1. Alfonso Boiano1, Flavio Loddo2, Pierluigi Paolucci1, Antonio Ranieri2
RPC’s HV-LV project
I.N.F.N. Naples
Introduction
System requirements and description
SASY-2000 project
Prototype tests
Cables and connectors
Summary
Alfonso Boiano1, Flavio Loddo2, Pierluigi Paolucci1, Antonio Ranieri2
1) I.N.F.N. of Naples, 2) I.N.F.N. of Bari

2. Pierluigi Paolucci - I.N.F.N. Naples
Introduction I
I.N.F.N. Naples
The RPCs sub-detectors of the LHC experiments will be for the first time equipped with a large part of the HV-LV system placed in a not accessible area.
The HV “remote hardware” will be placed on the balcony and it will be accessible just in some dedicated period.
The system will work in very hard conditions for the high magnetic field and high radiation environment.
11/27/2018
Pierluigi Paolucci - I.N.F.N. Naples

3. Pierluigi Paolucci - I.N.F.N. Naples
Introduction II
I.N.F.N. Naples
The idea of the HV-LV system for the RPC detector of the LHC experiments is to split the system in two:
LOCAL: SY1527 mainframes placed in control room and a 48 Volts High Power Source;
REMOTE: distribution system placed in the UXC zone around the detector. It consists of a 6U custom crate housing 2 independent controllers and up to 8 distribution board equipped with 4 HV + 8 LV floating channels.
The system will work in very hard conditions due to the high magnetic field and high radiation environment.
A common project (SASY 2000) to realize this system is going on between the I.N.F.N. and the CAEN company.
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Pierluigi Paolucci - I.N.F.N. Naples

4. detector description I
I.N.F.N. Naples
RB3/RB4
ALV1
DLV1
ALV2
DLV2
HV1
HV2
Bigap
ALV1,ALV2,ALV3
DLV1,DLV2,DLV3
Bigap
RB2 reference plane
RB1/RB2in
Bigap
ALV1
DLV1
ALV2
DLV2
HV1
HV2
HV1
HV2
HV3
Two non adjacent gaps will be connected to the same HV channel
in order to halve the # of HV channels “without” reducing the trigger efficiency.
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Pierluigi Paolucci - I.N.F.N. Naples

5. 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 Working Cur. = 0.42 A
DLV Digital Voltage = 7V Working Cur. = 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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Pierluigi Paolucci - I.N.F.N. Naples

6. requirements and numbers
I.N.F.N. Naples
requirements:
system working in high magnetic field;
system working in an high radiation environment;
local system in control room + distributed remote systems on the detector;
low voltage (48 Volts) running from the local to the remote system;
floating HV (12KV–1mA) and LV (7V–0.42A (ana.) and 7V–0.9A(dig.)) channels (noise reduction).
wheel 1 2 3 4 5
TOT
gaps
408
2040
HV ch.
204
1020
front-end
936
4680
LV ch.
312
1560
having chosen 2 gaps per HV channel and 6 FEBs per LV channel
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Pierluigi Paolucci - I.N.F.N. Naples

7. Pierluigi Paolucci - I.N.F.N. Naples
SASY2000 project for RPC I
I.N.F.N. Naples
Electronic house 1 1
Branch controller
From 1 to 16 4 4
All independent
floating channels
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Pierluigi Paolucci - I.N.F.N. Naples

8. Pierluigi Paolucci - I.N.F.N. Naples
SASY2000 project for RPC II
I.N.F.N. Naples
Detector region
Electronic house 4 8 … 16
HV #1
HV #2
Branch controller #1
Complex ch. 1
256
Remote
boards
LV #1
LV #4
Branch controller #2
HV #1023
HV #1024
Complex ch. 512 …
256
LV #2047
LV #2048
Branch controller #16
What do we need ??
26 ch * 12 sect * 5 wheels = 1560 LV
17 ch * 12 sect * 5 wheels = 1020 HV
One mainframe is enough for the barrel
The remote board has 2 Complex ch. each equipped with: 2 HV ch and 4 LV ch.
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Pierluigi Paolucci - I.N.F.N. Naples

9. RPC HV-LV prototype SASY2000
I.N.F.N. Naples
The HV-LV CAEN functional prototype consists of: 1 HV board, LV board and 1 controller.
The prototype has been split in three pieces, following the “logical separation” of the system, in order to study the functionality of every single piece and component.
The final HV-LV board will
have 2 complex channel
each with 2 HV + 4 LV
floating channels .
It will be 6U high and 2 slots
width.
After the tests the factory will begin to design the final board
integrating all these components in a single 6U – 2 slots boards.
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Pierluigi Paolucci - I.N.F.N. Naples

10. Pierluigi Paolucci - I.N.F.N. Naples
Test performed
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).
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Pierluigi Paolucci - I.N.F.N. Naples

11. 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)
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Pierluigi Paolucci - I.N.F.N. Naples

12. 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
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Pierluigi Paolucci - I.N.F.N. Naples

13. 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 very 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 voltage 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.
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Pierluigi Paolucci - I.N.F.N. Naples

14. 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.
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Pierluigi Paolucci - I.N.F.N. Naples

15. High Stress Test description II
I.N.F.N. Naples
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);
OFF position.
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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Pierluigi Paolucci - I.N.F.N. Naples

16. High Stress Test description III
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).
A C program has been written to control all the operations of the micro-controller. The program is stored in the internal flash memory. It also calculates the voltage from the measured current and takes in account the offset of each full scale.
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Pierluigi Paolucci - I.N.F.N. Naples

17. Pierluigi Paolucci - I.N.F.N. Naples
The HST test box
I.N.F.N. Naples
rotating switch
display
RS232 port
step motor
manual control
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Pierluigi Paolucci - I.N.F.N. Naples

18. Pierluigi Paolucci - I.N.F.N. Naples
HST LabVIEW display
I.N.F.N. Naples
output
table
Vmon
Imon
current
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Pierluigi Paolucci - I.N.F.N. Naples

19. Pierluigi Paolucci - I.N.F.N. Naples
HV cable
I.N.F.N. Naples
The HV cable has been chosen and approved
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 and 3 conductors cable)
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Pierluigi Paolucci - I.N.F.N. Naples

20. Pierluigi Paolucci - I.N.F.N. Naples
HV connectors I
I.N.F.N. Naples
The HV connector has been chosen and approved
Possibility to stack it up
Electrical characteristics:
Operating voltage: 15 kV
Testing conditions: 20 kV
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%) (Conforming to TIS Rules)
Metal cover connected to external chamber aluminum frame
ZAMA (UNI 3717 G-Zn A14 Cu1)
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Pierluigi Paolucci - I.N.F.N. Naples

21. Pierluigi Paolucci - I.N.F.N. Naples
HV connectors II
I.N.F.N. Naples
By CPE (
Price: 3 CHF/contact/ pieces
Schedule:
The connector has passed CERN tests for chemical analysis
Made electrical test performance (before and after radiation exposure)
We are waiting for the final quotation before final order
11/27/2018
Pierluigi Paolucci - I.N.F.N. Naples