cms me csc hv system

CMS ME CSC HV systemCMS ME CSC HV system

Alex MadorskyUniversity of Florida

November 2003, CERNAlex

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Cathode Strip ChambersCathode Strip ChambersMain purpose of the CMS EMU CSC HV system:

Provide High Voltage for CMS Endcap Muon Cathode Strip Chambers (CSC)

CSC features that affect HV system design: Small HV segments – high tolerance to

HV failures Same working voltage with small

variations from segment to segment Problematic segment can be fixed by:

Reducing voltage Disconnecting from HV

Needs precise consumption current measurement for each segment

One HV segment


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Voltage and current parametersVoltage and current parametersCosmic Ray Count Rate, 4/6

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4

HV (kV)

Co

un

t R

ate

(k

Hz)

40+50+10

Ar+CO2+CF4

Voltage:

•The operational point 3.6 kV (full efficiency)

•The end of plateau is at 3.9 kV

Current:

•Current per channel averaged over the full Encap Muon System: ~0.7 uA/segment

•Maximum expected current per segment: 2uA

•Needs to be monitored on each segment with good precision, to detect possible troubles.


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UF/PNPI designUF/PNPI design

UF/PNPI HV system design:

3.5 years of development 3 prototypes + pre-production prototype produced Prototypes passed all tests


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Target specifications (1)Target specifications (1)

System structure See Figure 1

Mainframe Power supply functions 1. “Master” High Voltage (Vmax) generation and regulation 2. Distribution boards control 3. Distribution boards low voltage power (under discussion) 4. User interface 5. CMS SCADA interface

Number of distribution boards 126 + 13 spares 36-channel boards 144 + 15 spares 30-channel boards

Number of output channels of the distribution board

36 or 30

Distribution board output organization Output HV connectors

One connector LEMO REDEL SLA.H51 for 30 HV outputs or two LEMO REDEL SLA.H51 for 18+18 HV outputs Pin assignment defined by customer, connectors with the HV wires (1 m) attached are supplied by customer. There are 30 or 18 wires for HV outputs in each connector, 3 ground wires, 2 interlock and 2 reserved wires.

Maximum output voltage, Vmax 4000 V

Voltage regulation individually for each output, software programmable

Vmax – 500 V to Vmax, with the possibility to turn off

Voltage regulation resolution, individually for each output, software programmable

Less or equal to 50V


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Target specifications (2)Target specifications (2)Channel to channel output voltage difference

20 V max

Voltage output Floating (HV return wire insulated from the system ground) Capacitive load for each output 0 - 60 nF

Maximum output current, Imax 100 A

Individual output turn-off (trip) speed Programmable, from 1 s

Trip level, software programmable 1 to 100 A

Trip level setting resolution 1 A

Hardwired trip level (erroneous software protection)

100 A

Maximum total output current of the board (sum of all outputs)

40 A * number of outputs

Ripple and noise 10 mV p-p maximum, bandwidth 100 Hz – 20 MHz Common mode ripple, measured on 1 KOhm resistor

50 mV p-p maximum, bandwidth 100 Hz – 20 MHz

Mutual influence of channels No trips because of other channel(s) tripping

Voltage measurement, individually for each output

Via software, resolution 10V, 0 to Vmax

Current measurement, individually for each output

Via software, resolution 100 nA or better for currents 0 - 1A, 10% or better for currents >1A to Imax

Channel to channel measured current difference

10% of measured value max.


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Target specifications (3)Target specifications (3)Current measurement period for each output in the entire system

10 sec or less

Rate of voltage change, software programmable

2 to 50 V/s

Output control via software Status: OK, tripped, interlock status, overload, on/off, ramp up, ramp down, current limit/measurement

Protection loop (interlock) Required, with an option to disable, software programmable. The chambers are equipped with the interlock switch, and HV cable has two interlock wires.

Low voltage power input and control From mainframe or external, 9 boards per 1 crate

High voltage power input From mainframe, one SHV connector

HV, LV and control connectors’ positions See Figure 2

LED indication HV on/off, LV on, trip, interlock open

Ambient magnetic field for distribution boards

0.3 Tesla constant field, B-field map is available

Radiation hardness of the distribution boards

2*1011 neutrons/cm2 and 0.5 krad of ionizing particles

Slow control Connection to CMS SCADA required

Construction of distribution board 6U or 7U Eurostandard board, up to 700 mm long, 9 or 8 boards per 19” crate (see Figure 2)


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Target specifications (4)Target specifications (4) Mainframe Power sources

(270 outputs)

Distribution Boards One HV conductor per

distribution board (270) plus control and Low Voltage power

One conductor per segment (8856)

~100m ~12 m average

Cha

mbe

rs

Figure 1

• System structure defined by us

• Master HV sources and control computers in Control Room

• Voltage regulation and monitoring, current measurement by Distribution boards near disks


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Target specifications (5)Target specifications (5)

Output connectors SLA.H51, for two small chambers, shown with the mating cable connector

Input connectors: HV, control. HV connector is SHV.

Front panel

36-channel distribution board

Output connector SLA.H51, for one large chamber, shown with the mating cable connector

Input connectors: HV, control

Front panel

30-channel distribution board

~ 700 mm max

6U-7U

6U-7U

81 mm

Figure 2

Two types of distribution boards:

• 36 channels (two small chambers)

• 30 channels (one large chamber)

Output connector defined by us.


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UF/PNPI HV system architectureUF/PNPI HV system architecture

Card 72

Counting Room Detector Area

Long Distance HV Cables ~ 100 m long

SHV Connectors on both ends

Primary HV Supply

Multiwire HV Cable ~ 12 m long

LEMO REDEL Connectors on both ends

Three Main Units: Primary HV Supply, Master Distribution Card, Remote Distribution Card One Primary HV Supply per up to 9 Master Distribution Cards Master Distribution Card: 1 Input, 8 Independent Outputs One Master Distribution Card per 8 Remote Distribution Cards Remote Distribution Card Type 1: 1 Input, 30 Independent Outputs

(One Card per one ME 23/2 Chamber) Remote Distribution Card Type 2: 1 Input, 36 Independent Outputs

(One Card per two ME1 Chambers)

Card 1

Card 9

Card 1

Master Distribution

Card

Remote Distribution

Card Type 1

Remote Distribution

Card Type 2

Multiwire HV cables, 100 m, one per 18 distribution boards

•Primary HV power supplies: off the shelf

•Master board: One output per distribution board. Regulates voltage 0-4KV (VMAX), measures current on each output.

•Remote Distribution board: powers one large or two small chambers (36 outputs max). Regulates voltage 1KV down from VMAX, measures current on each output. Each output can be disconnected from HV if necessary.


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Control interfaceControl interface

HOST PROCESSOR

PCI BUS

RE

MO

TE

DIS

TR

. C

AR

D 9

RE

MO

TE

DIS

TR

. C

AR

D 1

VGA

ETHERNET USB-GP-IB

REMOTE DISTRIBUTION CRATE 1

PRIMARY HV POWER SUPPLY

SE

RIA

L B

US

1

SE

RIA

L B

US

5 SERIAL BUS 6

UP TO 144 MULTIWIRE HV CABLES IN TOTAL UP TO 2582 LEADS

SCADA INTERFACE (DIM SERVER)

HOST PROCESSOR UNIT

HOST CARD 1

9

HOST CARD 2

HOST CARD 6

HOST CARD 5

RE

MO

TE

DIS

TR

. C

AR

D 9

RE

MO

TE

DIS

TR

. C

AR

D 1


9

RE

MO

TE

DIS

TR

. C

AR

D 9

RE

MO

TE

DIS

TR

. C

AR

D 1


9

MA

ST

ER

DIS

TR

. C

AR

D 9

MA

ST

ER

DIS

TR

. C

AR

D 1

MASTER DISTRIBUTION CRATE

SE

RIA

L B

US

2

72 HV CABLES (ONE PER REMOTE CARD)


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US CMS ReviewUS CMS Review

Conducted on June 24th 2003 in UFUF/PNPI system selected over CAENReasons:

Price Design features:

Simple and robust designNo programmable logic in radiation – no SEU


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UF/ PNPI UF/ PNPI CMS EMU CSC HV System Main Design FeaturesCMS EMU CSC HV System Main Design Features

Main technical approaches are shownHV regulatorCurrent sensorFuse controlDigital control interfaceMechanical design


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HV regulator (distribution board)HV regulator (distribution board)Q1

R1

-

+

U1AR2

-

+

U2A

Q2

R3

C1

C2

HV CONTROL INPUT

CONTINUOS CLOCK

HV MONITOR

HV OUTHV IN

• Output voltage controlled by linear regulator (Q1)

• Regulates down to –1000V from input voltage

• Voltage measured by divider R1-R2 and U1A opamp.

• Regulator feedback via U2A

• Q2 and C1 provide HV decoupling


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Current sensorCurrent sensor

R2 R3

D1C1 C2

+

-

U3A

R5

R4

I

Cv=KU

U=IRs

Q=UgCv

Ug

CHARGE SENSITIVE AMP.

Uout=QCf=UgCvKuIRsCf=KI

Rs

Uout

Cf

• Current measured across Rs

• Varicap D1 is used as voltage-sensitive element

• Input pulse is applied via C1

• U3A is a charge-sensitive amplifier


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Fuse controlFuse control

HV CABLEHV CABLE

FUSE

DIODE

RESISTORQ3

REMOTE CARDMASTER CARD

4KV REGULATORPOSITIVE

LV POWER SUPPLYNEGATIVE

HV IN

1KV REGULATOR

FUSE CONTROL

100mA

COUNTING ROOM

100K

DETECTOR AREA

HV RELAY

GND

• Situation requiring permanent disconnect is extremely rare (never happened on FAST sites)

• Fuse is used to disconnect channel from HV permanently

• To blow fuse:

• Low negative voltage applied to channel input

• Switch Q3 shorted

• Fuse can be quickly replaced during short access


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Control interfaceControl interface

12 LINE HVM SERIAL BUS

ANALOG ANALOG ANALOG MULTIPLEXERMULTIPLEXER MULTIPLEXER

CLK COUNTER

ADDRESS

RST

SERIAL ADC

SERIAL ADC

36 CHANNEL HV MONITOR

SERIAL DAC

36 CHANNEL HV CONTROL36 CHANNEL I MONITOR

FROM/TO 36 HV CARDS

COUNTER

N MODULE

LOGIC

CLK R/W

CLK

RST

DATA OUTDATA OUTDATA IN

• Differential signal transmission (RS-485)

• Optically insulated

• Built completely on discrete logic


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Control softwareControl software

Based on PVSS and DIM serverInitial version of DIM server and PVSS shell worksWritten with excellent assistance of Valery Sytnik (UC

Riverside)Targeted for full DCS compatibilityWork in progress


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Mechanical constructionMechanical construction

• Final mechanical construction

• Simple and rugged design

• PCB is optimized for automatic assembly


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Distribution RackDistribution Rack

Fan unit & heat exchanger

Distribution crate

Distribution boards

HV and control cables patch panel

Output HV cables to chambers

Need from CMS:

1. Racks

2. Fan units & heat exchangers

3. Strain reliefs

4. Space in front and behind the racks

5. Low Voltage power for distribution boards


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Distribution RacksDistribution Racks

Disk 1(Station 1) Disk 2 (Stations 2 and 3) Disk 3 (Station 4)

Position in Rack Rack 1 Rack 1 (right half of the disk)

Rack 2 (left half of the disk)

Rack 1

TOP Crate 1: 936 Crate 1: 930 Crate 1: 930

Crate 2: 936 Crate 2: 930 Crate 2: 930

Crate 3: 936 Crate 3: 930 Crate 3: 930

Crate 4: 936 Crate 4: 930 Crate 4: 930 Crate 1: 936

BOTTOM Crate 5: 936 Crate 5: 936

In the table above:

• 9x30 means 9 boards of 30 channels. One board of 30 channels powers one ME23/2 chamber

• 9x36 means 9 boards of 36 channels. One board of 36 channels powers two ME23/1 (or similar) chambers

• This table shows the HV distribution boards necessary for one Endcap (+ or -).


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Rack position for YE1 and YE2Rack position for YE1 and YE2

YE1 has only one rack


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Low Voltage Requirements for Low Voltage Requirements for Remote Distribution CardsRemote Distribution Cards

Parameter Min Max

Positive voltage 7 V 8 V

Negative voltage -8 V -7 V

Current on both channels

300 mA

Power per distribution board

4.2 W 4.8 W

Ripple/noise 100 mV

• Low voltage power will be provided by CMS AC/DC LV system


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CoolingCoolingOnly remote distribution racks are discussed.

Dissipated heat:4.8 W maximum per distribution board (about 3-4% of one

chamber LV power)~216 W per rack maximum (45 boards)~1335 W for all distribution boards

Cooling of distribution boards:No enforced cooling is currently plannedRacks must be open on top and bottom for convectionNeed heat exchangers to remove generated heatMay need fans (unlikely, will decide later)


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SafetySafety

HV CablesKERPEN halogen-free cablesPassed CERN flammability test

HV ConnectorsLEMO/REDEL, bought from CERN stock

PCB materialFR-4, flammability rating 94-V0

Other componentsWill be checked for CERN safety compliance


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Design statusDesign status

Boards’ design complete (electrical and mechanical) Pre-production prototype constructed in UF, under tests nowTests of the pre-production prototype:

Full bench test – OK Chamber test on FAST site – OK Radiation test – OK Magnetic field test – November ’03

Production boards - exact copy of the pre-production prototype


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UF-PNPI collaborationUF-PNPI collaboration

MOU between UF and PNPI is signedArrangement is very similar to chamber production

UF responsibility: Development and production management Pre-production prototype construction and testing Test stands construction Test procedures verification, instructions Off-the-shelf components procurement Bare PCBs manufacturing Automated SMT assembly US labor and components contingency


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UF-PNPI collaborationUF-PNPI collaboration

PNPI responsibility: Simple mechanical components manufactured Pre-production and production manual assembly Pre-production and production testing PNPI labor and space contingency


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ScheduleSchedule

ESR – November ’03Board production and SMT assembly start in US – end of

November ’03Start of pre-production run in PNPI – end of January ’04Pre-production system test in UF – May ’04PNPI production readiness review, production start – July ’04Production finish – June ‘05


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Installation and commissioningInstallation and commissioningInstallation:

To be done by CERN crew & UF/PNPI visitorsWill start as soon as the first shipment arrives to CERN (Oct

04’)Very uncomplicated278 distribution boards, 30 cratesHV cables already installed by that time

Commissioning:LV power supplies are necessary – at least prototypeWould like to start as early as possible (Oct ‘04)


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ConclusionsConclusions

Design solutions are proved to be workingPre-production prototype builtPre-production prototype passed testsSatisfies CMS EMU CSC HV system specsProduction documentation is being prepared


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Radiation environmentRadiation environmentExpected:

Neutron Fluence: (1 - 4) x 10^10/sq cmTotal Ionizing Dose: ( 0.07 – 0. 7) kRad

cms me csc hv system

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