Powering The RHIC EBIS at BNL (And a few words on other new projects within the Collider –Accelerator Dept.) Bob Lambiase 16 June 2019

Bob Lambiase 16 June Electron Beam Ion Source (EBIS) The EBIS is a replacement ion source for the aging Tandem Van de Graaff. It is designed to support eight different users, each with a different species of ion. For each user, beam is produced at up to a 5 Hz rate. It only takes one second to switch users. The EBIS requires 184 power supplies, most of which are high voltage, low or medium power. The construction techniques were developed on a R & D EBIS, which is still operational. The system is now in the final stages (beam is being sent through LINAC) of commissioning, and should be injecting beam into the C-AD booster by August Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Equipment Layout (From External Source to LINAC Output) Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June External Ion Source (Hollow Cathode) Powering Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Typical Floating Deck Construction The rack shown contains the Liquid Metal source power supplies, but the construction is typical for EBIS floating decks. 19” racks are supported by Glastic platforms within 24” cabinets. Additional insulation is placed between the racks and the sides of the cabinet. Control is provided by standard BNL Power Supply Interface (PSI) modules over a fiber optic link. The cabinet is at ground potential, and the shields of the cables leaving the cabinet are at ground potential. The cable is then run through tray at ground potential. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June EBIS Deck Powering Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June The EBIS Platform Most of the power supplies are referenced to the EBIS Platform. This platform is pulsed to 100kV after the EBIS is filled by the external ion sources. Pulsing this deck, rather than just operating the deck at a DC level of 100kV permits development of additional external ion sources near ground potential. There are three power sources that provide power to this deck – a 200KVA transform for general power, a 200KVA step up rectifier transformer for the collector power supply, and a 20KVA emergency power transformer. These transformers have only 1nF of capacitance from secondary to primary, reducing the current requirements for the 100 kV pulser. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June EBIS Platform Safety Considerations The EBIS platform equipment is enclosed within a cage. When the deck pulsing in inhibited, the cage can be entered and all other power supplies operated. Within the cage, the smaller supplies are enclosed by 24” cabinets as is done with the external ion sources, and the large collector supply, which can float up to 20kV below the EBIS deck, floats within a cage at EBIS platform potential. All cabling is either run in conduit at EBIS potential or cable with shielding at EBIS potential running in tray at EBIS potential. Kirk Keys are used to ensure power to all racks is removed prior to accessing any enclosure with a floating deck. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Low Energy Beam Transport (LEBT) Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Time of Flight Arm Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Pulsed Quadrupoles and Beam Transport Lines Powering The RHIC EBIS at BNL (And a few words on other new projects) Four MEBT quadrupoles, a triplet in the LINAC, and a triplet in the HEBT directly following the LINAC are pulsed to as much as 925 Amps at 5 Hz with a precision of 100ppm. Slow pulsed (0.5 Hz max) quadrupoles use a modified version of the Kepco 1kW BOP. The modified version has a ZFCT for 100ppm stability, and additional filtering to reduce ripple. Two large 72° dipole magnet bend the EBIS beam into position for injection into the booster. These are powered by a single 2,700Amp, 300V, two quadrant supply. Trim windings on the two magnets are connected in opposition to a small power supply for offset.

Bob Lambiase 16 June Control Features The standard BNL power supply interface (PSI) was well suited to this application because of the fiber optic isolation. But a new version (PSI-II) had to be developed to meet all the requirements. The PSI-II could be configured to either operate with a 10kHz rate to be compatible with the older units, or a 100kHz rate to meet new demands. When configured as 100kHz unit, the interface is controlled through a quad function generator as opposed to the six channel power supply controller (PSC). It is available with the original single set point output or a push – pull pair of outputs to control electrostatic deflection plates. A direct machine protection input was added. This is different from shutting a supply off, as it drives the output to the safe level of zero. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Energy Recovery LINAC (ERL) The 20MeV ERL currently under construction is an R&D accelerator. It has applications for fourth generation light sources where the energy from a previous turn is stored in a cavity and each bunch only goes around the ring once. It also has applications for other projects in the active proposal stage, including MeRHIC / eRHIC and e-Cooling. These projects will be described in later slides. The 1MW and 50kW RF systems are now fully operational. Other portions of the system are coming on line slowly, due to funding limitations. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Equipment Layout Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June MW CW Transmitter The e-gun cavity requires 1MW CW at MHz. This as accomplished with a CPI klystron similar to one made for LANL (we had no modulating anode). Continental Electronics made the power supply, rated 100kV at 21A, which ran at 92kV at 17A for 1MW. Support equipment included heater and solenoid supplies, Vac-Ion pump controllers, water flow and temperature monitoring, air flow and temperature monitoring, as well as RF amplification and monitoring of forward and reverse power. The circulator was manufactured by AFT, and the water cooled dummy load was made by CML. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Magnet Power Supplies The main ring magnets are powered by an IE Power 320A, 35V SCR power supply, similar to medium range units bought by us for the SNS accumulator ring. The main quadrupoles, single solenoids, and single steering magnets are powered by Danfysik 10A, 15V shim supplies. These are low power versions of the SNS low field correctors which were developed for trim magnets in MRI machines. The multiple magnet steerers and solenoids are powered by the recently developed Kepco high precision (100 ppm) BOP, rated 20A at 50V. The back leg windings of the main dipoles are used for horizontal correction, and are powered by BiRa 6A MCOR modules. The other correction elements are powered by 2A MCOR modules. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June e - Lens The e - Lens equipment is designed to increase luminosity in RHIC using beam - beam compensation. The equipment is in the design stage. The design is similar, but simpler than the EBIS. Some equipment may use the NSLS-II developed PSI-III, which combines the fiber optic interface of the PSI-II used in EBIS with a precision current regulator. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Power Supply Arrangement (Not the Final Configuration) Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June MeRHIC The MeRHIC program will enable the collisions of polarized and unpolarized e - and e + at 4 GeV with polarized protons and ions in the 50 – 250 GeV range. MeRHIC equipment would be able to be upgraded into eRHIC to increase the energy of the leptons to 20 or 30 GeV. This project is in the active proposal stage. Conceptual designs have been made to estimated costs to construct. Powering The RHIC EBIS at BNL (And a few words on other new projects)

Bob Lambiase 16 June Magnet Power Supplies There are seven separate arcs – one for each energy on the beam’s way up from 100 MeV to 4 GeV in 0.65 GeV increments. The are many spreader / combiner elements to combine the beams into one to get them into the main ERLs, and then spread them out on the other side. In addition, the 100 MeV beam needs to be broken out to get to / from the source ERL, and the 4.0 GeV beam need to be broken out to interact with the RHIC beam. Warm magnets will be used to steer the beam to interact properly with the ion beams at the 2:00 crossing point. The source ERL will likely use two rings to get up to 100 MeV. All of this means there will be a lot of power supplies! Powering The RHIC EBIS at BNL (And a few words on other new projects)