# In-gas-jet laser spectroscopy with S3 -LEB, status and perspectives

Wenling Dong, Anjali Ajayakumar, Yazeed Balasmeh, Alexandre Brizard, Lucia Caceres, Pierre Delahaye, Piet van Duppen, Rafael Ferrer, X. Fléchard, Serge Franchoo, et al.

► To cite this version:

Wenling Dong, Anjali Ajayakumar, Yazeed Balasmeh, Alexandre Brizard, Lucia Caceres, et al. In-gas-jet laser spectroscopy with S3 -LEB, status and perspectives. ISOLDE Workshop and Users meeting 2023, Nov 2023, Genève, Switzerland. pp.10. hal-05238615

HAL Id: hal-05238615

https://hal.science/hal-05238615v1

Submitted on 3 Sep 2025

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# In-gas-jet laser spectroscopy with S³-LEB, status and perspectives

Wenling Dong

IJC Lab, Orsay, France

November 29, 2023

for the S³-LEB collaboration
<figure><img src="image_2.png" /></figure>

Laboratoire de Physique
des 2 Infinis

* Off-line laser spectroscopy measurements with S³-LEB

* Design of the FRIENDS³ prototype

* Preliminary simulation study

* Test-bench study

* Conclusion and outlook

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# S³-LEB setup

<figure><img src="image_6.png" /></figure>

GANIL
laboratoire commun CEA/DRF
CNRS/IN2P3

* In-gas jet laser ionization and spectroscopy (IGLIS)

* Mass spectroscopy

* Decay spectrometry

<footnote>[1] A. Ajayakumar et al. Nuclear Inst. and Methods in Physics Research, B 539 (2023)</footnote>
# S³-LEB laser spectroscopy technique

Stop, neutralize in the gas cell and extract the atoms

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In-Gas Laser Ionization and Spectroscopy (IGLIS) technique with NB Ti:sa system

<figure><img src="image_10.png" /></figure>

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High-resolution in-gas-jet laser spectroscopy FWHM ~ 200 MHz

<figure><img src="image_12.png" /><figcaption>Isotope shift</figcaption></figure>

<figure><img src="image_13.png" /></figure>

## Nuclear properties

Differences in mean-square charge radii, moments and nuclear spins...

<figure><img src="image_14.png" /><figcaption>Hyperfine splitting</figcaption></figure>
<figure><img src="image_15.png" /></figure>

First off-line measurement, studied
by J. Romans and A. Ajayakumar.

## What has been achieved:

* The in-gas-jet resonance laser ionization were explored in detail for Er (S³ first physics case).

* The transmission across the whole setup was preliminarily optimized to 80-100%.

## Recent work:

* check the other sensitive schemes that are efficient and sensitive to nuclear properties.

<figure><img src="image_16.png" /></figure>
<figure><img src="image_17.png" /><figcaption>TOF spectrum of stable Er behind PILGRIM</figcaption></figure>

<figure><img src="image_18.png" /></figure>
King plot analysis for IS factors

$$ \delta v_{409}^{A',A} = F_{409} \Lambda^{AA'} + M_{409} \frac{A' - A}{A'A} $$

<figure><img src="image_19.png" /></figure>

$$ F_{409} = 11679(2943) \text{ MHz fm}^{-2} $$

$$ M_{409} = -9459 (6435) \text{ GHz} * u $$

Hyperfine structure constants A and B for different FES of ¹⁶⁷Er

<figure><img src="image_20.png" /></figure>

<table><thead><tr><th>Atomic states</th><th>excitation step</th><th>Method</th><th>A(MHz)</th><th>B(MHz)</th></tr></thead><tbody><tr><td>4f<sup>11</sup>(<sup>4</sup>I)5d6s<sup>2</sup>,<br>J=6</td><td>408.8 nm</td><td>gas jet</td><td>-123.9(0.4)</td><td>213.4(22.6)</td></tr><tr><td rowspan="3">4f<sup>12</sup>(<sup>3</sup>H<sub>5</sub>)6s6<br>p,<br>J=5</td><td rowspan="3">415.2 nm</td><td>gas jet [1]</td><td>-147.1(7)</td><td>-1936(24)</td></tr><tr><td>ABU [2]</td><td>-147.66(83)</td><td>-1888(58)</td></tr><tr><td>ref [3]</td><td>-146.6(3)</td><td>-1874(16)</td></tr><tr><td>g.s.</td><td>-</td><td>ref [2]</td><td>-121.80(75)</td><td>-4563(53)</td></tr></tbody></table>

<footnote>[1] A. Ajayakumar et al. Nuclear Inst. and Methods in Physics Research, B 539 (2023)</footnote>

<footnote>[2] J. Romans et al. Nucl. Instrum. Meth. B 536 (2023)</footnote>

<footnote>[3] W.J. Childs et al., Phys. Rev. A 28 (1983)</footnote>
* Off-line laser spectroscopy measurements with S³-LEB

* Design of the FRIENDS³ prototype

* Preliminary simulation study

* Test-bench study

* Conclusion and outlook

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<figure><img src="image_22.png" /></figure>

COMSOL
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## Limitations of current gas cell:

- Extraction time too long for short-lived S³ products

- Neutralization efficiency depends on the beam intensity

## Objectives of FRIENDS³ project:

- Reduce extraction time ~ 100 ms.

- Improve neutralization efficiency

- Ideally both at the same time

<figure><img src="image_24.png" /></figure>

S. Raeder et al., NIM B 463, 272-276 (2020)

JETRIS collaboration

- Simulations

- experimental tests

COMSOL + SIMION

<figure><img src="image_25.png" /></figure>
## Study of simulation tools and methods: COMSOL + SIMION

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COMSOL

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### Multiphysics problem: COMSOL

* Laminar gas flow through the cell

* Calculation of static and dynamic electrical fields

* Particle tracing under the action of gas flow (drag) and electrical field (drift)

* Plasma processes (ion recombination)

<figure><img src="image_28.png" /></figure>

### Statistical Diffusion Simulation (SDS): SIMION

* Diffusion effect in high pressures

$$F_E + F_{drag} + \text{diffusion}$$

<figure><img src="image_29.png" /></figure>

* Flow simulated by COMSOL, ion transport simulated by SIMION.

### Simulated performance:

* extraction efficiency ~ 30%.

* extraction time ~ 120 ms.

* time available for neutralization ~ 55 ms.
The mechanical study of the test bench is almost completed.

<figure><img src="image_30.png" /></figure>

* Study ion extraction times and neutralization efficiencies.

* Mass filtering and identification.

* Perform in-jet laser spectroscopy.

<figure><img src="image_31.png" /></figure>

Bent RFQ et mini-RFQ: contribution of KU Leuven (Kudryavtsev et al., NIMB 297, 2013)
# Test-bench study: tests of the beta source

90Sr source installation,
Cu window 100 µm

90Sr, 37 MBq

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RFQ for ion extraction

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Gas cell for Phase I

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Detection chamber

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Current with/without beta source

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The first off-line results for Er(415.2 nm to FES) are in good agreement with the literature values:

* the laser system and technique is capable of the intended first physics cases at the SPIRAL2-GANIL S³ facility.

* the systematic uncertainties are under control.

A more sensitive scheme (408.8 nm to FES) for Er was mearsured in the scope of S³ first physics cases:

* IS and HFS constants have been found for this transition.

The results from the in-gas-jet RIS show the potential of the S³-LEB to perform high-resolution laser spectroscopy for on-line studies.

In the future,

* the connecting part to PILGRIM will be replaced by a 90° bender to couple to SEASON.

* S³-LEB will be put at S³ after the commissioning, first experiments with S³-LEB are forseen for 2025.

* FRIENDS³ test bench will be moved to GANIL at 2024.
**GANIL:**

Anjali Ajayakumar; Dieter Ackermann; Lucia Caceres; Samuel Damoy; Pierre Delahaye; Patrice Gangnant; Nathalie Lecesne; Thierry Lefrou; Renan Leroy; Franck Lutton; Alejandro Ortiz; Benoit Osmond; Julien Piot; Blaise-Maël Retailleau; Hervé Savajols; Gilles Sénécal

**LPC:**

Frédéric Boumard; Jean-François Cam; Philippe Desrues; Xavier Fléchard; Julien Lory; Yvan Merrer; Christophe Vandamme

**IJCLab:**

Wenling Dong; Patricia Duchesne; Serge Franchoo; Vladimir Manea; Olivier Pochon

**KU Leuven:**

Arno Claessens; Rafael Ferrer; Mark Huyse; Fedor Ivandikov; Sandro Kraemer; Yuri Kudriavtsev; Jekabs Romans; Simon Sels; Paul Van den Bergh; Piet Van Duppen; Matthias Verlinde; Elise Verstraelen

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**JGU:**

Sebastian Raeder; Dominik Studer; Klaus Wendt

**JYU:**

Ruben de Groote; Iain David Moore; Michael Reponen; Juha Uusitalo

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STUDIECENTRUM VOOR KERNENERGIE
CENTRE D'ETUDE DE L'ENERGIE NUCLEAIRE

**IPHC:**

Emil Traykov

**IRFU:**

Martial Authier; Olivier Cloue; Antoine Drouard; Thomas Goigoux; Emmanuel Rey-Herme; Damien Thisse; Marine Vandebrouck

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AGENCE NATIONALE DE LA RECHERCHE
ANR

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RÉGION
NORMANDIE

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ENSAR2

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erc

European Research Council

Supporting top researchers

From anywhere in the world

and the RESIST network in ENSAR2