRAP center round box 900px><tabcaption connector> |
| | 2 | No Connect | | | | ^ Hirose Pin ^ DB-9 Pin (if applicable) ^ Input Voltage ^ Max Current Draw ^ Notes ^ |
| | 3 | +5V Ground | | Return path for high current +5V. | | | 1 | 4 and 5 | Signal Power Ground | | Return path for power rail. | |
| | 4 | Signal Ground | | Return path for voltages on pins 5 & 6. | | | 2 | 8 | -15 V | 100mA | See note below. | |
| | 5 | -15 V | 100mA | See note below. | | | 3 | 9 | +15 V | 100 mA | See note below. | |
| | 6 | +15V | 100mA | See note below. | | | 4 | 6 and 7 | +5 V | 1.5 A / 2.5 A | 2.5 A max with Doppler subtraction option, 1.5 A max without. | |
| | | 5 | | No Connect | | | |
| | | 6 | 1 and 2 | +5 V Ground | | Return path for high current +5V. | |
| | </tabcaption></WRAP> |
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| <wrap lo>**Note:** See D2-005 manual for pin out on D-Sub 9-pin connector.</wrap> | |
| </WRAP> | |
| **Signal Output (SMA)** | **Signal Output (SMA)** |
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| <imgcaption trimpots1|Locations of temperature setpoint and offset trimpots.>{{ :d2:d2-212:trimpotlegend.jpg?nolink |}}</imgcaption> | <imgcaption trimpots1|Locations of temperature setpoint and offset trimpots.>{{ :d2:d2-212:trimpotlegend.jpg?nolink |}}</imgcaption> |
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| <imgcaption trimpots2|Locations to probe with voltmeter while settings while adjusting trimpots.>{{ :d2:d2-212:trimpotlegend2.jpg?nolink&400 |}}</imgcaption> | <imgcaption trimpots2|Locations to probe with voltmeter while adjusting trimpots.>{{ :d2:d2-212:trimpotlegend2.jpg?nolink&400 |}}</imgcaption> |
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| The extent of the trim range can be determined by probing the location shown in <imgref trimpots2> with a voltmeter referenced to case ground (the outer shell of the SMA connector is a good reference point). Probing this location gives the wiper voltage of the trimpot which corresponds to temperature as shown in the tables below. This 10-turn trim pot sets temperature from 15°C (fully CCW) to 75°C (10 turns CW). The 5-turn point is approximately 42°C. The following table gives approximate temperature settings for the three available alkali options: | The extent of the trim range can be determined by probing the location shown in <imgref trimpots2> with a voltmeter referenced to case ground (the outer shell of the SMA connector is a good reference point). Probing this location gives the wiper voltage of the trimpot which corresponds to temperature as shown in the table below. This 10-turn trim pot sets temperature from 15°C (fully CCW) to 75°C (10 turns CW). The 5-turn point is approximately 42°C. The following table gives approximate temperature settings for the three available alkali options: |
| <WRAP center round box 300px> | <WRAP center round box 300px><tabcaption temperature> |
| ^ Alkali ^ Turns CW ^ Wiper Voltage ^ Temp ^ | ^ Alkali ^ Turns CW ^ Wiper Voltage ^ Temp ^ |
| | cesium | 2 | 6.8V | ~30°C | | | cesium | 2 | 6.8V | ~30°C | |
| | rubidium | 4-5 | 5.7V | ~40°C | | | rubidium | 4-5 | 5.7V | ~40°C | |
| | potassium | 8-9 | 3.9V | ~60°C | | | potassium | 8-9 | 3.9V | ~60°C | |
| </WRAP> | </tabcaption></WRAP> |
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| **Window Offset Adj.** | **Window Offset Adjustment** |
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| This trimpot, labeled in <imgref trimpots1> as "Window Offset", sets the operating temperature offset of the slave TEC relative to the master TEC setpoint (set by Temperature Setpoint Adj, described above). The slave TEC controls the temperature of the vapor cell's windows. If the trimpot is turned fully CCW, then there will be zero offset and the slave TEC (and the vapor cell windows) will be at the same temperature as the master TEC. In practice, this is usually undesirable as the Alkali metal in the cell can condense on the windows and block transmission. Usually, the slave TEC should be set to a higher temperature than the master to prevent condensation on the windows. Adjusting the trimpot to a value CW increases the offset of the slave TEC temperature setpoint relative the to setpoint of the master TEC. This offset will always be to a higher temperature relative to the master. This temperature offset will track changes to the master TEC's setpoint, so the offset will not need to be changed if the master TEC's temperature setpoint is changed later on. | This trimpot labeled in <imgref trimpots1> as "Window Offset" sets the operating temperature offset of the slave TEC relative to the master TEC setpoint (set by Temperature Setpoint Adjustment, described above). The slave TEC controls the temperature of the vapor cell's windows. If the trimpot is turned fully CCW, then there will be zero offset and the slave TEC (and the vapor cell windows) will be at the same temperature as the master TEC. In practice, this is usually undesirable as the Alkali metal in the cell can condense on the windows and block transmission. Usually, the slave TEC should be set to a higher temperature than the master to prevent condensation on the windows. Adjusting the trimpot to a value CW increases the offset of the slave TEC temperature setpoint relative the to setpoint of the master TEC. This offset will always be to a higher temperature relative to the master. This temperature offset will track changes to the master TEC's setpoint, so the offset will not need to be changed if the master TEC's temperature setpoint is changed later on. |
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| **Master Proportional Gain Adj.** | **Master Proportional Gain Adjustment** |
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| This trimpot is located to the right of the "Temp Set" trimpot shown in <imgref trimpots1>. This controls the proportional gain of the master TEC's PID control loop. It is factory set for loop stability, but it may be adjusted if there are stability issues. Turning this CW increases gain, while CCW decreases gain. It's setpoint may be recorded by using an Ohm-meter to measure the resistance from the trimpot's wiper lug (similiar to the probe points shown in <imgref trimpots2> to case ground while the D2-212 module is unpowered. The factory setting is generally about 2kΩ to ground. | This trimpot is located to the right of the "Temp Set" trimpot shown in <imgref trimpots1>. This controls the proportional gain of the master TEC's PID control loop. It is factory set for loop stability, but it may be adjusted if there are stability issues. Turning this CW increases gain, while CCW decreases gain. It's setpoint may be recorded by using an Ohm-meter to measure the resistance from the trimpot's wiper lug (similiar to the probe points shown in <imgref trimpots2> to case ground while the D2-212 module is unpowered. The factory setting is generally about 2kΩ to ground. |
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| **Slave Proportional Gain Adj.** | **Slave Proportional Gain Adjustment** |
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| This trimpot is located to the right of the "Window Offset" trimpot shown in <imgref trimpots1>. This controls the proportional gain of the slave TEC's PID control loop. It is factory set for loop stability, but it may be adjusted if there are stability issues. Turning this CW increases gain, while CCW decreases gain. It's setpoint may be recorded by using an Ohm-meter to measure the resistance from the trimpot's wiper lug (similiar to the probe points shown in <imgref trimpots2> to case ground while the D2-212 module is unpowered. The factory setting is generally about 2kΩ to ground. | This trimpot is located to the right of the "Window Offset" trimpot shown in <imgref trimpots1>. This controls the proportional gain of the slave TEC's PID control loop. It is factory set for loop stability, but it may be adjusted if there are stability issues. Turning this CW increases gain, while CCW decreases gain. It's setpoint may be recorded by using an Ohm-meter to measure the resistance from the trimpot's wiper lug (similiar to the probe points shown in <imgref trimpots2> to case ground while the D2-212 module is unpowered. The factory setting is generally about 2kΩ to ground. |
| - View the output of the servo Error Input monitor on an oscilloscope in DC coupled mode. | - View the output of the servo Error Input monitor on an oscilloscope in DC coupled mode. |
| - Turn on the laser and ensure it isn't on transition. We are going to ensure the photodetector in the D2-212 isn't saturated by checking its DC level on the oscilloscope. | - Turn on the laser and ensure it isn't on transition. We are going to ensure the photodetector in the D2-212 isn't saturated by checking its DC level on the oscilloscope. |
| - Adjust the λ/2 waveplate on the front of the D2-212 to attenuate the input signal until the DC level on the scope of the Error Input monitor is below 3V. If the DC level is higher than this, the photodetector circuitry may saturated and show erratic behavior. | - Adjust the λ/2 waveplate on the front of the D2-212 to attenuate the input signal until the DC level on the scope of the Error Input monitor is below 3V. If the DC level is higher than this, the photodetector circuitry may saturate and show erratic behavior. |
| - The module should now be set up for spectroscopy. | - The module should now be set up for spectroscopy. |
| =====Troubleshooting===== | =====Troubleshooting===== |
| ==== Rubidium on Vapor Cell Windows ==== | ==== Metal Atoms on Vapor Cell Windows ==== |
| TBD | TBD |
| ==== Polarization Sensitivity==== | ==== Polarization Sensitivity==== |
