FACTS ABOUT THE TRIUMF CYCLOTRON by Fred Bach last edit: 24 Sep. 1993 **** (collected items from the some of the people who built TRIUMF) VAULT: 100ft (30.5m) x 100.5ft (30.6m) x 39ft (11.9m) (bsmt floor to roof beams). Walls 16ft (about 5m) thick concrete. 132 roof beams in 3 layers separated & air-sealed by heavy polyethylene film. Each beam has the following approximate dimensions: length: 100 feet (30.48m) width: 3.5 feet (1.07m) depth: 5.3 feet (1.6m) weight: 100 tons (90,090 kg) material: ordinary concrete, specially reinforced, pre- & post- tensioned for strength and minimum sag. Manufactured on site. All this shielding prevents hazardous forms of radiation,(neutrons, protons, gamma and beta rays), produced when the cyclotron is operating, from escaping the vault. basement min 8ft (2.4m) to max 17ft (5.2m) thick high-strength floor: (6000 psi) concrete with lots of extra heavy, pre-welded reinforcing steel. The magnet-sector support columns are potted in large, heavy steel containers set into the floor, thus providing 0.1g earthquake protection. The cyclotron, its supporting structure, and shielding blocks rest on a 12-sided "circular" steel reinforced concrete pad, ~ 65 feet in diameter, which varies in thickness from 8 feet at the edge to 17 feet at the centre. This pad is horizontally separated from the surrounding floor, which is 8 feet thick, by a 1 inch thick elastic material. This extremely rigid pad thus surrounded by the floor provides a good level of protection from possible earthquake-induced misalignment or damage. ventilation: large fans exhaust vault air through absolute filters. The Vault is under negative pressure. walkaround: coated aluminum (short activation-product half lives) shielding: more than 200 high-density movable concrete blocks surround the cyclotron to shield work areas. (Concrete has lots of water to trap neutrons and lots of heavy elements to stop gammas). CYCLOTRON: function: accelerates H-minus ions, from 300kev to 520 Mev. (An H-minus ion is a proton orbited by 2 electrons.) Vacuum tank: defines a volume where the beam can accelerate in a very good vacuum to reduce air molecule collisions. Manufactured by Ebco Industries, Richmond, B.C. Canada radius: about 28 feet (almost round: 329 inches to 353 inches) (about 17.1m diameter, or min/max radii 836cm x 897cm) Vacuum tank height: about 18 inches (46cm) when closed floor: 7/8 inch (2.2cm) non-magnetic 316 SS (stainless steel) lid: same as the floor sides: 1-3/8 inch (3.5cm) 316 SS with 4-inch (10.1cm) midplane only 1/32 inch (0.8mm) thick, periodically supported by double-wall channels about 1/16 inch (1.6mm) each wall. vacuum Less than 5 x 10-8 torr (0.00000000006 of 1 atmosphere) system: Double seal at edge of lid with seal-space pumped. Six cryogenic pumps, three turbo-molecular pumps, two 35-ft (10.6m) cryopanels (each has both 77K & 20K lines). Atmospheric about 1700 tons (~1,500,000 kg.) pushing down on the lid and the same pushing up on the bottom, all held by the center post and 664 1.5-inch (3.8cm) tie-rods (332 on the tank floor and 332 on the lid), resulting in about 8 tons (7300kg) on each tie-rod. The tank is leveled under vacuum by using the tie-rods' length adjustments. support A 12-armed "spider" support structure weighing about structure: 120 tons (109,000kg), made of heavy steel I-beams supports the upper magnet sectors and upper tie-rods. Includes lower columns & pods. Designed to withstand thermal stresses and moderate earthquakes. elevating Manufactured by Canron Construction, Vancouver, B.C. system: 12 20-horsepower electric motors drive 24 gear-reduction boxes, which drive 24 counter-rotating screw jacks, are lubricated with a special grease in a closed system. Substantially improved by on-site overhaul program. 35 minutes travel time to 48-inch (122cm) limit. Each pair of jacks has a servo which reads the amount the jack has moved. When the lid is travelling, each of the 12 servos is being compared to a master servo which is being driven by a small motor which is effectively running just a little slower than the jacking motors. When a jack servo gets 0.03 inch ahead of the master servo, the elevating control system shuts off the respective motor until the master servo catches up. So the entire top half of the cyclotron (3000+ tons) can be raised 48 inches with no more than + or - 0.050 inches difference between the jacks. If any jack gets too far out of range, the entire system in stopped. MAGNET: Manufactured by Davie Shipbuilding, Luzon, Quebec, Can. configuration: "Pinwheel", 6-sectors trailing CCW looking from top type: Sector-focussed (sectors shaped for particle mass gain) Sectors are numbered 1 to 6 in CCW order starting with Sector 1 in the south-east. The spaces between sectors are called valleys. Valley 1 is between Sector 1 and Sector 2. The sectors are colour-coded. This helped avoid confusion during the 18-month shimming phase. pole diameter: 59 feet (~18 meters) (must be LARGER than the tank) weight: 4400 tons (4,000,000 kg) total upper and lower sectors sectors & poles: Special magnetic low-carbon steel in 3-inch (7.6-cm) and 5-inch (12.7-cm) laminations. field: 5760 Gauss peak (approx 3000 minimum and 4600 average) field trimming: coarse: Many shims (various thicknesses) fine: 54 trim-coil pairs (circular) 13 harmonic-coil sets (modified pie-shaped) stability: Better than 1 part in 10**6 with remote field sensing COIL: number of turns: 30 (15 upper and 15 lower) conductor material: Aluminum direct cooling (water flows in the conductors) cooling: Low conductivity "aluminum only" closed water circuit. conductor weight: 170 tons (153,000 kg) power: 18,400 amperes at 75 volts DC (1.38 megawatts) (plus 68 kilowatts in the trim coils) constructed by: National Electric Co., Columbus Ohio USA ACCELERATION SYSTEM: type: Resonant RF cavity, transverse-magnetic (TM) push-pull number of DEES: 2 (180 degrees apart).(RF boosters are possible) First RF booster used for normal beam delivery Feb/92. resonator segments: 80 in all.(10 in each of 4 upper and 4 lower quadrants) Manufactured by Ebco Engineering, Richmond B.C. Canada beam aperture: 8 centimeters tuning: Coarse: mechanical adjustment of segment electrodes Fine: cooling water pressure (Bourdon effect) operating frequency: 23.0380 Mhz to 23.0710 Mhz. (nominal 23.0550 Mhz.) operating voltage: 93 kv typical (hot-arm-to-ground) 186 kv DEE-to-DEE voltage stability: about 1 part in 10**4 beam phase stability: +/- 2 degrees RF freq/orbit freq: 5. (must be ODD for cyclotron to accelerate beam. (harmonic number) The RF makes 5 full cycles in one orbit of the beam.) main RF power input: typically 1 MW from 4 500kW Push-Pull Power Amplifiers RF reflected power: typically 1 to 10 KW beam loading: ~85 KW when simultaneously delivering 150 microamps to BL1, 50 microamps to BL2, and 10 microamps to BL4. frequency modulation: has been used experimentally to stabilize beam phase. INJECTION SYSTEM: beam: hydrogen (1p & 1e) - add 1e to give H- (energy 300 kV) type: electrostatic sources: 4 presently. Source 1: high-intensity CUSP source. Source 2: post-polaraized Duo-plasmatron source. Source 3: high-intensity CUSP source. Source 4: med-intensity laser-pumped polarized EXTRACTION SYSTEM: type: electron stripping. H- ions are changed into protons (H+ ions) by stripping the electrons in a 0.001-inch (0.025-mm) thick stripping foil. The particles then curve (CW) out of the cyclotron into the beamlines. stripping foil type: carbon (pyrolytic graphite) on stainless-steel or phosphor-bronze frame (was aluminum frame until ~1988) extraction eff'cy.: 99.95 percent. energy range: BL2: 70 to 100 MeV (150 inches to 177 inches) BL1 & BL4: 180 to 520 MeV (220 to 312 inches) energy spread: extracted beam has typical energy spread of 1MeV. with resolution down to 100keV with MRS operation. (delta-E/E is 0.3 percent) emittance: 3 pi-millimeter-milliradians (both axial and radial) pulse width: microstructure: >25 degrees of the RF cycle (typ 4 nsec) macrostructure: 99% on 1% off @ 1 kilohertz pulser rate # extraction ports: 4 possible in Valleys 1,2,4,5. None possible in 3 & 6 since the resonator flux guides which couple the top & bottom segments would be in the path of the extracted beam. Presently we have 3 extraction ports in use to extract beam: Extraction 1,2 and 4. Extraction ports 5 and 2 now house high-energy beam probes HE3 and HE4. Extraction ports & their corresponding beamlines are named after the valley they are in. The valleys follow the magnet sector numbers. See above under "MAGNET" extraction split: ratio of beam currents simultaneously extracted in Beamline 1 to Beamline 4 typically runs at 10**6. Typical Beamline 1 to Beamline 2 split ratio is 20. material: non-magnetic stainless steel vacuum seals: all double-knife-edge steel on indium. Other forms are used for temporary setups (eg. during maintenance) magnets: Front end elements are radiation-hard and remotely handlable. The conductors are directly cooled hollow copper tubes. Combination-magnet conductors are mineral- insulated and indirectly cooled. Water cooling is via a closed-circuit, low-conductivity, copper-only system. Magnet specs are available in the Control-Room copy of the TRIUMF MAGNET INDEX which lists all the beamline magnets on the site and gives their specifications. vacuum system: Some pumping from the tank, but it is mostly done by turbo-molecular and ion pumps for the VAULT BL sections. beam tunes: Both Achromatic and Dispersed tunes are possible. BL1 runs achromatic most of the time, but many dispersed tunes (at 6 to 10 cm per percent) are run on BL4. Beamline 1 runs mostly at 500mev, while Beamline 4 is usually used as the variable-energy beamline. SAFETY SYSTEM: lockup: The SAFETY SYSTEM will not allow beam to be injected until the Vault is secured. The doors must be closed and one operator holds a dead-man switch at the first watchman station while another goes around in a pre- determined path and checks that no personnel are left in the vicinity. He then pushes a button to activate that watchman station. When all the watchman stations have been activated, the operators may leave the vault by a certain door. The door is then locked, and its key is then locked into the Area Safety Unit (the ASU). (This key then may only be released from the ASU if the Safety System is satisfied it would be safe to do so.) If the walkaround were to be interrupted by someone entering the vault, or if the first operator were to release his dead-man switch, or if the lockup were to take too long, the lockup sequence would be aborted, and must be done again. After a successful lockup, the operator waits for the walkaround timer to time out, and then he pushes a button which causes a very loud horn sounds for about 1 minute. THERE SHOULD BE NO ONE IN THE VAULT AFTER THE WALKAROUND. However, as as extra safety measure the horn warns anyone still in the vault when the horn sounds to leave immediately, using a breakbolt on the exit door, if necessary. This would cause the vault to go unsecured. Only after a proper lockup-and-horn sequence would the Central Safety System allow the operators to inject beam into the Cyclotron. beamspill monitors: There are about 10 beamspill monitors continuously operating in the vault to warn the operators if excessive beam should strike the cyclotron or beamline elements. Some of these monitors will shut off the cyclotron if the spill reaches a pre-determined level. These BSM's are also used to measure the residual fields so that entry may be permitted. As well, there are several neutron monitors measuring neutron fields in many areas, providing warnings in the Control Room. Also, there are air-activation monitors which are recorded and, along with air-ventilation monitors, can be watched and can sound alarms in the control room. Surveys: Before any workers can do installation or maintenance in the Vault, the area is surveyed by Safety personnel and signs are posted. Every worker must carry a pocket dosimeter to record any radiation dose. Thus, the dose for each job may be predicted the next time. Notice that there are shielding blocks strategically placed to keep activation of common work areas low. television: During shutdowns or extended maintenance periods, we expand our television security system to the vault. We remove the cameras, however, for beam operation. MISCELLANEOUS: drainage: The Vault is more than 20 feet (>5m) below the water table. Thus we have sumps to drain the outside ground water away. In case of power failure, the pumps are automatically powered by our 187.5 kVA diesel generator. This also powers emergency systems including lighting. cost: The cyclotron and its systems itself cost about $12,000,000 in 1974 dollars. first beam out: December, 1974. peak intensity: 400 uA peak at 50% duty cycle achieved June, 1987. beam delivered to date: about 3,900,000 microamp-hours to 31 Dec 1992.