1. Power Supply Studies for the Calorimeters & Muon Spectrometer Mauro Citterio, on behalf of the INFN-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. The actual PS systems Extensive use of the DC/DC technology, which requires also 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, to place modules in the experimental cavern Necessity of B-tolerant systems, to place them close to detectors Implementation of redundancy, to face difficult or no access Complex DCS systems, to achieve full remote control Industrial engineering design and industrial scale production 11/16/2011M. Citterio - Atlas Upgrade Week2

3. Requirements for PS system for Hi-LHC upgrade ….. and new experiments New design  full replacement of the present systems, whose design dates back at year 2000 Increased rad-hard performance  related to increased luminosity of the accelerator Minimization of power loss in cables used for carrying current from “PS distributors” to detectors front-ends  move “distributors” as close as possible to the front-end Increased B-tolerance of systems  to mount PS closer to detectors and magnets Better reliability and controls, in order to reduce access time and increase the overall detector efficiency Avoide industrial intellectual property  by implementing the CERN Open Hardware Policy 11/16/2011M. Citterio - Atlas Upgrade Week3

4. New system architectures – a proposal 11/16/2011M. Citterio - Atlas Upgrade Week4 Case study: ATLAS LAr calorimeters CRATE 280 Vdc Main DC/DC Converter Card #3 PO L LDO Convert er PO L LDO Convert er PO L LDO Convert er Card #2 PO L LDO Convert er PO L LDO Convert er PO L LDO Convert er 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. New system architectures – a proposal 11/16/2011M. Citterio - Atlas Upgrade Week5 Muon Detectors 280 Vdc Main DC/DC Converter Chamb #3 PO L LDO Convert er PO L LDO Convert er PO L LDO Convert er Chamb #2 PO L LDO Convert er PO L LDO Convert er PO L LDO Convert er 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, installed on-chamber and high B-tolerant Parallel study: ATLAS Muon Spectrometer

6. The topology of the Main DC/DC Converter 11/16/2011M. Citterio - Atlas Upgrade Week 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 3 modules 1.5 kW each redundancy n+1 current sharing interleaved operations Switch In Line Converter - SILC phase shift operation Phased shifted converter well suited for multi-outputs, or-ed connection and single pole dynamic ZVS transitions high efficiency reduced switch voltage stress high frequency capability Transient response V out I load Output voltage response to a load step change (25 A  37 A ) 13 cm 33 cm 7 cm

7. The planar transformer in the main converter 11/16/2011M. Citterio - Atlas Upgrade Week7 Turn ratios 10:10:2: 4 units connected in parallel 4.71mm 22 layers 10 layers 2 concentric turns in each layer 4 layers

8. Planar transformer test 11/16/2011M. Citterio - Atlas Upgrade Week8 11/16/20118 orange = primary winding voltage blue = secondary winding voltage magenta = primary winding current green = snubber current (proportional to the switching losses). B stat. 789 GaussB stat. 2591 Gauss Transformer behavior in stationary Magnetic Field

9. Study of new materials for operation in high magnetic fields 11/16/2011M. Citterio - Atlas Upgrade Week9 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

10. Thermal Analysis of the main converter

11. Point of load studies 11/16/2011M. Citterio - Atlas Upgrade Week11 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

12. More studies on Point of Load 11/16/2011M. Citterio - Atlas Upgrade Week12

13. Radiation studies on the “critical” components 11/16/2011M. Citterio - Atlas Upgrade Week13 Look 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

14. Power Mosfets exposed to gamma rays Devices under test: 30V STP80NF03L-04 30V LR7843 200V IRF630 Devices under test: 30V STP80NF03L-04 30V LR7843 200V IRF630 Used doses: I 1600 Gray II 3200 Gray III 5890 Gray IV 9600 Gray Used doses: I 1600 Gray II 3200 Gray III 5890 Gray IV 9600 Gray Measurements : Breakdown Voltage @ VGS=-10V Threshold Voltage @ VDS=5V ON Characteristic @ VGS=10V Gate Leakage @ VDS=10V Measurements : Breakdown Voltage @ VGS=-10V Threshold Voltage @ VDS=5V ON Characteristic @ VGS=10V Gate Leakage @ VDS=10V For each type of device 20 samples were tested, 5 for each dose value (tested at the ENEA Calliope Test Facility)

15. Mosfet Exposed to Heavy Ions. The SEE framework Drain P + N + P _ GateSource N _ Body N + Drain P + N + P _ GateSource N _ Body N + Destructive Single Event Effects in Power MOSFETS (tested at INFN Catania) Single Event BurnoutSingle Event Gate Rupture 11/16/2011M. Citterio - Atlas Upgrade Week15

16. The SEE experimental set-up Fast Sampling Oscilloscope Parameter Analyzer Drain P + N + P _ GateSource N _ Body N + Cg Cd 50  1 M  Vgs Impacting Ion DUT Vds The current pulses The IGSS evolution during irradiation 11/16/2011M. Citterio - Atlas Upgrade Week16

17. The SEE analysis TIME DOMAIN WAVEFORMSSCATTER PLOT MEAN CHARGE vs BIAS VOLTAGEΓ-LIKE DISTRIBUTION FUNCTION 11/16/2011M. Citterio - Atlas Upgrade Week17

18. The SEE experimental results 200 V Mosfet: IRF630

19. The SEE experimental results D21 0Gy Vds=110V Vgs=-2V 11/16/2011M. Citterio - Atlas Upgrade Week19

20. The SEE experimental results Scatter-plot Vds=50V 11/16/2011M. Citterio - Atlas Upgrade Week20

21. Characterization requires that an SEB circumvention method be utilized SEB characterization produces a cross-sectional area curve as a function of LET for a fixed VDS and VGS.  Generally SEB is not sensitive to changes in the gate bias, VGS.  However, the VGS bias shall be sufficient to bias the DUT in an “off” state (a few volts below V TH ), allowing for total dose effects that may reduce the V TH. Mosfet Exposed to Protons SEB characterization The only difference in the test set-up was that the current probe was on the Mosfet Source 11/16/2011M. Citterio - Atlas Upgrade Week21

22. Mosfet Exposed to Protons The results are still preliminary. Only the 200V Mosfets (IRF 630) were exposed Proton energy: 216 MeV ( facility at Massachusetts General Hospital, Boston) Ionizing Dose: < 30 Krads An “absolute” cross section will require the knowldege of the area of the Mosfet die which is unknown. 11/16/2011M. Citterio - Atlas Upgrade Week22

23.  The number of SEB events recorded at each VDS was small  less then 30 events for the ST  less than 150 events for the IR devices  Large statistical errors affect the measurements  The cross section at VDS = 150 V (“de-rated” operating voltage) can not be properly estimated To effectively qualify the devices for 10 years of operation at Hi-LHC, the cross section has to be of the order of 10 -17 / cm 2, which puts the failure rate at <1 for 10 years of operation Proton irradiation campaigns with increased fluences are planned. Work still in progress …………….. Mosfet Exposed to Protons 11/16/2011M. Citterio - Atlas Upgrade Week23

24. Conclusions 11/16/2011M. Citterio - Atlas Upgrade Week24  Distributed Power Architecture has been proposed  Main converter (SILC topology)\  Point of load converter (IBDV topology)  Critical selcction of components to proper withstand radiation  Controller, Driver and Isolator  FPGA for overall monitoring  MOSFETS  Mosfets Devices have identified and tested  Gamma ray  Heavy ions  Protons  Some results are encouraging, however they require more systematic validation