1. RPC HV&LV systems Introduction Detector description Requirements
I.N.F.N. Naples
Introduction
Detector description
Requirements
SASY 2000 prototypes tests
More systems description
Cables and connectors
Solutions and costs
Conclusions
A. Boiano1, F. Loddo2, P. Paolucci1, D. Piccolo1, A. Ranieri2
1) I.N.F.N. of Naples, 2) I.N.F.N. of Bari
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

2. Different solutions are under study by the CMS RPC group
Introduction I
I.N.F.N. Naples
The CMS sub-detectors will be equipped with a large part of the HV and LV systems placed around the detector; in a not “easily accessible” area.
The CMS and ATLAS RPC groups are investigating the possibility to have both the systems around the detector, working in a very hard conditions for the high magnetic field and high radiation environment.
The LHC RPC groups, in collaboration with the CAEN, have designed and tested an HV-LV prototype (SASY 2000) able to work in an hostile area. The system is based on the idea to split in two the HV and LV systems:
LOCAL: Central system (mainframes) placed in control room;
REMOTE: distribution system placed around/on the detector, consisting of a crate housing the HV and LV boards.
A natural evolution of the SASY2000 has been presented to CMS (May 03) by the CAEN company: EASY system.
Different solutions are under study by the CMS RPC group
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

3. Detector description I
I.N.F.N. Naples
There are 3 different kind of chambers with 2 or 3 bigaps and equipped with
6 or 12 or 18 Front-End Boards
RB2/3
Bigap
ALV1
DLV1
ALV2
DLV2
HV1
HV2
RB3 and RB4
ALV1
DLV1
ALV2
DLV2
HV1
HV2
Bigap
RB1 and RB2/2
Bigap
ALV1
DLV1
ALV2
DLV2
HV1
HV2
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4. Detector description II
I.N.F.N. Naples
RB1/RB2in
RPC chamber
Front-End
Bigap
Distrib. board
Bigap
ALV1
DLV1
ALV2
DLV2
ALV Analog Voltage = 7V Absorb. (6FEBs) = 0.42 A
DLV Digital Voltage = 7V Absorb. (6FEBs) = 0.9 A
I2C input
LV+I2C FEB out
LV in
Distributes analog and digital LV
It supplies LV power to 3 FEB chains
It supplies the I2C main line from LB
and one backup line from DT.
Total power/(ALV+DLV) ch.: 1.32 A * 7 V = 9.24 W
Expected Power  120 W/sector  7.2 kW/Barrel
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5. Pierluigi Paolucci - I.N.F.N. Naples
Barrel wheel overview
I.N.F.N. Naples 1 2 3 4 5 6 7 8
Muon racks 12 11 10 9
5 CMS wheels
12 sectors
balcony
12 sectors * 5 wheels = 60 sectors
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6. HV-LV schema for a Barrel sector
I.N.F.N. Naples
78 FEBs = 13 ALV+13 DLV ch bi-gaps = 34 HV ch.
DT chamber
RB4
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
4+4 HV
DT chamber
RB3
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
4+4 HV
6+6+6 FEBs / 3 bi-gaps
6 LV
6 HV
RB2
DT chamber
4 LV
6+6 FEBs / 2 bi-gaps
4 HV
4 LV
6+6 FEBs / 2 bi-gaps
4 HV
RB1
DT chamber
4 LV
6+6 FEBs / 2 bi-gaps
4 HV
2 bi-gaps = 96 strips = 6 FEBs
LVD channel
HV channel
LVA channel
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Pierluigi Paolucci - I.N.F.N. Naples

7. Pierluigi Paolucci - I.N.F.N. Naples
System requirements I
I.N.F.N. Naples
General requirements:
working in high magnetic field (up to 2 Tesla);
working in an high radiation environment (5*1010 p/cm2 & 5*1011 n/cm2 & kRad);
local system in control room + distributed remote systems on the detector (at least for the LV);
redundancy of the control electronic devices (mP per board)
input voltage from the CMS AC/DC 48V power supply;
looking forward common CMS solutions in order to simplify the hardware and software development/maintenance of the systems
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8. System requirements II
I.N.F.N. Naples
HV requirements:
12KV/1mA
Ripple < 100 mV pp at load per f < 20 MHz
Programmable voltage 0-12KV
Voltage step 10V
Voltage precision < 10V
V/I/Trip/Status control and monitoring
Error/Power leds
LV requirements:
7V/3A
Ripple < 10 mV pp at load per f < 20 MHz
Programmable voltage 0-8V
Voltage step 100 mV
Voltage precision 100 mV
V/I/Trip/Status control and monitoring
Individual ON/OFF
Error/Power leds
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9. System requirements III
I.N.F.N. Naples
Control and monitoring system requirements:
Common hardware and software (PVSS II) solution;
Detailed control/monitoring of the remote channels:
voltage/current and temperature
protections, errors and hard-reset for communication lost.
A second independent way to control them (telnet/ssh......)
Design requirements:
Possibility to easily increase the HV granularity;
Possibility to easily fix RPC problems:
disconnect high-current/sparking gap/bi-gaps;
modify the HV map in order to group bi-gaps with same working point;
Possibility to measure the RPC working-point in standalone.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

10. Pierluigi Paolucci - I.N.F.N. Naples
HV-LV system design
I.N.F.N. Naples
Different HV and LV designs will be described in order to reduce the total cost preserving the system requirements, already analyzed and the trigger functionality:
1 HV/bigap 2 LV/6FEBs; FULL OPTION
1 HV/chamber 2 LV/chamber; CHAMBER OPTION
1 HV/station 2 LV/station; STATION OPTION
Then we will analyze two different solutions for both the HV and LV system based on the idea to have them on the detector or in control room.
HV in control room HV on the detector
LV in control room LV on the detector
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11. HV-LV schema for FULL option
I.N.F.N. Naples
26 LV channels HV channels
Chambers have been designed with 2 gaps, of adjacent bi-gaps, connected to the same HV channel, in order to reduce the number of HV channels preserving the number of station available for the muon trigger
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
2+2 HV
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
2+2 HV
6 LV
6+6+6 FEBs / 3 bi-gaps
3 HV
4 LV
6+6 FEBs / 2 bi-gaps
2 HV
4 LV
6+6 FEBs / 2 bi-gaps
2 HV
4 LV
6+6 FEBs / 2 bi-gaps
2 HV
wheel 1 2 3 4 5
TOT
gaps
408
2040 HV
204
1020
FEBs
936
4680 LV
312
1560
FULL option
1 HV channel per 2-gaps
2 LV channels per 6-FEBs
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12. HV-LV schema for CHAMBER option
I.N.F.N. Naples
16 LV channels HV channels
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
1+1 HV
2+2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
1+1 HV
2 LV
6+6+6 FEBs / 3 bi-gaps
1 HV
Reduction of
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
HV 1020  480 ch
LV 1560  960 ch
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
wheel 1 2 3 4 5
TOT
gaps
408
2040 HV 96
480
FEBs
936
4680 LV
192
960
CHAMBER option
1 HV channel per chamber
2 LV channels per chamber
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

13. HV-LV schema for STATION option
I.N.F.N. Naples
12 LV channels HV channels
2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
1 HV
2 LV
6 FEBs / 2 bi-gaps
6 FEBs / 2 bi-gaps
1 HV
2 LV
6+6+6 FEBs / 3 bi-gaps
1 HV
reduction
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
HV 1020  432 ch
LV 1560  720 ch
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
2 LV
6+6 FEBs / 2 bi-gaps
1 HV
wheel 1 2 3 4 5
TOT
gaps
408
2040 HV 72
432
FEBs
936
4680 LV
144
720
STATION option
1 HV channel per station
2 LV channels per station
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14. More numbers about HV and LV
I.N.F.N. Naples
Looking at different solutions seems to be reasonable to have the following crate/board design:
HV board with 6 ch. (12 KV / 1 mA) 3 slots width;
LV board with 12 ch. (7 V / 3.2 A) 3 slots width;
6U standard Eurocard crate housing up to 6 HV/LV boards.
What do we have in the Station (final !) option ?:
1 HV board/sector  60 HV boards
1 LV board/sector  60 LV boards
The number of crates depends on where they will be dislocated and so are different in the Detector/Control Room solutions
12/8/2018
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15. Pierluigi Paolucci - I.N.F.N. Naples
SASY 2000 prototype
I.N.F.N. Naples
SASY 2000 prototype
The HV-LV prototype 0 consists of: HV board (SA2001), 3 LV boards (SA2002) and 1 controller.
It has been split in three pieces, following a “logical separation” of the system, in order to study the functionality of every single piece and component.
The following tests has been performed on both the prototypes and will be repeated for the final boards:
Magnetic field test up to 7 KGauss (at CERN) (results shown by CAEN at CERN in May 2002)
Radiation test up to 10 LHC eq-years (at Louvain La Neuve) (results shown)
Test on the RPC to study the noise condition (to be performed at the test station in Bari);
High Stress Test to study the system under very hard conditions (under test in Napoli).
12/8/2018
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16. Neutron radiation test
I.N.F.N. Naples
The SASY2000 HV-LV prototype has been tested twice (May-Aug 2002) at the Louvain La Neuve radiation facility.
The total neutron fluence requests
for 10 LHC years is about 1x1012 n/cm2 (note: in RE1/1 region) corresponding to 2 hours and 40 min with a beam at 1 mA at 70 cm
SASY2000
In first session the system worked well for 30 min. corresponding to 1.8 • 1011 n/cm2 (a factor 6 higher than that expected on RB4!) We lost the communication with the prototype. CAEN reported a known loss of current gain due to irradiation on CNY17 opto-insulator used to enable the HV/LV channels. The prototype was irradiated for 80 min corresponding to 4.8*1011 n/cm2.
On the second prototype (ATLAS one) the gain current loss was cured using a lower value biasing resistor. Was registered a few SE on the controller with loss of communication but the normal condition was restored after 1 s on power OFF/ON condition (it will be implemented by firmware an HOT RESET to recover the communication without interruption of remote power supply).
After the irradiation the SASY2000 was tested outside, preserving its original functionality. (robustness of hardware)
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

17. Magnetic field test setup
Magnet: MNP24-1 at CERN Bldg. 168
B: up to 10 KGauss B around CMS: .44T
Test condition: 0-7 KGauss
Magnetic Field:
up to 5 KGauss
Test condition
SA2001: VOUT = 8kV, Rload=12 M
SA2002: VOUT0 = 4.7 V, VOUT1 = 5.0 V, IOUT0,1 = 1.9A
from 0 a 5 KGauss: loss of efficiency 2% (// B) 0% ( B)
(efficiency defined as =Pload/PDC-DC converter) (75%  73%)
Future improvements:
transformer oriented according  B  it will work reliably up to 8 KGauss
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

18. High Stress Test in Naples I
I.N.F.N. Naples
The High Stress Test system has been designed and developed by the group of Naples in order to make a complete test of any HV-LV power supply.
It consists of a test-box controlled by a PC running LabVIEW 6.1
At present the HST system is able to make:
Long term test: A cycle of measurements (voltage and current) made using different resistive charge (from 1M to 10 G) to explore the whole range of the PS.
Spark test: A cycle of spark at different voltages are generated in order to test the hardware/software behavior of the PS under this critical conditions.
Calibration: independent measurement of the voltage and current (PS and test-box). The Trip-time, the rump-up and rump-down are also calibrated.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

19. High Stress Test description I
I.N.F.N. Naples
The test-box consists of a custom rotating switch controlled by a step-to-step motor through a microcontroller (Microchip) .
Each position of the switch corresponds to an electrical contact placed on a PCB and positioned on a circle at a distance of 22,5o each others.
The motor needs 400 steps to make a complete turn corresponding to about 0.9o/step.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

20. High Stress Test description II
I.N.F.N. Naples
The micro-controller PIC 16F is used to:
controls the motor through a custom board housing a “power driver” used to generate the phases needs to control the motor.
drive the LCD monitor placed on the box and the manual control.
drive the communication through a serial port RS232 used to connect it to a PC.
control an internal ADC (10 bits) and drive a Programmable Gain Amplifier. It is used to measure the current provided by the PS at different full scale (1mA, 100 mA, 1mA).
Each position of the commutator is connected to:
a different resistive charge (10G, 5G, 1G, 100M, 9M, 6);
one of the four spark systems (10KV, 5KV, 2KV, short);
The spark system consists of two electrodes connected between the high voltage and the ground, placed at a fixed distance in order to generate sparks at a predetermined voltage.
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21. Pierluigi Paolucci - I.N.F.N. Naples
Ripple measurements
I.N.F.N. Naples
We are studying the noise and ripple of the HV and LV boards using a scope connected to a PC equipped with LabVIEW.
After a month we have not seen any unusual noise/events on both the boards.
The ripple peek to peek at load (f < 1 MHz) of the 2 HV channels is < 20 mV while for the 6 LV channels it is about 200 mv ???
The problem is present also when LV is OFF but mainframe is ON (could be a bad ground connection ?) is under study.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

22. CMS common LV solution proposal
I.N.F.N. Naples
In the 2002 the CMS collaboration decided to evaluated the possibility to have a common solution for the LV (and HV) system in order to minimize: costs, installation, software, spare, expertise and maintenance.
The idea has been enthusiastically accepted by the sub-detector unless HCAL.
CMS has contacted a lot of electronic companies asking them to propose a common LV solution for all the subsystems giving them some general requirement and all the requirement got from each sub-detector.
In the last CMS Electronic week (May 2003) companies have been invited to present a LV system for all the CMS subsystem.
Two companies; CAEN and WIENER presented two projects for LV (and HV)
The CAEN project, called EASY, is a natural evolution of the SASY 2000
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23. Radiation & Magnetic Field
CAEN EASY project I
I.N.F.N. Naples
EASY +
DCS
OPC SERVER
CAN Bus based link
Ad-hoc protocol
Speed and reliability
No interoperability issues
Can work in hostile area
It seems to respect the
hardware and software
requirements made
by CMS but we need
a prototype to say YES
Standalone
EASY
3000
4000
Rack Mount
Radiation & Magnetic Field
Full integration in SY1527/SY2527
21 slots per crate
3 kW Maximum Output Power
Magnetic field capability: 2 kGauss
Expected rad.tol.: 5*1010 p/cm2 , 2*1011 n/cm2 ,15 kRad
Per channel:
Independent ON/OFF
Vmon (Connector and Load), Imon
Vset (Software or Hardware)
Programmable Trip, Sense wires
Status Signals
Imax per module (Hardware)

24. boards ready to be produced (on catalog)
CAEN EASY project II
I.N.F.N. Naples
boards ready to be produced (on catalog)

25. Other LV companies RPC LV system:
I.N.F.N. Naples
RPC LV system:
the Wiener proposed a set of Power Supply (power, dimension) of very high quality with also some software developed. Magnetic and radiation requirement under discussion !
we did not found any other Power Supply company interested in produce a PS with our requirements (B & rad)
we contacted 3 companies for standard LV power supply (control room):
the monitor/control hardware system to be developed;
software and DCS integration to be developed;
crate (cooling) to house them to be developed;
prices are similar with sensing;
Have the LV in control room means: long cables (cooling),
patch panels, hardware/software to similar price
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

26. HV cable and connectors
I.N.F.N. Naples
The HV cable and connectors have been chosen and approved by CERN
2 high voltage pins to supply –12 kV
1 pin for signal return
insulating material
Polietilene HDPE (Eraclene Polimeri Europa (57%)
Masterbatch (GPO1246 Viba) (43%)
Metal cover connected to external chamber aluminum frame
ZAMA (UNI 3717 G-Zn A14 Cu1)
Suitable to sustain up to 15 kV
Cable characteristics:
According CERN safety instruction IS 23
Single conductor- = 0.16 mm
Conductor 20°C = 147 /Km
Core- = 3 mm
Screen wire-=0.2 mm (for 10 conductors)
Overall diameter = 8.4 mm (for 3 conductors)
Price: €/Km (for 10 Km)
Price: 24 Euro/couple pieces
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

27. LV connector and cable
I.N.F.N. Naples
The LV cable and connectors are under discussion
LV cable: 8 wires  outer diam. = 7.5 mm Price 1,00 Euro/m
12 wires  outer diam. = 8.5 mm Price 1,50 Euro/m
LV cable connector:
female 12 pins Molex Microfit-Fit 3,0 ( ) Price 3,49 Euro/5
female pins 20 AWG Molex Microfit-Fit 3,0 ( ) Price 10,37 Euro/100
LV RPC connector:
male 12 pins Molex Microfit-Fit 3,0 ( ) Price
12/8/2018
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28. LV and HV CAD cable design
I.N.F.N. Naples
Max LV/HV local cable lenght = 15 mt
Min LV/HV local cable lenght = 6 mt
Average lenght = 12 mt
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Pierluigi Paolucci - I.N.F.N. Naples

29. Detector and Control Room option
I.N.F.N. Naples
Looking at our requirements seems to be clear that is much better to have the HV system in control room and the LV on the detector but we have analyzed both the solutions in order to have a complete picture of the systems.
What do Detector and Control Room mean ?
Detector: the HV/LV crates are in the racks placed on the balconies (4 per wheel)
Control room: the crate are in the USC zone (150 ?? mt far from the detector).
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30. detector/control room option 1cable/balcony  60 cables
I.N.F.N. Naples
Control Room HV
patch
panel
crate
HV patch panel = 6 U
LV crate = 6+1 U
Total = 13 U HV
patch
panel LV
crate
1cable/balcony  60 cables 3 4 3 4 2 5
control room option 1 6
detector option 12 7 HV
patch
panel LV
crate 11 8 10 9 5 6
HV patch panel = 6 U
LV crate = 6+1 U
HV crate = 6+1 U
Total = 20 U
Detector
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31. Pierluigi Paolucci - I.N.F.N. Naples
HV on the detector
I.N.F.N. Naples
60-80 HV boards placed in 20 crates (1 per balcony)
No easy access, no way to disconnect a bigap, difficult upgrade
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Pierluigi Paolucci - I.N.F.N. Naples

32. HV in Control Room 60 HV boards placed in 10 crates
I.N.F.N. Naples
Power consumption:
board = 72 W
crate = 430 W
Total 4.3 KW
60 HV boards placed in 10 crates
60 long cables (130 mt), double patch panels
Easy operation on HV (bigap, chamber....)
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33. Pierluigi Paolucci - I.N.F.N. Naples
LV on the detector
I.N.F.N. Naples
60 LV boards placed in
20 crates (1 per balcony)
Power consumption:
board (12 ch.)  116 W
crate (3 boards.)  350 W
wheel (4 crates)  1.4 KW
Total  7.0 KW
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Pierluigi Paolucci - I.N.F.N. Naples

34. HV and LV cost estimation
I.N.F.N. Naples
The total costs of the systems are calculated using a spreadsheet having as inputs the following items:
number of: connectors, cables, patch panels, boards, crates, controllers and mainframes
cable length and installation costs
cost of each of those items
We have used the following prices (Euro): 3500 HV board,
2500 LV boards, 1500 crates, 3500 branch contr, 10K mainframe.
HV control room
HV on detector
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Pierluigi Paolucci - I.N.F.N. Naples

35. Pierluigi Paolucci - I.N.F.N. Naples
HV and LV cost comments
I.N.F.N. Naples
The difference in price between the two solutions, after the HV and LV descoping, is less than 50K€ that is not enough to push forward the HV on the detector.
Have the HV in Control Room means (EASY ACCESS):
Possibility to disconnect an high-current or sparking bigaps without switching of the other bigap;
Increase the granularity when more HV boards will be available;
Increase the number of HV channel when/if some station will drawn to much current.
We hope to increase asap the number of HV boards from 60 to 80 in order to decoupling the RB3 and RB4 stations.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

36. They cost now: 220K€ (LV) + 400/450 K€ (HV)
Conclusions I
I.N.F.N. Naples
We have designed a “reduced” HV and LV systems for budget limitation, keeping our requirements, consisting of:
HV: from 1020 to 432  80/60 boards  20/10 crates
LV: from 1560 to 720  60 boards  20 crates
They cost now: 220K€ (LV) + 400/450 K€ (HV)
We hope to upgrade the HV system as soon as possible at least to decoupling the RB3 and RB4 stations (from 60 to 80 boards).
The two options (Detector and Control Room) have an estimated cost difference of less than 50K€.
The HV in Control Room is a much better solution from any point of view.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples

37. Pierluigi Paolucci - I.N.F.N. Naples
Conclusions II
I.N.F.N. Naples
Have a common LV (HV) system for CMS is a very important step forward a cost reduction and system simplification.
Have the LV in control room means: long cables (cooling), patch panels, hardware/software to similar price and so we thing is not the best solution.
For the HV system, the CAEN is, up to now, the only company able to give us a very high quality system in a so short time.
We need prototypes to test (B/rad/stress) for the 2003 in order to put the order in the second part of the 2004 and install the system in the 2005.
12/8/2018
Pierluigi Paolucci - I.N.F.N. Naples