Table of Contents
Overview | 1 2
Quick Start | 2 3
Hardware | 3 4
Housing | 3.1 5
Drive Train | 3.2 7
Control | 3.3 10
Graphical User Interface | 4 11
Drawings | 5 16
Housing | 5.1 17
Drive Train | 5.2 20
Mounting | 5.3 25
Suppliers | 6 27
Acknowledgements | 7 28
Appendix | 8 29
Overview | 1
The Rotating Target Source 2.0 (RTS2) is a remake of the original RTS from the ground up. The original RTS could output the characteristic x-ray bands of one of eight samples chosen by the user operating it via a computer for the purpose of testing and calibrating an x-ray spectrometer. The device was however limited to relatively high Z samples due to atmospheric absorption of low energy x-rays. This second generation RTS, once loaded and evacuated, maintains the x-ray source, a six sample wheel, and the spectrometer sensor window in a high vacuum. This allows for testing and calibration with lighter element samples. The user can select various samples or run a preprogrammed set of tests using the RTS Control GUI.
The RTS2 has a custom made aluminum sample wheel capable of holding six 30mm x 30mm x 4mm samples. The faces of the wheel are at a 43˚ angle to the x-ray source, in order to avoid x-ray reflection off of the sample’s crystal planes and guarantee that only x-rays emitted by the illuminated sample enter the spectrometer. The wheel is mounted on a rotating shaft that, through a series of vacuum bearings, bellow couplings, and a Ferro fluidic rotary feed through, is driven directly by a 10 Watt ironless-core DC motor. The combination of this high precision Maxon motor, the absence of gears, the relatively large dampening torque of the feed through, and the ABEC-3 precision bearings with Teflon retainers means that the RTS2 produces no detectable vibrational noise and can be mounted directly onto the spectrometer’s Dewar assembly without the risk of phonon interference. Likewise, electromagnetic noise generated by the RTS2 is minimal as the motor is driven with a variable voltage instead of the noisier pulse-modulation, eliminating the need for EM shielding.
In order to maintain a high vacuum, the RTS2 body consists of a conflat 6” OD x 2.75” OD reducing cross. Opposite the spectrometer is the 6” OD mounting plate that alone supports the drive train assembly by two tripod-like brackets and a rotary feed through. This plate, along with the entire drive train, can be removed from the housing in order to mount the samples onto the wheel. On the spectrometer side of the RTS2 is the output port, a custom made 6” OD to 2.75” OD offset reducing flange that ensures that the sample is centered on the spectrometer’s sensor. Of the two smaller flanges, one is the attachment point for an x-ray source and the other is a .75” Swagelok vacuum tube attachment fitted with a .75” vacuum hose converter to be used to evacuate the chamber before operation.
The entire RTS2 device weighs approximately 18 lbs and is too heavy to be supported by its spectrometer interface alone. A mounting case that has four .25” mounting holes arranged in a 5” by 6” rectangle on the bottom and houses all of the RTS2’s electronic components supports the RTS2. There are two female ports on the vacuum pump side of the case: one takes a 6V regulated DC power supply plug, the other is a female type B USB port for computer control of the RTS2. The two cables protruding from the drive train side of the case are the motor power and the five pin encoder connection that needs to be plugged into the encoder on the back of the motor, with the snap latch facing away from the RTS2. The encoder cable must be disconnected prior to removing the drive train mounting plate when replacing samples to avoid damaging the electronics contained within the case. The motor cable cannot be disconnected, but it is long enough to safely remove the drive train from the housing.
Quick Start | 2
Setup
· Secure the RTS2 on a suitable stand, aligning the x-ray output port with the sensor window.
· Remove the drive train and mounting plate, minding the cables.
· Mount samples onto the sample wheel with two sided tape, keep track of the sample’s numbers.
· Replace the drive train, aligning the leak test notches and keep the cables on the bottom.
· Attach the x-ray source to the rotating 2.75” OD flange, and a vacuum pump opposite it.
· Plug the 6VDC regulated power supply into a wall socket and the case.
· Plug a USB cable into the port on the case and into a Mac OS capable computer.
Installation
· Download all files from the Software section of the Project.
· Unpack the FLTK snapshot into a directory.
· In that directory, run “./configure –enable-threads”.
· Then run “sudo make install”.
· Install the USB-Serial driver.
· Unpack the source code into a directory.
· Run “make” in that directory.
· The program can be run by double-clicking the icon or “./rtscontrolmulti”.
Operation
· ‘Warm up’ the ferrofluidic feedthrough either by spinning the motor shaft by hand for a minute with the motor controller unplugged or run the RTS2 in continuous cycle mode for six minutes.
o Plug in the motor controller and start up the GUI if warmed up by hand.
· Evacuate the chamber.
· Turn on the x-ray source.
· Calibrate the RTS2 through the File menu à Calibrate.
· Switch into Dial mode, and proceed to test the spectroscope, switching from sample to sample by clicking on their corresponding buttons.
Hardware | 3
The RTS2 weighs in at 24 lb, and is made up of over 30 individual parts, not counting nuts and bolts. The total price of all the parts used in the RTS2 adds up to $2,910.32, including shipping and taxes. The parts used along with their prices, suppliers and part numbers are laid out in the table below. To order replacement parts, contact information for the suppliers can be found in section 6. For custom parts, refer to the drawings provided in section 5.
PART NAME / PRICE $ / Ship+Tax $ / SUPLIER / PART #Encoder HEDS 500CPT / $137.10 / $0.00 / Maxon Motors / 110511
10 Watt, PM-brush ‘RE 25’ DC Motor / $224.35 / $22.69 / Maxon Motors / 118746
Bore Reducer / $5.74 / $0.00 / SDP-SI.com / A 7A30-250309
Shaft Reducer-Extender / $8.23 / $0.00 / SDP-SI.com / A 7X 3-0812C
Bellow Coupling x2 / $85.43 / $7.72 / SDP-SI.com / S50PB9-EB2012
Nut-Mount Feed through / $395.00 / $0.00 / Rigaku / FD-LSR-0375FLC
Chrome Plated Steel Shaft 12" / $10.67 / $5.06 / McMaster-Carr / 5947K12
.375" x .875" WS2 Lube Bearing x 3 / $148.80 / $31.00 / Bearing Works / CSR6XXWSPT5
5052 Al Sheet .08" x 24" x 24" / $28.80 / $0.00 / McMaster-Carr / 88895K55
6061 Al Bar 1.5" x 1.5" x 12" / $21.58 / $9.25 / McMaster-Carr / 9008K461
6061 Al Disc 4" Diameter 6" Thick / $55.74 / $5.25 / McMaster-Carr / 1610 T43
Noiseless Cable and Accessories / $87.59 / $22.38 / Newark InOne / ------
Mounting bolts(8-32 and M2) / $13.97 / $0.00 / McMaster-Carr / #######
6" by 4" reducing CF cross / $567.00 / $198.00 / Scanwel / CFRXR150-070
Blank 6" CF flange x2 / $142.00 / $0.00 / LDS Vacuum shopper / 600-000
6" flange bolt-nut kit x2 / $30.00 / $0.00 / LDS Vacuum shopper / 600-BK
6" copper gasket 10 pack / $33.00 / $0.00 / LDS Vacuum shopper / 600-CG
Blank 2.75" CF flange x2 / $24.00 / $0.00 / LDS Vacuum shopper / 275-000
2.75" CF to .75" tube adapter / $90.00 / $0.00 / LDS Vacuum shopper / 275xSWG-75
2.75" flange bolt-nut kit x3 / $34.50 / $0.00 / LDS Vacuum shopper / 275-PNK
2.75" copper gasket 10 pack / $14.00 / $0.00 / LDS Vacuum shopper / 275-CG
.75" tube to .75" hose adapter / $19.60 / $8.60 / Swagelok / SS-12-HC-A-1211
6" to 2.75" custom offset flange / $335.00 / $14.00 / Lesker / custom part
Analog Motor Controller / $75.00 / $9.98 / Solutions-cubed.com / MOTM_1
.874" reamer / $41.98 / $8.46 / McMaster-Carr / 3087A63
6VDC 2.5A Regulated Power Supply / $29.95 / $0.00 / "You-Do-It" Electronics / 29-SW62F
Miscellaneous Small Parts / $60.00 / $0.00 / Various Vendors
SUB-TOTAL: / $2,581.93 / $342.39
TOTAL / $2,924.32
The RTS2 is comprised of three different systems: the drive train, the housing and the control. The drive train is enclosed within the vacuum chamber part of the housing and the control is enclosed within the mounting case that supports the vacuum chamber. The following three subsections will deal with these three systems in depth.
Housing | 3.1
The housing is comprised of the vacuum chamber and the mounting case. The vacuum chamber is a 12 lb, 6” OD to 2.75” OD reducing cross, with conflat flanges. The rotating 6” OD flange is fitted with a custom made offset reducing flange that acts as the output port for the x-rays produced with in the RTS2. It is aligned with the rotating 2.75” OD flange that will act as an x-ray spectrum input port, once an x-ray source is attached, so as to center the sample specific x-rays onto the sensor. It comes with a copper flange crushed in the seal and bolted with the 16 attachment bolts that prohibits the flange from rotating and coming out of alignment. If for any reason the offset flange needs to be removed, care must be taken when attaching it back on to ensure that the RTS2 outputs the x-rays properly. The fixed 2..75” OD flange is fitted with a Swagelok .75” vacuum tube connector which in turn holds a vacuum tube to .75” vacuum hose converter for the evacuation of the chamber. This can be used or replaced as needed to evacuate the chamber with the vacuum pump on hand. Finally, the 6” OD fixed flange is the attachment point for the mounting plate that holds the drive train. This plate needs to be removed with the entire drive train every time samples need to be replaced. Use standard Conflat vacuum seal procedures when dealing with the vacuum chamber.
The mounting case supports and holds the vacuum chamber, houses the motor control electronics, and has four .25” mounting holes arranged in a 5” by 6” rectangle on the bottom that hold adjustable legs, when the RTS2 is shipped. The case is made of two sheet aluminum parts and a blue foam core. The vacuum chamber lies nestled in the blue foam bed and is strapped down to the case with two 16” circumference length adjustable hose clamps that fit around the two smaller sections of the cross and feed through the blue foam core and the aluminum case covers. In order to remove the vacuum chamber or access the inside of the case, these hose clamps can be removed by loosening the hose clamp pilot screws concealed within the case on the output side of the RTS2 using a nut driver. The two parts of the case cover are held together with four bolts on the 2.75” OD flange sides and by whatever is in the mounting holes on the bottom corners of the case. Once these bolts are removed, the outer part of the case cover can slide off of the foam core and finally, the electronics can be accessed by sliding the foam core up out of the inner case cover and flipping the foam over. They are Velcroed to the inside of the hollow. When reassembling the case, make sure to align the wire holes in the foam core with those in the case cover and that the vacuum chamber is replaced so that the motor will be on the side with its power and encoder cords.
Because of space limitations the 2.75” OD flanges come with plate-nut sets for quicker assembly and extra clearance between the flanges and the case. Drawings of the housing components can be found in section 5. The following is a list of the most parts that make up the housing, with pictures for reference.
Housing | 3.1
Components
Stainless Steel Reducing Conflat Cross2 ends 6” OD, one rotating, one fixed
2 ends 2.75” OD, one rotating, one fixed /
Custom Conflat Flange
Produced by Lesker
2.75” flange offset by 1.25”
5” length /
6” Conflat Bolts and Nuts
Bolts: .3125” Length: 2” /
2.75” Conflat Bolts and Nuts
Bolts: .25” Length: 1.25” /
Copper Gaskets /
Mounting Case
Custom made (see drawings, section 6)
.08” 5052 Aluminum Sheet
Extruded Polystyrene, “Blue Foam Insulation” /
Drive Train | 3.2
The entire drive train assembly is centered around a 6” OD blind CF flange that fits onto the vacuum chamber. On one end of the drive train is the sample wheel. This wheel was machined out of 6061 Aluminum and is designed to hold six 30mm by 30mm samples at 43˚ to the incoming x-ray spectrum. The samples are to be mounted onto the center of the wheel’s numbered faces with two sided tape. Keep track of the numbers corresponding with each sample so that GUI can be programmed to display that particular sample name when the RTS2 is operated. The sample wheel is secured onto chrome plated steel shaft with a set screw. This shaft is supported by an aluminum bearing block that holds two vacuum ready bearings separated by an aluminum spacer between a cover plate and the three legged spider that is screwed into the mounting plate. The shaft is attached on the other end to a Ferro fluidic rotary vacuum feed through via a flexible bellows coupling to avoid over constraint. The feed through is mounted through the 1” hole in the middle of the mounting plate and holds the vacuum with a Viton rubber O-ring located on the outside portion of the feed through. The feed through itself is attached to a 10 Watt motor with another bellows coupling using a shaft and bore reducer to accommodate the reduction of the shaft diameter from 3/8” on the feed through to the 3mm on the output shaft of the motor. The motor is supported by another three legged spider that’s screwed into the mounting plate’s partially bored and taped holes.