Gustavo Alverio

Upgrade of the 600L/s IPPS

Gustavo Alverio

University of Central Florida

August 4, 2003

Reggie Martin

Abstract

The following report is about the upgrade of the Ultek 600 liter per second ion pump power supplies. The upgrades reported on will only focus on the Perkin-Elmer 222-0800 ion pump power supply model, as there are about 4 different models of ion pump power supplies which function for the Ultek 600 liter per second ion pump. The ion pumps are located around the booster tunnel ring. Ion pumps reduce the amount of pressure in the vacuum in which the beam travels. Lower pressure means a lesser amount of ions, and a better vacuum for the beam. The ion pumps absorb any of the ions created in the vacuum, thus effectively creating a better quality beam. Ion pump power supplies, mainly the Perkin-Elmer 222-0800 series, deliver power to the ion pumps. These ion pump power supplies are located around the booster gallery, and not in the tunnel, for easier access. The purpose of the project begins in the necessity to upgrade the 30 year old ion pump power supplies. The old ion pump power supplies create inaccurate read-backs of the vacuum. Noise produces the inaccurate read-backs of the vacuum. The new ion pump power supplies filter the noise, therefore creating accurate read-backs and increasing the productivity of the ion pumps. They are modifications of the old ion pump power supplies, and the subject of this project.

Introduction

To fully understand the project, it is necessary to give background information on how the Ultek 600 liter per second ion pumps work. Fig 1 shows a picture of an ion pump. There are 80 ion pumps located around the booster accelerator ring. They are placed in the tunnel to regulate the vacuum, as well as record the pressure. Each ion pump regulates a small section of the booster ring. The pumps operate on electrical power supplied by the Perkin-Elmer 222-0800 power supplies. Since the ion pumps rely solely on electrical power, they do not require oil, water or refrigerants. Inside the ion pump are plates. These plates are electrically discharged in a magnetic field to sputter reactive metal from a cathode plate. The ions combine with the charged plates thereby eliminating them in the beam system. The eliminated ions cause a decrease in pressure, which is the main purpose of the ion pumps.

Fig 1 – Ion pump

Ion pumps are best for applications where high vacuum is needed. Accelerators work best at high vacuum states. The 600 liter per second model was chosen because of certain criteria. The pumping speed is determined by the number of anode cells, the voltage supplied, and the magnetic field. The cylindrical design of the ion pump was determined by manufacturers to offer the best pumping efficiency. Since there were to be 80 pumps, cost was also an issue. Ultek offers different amounts of pumping speed such as 50 liters per second, the lowest, to 2400 liters per second, the highest. Increases in pumping speed mean increases in the number of ion pump power supplies. The 600 liters per second requires one power supply to each ion pump. Following the 600 liters per second model comes the 1200 liters per second model. At this speed, 2 power supplies were needed for each ion pump, which proved to be costly. The ion pumps have worked along side the tunnel for 30 years. Operation life of the ion pumps are in excess of 40,000 hours at 10E-6 torr. The life expectancy is inversely proportional to the pressure in the vacuum. For example, operation life is 400,000 hours for 10E-7 torr.

Attached to the ion pumps are the ion pump power supplies. There are about four different models that supply power to the ion pumps, such as the -800 series and the -600 series. Power supplies for the ion pumps can be seen in shelves around booster gallery (see Fig 2a, b). The ion pump power supplies are grouped by the section in which the ion pumps are located. When connecting to the ion pumps, the technician attaches the load cables to the backside which run to the beam enclosure. Therefore, there is no need to enter the tunnel to change out ion pump power supplies. When changing out power supplies, a call needs to be made to the main control room. The main control room can shut down a portion of the tunnel so that the entire tunnel does not shut off when the ion pump is shut off.

Fig 2a – Left, shows ion pump power supplies modified and set into place

Fig 2b – Right, shows modified power supplies into place in booster gallery

The power supply operates by supplying voltage to the ion pump. Located inside the ion pump power supplies are: capacitors, resistors, diodes, transformers, a daughter card, a breaker, solid state relay, burndy connector, a fan, a PCB, phono jacks, and wires. By following the schematic diagram, each component is wired. With all components in place, the circuitry is also designed to shut itself off in cases of emergencies. One safety design is that the ion pump power supply will shut itself off if too much current is drawn from the ion pump. In this scenario, the ion pump power supply functions as a fuse. Too much current can cause the power supply to heat up. Other safety features are mostly taken into play while testing is occurring. Breakers and Enables are inserted to remind the tester that the power supply is turned on. Each power supply is tested to ensure proper function and replaces an old power supply to be modified.

Problem

This project begins with the need to improve the quality of the beam. One such method of improving beam quality is by improving the vacuum through which the beam travels. The ion pumps produce the vacuum. Current models of the power supplies for the ion pumps produce inaccurate read-backs. The ion pump power supplies were also poorly efficient. Given this problem, a team of engineers investigated methods of increasing the efficiency of the power supplies. As part of their solution, the addition of the daughter card was proposed. When the daughter card is inserted into the ion pump power supply, along with eliminating the old components and adding new components to the power supply, the ion pump power supply was more productive.

Procedure

Part 1 – Daughter card

Certain knowledge of electricity and power were needed to introduce the daughter card (refer to Fig 3). One problem with the current power supplies was that the current was sent to a different unit, and translated into a voltage, and then sent off to the ion pump. After many years, the cables began to deteriorate, and insulation became poor. Dust and worn out equipment create interference with the current. The solution of this problem began by eliminating the extra cables and inserting the conversion of current to voltage inside the power supply. The circuitry of the daughter card includes resistors, capacitors, diodes, and logical gates. The daughter card is the component that improves the read-backs.

Fig 3 – Daughter card with components in place

The daughter card contains three main circuitries. The top circuit contains capacitors, op-amps, resistors, and diodes. In this circuit, the current contained in the ion pump power supply is converted to volts. Following this conversion, the top circuit contains a 759P op-amp. This component linearizes the ion pump calibration curve. The 759P chip converts the scale into a logarithmic scale. At the same time, the chip inverts the graph. The middle circuit contains diodes, capacitors, and voltage regulators. The voltage regulators controls the amount of voltage that is sent through the circuit. The 3 regulators are +15V, +5V, and -15V. Each of these voltages is sent throughout the card, powering the card. The bottom circuit contains the logistics of the power supply. Components include logical gates, resistors, flip-flops, capacitors, and timing devices. This circuit is responsible for the switches located on the front of the ion pump power supply. The switches are attached to a PCB which runs to the daughter card Cinch connector. On the PCB are the on, off, and enable switches. By enabling the switches, the ion pump power supply will follow the switch command.

Actual building of the card begins with a bare green board. The board is labeled with holes indicating where each component is to be soldered. All lowest lying components are inserted into place. A device holds the components into place, and the board is flipped over and each joint is soldered. Lowest lying components are to be soldered first because taller components can cause lower components to fall when the daughter card is covered and flipped over. Once all lowest lying components are in place, the taller components are placed into their spots. The process is repeated until all components on the daughter card are in place.

The next process for the daughter card is that the card needs to be tested to ensure that it functions properly. The first step is to visually check all components to verify that each is correct. If there are any incorrect components, the card is sent back to be corrected. If all components are correct, the daughter card is sent for further testing. With a fully modified ion pump power supply, an extender card is fixed onto the Cinch connector. This is for safety purposes so that the daughter card is located outside the power supply and is easier to access. The input power cord and BNC connector for the front panel current output are attached to the ion pump power supply. The following steps are then followed:

Verify the timing switch on the front panel is set for 10 min;
Switch on the breaker and read the measurement from the front panel current output;
Adjust the R30 pot so that the front panel current output reads 6.1 V (it is read in volts because the current has been converted to volts);
Using a voltmeter, measure the voltage across R19, and verify a measurement of about 4.01V. Verify that U13, U12, and U11 read +15V, +5V, and -15V respectively;
Turn off breaker switch;
Insert a 759P chip into place at U6;
Attach a 27M load onto the ion pump power supply;
Turn on the breaker and the ion pump power supply;
The front panel current output should read from 4.135 to 4.175V;
The front panel linear output should be 0V;
Run until the “run” light turns on at about 10 min.

If no problem arises, the card has been fully tested. The date of testing is attached to the back of the card to indicate that it is ready for insertion.

Part 2 – Ion Pump Power Supply Modification

The ion pump power supply modification contains several steps. The first step is to obtain an old power supply. Only the Perkin-Elmer 222-0800 model power supplies will be discussed (see Fig 4). There are 55 of these ion pump power supplies. The main control room allows certain power supplies to be shut off at certain times. When the main control room confirms that a power supply can be switched out, a fully tested modified power supply is inserted to take the place of the previous supply. The main control room must confirm the switch, because some ion pumps are interlocked. If one power supply is turned off, it will switch off an ion pump, and may damage the data of the beam. With the old ion pump detached from the system, it is sent to be modified.

Fig 4 – Perkin-Elmer 222-0800 power supply

The next section is actual modification of the Perkin-Elmer 222-0800 model ion pump power supply. The following steps should be followed:

The first step is removing the components. All wires except the short jumpers on the 7-ring terminal strip, the green wire attached to the 120 volt outlet for current relay, and the HV transformer output wires are to be removed;
Save the diodes attached between the high and low pots at the back of the ion pump power supply;
The front panel is unscrewed. The aluminum panel, rotary switch, toggle switch, pilot light, meter frame, and meter frame brackets are removed. Only the torr meter is reused;
On the right side panel all components are kept, but all wires are removed;
On the left side panel, the contactor, capacitor 28MFD 660VAC 3579, bracket for capacitor mounting, circuit breakers, and wire harness are removed;
On the back panel, the bridge rectifier, circular amphenol, and voltage switch are removed. The fan is removed and cleaned to be reused;
The ion pump power supply is finally cleaned with Windex.

After the ion pump power supply is cleaned, the drilling can proceed.

Fig 5 – All items circled in red are removed. Starting from top left, the voltage switch below the fan and bridge rectifier, in green, are removed from back panel. Top right picture features the amphenol. The contactor and 2 circuit breakers are removed as shown in bottom left. No components are removed in right side panel.

The following lists all of the drilling specifications as shown in table 1.

Panel	Drilling specifications
Front	All 8 holes redrilled to 15/64”
Left	8 holes drilled to 11/64”
Right	None
Back	2 handle holes drilled to 3/16” Ceramic standoff hole size 9/64” J2 phono jack hole redrilled to 29/64”
Bottom	2 holes drilled to 7/64” for cinch connector

Table 1

The diagrams show all the measurements to drill holes. The phono jack is replaced with fiber washers attached between the jack and the nut to isolate the jack from the chassis of the frame. Use a multimeter to verify that the phono jack is isolated, by setting it to continuity mode. The left panel has a drilling template used to locate the holes. The top panel has 2 new notches placed for the handle.

After all holes are drilled, the new components can be attached. The front panel receives a volt meter, reused torr meter, 6-pole circuit breaker, PCB switch board, timer toggle switch, and 2 black handles. The left panel is comprised of a new contactor, solid state relay, and a control transformer. The back panel has a new ceramic stand off, Burndy connector, and reused fan. The bottom holes are placed with a cinch connector.

Fig 6 – Modified front panel

The next step is to wire up the ion pump power supply. The wires are group and tied to clear out the inside of the ion pump power supply. Tables 2-8 show the wiring for each component.

Cinch connector wiring

Cinch Pin #	Color	Location	Length(in)
A-1	Black Black Black Capacitor plus	PCB term #9 Middle of timer switch Burndy G F-6	18 15 34
B-2	Brown	Front panel BNC/linear	30
C-3	None
D-4	Light purple	PCB term #1	15
E-5	Orange	Timer toggle switch	15
F-6	Yellow Capacitor minus	To J2 body A-1	25
H-7	Green Green	Burndy F Front panel BNC/current	18 27
J-8	Blue Blue	Burndy E PCB term #2	18.5 15
K-9	Violet	Burndy D	18.5
L-10	Gray	PCB term #4	15
M-11	White	Burndy C	19
N-12	Wht/Blk	PCB term #8	16
P-13	Wht/Brn	Burndy B	19
R-14	Wht/Red	PCB term #6	15
S-15	Wht/Org	Burndy A	19.5
T-16	Wht/Ylw	SSR term 4	8
U-17	Wht/Grn	Transformer bottom front	9.5
V-18	Wht/Blu	Transformer top front	9.5
W-19	Wht/Vio Wht/Vio	PCB term #10 SSR term 3	15 9
X-20	Wht/Gray	PCB term #7	15
Y-21	Black	Ground to chassis	3
Z-22	Black Black	BNC Amerlock ground lug/current Transformer middle front	25 9.5

Table 2

Power Plug wiring

Power Plug slot	Color	Location	Length(in)
Y	Red (10 gauge)	Breaker pole 2 top	20
X	Black (10 gauge)	Breaker pole 1 top	20
N	White (16 gauge)	Contactor front side	27
N	White (16 gauge)	Fan rear terminal	6.5
N	White (16 gauge)	120 volt outlet	11.5
Gnd	Green (12 gauge)	Ground to Chassis	7

Table 3

Contactor Wiring

Contactor	Color	Location	Length (in)
Top Left Line	Red (10 gauge)	Breaker Pole 2 bottom	8.5
Top Right Line	Black (10 gauge)	Breaker Pole 1 bottom	9
Bottom Left Load	Red (10 gauge) Red	HV Transformer 230 PCB term #3	19 6
Bottom Right Load	Black (10 gauge) Red	HV Transformer Com PCB term #5	21 6

Table 4

High Voltage Wiring

Component	Location	Length(in)
HV Rectifier +	HV Capacitor +	4
HV Rectifier -	HV Capacitor -	4
25 Ohm resistor	HV Capacitor +	8
25 Ohm resistor	10 Ohm resistor	7.5
10 Ohm resistor	10 Meg resistor	6
10 Ohm resistor	J4 Outputs	5.5
10 Ohm resistor	J6 Outputs	5.5

Table 5

Front Panel

Component	Color	Location	Length(in)
Torr meter resistor (10K)	Red	Top of 1 Meg pot	30
Torr meter +	Red	Torr meter resistor (10K)	2.5
Volt meter +	Yellow	5 Meg resistor at ceramic stand off	27
Torr meter -	Black	Volt meter -	12
Volt meter -	Black	Term 1 of 7-ring strip	28.5

Table 6

7-ring Terminal Strip

Term

Color

Location

Length(in)

Black

Cathode diode1

Capacitor minus

400 Ohm resistor

HV capacitor –

Volt meter -

Term 3

Term 4

28.5

Brown

Cathode diode2

Anode diode1

Capacitor plus

High pot middle ring

Current Interlock tip

Term 5

Term 1

400 Ohm resistor

20K resistor

Term 1

Term 7

Wht/Blk

Anode diode2

Cathode diode3

J2 tip

Current Interlock body

Term 3

J2 body

4.5

Wht/Red

20 K resistor

Blue 10 Meg resistor

Term 4

Table 7

Remaining Wires

Component	Color	Location	Length(in)
Contactor Coil back	Red (16 gauge) Red (16 gauge)	Fan front side 120 current outlet	33.5 39
Breaker Pole 3 bottom	Red (16 gauge) Red (16 gauge)	SSR term 1 Transformer bottom back	10.5 16
Breaker Pole 3 top	Red (16 gauge)	Breaker Pole 2 top	2
Contactor back side	White (16 gauge)	Transformer top back	11

Table 8

All wire gauges are 22 gauge except otherwise noted. Both types of phono jacks list the naming of the terminals. There are two 10 Mega-ohm resistors that are tied in parallel to obtain 5 Mega-ohm. The resistor connects to the HV Capacitor + to the ceramic stand off. All wires should be checked for proper connections.

Fig 7 – All panels after modification. Starting from top left and going clockwise panels are: back, right side of back, right, and left.

The final procedure for the ion pump modification is the testing. There are several tests used in this procedure. The first is calibrating the torr meter. At given pressures, the current should give a certain value. The procedure is as follows:

Using a separate power supply, measure the current across the capacitor on the 7-ring terminal;
Set the current on the separate power supply to 80 milliamps. The voltage was set at two volts, because at that value, a current of 80 milliamps was produced;
Adjust the high pot so the torr meter reads 1E-5;
Set the separate power supply to .45 volts. The current should read 70 microamps;
Adjust the low pot to read 1E-8;
Continue between two volts and .45 volts until adjustments are no longer needed.

The next step is taking data.

Insert a tested daughter card. Loads must be placed onto J4 and J6. The loads act like air inside the beam;
The V remote meter is attached onto the burndy connection;
Meters are attached onto J2 and J3;
All loads are tested and the data is recorded onto the data sheet. Values should fall at about the known values.

After recording all data, a 10/20 minutes test is run. The power supply runs under a 6.38 kilo ohm load for 10/20 minutes, depending on the setting of the timer switch. The ion pump power supply should turn itself off after about 10/20 minutes. The times are recorded onto the data sheet, and the testing continues.

The current overload test insures if a large amount of current is suddenly drawn by the ion pump; the ion pump power supply will shut itself off.

J4 is attached to an 80 Meg load;
Set the timer to 10 min, and run the power supply until the run light turns on;
Attach the 6.38 k load to J6, and the power supply should shut itself off in about 5 seconds;

The final step is to run an eight hour simulation test. A prototype (shown in Fig 8) previously built, mocks the vacuum of the beam. The power supply runs in this environment for eight hours to ensure proper functioning. After the power supply has successfully completed all testing, the modified power supply is sent to replace an old power supply.

Fig 8 – Ion pump can be seen at the right of the picture. The tube is the simulated beam with ion gauges (to measure vacuum) attached on top.

Conclusion

With the upgraded ion pump power supplies in place, read-backs are accurate. The accurate read-backs will help better analyze methods to improve the vacuum. Old ion pump power supplies gave inaccurate readings of the vacuum. With the modification, the read backs are highly improved.

As in any project, setbacks are common. In the upgrading, several set backs presented themselves throughout the months of the procedure. The common setback was troubleshooting the power supply. Most mistakes were found in the wiring of the power supply. In several daughter cards, incorrect resistors were placed throughout the board. During the project, the schematic diagram would change for better efficiency, causing slight changes in the procedures. Lastly, materials were in low supply, and caused a delay in schedule when having to wait for them to arrive.

The project featured many aspects of the electrical engineering field. Knowledge in electrical circuits is important to understand the overall effect of the power supply. Techniques used in the upgrading include soldering and drilling. Resistors, capacitors, and diodes were several components in electronics featured in the power supply. Modifying power supplies is a well in depth project for those interested in the electrical engineering field.

References

Ultek Instruction Manuel: High Vacuum Ion Pumps; Differential & Conventional. Ultek: Feb, 1968.