Ultra High Vacuum Technology Section

Design & Development

1. Dipole Chamber for Indus-2
  • 3571mm (L) x 645mm (W), 22.50° bending angle
  • Quantity: 16 Nos
  • Material of Construction: AA5083-H321
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • Sealing: Helicoflex
  • Design : UHVTS , RRCAT
  • Machining: HAL, Nasik
  • Machining of ports/flanges, Chemical Cleaning, TIG Welding : DMTD, RRCAT:
  • Helium Leak Testing, Bakeout & UHV Testing, Installation : UHVTS, RRCAT
Fig-1: Photograph of Dipole Chamber Assembly
2. Straight Section Vacuum Chambers for Indus-2
  • Quantity : 44 Nos
  • Length : 950 to 3650 mm
  • Material of Construction: AL6063 T6, Al 2219-T851, Al-SS Transition joints
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • Sealing: Diamond Profile Al Seal
  • Design : UHVTS , RRCAT
  • Machining: HAL, Nasik
  • Machining of flanges, Chemical Cleaning, TIG Welding : DMTD, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing and Installation: UHVTS, RRCAT
Fig-2: Photograph of  Straight Section Chamber
3. Septum Magnet Chamber for Indus-2
  • Size: 1392 mm L x 448 mm ID
  • Material of Construction: SS316L
  • Helium Leak Tightness: Better than 2x10-10 mbar l/s/cm2
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • End Flange Sealing: Wire seal
  • Design : UHVTS , RRCAT,
  • Machining, Chemical Cleaning, TIG Welding: DMTD, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing, Installation : UHVTS, RRCAT
Fig-3: Photograph of  Septum Chamber
4. Diamond Seal UHV Flange for Indus-2
  • Size: DN 40, DN63, DN100, & DN160
  • Material of Construction:AA2219-T851/SS316L Seal Cross Ssection : Diamond shape
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • Design: UHVTS , RRCAT,
  • Machining, Chemical Cleaning, TIG Welding: DMTD, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing and Installation: UHVTS, RRCAT
Fig-4: Photograph of  Diamond Seal Flange
5. Water Cooled End Flange For Indus-2
  • Flange Size: DN100, & DN160
  • SR Power Density: 800 – 1000 W/cm2
  • Material of Construction: OFHC Cu/SS316L
  • Sealing : Helicoflex
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • Design: UHVTS , RRCAT,
  • Vacuum Brazing Process Development & Batch Production: DMRL, Hyderabad:
  • Batch Production : LPSC Bengaluru
  • Helium Leak Testing, Bakeout & UHV Testing and Installation: UHVTS, RRCAT
Fig-5: Photograph of  water cooled end flange
6. Photon Absorber for Indus-2
  • Quantity : 64 Nos
  • Flange Size: DN100, & DN160
  • SR Power : 2 - 4.8 kW
  • SR Power Density: 800 – 1000 W/cm2
  • Material of Construction: OFHC Cu/SS316L
  • Sealing: Helicoflex
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~ 5 x 10-10 mbar
  • Design: UHVTS , RRCAT,
  • Vacuum Brazing Process Development & Batch Production: DMRL, Hyderabad:
  • Batch Production : LPSC Bengaluru
  • Helium Leak Testing, Bakeout & UHV Testing & Installation : UHVTS, RRCAT
Fig-6: Photograph of  Photon absorber
7. RF-Shielded Bellow for Indus-2
  • Quantity : 44 Nos
  • Size: ID 133mm x 152mm OD
  • End Flange: DN160-DSF/CF/HF
  • Stroke:15mm Compression, 10mm Expansion
  • Material of Construction: SS316L, Be-Cu
  • Helium leak rate: < 1 X10-10 mbar l/s
  • Ultimate Compatibility: ~ 5 x 10-10 mbar
  • Bellow Type: Edge Welded
  • Design : UHVTS, RRCAT,
  • Fabrication: Indian Industry
  • Chemical Cleaning, TIG Welding: DMTD, RRCAT
  • Be-Cu Heat Treatment: Glass & Ceramic Components Development Facility, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing and Installation : UHVTS, RRCAT
Fig-7: Photograph of rf-shielded bellow
8. Titanium coated Alumina Ceramic Chamber for Pinger Magnet in Indus-2
  • Internal Size: 86 mm x 36 mm
  • Material of Construction: 99.7% Alumina
  • Isostatic Pressing & Sintered
  • Ceramic to metal Joint: Active Brazing
  • End Flange: DN160-DSF
  • Helium leak rate: < 1 X10-10 mbar l/s
  • Titanium Coating thickness ~ 0.5 micron
  • UHV Compatibility:~ 5 x 10-10 mbar
  • Design : UHVTS, RRCAT
  • Fabrication: Indian Industry
  • Helium Leak Testing, Bakeout, UHV Testing, Ti Coating and Installation: UHVTS, RRCAT
Fig-8: Photograph of  Ti coated Alumina Chamber
9. NEG coated UHV chamber for Undulator in Indus-2
  • Extrusion Material : AA6063-T6
  • 81mm(W)x17mm(H) internal x-section, 2700mm L
  • End Flange: AA6061-T6, DN160 DSF
  • Straightness : 0.2 mm / m
  • Molecular flow conductance : 6 l/s/m
  • Specific Outgassing Rate: < 1x10-12 mbar l/s/cm2 after bakeout at 170º C X 48 hr
  • NEG Coating Chemical Composition: 30% Ti, 30% Zr, 40% V (Atomic %)
  • UHV Compatibility: ~5x10-10 mbar
  • Design : UHVTS , RRCAT,
  • Fabrication: Indian Industry
  • Chemical Cleaning, TIG Welding: DMTD, RRCAT
  • Helium Leak Testing, Bakeout, UHV Testing, NEG Coating : UHVTS, RRCAT
Fig-9a: Photograph of AA6063-T6 Extrusion for Undulator Chamber
Fig-9b: Photograph of Undulator Chamber Assembly
Fig-9c: Cross Section of Undulator Chamber
10. Taper Transition Chamber
  • Taper transition chamber is required for gentle transition of beam aperture of 86mmx36mm of normal quadrupole chamber to 81mmx17mm of undulator chamber to meet the beam dynamics requirement
  • Material of Construction: SS316L & OFE Copper
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~5x10-10 mbar
  • Design : UHVTS , RRCAT
  • Fabrication: Indian Industry
  • Chemical Cleaning, TIG Welding: DMTD, RRCAT
  • Helium Leak Testing, Bakeout, UHV Testing, NEG Coating : UHVTS, RRCAT
Fig 10: Photogrpah of  taper chamber assembly
11. Glidcop to OFE Copper UHV Compatible brazed joint
  • Material of Construction: Glidcop and OFE Copper
  • End Flange: DN160-HF
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV compatibility: ~5 x 10-10 mbar
  • Shear strength of the joint was ~ 130 MPa
  • Design : UHVTS , RRCAT,
  • Machining: Indian Industry
  • Brazing: UHVTS, RRCAT
  • Chemical Cleaning: DMTD, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing, Installation : UHVTS, RRCAT
Fig.11a:Prototype Glidcop Absorber (upside down view)
Fig. 11b: Prototype Glidcop Absorber (Side view)
12. Quick Disconnect Flange Joint
  • Material of construction: Flange Ti Gr-5, Chain clamp: AA7075-T652, Links: SS316
  • Sizes: NW40/160/200/250/300/350
  • Sealing: Al diamond profile seal
  • Helium leak rate: < 1 X10-10 mbar l/s
  • UHV Compatibility: ~5 x 10-10 mbar
  • Radiation resistant
  • Quick assembly and disassembly (6 to 8 minutes for assembly and 3 to 4 minutes in disassembly for typical NW160 size flange joint)
  • Application : Accumulator Ring for IFSR
  • Design : UHVTS , RRCAT,
  • Machining: Indian Industry
  • Chemical Cleaning: DMTD, RRCAT
  • Helium Leak Testing, Bakeout & UHV Testing: UHVTS, RRCAT
Fig 12: Photograph of the QDF joint
13. Differential Pumping System for Soft X-ray Beam Line of Indus-2
  • Differential vacuum pumping system provides windowless transition between high vacuum region (10-6 to 10-7 mbar) and ultra high vacuum region (10-9 to 10-10 mbar) by using series of vacuum pumps and conductance limited openings (tubes).
  • It is highly useful for the SRS beam lines where 10-6 to 10-7 mbar pressure is maintained at an experimental station.
  • It is supposed to maintain a pressure ratio of 1000 across 415 mm length along beam direction.
  • Schematic of the differential pumping setup is shown in Fig 13a.
  • A two stage differential pumping system was designed, developed in-house, assembled, tested and integrated with BL-3 of Indus-2
  • A customised 35l/s in-line sputter ion pump was developed in-house for this purpose.
  • Assembly of the system is shown in Fig 13b.
Fig 13a: Outline sketch of the Differential Pumping Setup
Fig 13b:  Photograph of the Differential Pumping Assembly
14. Sputter Ion Pump Power Supplies
  • Produced by ECIL, Hyderabad
  • Model No. SP4806A
  • Output voltage at no load 6.2KV DC negative ± 5%
  • Output current at short circuit 1000 mA ± 5%
  • Line Regulation ± 3 % for ± 10% line variation
  • Load Regulation Poor, Drooping Characteristic
  • Over load protection Relay cutout for pressure set for 10-5 mbar
  • Display: 3½ digit Digital Panel Meter for
  • Current ranges 1000mA and 1000μA, Accuracy: ± 5%
  • Voltage in K.V
  • Input 230V AC, +10%, -10%, 50HZ
  • Weight 80 Kgs approx.
  • Dimensions 19” x 450 mm x 5U (w x d x h)
  • Nearly 100 nos. of SIP power supplies are working on 24x7 basis in Indus accelerators.
Fig 14a. SIP PS front panel
Fig14b. SIP PS back panel
15. Upgradation of SIP power Supplies in Indus-2 and TL-3
  • To display SIP current in control room
  • SIP current gives an estimation of vacuum and can be correlated with nearby BAG.
  • 60 Nos. of power supplies upgraded.
  • Current displayed in the range from 1000µA to 1µA
  • Corresponds to pressure approx. 1E-07 mbar to 1E-10 mbar
Fig 15a & b. SIP Power Supply in Indus-2 before & after modification
Fig15c. SIP Current display in control room
16. Design & Development of Titanium Sublimation Pump Controller
  • Mains Supply 230 Volts +/- 10 %, 50 Hz.
  • Output Power variable 300 Watts maximum
  • Filament Current 1- 60 Amp RMS
  • Filament voltage variable 1-5 volts RMS
  • Load: ‘U’ hair Pin type of Filament of Ti 85% + 15% Mo.
  • Sublimation Pattern – Constant Power at preselected wattage
  • Time delay between successive sublimations 1-999 minute maximum for Indus-1 & 1-9999 minute maximum for Indus-2
  • Degassing Pattern - Series degassing of pumps of two filaments to maximum 25 amps. RMS in continuous mode, also called BAKE mode.
  • Dimensions in mm - 480(L) X 485(B) X 130 (H) Control unit - 210(L) X 280 (B) X 180 (H) Auxiliary unit
  • Weight 7 Kg.
  • ~ 64 nos. of TSP controllers are working on 24x7 basis in Indus accelerators.
Fig 16. TSP controller transformer unit and control unit front panel
17. Design & Development of Penning Gauge Controllers

Specifications
  • Vacuum Range: 10-2 to 10-9 mbar ( 7 decades)
  • DC Voltage: -3.2 KV DC
  • Permanent Magnetic field:0.14T
Presently these controllers are deployed in TL-2
Fig 17. Front panel of Penning Gauge Controller
18. Design & Development of new BAG Controllers:
  • Modular construction of cards for ease of maintenance.
  • 40% reduction in weight and size compared to existing controllers
  • Temperature compensation of log amplifier and current Source in Log amplifier card for immunity to ambient temperature variations thereby ensuring better accuracy.
  • Filament protection by means of over current sensing, increasing life of filament and thereby reliability.
  • Pressure range 10-3 to 10-11 mbar
  • Degas power parameter limited to 36 W, enhancing life of filament.
  • Fixed discrete setting for sensitivity (10/15/19/20/25 mbar-1).
  • Additional process control status provided.
  • Isolated output of 0 to 10 V and 4 to 20 mA for remote monitoring
  • 32 nos. produced by M/s Aplab Ltd., Mumbai
  • Approximately 15 nos. have been installed in Indus-2 and beam lines.
Fig 18a: Front panel of the new BAG Controller
Fig 18b: Rear  panel of the new BAG Controller
Fig 18c: Modular construction of the new  BAG Controller
Fig 18d: Linearity Curve of New BAG controllers w.r.t Agilent Controller
19a. 160 Channel Distributed Temperature Monitoring System in Indus-2
  • To measure temperatures of dipole chambers, 64 water-cooled photon absorbers & 48 water-cooled end flanges
  • No of channels: 8
  • Temperature sensor: K-type thermocouple grounded/non-grounded.
  • Measurement range : 0-500 °C
  • Resolution : 1°C
  • Sampling Rate: 20 mS
  • I/P Impedance: 10 GΩ
  • CMRR: 100 dB @ gain = 10
  • Filter: RC-type common mode & differential mode.
  • Serial communication: Isolated RS-485.
  • Status available: Trip & serial communication.
  • Interlock: potential free 1 NO contact.
  • The N/O contacts of all trip relays are integrated & single contact is given to Machine Safety Interlock System (MSIS).
Figure 19a. Front & Back Panel of TMU 8 Channel
19b. Development of 16 channel Temperature monitoring unit (TMU)
  • 16-channels support in compact size.
  • To extend probing further at more locations on dipole chambers
  • Quick replacement connectors for sensor & RS-485 .
  • RS-485 address setting using DIP switch on backpanel.
  • Provision of on-site firmware upgrade.
  • 40 such units have been manufactured and their testing is under progress
  • For initial testing of the units in lab, GUI was developed in visual basic.NET. The GUI has following features:
  • Data logging of 320 channels.
  • Selection of active units.
  • Trip signal status indication & logging.
  • Detection of open Thermocouple states.
  • TRIP test facility.
  • Trip set point programming.
  • Support for fault finding of ADC & calibration.
  • The communication on RS485, checksum.
Fig 19b. Front & Back panel view of TMU 16 Channel
Fig 19c. GUI Panel for TMU
20a. Baking System
  • an essential process for achieving Ultra High Vacuum in vacuum systems
  • an intelligent ON/OFF control system is designed & developed incorporating modular baking system with distributed controls
  • contains following blocks:
  • Temperature controller unit (TCU)
  • Pressure Monitoring Unit (PMU)
  • Baking Application GUI.
  • TCU:
  • Number of channels: 8
  • Thermocouple Type: K-type
  • Resolution : 12 bit
  • Sampling Rate: 20 mS
  • I/P Signal range: 500 ºC. (+/- 20mV)
  • I/P Impedance: 10 GΩ
  • CMRR: 100 dB @ gain = 10
  • Filter: RC-type
  • Heater Power/Channel: 4 kW using Short circuit protected SSR
  • PMU: For integrated data logging of pressure reading of various gauges along with baking data
  • Number of channels: 8
  • Input range: 0-10V
  • Serial communication: Isolated Rs-485
Fig 20a: TCU & PMU
20b. Baking application GUI for overall supervision & control and data logging of temperature & vacuum Main features of GUI:
  • Auto/Manual set point provision.
  • Supports eight auto set point profiles.
  • Supports 8 TCU (48 channels).
  • Supports 8 pressure monitoring gauges.
  • Provision for keeping uniform temperature between channels.
  • Provision for user notes, channel names & cycle name.
  • Status displayed communication status, serial data, heater status etc.
  • Data logging in .CSV format & update status displayed.
  • Auto recover after power failure.
  • PMU support for 11 types of gauges.
Fig.20b: Screenshot of software showing overall GUI
20c. Upgradation of GUI for baking application :
  • To fulfil the need of dual ramp for NEG coated parts
  • To avoid pre-activation of NEG surfaces
  • In first ramp NEG surfaces are kept ~100 ºC whereas in second ramp they are heated upto ~180ºC.
Fig.20c: Result of a baking cycle conducted for ID BPI
Fig 20 d. Screenshot displaying set point profile for baking with NEG activation
21. Development of centralized GUI for Large Coating Setup
  • For the large coating set up in UHVTS lab having various instruments.
  • The prototype controller developed is using mbed LPC1768 processor. Following instruments data is monitored:
  • Filament power supply 2U GENESYSTM 3.3kW DC Power Supply.
  • Solenoid power supply.
  • TMP controller TwisTorr 304 FS AG.
  • Vacuum gauge controller TPG 262 for gauge head CMR361 & 364.
  • BA Gauge controller.
  • Dew point and Pressure Transmitter DPT146 (Qty: 02 Nos).
  • Mass flow meter:
Fig 21. Screenshot of GUI for Large coating setup
22. Pneumatic Sector & Gate Valve (GV0) Controller in Indus-2
  • Indus-2 with a circumference of 172 metres partitioned in 14 vacuum sectors using pneumatically operated RF-shielded gate valves
  • 19 nos. of all metal pneumatic Gate Valves installed in the beam lines & two in TL-3
  • Valve controllers designed & developed to open the valves during beam filling condition and close them in the event of vacuum failure or any upgradation/maintenance work.
  • Salient features of these units:
  • Microcontroller based controllers.
  • Provides status of valve& latching of interlock status.
  • Support for RS232 & Isolated RS-485 communication.
  • Local/Remote operation.
  • Provides interlock to MSIS if any valve is in not OPEN state.
  • Pneumatic pressure interlock using pressure switch.
  • Vacuum interlock using BAG near both side of valve.
  • Solenoid support 24V/230V.
Fig 22: Modular Valve controllers with front & back panels view
23. Development of thin film heaters for baking & NEG activation of spare Undulator chamber for Indus-2
  • To address the issue of decreasing gaps between magnetic elements and vacuum chambers in high brilliance synchrotron light source
  • Polyimide film insulated flexible thin heater of thickness ~ 0.6 mm developed indigenously
  • Mounted on indigenously developed Al alloy extruded spare undulator chamber for Indus-2
  • Baking done at 170C for 48 hrs.
Selection criteria for materials:
  • Minimum radiation resistance > 5 MGray
  • Design temperature: Maximum: 200ºC; Operating temperature: < 200°C
  • Thin & flexible as much as possible.
  • Safe, reliable & rugged in working.
  • Uniform power densities with excellent electrical insulation properties.
  • Duration of Thermal cycle close to ~ 72 hrs.
  • Suitable for Aluminum alloy chambers
  • Suitable arrangement for tightening / mounting on the chamber
Material Configuration
The thin film heater had four different classes of materials
  • Base material
  • Conductor Material (Foil)
  • Adhesive
  • Cover material
  • Figure 23d presents the baking profile of ~ 60 hours duration for undulator vacuum chamber with thin film heaters mounted on chamber.
Fig 23a. Thin Film heater make up
Fig 23b. Developed long thin film heaters for prototype Undulator vacuum chamber
Fig 23c. UHV qualification test employing long thin film heaters for prototype Undulator vacuum chamber
Fig 23d. Baking temperature profile of spare Undulator vacuum chamber by long thin film heaters
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