A blog on the repair, operation and calibration of surface analysis systems and components including electron spectrometers, sputter ion guns and vacuum related hardware. Click on the Index tab below to see a list of all posts. Visit our website at http://www.rbdinstruments.com
year, RBD introduced an updated 9103 USB Picoammeter, with 3 new
High-speed: 500 reads / second compared to 40 for the Standard Model
High-voltage: an isolated signal input with the ability to float the 9103 Picoammeter to ±5000 VDC.
High-speed / High Voltage: One model combining both features.
This year we’ll be working on adding new features to our Actuel application software and providing more comprehensive support and programming documentation.
Actuel 1.6 is Released
The latest version of Actuel (1.6) is now available, as is an updated User Guide. The guide has new information on setting up and programming the 9103 for high-speed communications. Both can be found here.
This release replaces the Beta release and has full support for high-speed sampling and data recording and graphing.
TechSpot Article Series
This year, we’ll be running a series of articles here on the TechSpot blog with more information on the new 9103 models and features, as well as detailed configuration, application, and programming advice.
of the topics we’ll be covering include:
the 9103 for high-speed data collection
the high-voltage reference
use of the input ground
Keep your eye on here on TechSpot for these and other articles covering all of RBD’s products, and please consider subscribing.
RBD Instruments has released a new version of its 9103 USB Picoammeter which incorporates faster reads per second with 5000 DC volts of isolation to chassis ground.
Increasing the DC voltage isolation from chassis ground to 5000 volts (5kV) opens up new possibilities for researchers such as direct DC current measurement of very small electron and photo multiplier signals. Electron and ion beam measurements can be biased to reduce secondary electrons or to retard the beam as needed for experiments.
Designed to provide accurate bipolar DC current measurements in noisy environments such as synchrotron beam lines, the 9103 can measure bi-polar DC currents from low picoamps to milliamps.
The drawing below shows how the 9103 is floated on your HV power supply. The high voltage is referenced to chassis ground, and the signal ground is referenced to the high voltage. To help keep the supply and signal connections clear, the HV connection is a MHV connector and the signal input is a SHV connector.
There are a number of manufacturers of programmable DC power supplies that can be used to float the 9103 up to whatever voltage is needed (as long as you do not exceed +/- 5 kV).
For example, TDK-Lambda provides a programmable 0 to 6.5kV supply that can be voltage limited to 5 kV and can drive up to 2 mA of current.
The model number for a 120 VAC line input is PHV6.5P2-USB-1P115. The base model has a ripple of 700mV which is somewhat high, but TDK-Lambda does offer a low ripple option that gets the ripple down to 75mV. You can also easily make a simple RC filter to do the same thing. A number of interface options are available (USB, Ethernet, Serial, analog….
TDK Lambda supply
The new high speed option for the 9103 increases the reads per second from 40 to over 500, which is fast enough to perform optical chopper experiments. And, by taking more reads in the same amount of time as the first generation 9103 could, the accuracy is improved.
The Actuel software included with the 9103 provides new features for high speed acquisitions and display, but you can also write your own software to control the 9103 using the simple ASCII commands or in LabVIEW.
Since 9103s can be synced, it is now possible to configure a multichannel DC Picoammeter with up to 256 channels that has high speed, high voltage, or both options.
And if you do not need the high speed or high voltage options, the standard 9103 USB Picoammeter is still available as well.
The 9103 USB picoammeter is often equipped with a +90 V bias option which improves the accuracy of electron and ion current measurements (by reducing the number of low energy secondary electrons that are generated by the beam from leaving the target).
The +90 V bias comprises two 45V batteries in series which are located inside the 9103 chassis. This blog post will explain how to test and replace the batteries in a 9103 picoammeter.
1. Connect a DVM (digital volt meter) to the 9103 Input BNC connector. A BNC to double banana cable works well. Set the DVM to DC volts.
2. In Actuel (the 9103 software), select the input Grounded and bias On.
3. Sample the current.
4. When the bias ON is checked there will be about +90V DC on the input of the 9103.
5 .The input impedance of most DVMs when measuring DC voltage is 10 meg ohms. The two 45 volt batteries should total 90 to 95V DC. The bias voltage divided by the input impedance of the DVM will equal the current. In this case the voltage of the two 45 volt batteries totaled 94V and the current was 9.414 uA.
9.4 uA in Actuel
94 V DC on DVM
6. It is recommended that the bias batteries be tested every 6 months and replaced when the voltage drops below 80 volts. It is normal for the batteries to wear out over time and with use. Once the bias voltage drops to less than 50 V the effectiveness of preventing secondary electron emission is greatly reduced, which in turn reduces the accuracy of electron and ion beam current measurements.
The RBD part number for the 45 V battery is BAT-45-213.
Whether you have an RBD 9103 USB picoammeter or an older Keithley with a PHI model 78 bias box, you should test the batteries as part of your preventive maintenance procedure and replace them as needed.
To replace the batteries in a 9103:
Unplug the 9103 USB power and input cables.
Using the Torx wrench that was included with the 9103, remove the screws from the front and rear 9103 chassis covers.
Slide the board out from the front of the 9103. You will need to rotate the back cover to feed it in. The back cover has a ground wire that is attached to the 9103 board. Also note which groove the 9103 board is in as you will need to put it back in the same groove.
Remove the battery support bracket (white plastic).
Carefully remove the old batteries.
Install the new batteries.You may need to adjust the contacts on the batteries to get them to fit onto the board snaps more easily.
Reattach the battery support bracket.
Carefully slide the back cover and board back into the chassis. Make sure that you put the board back in the same groove that it came out of. If the front cover does not line up with the chassis then you are not in the correct groove.
Reattach the screws to the front and back covers. Do not over tighten the screws!
Once you have installed the new batteries, test the voltage. You should have 90 to 95 Volts.