RILIS operation
Presented to Standing group for the upgrade of the ISOLDE
facility
July 7, 2011
By V. Fedosseev
2008: First step of RILIS upgradeCopper Vapor Lasers are replaced by Diode Pumped Solid State Nd:YAG Lasers
Laser generates 3 beams at 10 kHz:Main green beam – 532nm, 70-80 W, 8 nsResidual green beam – 532 nm, 12-28 W, 9 nsUV beam - 355 nm, 18-20 W, 11 ns
Main green beam
Residual green beam
UV beam
•Two lasers are available: •one in use, second as a backup
New Dye Lasers installed
Benefits:• Greater efficiency and stability.• Higher UV power and better beam quality.• Enable UV pumping to provide beams in the 380 – 540 nm range.• Wavelength control via LabVIEW
2009-2010: Second step of RILIS upgrade
Ti:Sapphire lasers constructed and installed
Frequency conversion unitdesigned by S. Rothe
Ti:Sa design
Photonics
NB-DL
Edge
wav
e
Sira
h 1
Sira
h 2
Ti:Sa
Ti:Sa
Ti:Sa
3, 4
3, 4
Photonics
Sirah 2
Sirah 1
EdgewavePower
+ chiller
Edge
wav
e
NB-DL
2010-2011: Third step of RILIS upgrade
Nd:YAG Dye 2
Dye 1 THG
SHG
RILIS Dye Laser System
GPS/HRS
Target & Ion Source
l – meter
Nd:YAG Ti:Sa 1
Ti:Sa 2 FHGSHG
RILIS Ti:Sa Laser System
l – meter
Master clock
Delay Generator
pA – meter
Faraday cup
The 3 RILIS laser upgrade steps are now completed
1) Pump laser replacement 2) Dye laser replacement 3) Ti:Sa laser installation
Dye 3 SHG
The complete RILIS Dye + Ti:Sa system
3 Ti:Sa lasers from Mainz university
RILIS cabin layout has been redesigned to accommodate the new lasers
Optical pumping in ISCOOL should be tested during 2011 shutdown
Dye and Ti:Sa synchronization and compatibility for mixed ionization schemes has been verified online during the At run
Harmonic generation unit for Ti:Sa system
Photonics Industries Nd:YAG pump laser for the Ti:Sa lasers
Sirah dye lasers with 2nd harmonic generation and UV pumping option
Edgewave Nd:YAG laser for dye pumping or non resonant ionization
Narrow band dye laser with computer controlled grating and etalon for high resolution spectroscopy or isomer selectivityDye laser 3rd
harmonic generator
Improved HRS laser beam launch system with a 4th laser beam path for laser transport to ISCOOL
Ti:Sa system is operating in testing/backup mode during 2011. It has so far been used for ionization of At and for Pr ionization scheme development
The new solid state Ti:sapphire laser system is operational Successfully used for Beam development of astatine and first physics results (bDF)
Prerequisite for geared operation: Temporal synchronization of the two laser systems
Powerful dye pump laser can provide non-resonant step for Ti:Sa schemes
Mixed schemes are now possible: Blue -VIS step from Dye and NIR step from Ti:Sa
Laser beams produced by dye and Ti:Sa are exchangeable
Highest efficiencies
New schemes possible
Unique for laser ion sources world-wide
Backup solution
Reduction in down time New elements
Keep one dye set up for future, use Ti:Sa instead
Outlook:• RILIS scheme development could
become partly parasitic (e.g. astatine)• Wavelength stabilization under
construction -> less maintenance• Pointing stabilization will be
implemented • In Ti:Sa-only mode, RILIS could be on-
call soon
1 cm
Maximum Surface Ion Suppression of ≈ 3000
-200 -100 0 100 200 300 400 500
1E-12
1E-11
1E-10
1E-9
48Ti
Ion Cu
rrent
(A)
Repeller Voltage (V)
No significant change of performance after two days with protons
-200 -100 0 100 2001E-12
1E-11
1E-10
39K before p 39K after p
Ion C
urre
nt (A
)
Repeller Voltage (V)
Different time of flight structures for different LIST settings
0.00000 0.00002 0.00004 0.00006 0.00008 0.000100
50
100
150
200
250
300
# Eve
nts
Time (s)
U Repeller: 10V U Repeller: 40V U Repeller: 120V
First On-Line Test of Laser Ion Source and Trap at ISOLDE
First on-line test of performance of the Laser Ion Source and Trap (LIST) at ISOLDE from 11/05/2011 untill 13/05/2011• LIST was implemented successfully at ISOLDE• LIST worked well over 2 days of proton taking• Measurement of
o suppression of isobaric contaminantso Mg ionization efficiencyo yields of different isotopes etc.
Preliminary Results:
RILIS ion beams•Ion beams of 31 elements are produced at ISOLDE with RILIS
elements available at ISOLDE RILIS1 2
H ionization scheme tested He3 4 5 6 7 8 9 10
Li Be ionization scheme untested B C N O F Ne11 12 13 14 15 16 17 18
Na Mg Al Si P S Cl Ar19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn87 88 89 104 105 106 107 108 109 110 111 112
Fr Ra Ac Rf Ha Sg Ns Hs Mt
58 59 60 61 62 63 64 65 66 67 68 69 70 71
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu90 91 92 93 94 95 96 97 98 99 100 101 102 103
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
Recent new beams: Sm, At
First RILIS Sm beam at ISOLDE
0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000
2E-10
2E-09
2E-08
Efficiency measurementξlaser+surf = 16 %
Time, s
Ion
curr
ent,
A
Attempted in 2010 with a GdB6 low work function cavity
Re-tested in April 2011 with a standard Ta ionizer
2010 test:16654.21 cm-1
2011 correct value:16650.46 cm-1
No Sm was seen using the 2010 scheme but we discovered a discrepancy between two published values for the 1st step wavenumber. An alternative value was tested and determined to be the correct one.
1st step wave-number:
First RILIS run of 2011 with the refurbished RILIS room and new laser layout.
All 3 transitions were saturated
1.5 W
3.5 W
5 W
Laser power before transmission to source:
Astatine beam developmentNovember 2010: I-086, Stage 1 completed• Confirmation of the two first excited states• first measurement of the ionization potential of At
May 2011: I-086, Stage 2a, Part 1 (NIR region) completed• energy levels found in Dec.2010 at TRIUMF
confirmed• one new level observed, starting from 224
nm first step• 6 ionization schemes were compared• up to 150 pA of 205At was obtained
75129 76000 780000.01
0.1
1
10
scan 1 on 224 nmscan 2 on 224 nmscan on 216 nm
cou
nt
rate
(s
-1)
total photon energy (cm-1)
44548 44549 44550
0
1
2
3
4
5
6
7
cou
nt
rate
(s-1)
wave number (cm-1)
46232.5 46233.0 46233.5 46234.0 46234.5 46235.0
0.0
0.2
0.4
0.6
0.8
1.0
1.2
cou
nt
rate
(s-1)
wave number (cm-1)
216 nm
224 nm 199At
199At
224 nm
Scan310
216 nm
At199
335 nm…
Dye + Ti:Sa range24 ion beams can be produced either with dye or Ti:Sa lasers Si, Ti, Fe, Ge, Pd, Hf, Pr are available
Dye scheme tested
Ti:Sa scheme tested
Ti:Sa and Dye schemes tested
Feasible
Released
Not releasedfrom ISOLDE target
Ti:Sa ionization schemes for Si, Ti, Fe, Ge, Pd, Hf, Pr are available
RILIS operation in 1994-2011
0
500
1000
1500
2000
2500
Hou
rs
1994 1996 1998 2000 2002 2004 2006 2008 2010
Year
•~ 2500 h – expected• -> 52% of the Total running time of ISOLDE facility
•870 h by today
Laser time per beam for the operation year 2011
Laser ON timein 2011:
Beam Sm Ga Mg At Pb Dy Nd Pr Ag Tl Cd Mn Ni Zn Mg
Planned 80 104 64 160 184 64 136 0 112 208 288 120 272 376 192
Real 89 165 64 154 221 35 110 4
RILIS operators:
2 CERN stuff members: Bruce Marsh, Valentin Fedosseev 1 CERN fellow: Marica Sjodin (contract ends on 31.08 2011) 2 PhD students: Sebastian Rothe, Daniel Fink ISOLDE Users (2 in average): Maxim Seliverstov, Dmitry Fedorov, Pavel
Molkanov, ...
At present RILIS operation is organized in 8-hours shifts:
4 persons on shifts + 1 person on-call
Regular breaks in laser operation are needed for rest:Not more than 3 weeks of work without free days.
RILIS remote monitoring / protection
Requirements for safe and reliable shift free RILIS operation fall into 3 categories:
AutomationPerformance monitoringMachine protection / safety
To avoid risk of equipment damage or danger to personnel.This must be a ROBUST system(PC independent).
Remote monitoring of key parameters with an alert system to request operator intervention.
To maintain RILIS performancetherefore reducing the frequencyof operator interventions.
ESSENTIALNON ESSENTIAL
STA
TU
S
Laser stop
Laser shutter
SMS
MACHINE PROTECTION/SAFETY
PERFORMANCE MONITORING
AUTOMATION
Mirror control
Laser control
Dye Leak: Fire hazard; laser damage risk
By Bruce Marsh
Machine protection/saftey
Up to 6 dye circulators each containing up to 3 L of ethanol flowing at 7 L/min.
Water cooling for Ti:Sa crystals. Water cooling network for each dye circulator.
Up to 40 W pump beam focused on dye cell. Almost immediate dye cell damage if dye flow stops.
Dye flow interruption: Fire hazard; laser damage risk
Water leak: Equipment damage risk; electrical safety hazard
Action required: Stop pump lasers, alert the laser operator.
Action required: Block pump beam to dye laser, alert the laser operator.
Action required: Stop pump laser, alert the laser operator.
Non invasive dye flow sensor(ULTRASONIC)
+ Micro-controllerand data logger +
Laser beam shutterFlip mirror/ beam dump assembly with controller
+Pump laser control by Hyper-terminal commandsand access to laser operator alert system (LABVIEW based)
Solution to be tested:
Install water leak sensor cables on laser table and RILIS cabin floorInclude sensor data logger in RILIS monitoring system
Organic solvent detector(breathalyzer)
+ Micro-controllerand data logger
Performance Monitoring / Automation
Dye ageing, harmonic crystal damage Symptom: loss of laser power and ionization efficiency
Wavelength drifts Symptom: reduced ionization efficiency
Beam pointing stability: Symptom: reduced ionization efficiency
Dyes have a finite lifetime (some hrs – 3/4 days depending on pump power)Harmonic generation crystals can be damaged due to UV light absorption, particularly at <225nm
Power measurement at reference point or light leakage through optics
RILIS status monitoring PCconfigured to provide SMS and email status alerts
STA
TU
S
Temperature fluctuations and mechanical instability can cause wavelength drifts. Even a small drift (<0.3 cm-1) can significantly reduce the ionization efficiency.
Simultaneous measurement of allwavelengths
STA
TU
S
Grating/etalon control
Laser controlsoftware andRILIS monitoringsystem
A commercial beam position stabilization device has been purchased. It should be able to stabilize short and long term beam position fluctuations for up to 3 laser beams.
Currently regular (~hourly) beam position adjustments are necessary. The biggest cause of abeam position drift is the intermittent switching of the RILIS A/C unit. An improvement in the air conditioning performance could be beneficial.