1. The APOLLO Project: LV Power Supplies For The Next High Energy Physics Experiments Milano, October 19, 2011 Agostino Lanza, on behalf of the APOLLO Collaboration M. Alderighi (1,6), M. Citterio (1), M. Riva (1,8), P. Cova (3,10), N. Delmonte (3,10), A. Lanza (3), R. Menozzi (10), A. Paccagnella (2,9), F. Sichirollo (2,9), G. Spiazzi (2,9), M. Stellini (2,9), S. Baccaro (4,5), F. Iannuzzo (4,7), A. Sanseverino (4,7), G. Busatto (7), V. De Luca (7) (1) INFN Milano, (2) INFN Padova, (3) INFN Pavia, (4) INFN Roma, (5) ENEA UTTMAT, (6) INAF, (7) University of Cassino, (8) University of Milano, (9) University of Padova, (10) University of Parma

2. Features of the PS systems required by the present experiments (mainly at LHC) Milano, October 19 2011 The APOLLO Project - Agostino Lanza 2 Extensive use of the DC/DC technology, which requires a careful design in terms of EMC Integration with detectors at the design level, to avoid both mechanical and electrical criticalities Necessity of rad-hard devices, so to place modules in the experimental caverns Necessity of B-tolerant systems, to be able to place them close to detectors Implementation of redundancy, because of difficult access of no access at all Very complex DCS systems, in order to get a fully remote control Industrial engineering design and industrial scale production

3. Requirements of future LHC upgrades and new experiments Milano, October 19 2011 The APOLLO Project - Agostino Lanza 3 New design, full replacing the present systems whose design dates from early 2000 years Increased rad-hard performance, because of the increased luminosity of accelerators Minimization of power loss in cables used for carrying current from PS distributors to the front-end of detectors, moving distributors as close as possible to the front-end Increased B-tolerance of systems getting closer to detectors and magnets Better reliability and controls, in order to reduce access time and increase the overall detector efficiency Avoiding industrial intellectual property, trying to implement the CERN Open Hardware policy

4. The APOLLO proposal – System architectures Milano, October 19 2011 The APOLLO Project - Agostino Lanza 4 Case study: ATLAS LAr calorimeters CRATE 280 Vdc Main DC/DC Converter Card #3 POLPOL POLPOL LDO Convert er POLPOL POLPOL POLPOL POLPOL Card #2 POLPOL POLPOL LDO Convert er POLPOL POLPOL POLPOL POLPOL Card #1 POL niPOL Converter POL niPOL Converter POL niPOL Converter Regulated DC bus POL Converter with high step-down ratio Characteristics: Main isolated converter with N+1 redundancy High DC bus voltage (12V or more) Distributed Non- Isolated Point of Load Converters (niPOL) with high step-down ratio

5. The APOLLO proposal – System architectures Milano, October 19 2011 The APOLLO Project - Agostino Lanza 5 Parallel study: ATLAS Muon detectors Muon Detectors 280 Vdc Main DC/DC Converter Chamb #3 POLPOL POLPOL LDO Convert er POLPOL POLPOL POLPOL POLPOL Chamb #2 POLPOL POLPOL LDO Convert er POLPOL POLPOL POLPOL POLPOL Chamb #1 niPOL Converter Regulated DC bus POL Converter with high step-down ratio Characteristics: Main isolated converter with N+1 redundancy High DC bus voltage (12V or more) Distributed Non- Isolated Point of Load Converters (niPOL) with high step-down ratio, on-chamber installed and high B- tolerant

6. The APOLLO proposal - Topologies Milano, October 19 2011 The APOLLO Project - Agostino Lanza 6 Q1Q1 Q2Q2 Q3Q3 Q4Q4 T1T1 CoCo C4C4 L V in V out + - C3C3 C2C2 C1C1 T2T2 T3T3 i T2 iLiL T4T4 + + + + V out = 12V The Main DC/DC Converter 3 modules 1.5 kW each redundancy n+1 current sharing interleaved operations Switch In Line Converter - SILC phase shift operation ZVS transitions high efficiency reduced switch voltage stress high frequency capability 13 cm 33 cm 7 cm Efficiency (B ext = 0) Output power kW] 0.20.40.60.81.01.21.41.6 0.5 0.6 0.7 0.8 0.9 1 Transient response V out I load Output voltage response to a load step change (25 A  37 A)

7. The APOLLO proposal – Thermal sizing Milano, October 19 2011 The APOLLO Project - Agostino Lanza 7 Thermal simulation and measurements 2 Preliminary thermal measurements on the air cooled whole converter Final requirements Main converter output power = 3x1 kW Case dimensions: 150 x 402 x 285 mm 3 Max case temperature = 18°C Water cooling system delivery = 1.9 l/min,  p = 350 mbar T inlet = 18°C, T outlet ≤ 25°C 3D Finite Element Model (FEM) FE modeling of the main heating components: Input power MOSFETs Output diodes Inductor Planar transformer Thermal measurements 1 Thermal characterization on single components, to validate models Thermal design Designed advanced solutions to improve heat exchange: Power MOSFETs mounted on IMS board ISOTOP diode isolated package directly mounted on baseplate Copper thermal layers for transformer core cooling Silicone gap filler for transformer windings cooling

8. The APOLLO proposal - Topologies Milano, October 19 2011 The APOLLO Project - Agostino Lanza 8 The Point of Loads S1S1 S2S2 S3S3 S4S4 L1L1 CoCo R C1C1 L2L2 U in UoUo + - U C1 + - D<50% U o = U in D/2 Interleaved Buck with Voltage Divider – IBVD Characteristics: Zero voltage switch turn on High step-down ratio Reduced switch voltage stress (U in /2) Interleaved operation with automatic current sharing and ripple cancellation CoCo C1C1 C in L1L1 L2L2 S1S1 S3S3 S4S4 Specifications: Input voltage: U g = 12 V Output voltage: U o = 2.5 V Output current: I o = 3A Op. frequency: f s = 1 MHz 350 nH air core inductors Dim.: L = 6cm, W = 4.2cm Specifications: Input voltage: U g = 12 V Output voltage: U o = 2 V Output current: I o = 20A Op. frequency: f s = 280 kHz 2.2  H ferrite core inductors Dim.: L = 7cm, W = 3.5cm

9. The APOLLO proposal – Rad-hard devices Milano, October 19 2011 The APOLLO Project - Agostino Lanza 9 Seeking for power MOSFETs radiation tolerant up to 10kGy and 10 14 /(s ∙ cm 2 ) neutrons and protons:  many components, with V d ranging from 30V to 200V and polarized in various configurations, were tested at the 60 Co  ray source in the ENEA center of Casaccia, near Roma  same components were tested with a heavy ion beam, 75 Br at 155MeV, at INFN Laboratori Nazionali del Sud in Catania  within the end of the year same components will be tested under neutrons, at the Casaccia nuclear reactor Tapiro, and under protons, at INFN LNS Seeking for power MOSFETs, controllers and FPGA radiation tolerant:  first irradiation was performed under 216MeV proton beam in Boston, at Massachusetts General Hospital facility, using some of devices irradiated in Italy. Other irradiation campaigns are planned at the same facilities in the next months Results are still preliminary and under analysis. Other irradiation campaigns are necessary in order to select good devices

10. The APOLLO proposal – Rad-hard devices Milano, October 19 2011 The APOLLO Project - Agostino Lanza 10 Some preliminary results of  irradiation up to 9600 Gy of the 200V MOSFET IRF630

11. The APOLLO proposal – New technologies Milano, October 19 2011 The APOLLO Project - Agostino Lanza 11 V DC vcvc DRIVER DUT L V CC + C1C1 i DUT R shunt + Turn on interval @ V cc = 100V, I DS = 0A U GS [1V/div] -I DS [1A/div] Time [10ns/div] R shunt = 85 m  Turn off interval @ V cc = 100V, I DS = 5A U GS [1V/div] U DS [20V/div] -I DS [1A/div] -p off (t) Time [10ns/div] Study of EPC GaNs:  Work in progress since early 2011  Two device types under test: 40V and 200V  Difficulties found for soldering devices on PCB  Electrical characterization in progress  Rad-hard tests will come soon Measured voltage and current during switching periods of a GaN device GaN test circuit

12. The APOLLO proposal – New technologies Milano, October 19 2011 The APOLLO Project - Agostino Lanza 12 Study of high-B materials:  Collaboration with the private company FN S.p.A.  Base material by Hoganas, FES168 HQ, Fe – Si(6.5-6.9%)  Problems found and solved in the injection moulding phase  Still problems in the sintherization phase  First B tests by end of the year (hopefully) First moulded samples of FES168 Collaboration with a CERN group (F. Faccio). It aims at studying current sharing of already existing integrated DC/DC converters with low output currents (< 3A), designed by that group