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

M. Citterio - Atlas Upgrade Week 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

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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

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New system architectures – a proposal

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Case study: ATLAS LAr calorimeters

CRATE

280 Vdc

Main DC/DC

Converter

Card #3POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Card #2POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Card #1POLniPOL

Converter

POLniPOL Converter

POLniPOL ConverterRegulated

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

M. Citterio - Atlas Upgrade Week 5

New system architectures – a proposal

11/16/2011

MuonDetectors

280 Vdc

Main DC/DC

Converter

Chamb #3POL

LDO Convert

er

POL

LDO Convert

er

POL

LDO Convert

er

Chamb #2

POL

LDO Convert

er

POL

LDO Convert

er

POL

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

The topology of the Main DC/DC Converter

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Q1

Q2

Q3

Q4

T1

Co

C4 L

VinVout

+-C3

C2

C1 T2

T3

iT2

iL

T4

+

+

+

+

Vout = 12V

3 modules 1.5 kW each• redundancy n+1• current sharing• interleaved operationsSwitch 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

Vout

Iload

Output voltage responseto a load step change (25 A 37 A)

13 cm

33 cm

7 cm

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The planar transformer in the main converter

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Turn ratios 10:10:2: 4 units connected in parallel

4.71

mm

22

laye

rs

10 layers2 concentric turnsin each layer

4 layers

4 layers

8

Planar transformer test

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orange = primary winding voltage blue = secondary winding voltagemagenta = primary winding currentgreen = snubber current (proportional to the switching losses).

Bstat. 789 Gauss Bstat. 2591 Gauss

Transformer behavior in stationary Magnetic Field

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Study of new materials for operation in high magnetic fields

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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

Thermal Analysis of the main converter

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Point of load studies

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Specifications:Input voltage: Ug = 12 VOutput voltage: Uo = 2.5 VOutput current: Io = 3AOp. frequency: fs = 1 MHz

350 nH air core inductorsDim.: L = 6cm, W = 4.2cm

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More studies on Point of Load

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Radiation studies on the “critical” components

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Look for power MOSFETs radiation tolerant up to 10kGy and 1014/(s ∙ cm2) neutrons and protons:

many components, with Vd ranging from 30V to 200V and polarized in various configurations, were tested at the 60Co g ray source in the ENEA center of Casaccia, near Roma

same components were tested with a heavy ion beam, 75Br 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

Power Mosfets exposed to gamma raysDevices under test:

30V STP80NF03L-04

30V LR7843

200V IRF630

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

For each type of device 20 samples were tested, 5 for each dose value

(tested at the ENEA Calliope Test Facility)

Mosfet Exposed to Heavy Ions.The SEE framework

N+

Drain

P +

N +

P _

GateSource

N_

Body

N+ N+

Drain

P +

N +

P _

GateSource

N_

Body

N+

Destructive Single Event Effects in Power MOSFETS (tested at INFN Catania)

Single Event Burnout Single Event Gate Rupture11/16/2011 M. Citterio - Atlas Upgrade Week 15

The SEE experimental set-up

Fast Sampling Oscilloscope

Parameter Analyzer

N+

Drain

P +

N +

P _

GateSource

N_

Body

N+

Cg

Cd

50 W

50 W

1 MW1 MW

Vgs

Impacting Ion DUT

Vds

0 500 1000 1500 2000-2.0

-1.5

-1.0

-0.5

0

Time [s]

Gat

e Le

akag

e C

urre

nt [

A ]

20 40 60 80 100 120

0

5

1

15

Time [ns]

Cur

rent

[mA

]

The current pulses

The IGSS evolution during irradiation

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0 10 30 400

0.5

1

1.5

2

2.5

x 1011

Charge [pC]

50 100 1508

10

12

14

16

Vds [V]

Cha

rge

[pC

]

Vds

20 40 60 80 100 120

0

0.5

1

1.5

0

0.5

1

1.5

0

Time [ns]

Cur

rent

[mA

]

10 20 30 40 10 20 30 40

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5x 1010

Charge [pC]

The SEE analysisTIME DOMAIN WAVEFORMS SCATTER PLOT

NUMERICAL INTEGRATION

Γ-LIKE DISTRIBUTION

FUNCTION PARAMETERS EXTRACTION

MEAN CHARGE vs BIAS VOLTAGE Γ-LIKE DISTRIBUTION FUNCTION11/16/2011 M. Citterio - Atlas Upgrade Week 17

The SEE experimental results

Devise TID Bias Conditions during Irradiation Drain Damage Gate DamageD21 0Gy Vds=20V-110V vgs=-2V Vds=100V-110V Vds=100V-110VD22 0Gy Vds=20V-120V vgs=-6V Vds=110V-120V Vds=100V-110VD06 1600Gy Vds=20V-70V vgs=-2V Vds=60V-70V Vds=60V-70VD10 3200Gy Vds=20V-50V vgs=-6V Vds=40V-50V Vds=40V-50VD14 5600Gy Vds=20V-55V vgs=-6V Vds=50V-55V Vds=40V-50VD16 5600Gy Vds=20V-50V vgs=-6V Vds=45V-50V Vds=40V-45VD17 9600Gy Vds=20V-45V vgs=-6V Vds=40V-45V Vds=40V-45V

The increase of the ϒ-dose causes a reduction of the critical bias condition at which drain and gate damages appear

200 V Mosfet: IRF630

0 20 40 60 80 100 120 140 160 180 200

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Time [ns]

Cur

rent

[mA

]

0 20 40 60 80 100 120 140 160 180 200

0

5

10

15

20

25

30

35

Time [ns]

Cur

rent

[mA

]

The SEE experimental results

Two different sensitive areas

The SEB current pulse

D21 0Gy Vds=110V Vgs=-2V

D21 0Gy Vds=110V Vgs=-2V

20 30 40 50 60 70 80 90 100

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

Vds [V]

Cha

rge

[pC

]

Mean charge vs Vds

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0 20 40 60 80 100 120 140 160 180 200-20

0

20

40

60

80

100

120

Time [ns]

Cur

rent

[A

]

D21 0GyD10 3200GyD14 5600GyD17 9600Gy

The SEE experimental resultsScatter-plot Vds=50V

The increase of the ϒ-dose causes a widening of the current pulses

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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

VTH), allowing for total dose effects that may reduce the VTH.

Mosfet Exposed to ProtonsSEB characterization

The only difference in the test set-up was that the current probe was on the Mosfet Source

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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.

10-12

10-11

10-10

10-9

10-8

10-7

182 184 186 188 190 192 194 196

IRF630 - ST

Cro

ss S

ectio

n [c

m-2

]

VDS [Volt]

10-12

10-11

10-10

10-9

10-8

10-7

175 180 185 190 190 195

IRF630 - International Rectifier

Cro

ss S

ectio

n [c

m-2

]

VDS [Volt]11/16/2011 M. Citterio - Atlas Upgrade Week 22

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/ cm2, 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

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Conclusions

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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