Maintenance activities at Laboratori
Nazionali di Legnaro
Davide CARLUCCI
Tandem-Piave-Alpi Operation Supervisor

LNL - INFN
Viale dell'Universita' 2, 35020 Legnaro (PD) - Italy
carlucci@lnl.infn.it
LNL – INFN – Legnaro -- Italy

LNL - INFN - Identity Card
MULTI TASKMULTI DISCIPLINARY
But mainly

Nuclear Physics Based
User Oriented
Laboratories

CORE RESEARCH ACTIVITIES
1.

Nuclear Structure and Dynamics

2.

Applications and Interdisciplinary use of ion
beams and nuclear techniques and methods

LNL – INFN – Legnaro -- ItalyLaboratori Nazionali di Legnaro
Tandem(founded in 1960)PIAVE-ALPI
Complex
AN2000 accelerator
High Energy
Physics Building

my officeCN accelerator

Main Gate

LNL – INFN – Legnaro -- Italy

Low energy electrostatic accelerators
7-MV - CN - Van de Graaff (1961)
2-MV - AN2000
Van de Graaff (1971)

LNL – INFN – Legnaro -- Italy

LNL –PIAVE-Tandem-ALPI- COMPLEX
EX. Hall 3

ALPI

SC Booster ALPIPI Injector PIAVE

77 SC Quarter Wave
Resonators (Nb,Nb/cu)
Veq ~ 44
VT ~14 MV at present

SRFQ

Tandem - XTU

XTU-TandemEX. Halls 1 and 2

Further PIAVE-ALPI upgrade included in the SPES
project framework (2016)

LNL – INFN – Legnaro -- Italy

Tandem-Accelerator(1981)

DDB, 5 Mhz, 10Mhz• Negative ion source• 14 MV terminal voltage• SF6 insulating gas at 7 bars
• Single o double stripping stages

Booster ALPI (1994)
77SC Quarter Wave
Resonators (Nb, Nb/cu)
Veq ~ 48 MV

20 Full Nb, 80
MHzLow β

PI Injector PIAVEXTU-Tandem

57 Nb /Cu, 160
MHzmedium βresonator

PIAVE- Positive Ion Injector (2005)

SRFQ Veq ~ 8 MV
PI Injector PIAVEXTU-Tandem

TABLE OF TANDEM-ALPI REPRESENTATIVE BEAMSBeamE [MeV]

E/A [MeV/A]

I target [pnA]

12C5+

240

20.0

212C6+

276

23.0

216O7+

328

20.5

216O8+

360

22.5

232S9+

448

14.0

20

32S10+

490

15.3

1232S12+

565

17.7

5

48Ca9+

454

9.5

1.7
LNL – INFN – Legnaro -- Italy

TABLE OF TANDEM-ALPI REPRESENTATIVE BEAMSBeamE [MeV]

E/A [MeV/A]

I target [pnA]

48Ca9+

454

9.5

1.7

48Ca10+

505

10.5

1.3

48Ca11+55011.50.5

58Ni11+550

9.51358Ni12+

602

10.4

1058Ni13+

650

11.2

4.5

58Ni16+

770

13.3

3
LNL – INFN – Legnaro -- Italy

TABLE OF TANDEM-ALPI REPRESENTATIVE BEAMSBeamE [MeV]

E/A [MeV/A]

I target [pnA]

58Ni16+770

13.3

365Cu11+545

8.4

1265Cu12+

600

9.2

965Cu13+

650

10.0

3.5

65Cu16+

777

12.0

2.5

74Ge11+

534

7.2

2.5

74Ge12+592

8.02
LNL – INFN – Legnaro -- Italy

TABLE OF TANDEM-ALPI REPRESENTATIVE BEAMSBeamE [MeV]

E/A [MeV/A]

I target [pnA]

74Ge13+

645

8.7

1

74Ge17+

826

11.2

0.3

82Se12+

582

7.1

782Se13+

639

7.8

4

82Se17+

820

10.0

1.5

90Zr12+610

6.8

190Zr13+

630

7.0

0.6

90Zr14+

700

7.7

0.3

100Mo11+

545

5.4

0.7

100Mo12+

600

6.0

0.6
LNL – INFN – Legnaro -- Italy

TABLE OF CURRENTLY AVAILABLE PIAVE-ALPI BEAMSBeamE [MeV]

E/A [MeV/A]

I target [pnA]

22Ne4+

243

11.02*

40Ar9+

390

9.8

4÷1084Kr18+

800

9.5

5÷10120Sn21+

850

7.1

1132Xe27+

1200

9.1

2132Xe26+

1050

81

136Xe34+

1240

9.1

0.3

197Au30+

1200

6.1

1
LNL – INFN – Legnaro -- Italy

Maintenance should be Preventive
and sometimes (in(in the rare case)case) Last
minute, predictive..., in the real life sometimes you can start with one
strategie and during the work, you change the last
strategy....or if the Maintenance is too big, thespecial maintenance is necessary (maybe you will dothe special maintenance in more steps in order tonot interfere too much with the acceleratoroperation)
I think is very important to keep constant attention toevery failure by statistic counter.
LNL – INFN – Legnaro -- Italy

How to decide the Maintenance aproach ?
Identify all the machine systems, the subsystem of eachsystem......, and after that you can decide the right aproach

Preventive
1 subsistem• Charge system control every maintenance• Laddertron change evry 14000 hours

2 Subsitem• Alternatore belt change every 20000 hours• Corona point change every 3 years

3 Subsistem• Voltage divider control every maintenance• Nylatron bar change every 40000 hours

Last minute• P.S. For the charge sistem in the terminal• P.S. For vacuum pom p sistem in the terminal

If the number of Last minute maintenance events
increases, change approach tos preventive maintenance,or development, or up-granding
LNL – INFN – Legnaro -- Italy

Not Maintenance alone
In any case the maintenace, preventive, Last minute, predictive,
Development and the Up-grading, they must complete the necessary
puzzle for high Relaiability, and high performance.

UpUp-grading
Preventive
Development

Last minute

LNL – INFN – Legnaro -- Italy

Why maintenance ?
Safety reason

CostPeoplecostElectricalpower

User cost
1 Day
beam loss
cost ~
30 K euro

LNL – INFN – Legnaro -- Italy

Exemple of Last minute Maintenance•July 2005
problem with resistors, valuechanged from ~500MΏ to ~340MΏ
(particularly in sec.1 & sec.8).
Initially resistors support broke Bad trasmission
 Low T.V.(12-12.5)MV
ReplecedResistor

Supportbroken
LNL – INFN – Legnaro -- Italy

Repeated problems with the Tandem ,the Last minute aproach increased the statistic• Ocober-December 2005:
10 unscheduled opening: 9 for broken resistor support and 1for vacuum problem

19LNL – INFN – Legnaro -- Italy

Analysis of the statistic problems
Tandem RS holders replacement by year2018161412108
6Tandeminstallation
at LNL

April:Nylatronbars
mounted

4
2

1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008

0

LNL – INFN – Legnaro -- Italy

After the statistic analysis theLast minuteBecame Preventive Maintenance

Fixed spacer bar among Rs holders(mat.: nylatron mc 901, in all the section ofthe machine are installed.)
LNL – INFN – Legnaro -- Italy

Could happen...Started as Development ended as
Maintenance of all cryostatsLNL started to think about ALPI, a heavy ion SC linac equipped with QW,Pb on Cu resonators, less expensive and easier to build than Nb QWR.
Since the beginning we investigated the possibility to substitute in thefuture Pb with Nb.
A laboratory for Nb QWR sputtering was set up and a devoted research
project was funded in 1987.
1987: Funding a Development on QWR Nb sputtering
 1988-1999: DC biased sputtering choice and system set-up 1990: Obtaining good SC performance on samples
 1991: Sputtering on a simplified prototype
 1994: Design of a ALPI high b resonator suitable for sputtering
production and compatible with existing cryostats 1995/1998 Production and installation of 4 high b cavities in ALPI 1998 Sputtering of a standard medium b ALPI resonator 2003 Upgrading of the medium b ALPI resonators


LNL – INFN – Legnaro -- Italy

CR10C 1
R10C 4
R1
2C 3
R13C 2
R14C 1
R14C 4
R15C 3
R16C 2
R17C 1
R17C 4
R18C 3R192

Accelerating Field [MV/m]

2003 Medium β ALPI cavities from Pb to Nb

6543210

Exemple of preventive maintenance 2009-10

Problem of mechanical fatigue, causing He gas leak from cryostat shields(VERY Dangerus).
Preventive Maintenance in all the cryostats
LNL – INFN – Legnaro -- Italy

Could happen... Started as maintenance Lowβ tuning device ended as an upgrade
The main source of detuning, in these cavities, is thechange of pressure of the helium bath. The standard
ALPI mechanical tuner, although sufficient for slow
corrections, is not well suited for frequency tracking in
the presence of fast pressure fluctuations, due to large
mechanical backlash and poor reproducibility.

1 mbar ~ 1 Hz

∆P in the Cold-box meaning ∆f in the cavity
1. Resolution ∼0.33 µm or better; this corresponds tofrequency resolution below 1 Hz.
2. Very small and reproducible backlash in order toallow a fast tuner recovery .
We used the lever design of the TRIUMF QWR tuner
with commercial backlash-free “C-FLEX” joints.
The system is linear and its theoretical resolution of on
the tuning plate is 0.1 µm. This results in about 0.3 Hz
tuning resolution for low-β quarter wave resonators; thisvalue is well suited for our application.

New tuner

LNL – INFN – Legnaro -- Italy

The same problem (∆P in the cold-box) trigger the start for
an Upgrade of RF coupler for the Low β QWR
A new, liquid nitrogen cooled RF coupler,
inspired by the ISAC_2 one, has been
designed in order to maintain stabletemperature with a forward power up to500W, while limiting the thermal load tothe liquid helium system within 1W. Themain difference from the TRIUMF modelis the 90 degrees corner near theconnector, that allows
keeping the overall length within 160 mm(the maximum available space in ourcryostats) while leaving an effective strokeof 80 mm; this results in a larger tuning
range. The calculated heat load towards
FIG 1: Cut view of the new cooled
the liquid He circuit is around1 W.
coupler prototype
LNL – INFN – Legnaro -- ItalyLow-β tuning device upgrading
30
25
2015

Spinta1
Ritorno1
Spinta2

1050-150-100-50-5 0-10-1550

Steps100150

Hz-20

Resolution ∼0.33 µm or better; thisFigure 5: Frequency
corresponds
to change vs. tuner step, tested at
4.2K with an 80
MHz superconducting
frequency
resolution
below 1resonator.
Hz.

• C-flex joints do not deteriorate the Q (> 109)of the QWR• good linearity, resolution and reliability• tuning range > 10 kHz
LNL – INFN – Legnaro -- Italy

Safety maintenaince of electrical wiring at Tandem
XTU

LNL – INFN – Legnaro -- ItalySmooth transition from an all-on-paper to all-on
DB E-Logbook

LNL – INFN – Legnaro -- ItalySmooth transition from an all-on-paper to all-on
DB E-Logbook

LNL – INFN – Legnaro -- ItalySmooth transition from an all-on-paper to all-on
DB E-Logbook

All the value of the magnets, and RF, are recorded every second
LNL – INFN – Legnaro -- Italy

Maintenance Future?

LNL – INFN – Legnaro -- Italy

My Big Job

LNL – INFN – Legnaro -- Italy

Thank you for your attention

LNL – INFN – Legnaro -- Italy