RILIS operation

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

EMAIL

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.