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INTC 63 minutes Page | 1

CERN-INTC-2020-019

INTC-063

5 – 6 February 2020

ISOLDE AND NEUTRON TIME-OF-FLIGHT

EXPERIMENTS COMMITTEE

Minutes of the 63rd meeting of the INTC held on Wednesday and Thursday, February 5 – 6 2020

The chairperson of the INTC (Karsten Riisager) opened the meeting by welcoming the INTC referees

who were present and those via Vidyo. The meeting began with the facility reports followed by the

presentation of the submitted proposals. Presentations from the open session may be found at the

following address: https://indico.cern.ch/event/880289/

Facility reports during the open session

ISOLDE technical report (Joachim Vollaire) Joachim Vollaire presented an overview of the ongoing shutdown work at ISOLDE. The status of the

two front ends was presented. Front end 10 – which will be installed on the GPS – has been extensively

tested on the offline separator. It will be transported to B. 179 before civil engineering works begin for

the new nanolab. Once installed, hard ware tests will be followed by a commissioning programme. The

assembly of the new HRS front end (FE11) is now progressing well and is expected to be tested at

offline2 in April. Once this testing is finished, the front end is due to be installed in the target area in

June – once the possibility of access is restored following the completion of nanolab civil engineering.

The ISOLDE laser ion source – RILIS – is undertaking many upgrades. At MEDICIS the MELISSA

ion source became operational in 2019 and beams of Tb, Er and Yb were produced allowing for

collections of these radioisotopes. At offline2 a laser lab is being prepared which will utilise some spare

equipment from the ISOLDE-RILIS to allow for laser tests at the offline separator. This is expected to

be ready soon. At ISOLDE an extension of the reference area for both GPS and HRS will allow for the

independent setup and stabilisation of laser beams for both separators, which will result in a quicker

switchover between runs. The optical layout is being optimised and an upgrade of the laser systems and

their controls is underway.

At ISOLDE the tasks for the low energy beams are all on schedule and will be completed to allow for

commissioning with stable beams in the second half of 2020. Among these are the refurbishment of the

GLM/GHM area to better comply with current safety regulations; the installation of the new tape

station; the overhaul of the beam instrumentation on all beamlines and maintenance of the cooling

stations and ventilation systems. All cooling water will be restored at the end of February.

Similarly, the upgrades, repair and maintenance at REX/HIE ISOLDE are also on schedule.

Maintenance on the REX Trap and EBIS have been completed. RF consolidation on the REX LINAC

is complete and the installation of 3 additional diagnostic boxes is underway. The vacuum maintenance

is also complete. The 4th cryomodule has been repaired and has been transported back to ISOLDE from

SM19 on 21st January. The re-connection of the cryomodule is on track and recommissioning of the SC

linac is foreseen from July 2020. In addition the beam instrumentation throughout the hall has been

consolidated and upgraded including a newly designed SEMGRID which will be put into use for Run3.

The approval for the early start of ISOLDE in 2020 which was recommended by the Research Board in

December will allow for a comprehensive programme of machine commissioning and development at

HIE-ISOLDE and in the low energy area. Commissioning will also be available for physics setups in

the second half of 2020.


Finally, a summary of MEDICIS in 2019 and its plans for 2020. In 2019 numerous sources of external

activity were imported allowing collections of 155Tb, 175Yb and 169Er. In total 870MBq was collected in

2019 and delivered to 4 of the collaboration institutes: PSI; HUG; KU Leuven and NPL. Eight targets

were produced and re-used up to three times. From January till March 2020 MEDICIS will have a

technical stop allowing for maintenance of the ventilation system along with a replacement of the

extraction electrode along with other shutdown tasks such as tests of the robot trajectories and exchange

of the laser windows. The facility will resume operation from mid-March with 155Tb collections.

Status of nTOF (Oliver Aberle) Oliver Aberle presented an overview of the nTOF shutdown progress: including the status of the EAR1

beamline, the exchange of the nTOF target and the status of the new control room.

The previous pulsing magnet has been replaced by a new permanent magnet. In addition a new SEM

grid will improve the beam diagnostics for this new target. The new target itself is progressing well in

its construction. It consists of a sliced pure Pb target which is cooled by N2 flow which is slightly above

atmospheric pressure. It is designed to comply with the physics requirements of the nTOF collaboration

and is on schedule for installation at the end of 2020.

The dismantling of the nTOF target required the collaboration of several technical groups but was a

success with a lower than expected cumulative dose received indicating the preparedness of the teams

involved. The new nTOF cooling station is also ready for installation: the next stage being confinement

of the nitrogen within the cooling circuit.

The shielding around the spallation target will also be reconfigured during LS2. It will be now moveable

and on rails, divided into 3 blocks. This will allow for more flexibility during running periods and will

permit occasional inspections of the facility. Unforeseen events such as flooding – which delayed a

restart in 2017 – can also be dealt with more effectively due to this new shielding. In addition to the

shielding replacement, this work will allow the anticipation of the Near Experimental ARea (NEAR)

for various applications in the future.

Within the experimental areas, the removal of all radioactive samples and a control of contamination

has been completed. The cabling campaign to remove the sweeping magnet’s cables is underway. The

recommendation from the ASN-OFSP for EAR2 is being followed up. In addition, upgrades and

consolidation of the alignment system, electronics laboratory, control room and DAQ are ongoing.

The new control room in B. 506 was handed over in December and will be set up with the DAQ upgrade

in early 2020. The schedule for the remainder of 2020 was shown and the commissioning plans for

2021 along with the future physics programme will be presented at the June meeting of the INTC.

Documents presented during the open session:

1. INTC-SR-095 & INTC-SR-096 IS626: Radiotracer diffusion of copper and potassium in

Cu(In,Ga)Se2 thin-film solar cells / IS627: Radiotracer diffusion in refractory high-entropy

alloys. Daniel Gaertner (University of Munster)

2. INTC-SR-097 Measurement of the 44Ti(alpha,p)47V reaction cross section, of relevance to

gamma-ray observation of core collapse supernovae, using reclaimed 44Ti. Alexander Murphy

(University of Edinburgh)

3. INTC-SR-098 Status report for the CRIS collaboration. Adam Vernon (University of

Manchester)

4. INTC-SR-099 Status Report on IS556 : Spectroscopy of low-lying single-particle states in 81Zn

populated in the 80Zn(d,p) reaction Riccardo Orlandi (JAEA)

5. INTC-SR-100 Cu(I), Ag(I), Cd(II), Hg(II), and Pb(II) binding to biomolecules studied by

Perturbed Angular Correlation of γ-rays (PAC) spectroscopy Lars Hemmingsen (University of

Copenhagen)


6. INTC-SR-101 Lattice sites, charge and spin states of Fe in InxGa1−xN studied with emission

Mössbauer spectroscopy Hilary Masenda (University of Witswatersrand)

7. INTC-SR-102 Local Probing of Ferroic and Multiferroic Compounds Armandina Lopes

(University of Porto)

8. INTC-SR-103 Study of the unbound proton-rich nucleus 21Al with resonance elastic and

inelastic scattering using an active target Beatriz Fernandez-Dominguez (University of Santiago

de Compostela)

9. INTC-SR-105 β-NMR of copper isotopes in ionic liquids Monika Stachura (TRIUMF)

10. INTC-SR-106 Implanted 7Be Targets For The Study of Neutron Interactions With 7Be : (The

Primordial 7Li Problem) Moshe Gai (University of Connecticut)

2. Discussions during closed session: Thursday 7th November 2019

Present:

Karsten Riisager (INTC Chair), Richard Catherall, Marek Pfutzner, Enrico Chiaveri, Alessia di Pietro,

Thierry Stora, Gerda Neyens, Michael Doser, Andreas Gorgen, Arjan Plompen (via Vidyo), Iain Moore,

Katharina Lorenz, Joachim Vollaire, Antonio Moro, Kristiaan Temst, Sebastian Rothe, Karl Johnston

(INTC Secretary).

Excused: Maurycy Rejmund, Achim Schwenk

The minutes of the 62nd meeting of the INTC were approved without further comment.

Matters arising:

At the 62nd INTC a decision on SR-075 concerning IS538 was postponed pending feedback from the

group regarding questions which arose at this meeting: in particular the use of a higher energy and

different target substrates compared to the original proposal. A reply has been received from the

spokesperson and it was agreed to close this experiment (IS538) and a new proposal taking into account

the new demands of the collaboration will be submitted in November 2020. The INTC notes that the

3 shifts of IS538 are not retained after LS2.

Discussion of the Facility reports:

1. ISOLDE technical report

The committee welcome the approval for the early start-up for beam commissioning in 2020. This will

afford the operators valuable time to better understand the machine which will be to their benefit and

to the physics users during Run3.

2. nTOF status report

The committee congratulate the nTOF collaboration on the progress made during LS2 especially with

regard to the exchange of the target. The low cumulative dose received exemplified the close

collaboration evident in the technical teams.

Enrico Chiaveri – in his final INTC meeting – thanks the INTC for their support and also encouraged

the continuing collaboration between nTOF and ISOLDE which has been productive in the past and has

much promise in the future.


Discussion and recommendations for the status reports presented at the open

session

INTC-SR-095 IS626 Status report: Radiotracer diffusion of copper and potassium in Cu(In,Ga)Se2 thin-film solar cells (4.5 shifts

remaining)

This experiment aimed at studying the diffusion processes in Cu(InGa)Se2 CIGS thin films which is a

promising material for low-cost/reasonable-efficiency solar cells. The authors intended to measure

copper self-diffusion (64Cu/67Cu) and the potassium impurity diffusion by radiotracer diffusion. Self-

diffusion measurements will give valuable information on defects and structure of the thin films. Alkali

metal doping was shown to improve PV performance.

Initial runs were hampered by the lack of good quality CIGS samples and the scheduled shifts were

instead used for Cu diffusion in high entropy materials. The original team who were interested in these

experiments no longer exists and there is insufficient manpower to continue this project. Considering

this, the committee recommend that the shifts are not retained after LS2.

The INTC recommends that the 4.5 shifts are not retained after LS2.

INTC-SR-096 IS627 Status report: Radiotracer diffusion in refractory high-entropy alloys (11 shifts remaining)

Measurements of diffusion mechanisms in the high entropy alloy AlScTiZrHf using radiotracer

diffusion of 46Sc. High entropy alloys, alloys with 5 or more principal elements, are expected to have

improved mechanical or electrical properties and decreased (sluggish) diffusion. In fact, diffusion is

important to understand materials properties such as creep for high temperature applications and

evaluate their kinetic stability against phase decomposition.

In a first run 6 samples were implanted with 47Sc in one shift. Measurements were not successful due

to oxidation of the samples during annealing at the ISOLDE set-up. This is why the proposers ask to

implant the 46Sc isotope for shipment and measurements at the home institution. This would furthermore

allow co-diffusion of 44Ti and 89Zr.

The case for continuing these studies was well made at the open session and the committee find the

proposed research still valid.

The committee took note that the physics case and original aim of the presented letter of intent

is still valid and timely. The outstanding 11 shifts should be retained for the duration of run3.

INTC-SR-097 IS543 Status report: Measurement of the 44Ti(alpha,p)47V reaction cross section, of relevance to gamma-ray observation of

core collapse supernovae, using reclaimed 44Ti (42 shifts remaining)

The 44Ti(,p)47V reaction is responsible for the 44Ti destruction in supernovae, thus the final amount of 44Ti in supernovae depends upon the reaction rate of this reaction. Previous measurements of this cross-

section are above the astrophysical relevant energy region (Ecm>6 MeV); the proponents aim at

extending the measure of this reaction in an energy region included in the Gamow region (4<Ecm<5

MeV).

The 44Ti(p)47V was measured at REX-ISOLDE in 2012. The 44Ti beam intensity on target ranged

from 5x105 to 2x106 pps, a factor about 10 smaller than expected. Moreover, only 10 shifts were

allocated. No protons coming from the 44Ti(,p) reaction were observed and only upper limits to the

cross-section were determined. After the addendum, the total number of shifts available is 42. The


committee deem that the science case is very strong to measure this reaction energies relevant for

astrophysics. However, there are technical issues which the collaboration needs to be aware of.

The beam tests performed so far indicates that an intensity of 1e7 pps on target can be reached, but

fluctuations in the beam intensity are possible. A sample of 50 MBq of 44Ti is still available for

producing the beam. The precise number of shifts which may be possible is difficult to guarantee and

42 may not be achievable. The collaboration will need to adapt their programme depending on the yield

of the beam. However, the physics motivation for this experiment is still highly relevant and the

experiment is feasible with a beam intensity of 1e7 pps.

The committee took note that the physics case and original aim of the experiment is still valid

and timely. The outstanding 42 shifts should be retained for the duration of run3.

INTC-SR-098 LOI 171 Status report: Status report for the CRIS collaboration (13 shifts remaining)

The CRIS collaboration present a short summary of an impressive campaign of experiments in the

recent running period, with one, LoI171 which has shifts remaining. The status report highlights several

technical advances enabling a rich scientific program. Ground state spins and magnetic moments of K

isotopes up to N=33 have crossed the proposed N=32 magic number for the first time. The study of

copper isotopes has been extended to 78Cu, and the charge radii have recently been accepted for a Nature

Physics. A long series of isotopes in the Sn and In chains have been measured, with the latter extending

between almost two shell closures. In a pioneering experiment, the first laser spectroscopy measurement

has been performed on a short-lived radioactive molecule, RaF, submitted for publication to Nature.

The committee appreciated the summary of publications and PhD students.

LoI171: Towards laser spectroscopy of exotic fluorine isotopes

The physics motivation behind the status report for LoI171, originally submitted in 2016, is still valid.

The fluorine isotopic chain with a single valence proton beyond the Z=8 shell closure represents a rich

playground for a variety of state-of-the-art theoretical approaches. Measurements of changes in mean-

square charge radii, spins and moments are proposed with the data expected to contribute as a probe for

the emergence of shell structure, the role of many-body currents as well as continuum effects in the

nuclear many-body problem. The status report also presents more recent developments in quantum

Monte Carlo methods, with calculations of the ground-state electromagnetic properties of fluorine

isotopes underway.

The experimental challenges as discussed in the original LoI remain as recognized by the committee.

Although three working plans were originally put forward as a means of tackling a number of

outstanding questions, it is clear that the use of negative ions will not be available until 2022 and

therefore the collaboration, along with the COLLAPS collaboration, are recommended to focus on the

use of positively-charged ions. The allocated 7 shifts of radioactive beam time and 6 shifts of stable

beams requested are retained.

The committee took note that the physics case and original aim of the presented letter of intent

is still valid and timely. The outstanding 13 shifts should be retained for the duration of run3.

INTC-SR-099 IS556 Status Report: Spectroscopy of low-lying single-particle states in 81Zn populated in the 80Zn(d,p) reaction (36 shifts

remaining)

The goal of the experiment is to obtain information on single-neutron states above the N=50 gap in 78Ni,

in particular on the ordering and energy of d5/2 and s1/2, and d3/2 orbitals. As transfer reactions on 78Ni itself are presently not feasible, the next best case to establish single-neutron energies is the reaction 80Zn(d,p)81Zn. Systematics of the heavier N=51 isotones and theoretical calculations predict a d5/2

ground state, and a decrease of the s1/2 orbital, forming a low-lying excited state in 81Zn. The transfer


reaction is expected to populate these single-neutron states and various other states based on their

coupling to the 80Zn core. The measurement of particle-gamma coincidences will give information on

the energies of the states. Proton angular distributions will give information on the angular momentum

transfer and should provide relative spectroscopic factors. The collaboration has previously performed

a successful experiment using the reaction 78Zn(d,p)79Zn.

The region around 78Ni has been extensively studied since the original proposal was submitted in 2012,

including gamma-ray spectroscopy of 78Ni, 79Cu, and 81-84Zn at RIKEN. However, the RIKEN

experiments using (p,2p) reactions probed mostly the proton orbitals and their role on low-lying

excitations, and are therefore highly complementary. The physics case for the (d,p) reaction is therefore

still valid.

The proposal assumes a five-fold increase in beam intensity due to the use of a new neutron converter,

positioned in the centre of a UCx target. The scheduling was delayed to await testing of this new

converter. There remains some doubt about the optimal target configuration, as the new converter in its

present design is incompatible with a quartz transfer line, which would suppress contaminants. It is also

not clear if the high beam intensity that is assumed in the proposal could be maintained over a long run.

Without an increase in beam intensity beyond what has been achieved earlier, it is questionable if

definite measurements of proton angular distributions and spectroscopic factors are feasible. However,

gamma spectroscopy gated on the proton ejectiles can be expected to yield important new information

on the neutron states even in the case of lower beam intensity. There is also a certain risk that the 1/2+

state remains undetected if it has a very low energy, and consequently a long lifetime, although

theoretical calculations predict that this is not the case.

In conclusion, the physics case is still valid, and despite some uncertainty about the beam intensity that

can be achieved, the measurement is expected to give important new results. ISOLDE is the only facility

in the world where such a measurement is feasible. The committee recommend that the 36 shifts

allocated to the experiment should be retained. However, the collaboration is recommended to

investigate in detail whether this is the optimal energy for observation of the ejected protons. Given

the time that the collaboration has been waiting for this beam, the experiment should be performed

during run3 and the collaboration should therefore assume the risk in terms of the yield for 80Zn. The

ISOLDE target team will consult closely with the collaboration so that the optimal strategy can be found

to deliver as reliably as possible the required beam.

The committee took note that the physics case and original aim of the presented experiment is

still valid and timely. The outstanding 36 shifts should be retained for the duration of run3.

INTC-SR-100 IS602 Status report: Cu(I), Ag(I), Cd(II), Hg(II), and Pb(II) binding to biomolecules studied by Perturbed Angular

Correlation of γγ-rays (PAC) spectroscopy (9.5 shifts remaining)

The project addresses a variety of questions concerning the function of metal ions in natural systems as

well as in synthetic biomolecules, and the toxic effect of some metal ions. For that, they employ the

technique of Perturbed Angular Correlation of γ-rays (PAC) spectroscopy.

The status report shows remarkable progresses in several lines of the project, in particular, those related

to the 199mHg PAC spectroscopy. They report however problems concerning the 68mCu and 111Ag

isotopes, so the sub-projects related to them have been discontinued. Because of that, the proponents

plan to focus on 111mCd, 199mHg, and 204mPb measurements for the remaining 9.5 shifts.

The status report mentions the strategy for these remaining shifts, which involves some research lines

not included in the original proposal. This raises concerns on whether these new projects should be part

of a new proposal. After the discussion of the INTC in the closed session it seems there is a general


consensus that the distribution of shifts should not be strict1 and hence some flexibility should be

allowed, when reasonably justified. In the opinion of the committee, this is the case of the present

proposal, the recommendation is to keep the remaining 9.5 shifts.


still valid and timely. The outstanding 9.5 shifts should be retained for the duration of run3.

INTC-SR-101 IS630 Status report: Lattice sites, charge and spin states of Fe in InxGa1−xN studied with emission Mössbauer spectroscopy

(4 shifts remaining)

The experiment aimed at measuring temperature- and angle-dependent eMs after 57Mn implantation to

investigate lattice location, charge and spin states of Fe in InxGa1-xN. The original proposal included

also rapid-cooling experiments and implantation with long-lived 57Co. These two last measurements

could not be performed for safety reasons and the current lack of a 57Co beam at ISOLDE.

Six out of the ten of the granted shifts have been already used. The results of the data analysis show a

decrease in the site population of magnetic contributions with increasing In concentration, as well as

the evolution of a single line component, the nature of which remains unclear. Using the 4 remaining

shifts the proponents aim at further investigating the single line component and identifying Fe on

different lattice sites and the effect of dopants in nitrides ternary semiconductors.

The work proposed is of interest although the committee had some caveats: There is known degradation

due to higher In content as such the collaboration are proposing to pre-implant with 29Si. It should be

remarked that it is difficult to create consistent samples with varying concentrations. The collaboration

are advised to characterise their samples as well as possible to know in advance to the online

experiments the structural properties of their samples. The collaboration are also advised to carefully

prioritise the final experiments to conclude the current programme and the committee look forward to

publications based on this work. In spite of some reservations, the committee recommend that the shifts

are maintained for run3.



INTC-SR-102 IS647 Status report: Local Probing of Ferroic and Multiferroic Compounds (4 shifts remaining)

This status report describes a large body of work on ferroic and multiferroic materials using local probe

PAC spectroscopy. PAC studies are ideally suited to investigate structural, charge, and orbital

correlations and their impact on the multiferroic behaviour. The PAC measurements are complemented

at the home laboratories by various other techniques, e.g. X-ray diffraction, TEM, SEM and so forth,

and by density functional theory calculations, all of which are essential tools for a conclusive

interpretation of the PAC measurements. The topic is scientifically highly interesting and relevant. With

many of the originally planned compounds measured, the group has already demonstrated that their

technique is a viable method for studying the connections between ferroelectricity and ferromagnetism

on multiferroics. The number of publications so far is high, with high impact publications submitted or

about to be submitted. The request for maintaining the 4 shifts of beam time in order to conclude works

almost completed and to proceed with studies initiated in 2018 is strongly supported by the committee.

The shifts are therefore maintained for run3.



1 See AOB, below.


INTC-SR-103 IS564 Status report: Study of the unbound proton-rich nucleus 21Al with resonance elastic and inelastic scattering using an

active target (43 shifts remaining)

The experiment aims at investigating the low-lying structure of 21Al by measuring resonance elastic and

inelastic scattering 20Mg+p with an active target. The proposal was submitted in 2012 and the

experiment has yet not been performed. The experimental setup of the original proposal was the active

target MAYA, in the present status report the ACTAR TPC device will replace MAYA. It requires a

beam intensity of 50 pps.

The committee deemed that the science case was still valid and timely. However, this experiment has

also been proposed at TRIUMF, where a beam intensity of at least a factor of 10 higher than at HIE-

ISOLDE is possible. As was discussed during the open session, were this experiment to be accepted at

TRIUMF, the proponents declared that they would perform the experiment there. Given that the

proposal has just been accepted at TRIUMF, the INTC recommend that the proponents withdraw the

proposal from ISOLDE especially as this experiment is more feasible at TRIUMF.

The INTC recommends that the 43 shifts are not retained after LS2.

INTC-SR-105 IS583 Status report: Beta-NMR of copper isotopes in ionic liquids (18 shifts remaining)

This status report refers to a previously accepted proposal submitted to the INTC in 2013. In short, the

proposal centers on a feasibility test of spin-polarization and β-NMR studies on short-lived isotopes of

copper, specifically 58,74Cu. The underlying motivation for the studies is the importance of Cu as a metal

ion in various bio-systems. In order to understand protein functions it is necessary to elucidate the

structure and dynamics in the proximity of a metal binding site. β-NMR is sensitive to chemical shifts,

line broadening and relaxation times – providing information about energies and dynamics of chemical

bonding. Experiments performed in TRIUMF on 31Mg by the authors have shown the validity of this

method, which is now to be applied to the copper isotopes as proposed here for the VITO beamline.

The committee finds the scientific motivation to be very strong and of interest. It is noted that no similar

experiments have been carried out elsewhere and it is understood that the yields of the requested copper

isotopes are currently appropriate to ISOLDE. Nevertheless, it has been brought to the committee’s

attention that the current planning for activities during run3 at the VITO beamline involves many

different experiments and does not leave any possibility for realising the Cu studies. The VITO plans

are outlined in LoI-213 and the authors of LoI-213 have clarified that they do not intend to pursue

copper for biochemistry applications. In these circumstances the committee recommends that

experiment IS583 is closed.

The committee does however advise that the polarization of copper for biochemistry applications is not

pursued in a future proposal, unless all relevant parties on the original proposal are invited to join.


INTC-SR-106 IS593 Status report: Implanted 7Be Targets For The Study of Neutron Interactions With 7Be : (The Primordial 7Li Problem)

(24 shifts remaining)

This proposal was accepted by the 47th meeting of the INTC held in June 2015. Astrophysical

observations of the primordial 7Li are about a factor of 3 off the prediction (the primordial 7Li problem).

The destruction of 7Be due to its interaction with neutrons would deplete the formation of 7Li and hence

this reaction is a promising candidate to explain the overestimation of the 7Li abundance. The proposal

aimed at producing a pure sample of 7Be via mass separation at ISOLDE that will be later used for the


neutron beam provided by the “Soreq Applied Research Accelerator Facility” (SARAF) in Israel. The

goal is to measure the (n,p) and (n,alpha) reaction rates.

As was already recognized by the INTC, the physics case of this proposal is very appealing. As such,

the proposal was granted with 24 shifts. This approval was however subject to the availability of

SARAF. Presently, this facility is being upgraded to its phase II and it is unclear when it will become

operational again as well as the conditions under which it will operate. This makes it difficult to make

a realistic estimate of the required activity of the 7Be target.

Because of these reservations – although the science case is valid – it seems advisable to discontinue

this proposal until the situation regarding SARAF-II is clarified.


Summary and recommendations for Letters of Intent reports which were

discussed during the closed session

The committee considered the letters of intent which have been received from collaborations wishing

to occupy space in the ISOLDE in the near to medium future. Although space within the hall is governed

by the ISOLDE collaboration, the proposed science cases are the domain of the INTC and additional

resources are to be approved by the Research Board.

Some questions on the management of the collaborations which have submitted letters of intent were

raised. The INTC recommend that the collaborations reach out to existing groups to synergise their

future plans; new setups should not be able to displace scientifically productive collaborations purely

by virtue of their novelty and/or financial resources.

Due to a lack of time, three of the submissions, in solid state physics – whose plans are in the more

medium future – were not considered at this meeting and will be discussed at the next INTC. The

committee expressed their appreciation for the influx of new ideas and physics among the solid state

collaborations. The relevant letters are I-208, I-211 and I-212.

INTC-I-208 Upgrade of the UHV-system ASPIC for the investigation of surfaces and two-

dimensional materials by ultra-low energy implantation and deposition of radioactive probe

atoms The discussion on I-208 was postponed until the 64th meeting of the INTC.

INTC-I-209 PUMA: antiproton Unstable Matter Annihilation This is an addendum to the already endorsed Letter of Intent and the Memorandum presented to the

INTC in February and June 2018, respectively. The current document confirms the intention to propose

experiments at ISOLDE with the PUMA apparatus when developed, with the goal to study the evolution

of neutron skins with isospin, as well as proton and neutron halos in exotic nuclei by use of trapped

antiprotons. The committee notes that the full proposal for PUMA was recently submitted to the SPSC.

It is anticipated that upon accepting this proposal by the SPSC the individual proposals for experiments

with PUMA at ISOLDE will be submitted to the INTC in 2021 with the aim at running these

measurements in 2022. The committee confirms its very positive attitude towards the PUMA project

and looks forward to the next stages of its development. The committee recommends that the ISOLDE

technical groups investigate how MIRACLS and PUMA can be accommodated without interfering with

existing productive setups e.g. Miniball and IDS.


INTC-I-210 Upgrade and scientific programme of LUCRECIA, the Total Absorption

Spectrometer at ISOLDE LUCRETIA is a total absorption spectrometer (TAS) based on a large NaI crystal of 38cm diameter

and 38cm length. The instrument has been used successfully for 20 years at ISOLDE, and it has

produced several PhD theses and publications. Contrary to more modern TAS spectrometers,

LUCRETIA is not segmented. This is a disadvantage, as it cannot not provide information on gamma

multiplicity and individual cascades.

The Letter of Intent provides an extensive list of physics cases that the collaboration intends to

investigate with TAS spectroscopy in the coming years. The questions that are addressed in these cases

are in general interesting, and experiments with LUCRETIA can be expected to provide valuable

information. The collaboration is presently refurbishing the tape system. As space around the beam line

is very limited, the impact on other experiments should be considered and needs to be discussed

carefully within the ISOLDE collaboration.

The collaboration should prioritize the cases where TAS spectroscopy can provide significant new

insight into the underlying physics questions. They should also focus on experiments that are unique to

ISOLDE and which cannot be investigated elsewhere. With the call for low energy proposals in June,

Lucretia are recommended to submit their strongest science cases as proposals which will benefit

from these proposed upgrades.

INTC-I-211 eMMA - Development of an emission Mossbauer apparatus at ISOLDE for the

investigation of magnetic materials

The discussion on I-211 was postponed until the 64th meeting of the INTC.

INTC-I-212 MULTIPAC-Setup for gamma-gamma Perturbed Angular Correlation

Experiments in Multiferroic (and Magnetic) Materials

The discussion on I-212 was postponed until the 64th meeting of the INTC.

INTC-I-213 Research plans for the laser-polarization beamline VITO at ISOLDE The letter presents future research plans for the VITO beamline at ISOLDE. This is truly a multi-

disciplinary proposal ranging from biophysics to nuclear structure. The LOI is concerned with an

upgrade of the existing laser-polarization beamline for radioactive nuclei VITO. The main goals are to

measure biological beta-detected NMR and beta-decay asymmetry. The future program is proposed to

include additionally (i) the determination of spins of the nuclear excited states by the measurements of

the beta-gamma-neutron correlations, (ii) the measurement of the electromagnetic nuclear moments and

the condensed matter studies using beta-detected NMR.

The proposed upgrades, which will increase the footprint of VITO, are as follows: (i) implementing a

superconducting magnet for fields up to 4.7 T in addition to the current electromagnet reaching 1.2 T

(ii) improvement of the differential pumping allowing the maintenance of the liquid samples at high

pressure (iii) implementing the compact magnet with combined beta, gamma and neutron detectors, (iv)

implementing a reionization cell (to ionize polarized atoms) allowing the deflection of ions to different

experimental stations (v) implementing switchyard.

The proposed improved VITO beamline is indeed very versatile and interesting. It will allow, with a

high sensitivity of beta-NMR, to address the problems related to the electronic/chemical environment

of metal ions in biologically relevant materials or the modification of the bulk properties in systems

with reduced dimensionality. From the nuclear physics point of view, (i) the high precision

measurements of electromagnetic nuclear moments, (ii) the determination of the spin of the excited


states populated in beta-decay and (iii) the high precision measurements of beta-decay asymmetry are

very attractive and important.

The committee endorses the proposed science case which was found to be innovative and wide-ranging.

The committee notes however that space is at a premium in the area of the hall where the proposed

upgrades should take place and the feasibility of these needs to be shown.

INTC-I-214 The SpecMAT active target SpecMAT is an active target based on a TPC that is combined with a compact array of CeBr3

scintillation detectors, to be used inside the ISS solenoid. Transfer reactions with RIB in inverse

kinematics suffer from two problems: low statistics due to low beam intensities, and poor energy

resolution due to the inverse kinematics. SpecMAT tries to overcome both: the use of an active target

leads to much higher luminosity compared to thin polyethylene targets. Placing the TPC into the strong

magnetic field of ISS allows determining the particle energy with high precision from the curved tracks.

The combination with gamma detectors gives even better energy resolution and makes the setup unique

in the world.

There is no doubt that SpecMAT has high scientific potential and will be a big asset for ISOLDE. Due

to the high luminosity and resolution, it will allow performing experiments that are not feasible with

the Miniball/T-Rex setup, or other similar setups elsewhere. The project has seen a delay of

approximately 9 month compared to the original schedule, but the performance of the components

seems to be very satisfactory. Installation at ISOLDE is planned for early 2020. Tests with stable beams

later in 2020 would be beneficial for the project.

The Letter of Intent mentions three physics cases, namely the shell structure around 78Ni, shape

coexistence in the neutron-deficient Hg and Pb region, and pygmy dipole resonances in neutron-rich

nuclei. It can be expected that experiments with SpecMAT will contribute important new results in

these areas. The instrument offers unique opportunities to contribute in an important way also to other

physics cases. It will without doubt be very attractive for a wider user community, and is in general a

very valuable addition to the ISOLDE infrastructure. The committee take note of the progress and look

forward to its implementation at ISOLDE.

INTC-I-215 MIRACLS – the Multi Ion Reflection Apparatus for Collinear Laser

Spectroscopy of radionuclides This addendum to the originally accepted Letter of Intent and Memorandum for the MIRACLS project

provides an update on the required resources in terms of space in the ISOLDE hall, electrical power,

testing of equipment and so forth. The committee have already favourably reviewed the project and

took note of the request at the time for stable beam testing during the long shutdown of ISOLDE, as

required by the collaboration in connection with the ERC funding period. The committee focused

therefore on the space requirements put forward in the addendum. These will need further discussion

as the layout is considerably larger than originally foreseen. The committee suggests that the

collaboration look at ways to minimize the space as currently presented.

However, the committee strongly supports the request that stable beam be provided during this period,

as originally requested, and suggests that the collaboration focuses on meeting the immediate

deliverables set out in the ERC project before discussing a longer-term perspective which will be

influenced by the current space within the ISOLDE hall.

AOB: The INTC chair has received a request from the ISOLDE solid state community to allow more flexibility

in the choice of isotopes for proposals where the strict allocation of shifts per isotope can be reduced;


rather a choice of isotopes within an allocated number of shifts is being sought which would allow more

flexibility for scheduling. This would allow these experiments to adapt to the ISOLDE schedule and

would permit such experiments to run more frequently: important as the time scale for impact within

solid state and materials physics is considerably shorter than other areas. The committee recommended

this approach – assuming that a strong science case is made – for the forthcoming proposals for run3

and also applied the rationale to the above-discussed status report, SR-100.

The openness of CERN proposals and presentations was discussed. The INTC is committed to

upholding CERN’s policy of openness of submitted proposals. Future calls for proposals will remind

proponents that documents will be publicly visible on the CERN website and collaborations are

expected to respect this and to adapt their proposals and figures so that potentially sensitive information

is not compromised within this policy.

Enrico Chiaveri – in his final meeting as nTOF spokesperson – thanked the committee for all its support

during his tenure. The committee in turn thanked Enrico for his contributions to the INTC and nTOF

over the years.

As this was also his last meeting as INTC Chair, Karsten Riisager thanked all the members of the INTC

for their efforts during his time in this position. On behalf of the ISOLDE Collaboration, Gerda Neyens

warmly thanked the outgoing chair for his contribution over the past years. The new chair of the INTC

will be Marek Pfutzner.

Low energy proposals will be accepted once again for the June 2020 meeting: the deadline for

submission will be 6 weeks before the open session.

The dates of the next meetings will be 24th and 25th June (Wednesday/Thursday) and on 3-4 November

(NOTE: Tuesday/Wednesday).

The meeting was then closed.

Minutes taken by Karl Johnston

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