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is is - infrastructure and general services which have been included in the Mid Term Plan (MTP2013) and approved by the CERN Council in June 2013. To mitigate a possible delay and to reduce the costs, the decision has been taken to re-use the old ALEPH cryogenic plant instead of buying a new one. The procurement of all components is progressing according to the plan. The crucial breakthrough has been achieved in the construction of the prototype superconducting RF cavities. In June, for the first time the performance of the cavity surpassed the HIE-ISOLDE specification of 6 MV/m at 10 W. Among the encountered problems was the accidental damage of a test cryostat, recovered by adapting an old unit, and the failure of a prototype Diagnostic Box during the tests. The re-design of the mechanical part of the DB will be necessary.

Status of n_TOF Experimental Area 2 (EAR2) project The report was presented by the Spokesperson of the n_TOF Collaboration, Enrico Chiaveri. The EAR2 is based on the new neutron beam line, coming vertically from the neutron spallation target. It is expected that it will provide a neutron fluence larger than at EAR1 by a factor of about 20. The construction started in May 2013 and it is planned to be completed in April 2014. Various aspects of the project, including simulations, civil engineering, and radiation protection issues were discussed. Main components of the new beam line such as the target region, collimators, permanent magnet, experimental area, and the beam dump were presented in more detail. Most of the equipment is in the construction phase and the project is proceeding according to the schedule. On the next INTC meeting in October 2013 the proposals for commissioning of the EAR2 together with proposals for the EAR1 will be presented. The first proposals for the EAR2 will be presented in the February 2014 INTC session.

Analysis of n_TOF experiments in 2012, status report The summary of experiments performed in 2012 was presented by Carlos Guerrero, the n-TOF Run and Analysis Coordinator. Fission cross section measurements for 240Pu and 242Pu, as well as neutron-induced capture and fission reactions on 235U were of importance for nuclear technologies. Of astrophysical relevance were the measurements of the (n, α) reaction on the s- process branching nucleus 59Ni and of the neutron capture cross sections for 25Mg and 93Zr. The (n, α) reactions on 33S and 10B, measured with newly developed Micromegas detector, were motivated by medical applications (neutron capture therapy). Within the basic nuclear physics research spin-dependent level densities in 87Sr were measured and the angular distribution of the fission fragments in the 234U(n, f) and 236U(n, f) reactions were determined. In addition, a few experiments using parasitic beams at the n_TOF beam dump were mentioned. The year 2012 was exceptionally successful for the n_TOF collaboration as illustrated by a few broken records. Maximum number of experiments in a single campaign were performed, the highest integrated beam intensity was achieved, and the largest number of papers was published in this year.

Presentation of proposals and related documents In the remaining part of the open session the following documents were presented (the order does not correspond to the sequence of presentations): CERN-INTC-2013-002, INTC-P-319-ADD-1, Addendum to the IS534 experiment - Part I:Beta-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy, by A. Andreyev; CERN-INTC-2013-003, INTC-P-369, Q-values of Mirror Transitions for fundamental interaction studies, by M. Breitenfeldt; CERN-INTC-2013-004, INTC-P-370, Probing intruder configurations in 186,188Pb using Coulomb excitation, by J. Pakarinen;

CERN-INTC-2013-006, INTC-P-372, Energy of the 2p1h intruder state in 34Al: an extension of the ”island of inversion”?, by P. Ascher;

CERN-INTC-2013-007, INTC-P-373, High-resolution laser spectroscopy of nickel isotopes, by B. Cheal;

CERN-INTC-2013-009, INTC-P-374, Beta decay of the N=Z, rp-process waiting points: 64Ge, 68Se and the N=Z+2: 66Ge, 70Se for accurate stellar weak-decay rates, by E. Nacher;

CERN-INTC-2013-010, INTC-P-375, Study of the stability of the gallium isotopes beyond the N = 50 neutron shell closure, by T. Cocolios;

CERN-INTC-2013-012, INTC-P-377, 18N: a challenge to the shell model and a part of the flow path to r-process element production in Type II supernovae, by W. Catford;

CERN-INTC-2013-013, INTC-O-017, VITO – Versatile Ion-polarized Techniques On-line at ISOLDE (former ASPIC UHV beamline), M. Stachura;

CERN-INTC-2013-014, INTC-P-378, Laser Spectroscopy of Tin and Cadmium: Across N = 82 and Closing in on N = 50, by D. Yordanov;

CERN-INTC-2013-015, INTC-P-379, Study of shell evolution around the doubly magic 208Pb via a multinucleon transfer reaction with an unstable beam, by J. J. Valiente-Dobon;

CERN-INTC-2013-016, INTC-P-380, Beta-delayed 1- and 2-proton decay of 35Ca, by J. Giovinazzo

CLOSED SESSION Thursday, June 27, 2013 at 9:00 h, room 60-6-015

Present: B. Blank, K. Blaum (chair),M. Block, M.G. Borge, W. Catford, R. Catherall, E. Chiaveri, G. De Angelis, J. Dobaczewski, C. Guerrero, Y. Kadi, E. McGlynn, A. Navin. (via internet connection), M. Pfützner (secretary), D. Ridikas, T. Stora, H. Wilkens Apologies: J. Vaagen, Z. Salman

1. INTRODUCTION BY THE CHAIRMAN The Chairman opened the meeting and welcomed all participants, especially the new members of the INTC. The procedural matters were shortly discussed.

2. MINUTES OF THE LAST INTC MEETING The minutes of the 43rd INTC meeting held on October 31 - November 1, 2012 were approved without amendments.

3. STATUS OF ISOLDE AND HIE-ISOLDE The technical and physics reports on ISOLDE were discussed. The committee congratulated all physics groups and the technical support group for the very successful year 2012. The excellent physics results achieved were applauded. The chairman informed on his recent presentation of the ISOLDE and n_TOF activities at the CERN Scientific Policy Committee (SPC) which was very well received, with extraordinary positive feedback. The Director General appreciated the commendable performance of ISOLDE and declared the continued support of the CERN management. The engagement of the whole ISOLDE group in the work going on during the long shutdown was highly appreciated. The progress of the constructions and upgrades was considered and the hope was expressed that the facility will be ready to resume the low-energy physics programme in June 2014. The status report on the HIE-ISOLDE was summarized. The successful efforts to keep the project on the track were recognized. Special congratulations were due for the breakthrough in the performance of superconducting cavities. The overall cost increase of the project by 12% is considered to be moderate and acceptable. Presently, the critical point may turn out to be a missing manpower for the beam instrumentation. The committee strongly recommended that the missing resources are secured and allocated, next year at the latest. The scope of the INTC meetings in the near future was discussed. The next meeting, in October 2013, will be open to all proposals, both for the low-energy beams and for the postaccelerated ones (HIE-ISOLDE). In the first meeting in 2014 (February) the low-energy IS experiments having still unused shifts will be asked to provide status reports in order to reclaim those shifts. An experiment may request additional shifts only by means of an addendum to the previously approved proposal. Similarly, the unfinished REX experiments will be the subject of an INTC meeting in the beginning of 2015. The status reports will be requested to claim the unused REX- physics shifts and to reallocate them for HIE-ISOLDE. It was noted that should the experiment require the final energy below 3 MeV/nucleon, it may not be possible in the first phase with only two cryo-modules. On the other hand, it is assumed that most of the unfinished REX experiments will profit from having the energy increased to 5.5 MeV/nucleon. Finally, it was agreed that the approval of experiments in this meeting will be valid for 3 years. If not completed within 3 years, such experiment will have to present the status report to claim the approved shifts.

4. STATUS OF n_TOF The committee congratulates the n_TOF collaboration for excellent physics results achieved in 2012. The topics addressed cover the broad range from the nuclear technologies, through medical applications to nuclear astrophysics and basic nuclear research. The committee welcomes and strongly supports identifying medical applications as an important branch of n_TOF scientific programme. The progress in the construction of the Experimental Area 2 (EAR2) is highly appreciated. The project is well on track and its budget is under control. It was suggested that for the next INTC meeting the n_TOF collaboration presents the report on the detector systems to be used at this new EAR2 station. The submission dates for n_TOF proposals were also discussed. The collaboration spokesperson (E. Chavieri) confirmed that about four proposals for the EAR1 station and the proposal for the commissioning of the EAR2 station will be submitted for the next meeting (October 2013). Many ideas for the EAR2 experiments are now considered by the collaboration and some 3-4 proposals will be prepared for the first INTC meeting in 2014.

5. DISCUSSION ON THE SUBMITTED DOCUMENTS The documents submitted to the session were discussed.

CERN-INTC-2013-001, INTC-CLL-009, Study of the unbound proton-rich nucleus 21Al with resonance elastic and inelastic scattering using an active target The document is the Letter of Clarification requested by the INTC at the October/November 2012 meeting. The original proposal (INTC-P-366) intended to study the structure of the unbound nucleus 21Al by resonance elastic and inelastic scattering using an active target. The physics case was found interesting, but it was not clear which active target device, MAYA or ACTAR, would be the best one for these studies. Therefore a clarification of this point has been requested. The authors provide a detailed analysis of the planned measurements and argue that the performance of the MAYA detector is more than adequate for the task. This argumentation was found to be clear, convincing and sufficient. The committee recommended for the approval of the Research Board 43 shifts.

CERN-INTC-2013-008, INTC-CCL-010, Solving the shape conundrum in 70Se It the document INTC-P-368, discussed by the INTC at the October/November 2012 session, it was proposed to determine the sign and the magnitude of the quadrupole moment of the first 2+ state in 70Se, by means of multistep safe Coulomb excitation using the MINIBALL setup. The physics case was found interesting and relevant. It was, however, not clear, whether the proposed experiment can provide definitive values for the E2 matrix elements from which the 70Se shape can be determined. Therefore, a Letter of Clarification was requested. In their response, the authors present full simulations of the multi-step Coulomb excitation in the reaction 208Pb(70Se,70Se*)208Pb* at a safe energy 5.5 MeV/u. The results of these simulations and the explanations provided were found to be satisfactory. The experiment is considered sensitive enough and capable of determining the relevant observables. A technical remark was made that before the delivery of the beam the yield of the requested isotope (70Se) has to be tested. The committee recommended for the approval of the Research Board 15 shifts.

CERN-INTC-2013-002, INTC-P-319-ADD-1, Addendum to the IS534 experiment - Part I:Beta-delayed fission, laser spectroscopy and shape-coexistence studies with astatine beams; Part II: Delineating the island of deformation in the light gold isotopes by means of laser spectroscopy It is proposed to continue the experiment IS 534 by studying the properties of long chains of isotopes of astatine (Part I) and gold (Part II). The main physics goals include the identification of beta-delayed fission, laser spectroscopy, and the determination of deformation and shape- coexistence. In Part I it is planned to measure isotope shifts and the hyperfine structure of astatine isotopes not covered in previous experiments as well as beta-delayed fission of isomerically pure beams of 194m1,m2At. In Part II hyperfine structure studies are planned for 175- 181, 182,183Au and for isomeric states in 187,191,193,195Au, as well as mass measurements of isomeric states in these gold isotopes. The previous, similar experiments performed by the same group are considered successful and the motivation for the proposed extension is found convincing and sound. However, the justification for the number of required shifts was found to be insufficient. In addition, some technical issues appeared concerning the yields of the lightest astatine isotopes, and the problems are still not resolved. Therefore, the committee decided to recommend for approval only Part II of the addendum, devoted to gold isotopes. Once this part is completed, the authors are encouraged to submit a further addendum, or a new proposal, dedicated to isotopes of astatine. In such a document the technical issues concerning the yields of astatine isotopes have to be addressed and the number of requested shifts has to be carefully justified. The committee recommended for the approval of the Research Board 18 shifts for the Part II of the addendum only (isotopes of gold).

CERN-INTC-2013-003, INTC-P-369, Q-values of Mirror Transitions for fundamental interaction studies The proposal aims at very precise measurements of Q values, using the ISOLTRAP setup, on pairs of nuclides that are of relevance to the test of the CVC hypothesis and the determination of the Vud element of the CKM matrix. The focus is on mirror nuclei with isospin Tz = 1/2, which is an alternative method to the studies of superallowed 0+  0+ beta decays. Four mirror pairs have been selected, in the first part 35Ar/35Cl and 19Ne/19F, and in the second part 23Mg/23Na and 21Na/21Ne. The addressed physics is important and interesting. It is observed, however, that the Q values of the nuclides selected for the first part are already known with the sufficient accuracy and do not represent the limiting factor in the determination of the parameters of interest. Thus, the motivation for the cases selected for the first part is found not convincing. The committee recommended approval only of the second part of the proposal. The committee recommended for the approval of the Research Board 8 shifts for the measurements of the 23Mg/23Na and 21Na/21Ne pairs.

CERN-INTC-2013-004, INTC-P-370, Probing intruder configurations in 186,188Pb using Coulomb excitation The proposal is aimed to study the shape coexistence, mixing, and quadrupole collectivity of low-lying levels in neutron deficient 188Pb. By using the MINIBALL setup together with the conversion electron spectrometer SPEDE, which is under development, the B(E2, up) from in- beam Coulomb excitation and the corresponding conversion coefficients will be measured for various states in 188Pb. In addition, beam development is requested for pure and intense 186Pb beam to extend the physics goals. The physics case of 188Pb is found compelling and well justified. The committee, however, does not find sufficient justification for the case of 186Pb at this time and would wait for the successful completion of this experiment before supporting the beam development of 186Pb. The committee recommended for the approval of the Research Board 10 shifts for the 188Pb measurement.

CERN-INTC-2013-006, INTC-P-372, Energy of the 2p1h intruder state in 34Al: an extension of the ”island of inversion”? It is proposed to measure the masses of two states in 34Al, the 1+ and 4− using the ISOLTRAP facility. The former state will be populated by the beta decay of 34Mg, while the latter will be produced and extracted directly from the ISOLDE target. The experiment may resolve an inconsistency of masses along N=21 chain and establish the nature of the ground state of 34Al. The proposed study will provide information about the extent of the island of inversion at N=20. The physics motivation is clear and convincing. The committee recommends acceptance of the whole programme, however, in view of the uncertainty concerning the production yield of 34Al, it strongly recommends the authors to contact the ISOLDE Technical Group to verify this yield. The committee recommended for the approval of the Research Board 17 shifts.

CERN-INTC-2013-007, INTC-P-373, High-resolution laser spectroscopy of nickel isotopes The proposal aims at determination of the nuclear spins, electromagnetic moments, and mean- square charge radii in the chain of nickel isotopes 56-71Ni by means of collinear laser spectroscopy. High precision data on this isotopes will provide insight on the structural changes from the shell closure (N=28), to the region beyond N=40. The results will be important for approaching the doubly-magic 78Ni. The physics case is found interesting and sufficiently justified. The committee recommended for the approval of the Research Board 18 shifts.

CERN-INTC-2013-009, INTC-P-374, Beta decay of the N=Z, rp-process waiting points: 64Ge, 68Se and the N=Z+2: 66Ge, 70Se for accurate stellar weak-decay rates It is proposed to study the β+/EC decays of the neutron deficient germanium and selenium isotopes with the Total Absorption Spectroscopy method. The focus is on the waiting point nuclei in the astrophysical rp-process. The proposed measurements shall provide a benchmark for testing models under terrestrial conditions and to shed light on the contribution of EC-decay rates to the X-ray burst explosions. The committee approved the part dedicated to the selenium isotopes 68,70Se. In addition, the committee supports the beam development for germanium isotopes 64,66Ge. The committee recommended for the approval of the Research Board 9 shifts for the measurements of selenium isotopes.

CERN-INTC-2013-010, INTC-P-375, Study of the stability of the gallium isotopes beyond the N = 50 neutron shell closure It is proposed to measure the hyperfine structure, isotope shifts, and half-lives for the chain of neutron-rich gallium isotopes and isomers around and beyond N=50 using the Collinear Resonance Ionization Spectroscopy (CRIS) setup. The data will be used to test the robustness of the most recent theoretical calculations, will shed light on the shape coexistence in the vicinity of 78Ni, and will have impact on the calculations of the astrophysical r-process. The proposed experiment is found to be well defined and sufficiently justified. The committee decided to approve the first part of the programme, comprising the isotopes 80Ga and 82,84Ga. After the completion of this part and presentation of the status report, the second part, dedicated to isotopes 85,87Ga, may be considered. The committee recommended for the approval of the Research Board 18 shifts for the first run dedicated to 80,82-84Ga.

CERN-INTC-2013-012, INTC-P-377, 18N: a challenge to the shell model and a part of the flow path to r-process element production in Type II supernovae It is proposed to study the bound states in 18N using the (d, p) reaction at 5.5 MeV/u in inverse kinematics with the T-REX and MINIBALL arrays. The data will be used to constrain the couplings between the p1/2 proton and sd neutrons which are not well determined in the shell model, and will serve as an input to calculate the cross section of the n-capture by 17N which is of astrophysical interest. In general the physics case is found to be interesting and important. However, the impact of the proposed study on the astrophysical calculations, on the shell model, and on the reaction theory was not clear. Therefore, a Letter of Clarification is requested where authors should further elaborate these points. The committee has not recommended any shifts for the approval of the Research Board.

CERN-INTC-2013-014, INTC-P-378, Laser Spectroscopy of Tin and Cadmium: Across N = 82 and Closing in on N = 50 The proposal aims at measuring ground-state properties in the tin and cadmium isotopic chains near N=50 and across N=82 using collinear laser spectroscopy (COLLAPS). The main motivation is to provide new data probing the nuclear structure in vicinity of 100Sn and 132Sn. In particular, the question of the yet unexplained dependence of the quadrupole moment on the neutron number, observed for cadmium isotopes, will be addressed. In general the physics case is regarded as sound and potentially fruitful. There is, however, a number of points which require additional explanations. The theoretical motivation for measurements of tin isotopes is not sufficient. How would the new data on tin isotopes help in the theoretical analysis? The detailed justification of the requested shifts is missing. In particular, the yields of cadmium isotopes should be considered with care. A Letter of Clarification covering these points is requested. The committee has not recommended any shifts for the approval of the Research Board.

CERN-INTC-2013-015, INTC-P-379, Study of shell evolution around the doubly magic 208Pb via a multinucleon transfer reaction with an unstable beam It is proposed to populate neutron-rich nuclei around 208Pb via multi-nucleon transfer reactions and to study them by gamma spectroscopy using the MINIBALL array. In particular, the focus is on medium- to high-spin states in 212,214Pb and 208,210Hg. The main goals include searching for the 16+ isomer in the lead isotopes and solving the puzzle of the 3− state in 210Hg. The expected results would provide important inputs for the shell model interactions in this region. In addition, this challenging application of multi-nucleon transfer with intense RIB may open new experimental possibilities at HIE-ISOLDE and eventually also at other facilities. The committee recommended for the approval of the Research Board 27 shifts.

CERN-INTC-2013-016, INTC-P-380, Beta-delayed 1- and 2-proton decay of 35Ca The proposal is dedicated to the study of beta decay of 35Ca. The spectroscopy of beta-delayed protons, two-protons, and gamma radiation are planned using the detection setup of much better granularity and efficiency than in the previous experiments on this nucleus. The goals include the improvement of the decay scheme and search for the direct (non sequential) beta-delayed two proton emission. In the opinion of the committee the presentation of the proposed measurements was not convincing and it is not clear which concrete physics questions are addressed and what will be learned. Thus, the science case is found not strong enough to recommend shifts approval. The committee has not recommended any shifts for the approval of the Research Board.

CERN-INTC-2013-013, INTC-O-017, VITO – Versatile Ion-polarized Techniques On-line at ISOLDE (former ASPIC UHV beamline) The Letter of Interest proposes to develop a dedicated beamline for producing polarized beams at ISOLDE by modifying the former UHV beamline hosting the ASPIC apparatus. Laser-based nuclear spin polarization will be used. Three end-stations are planned, (i) ASPIC + UHV beta- NMR, (ii) beta-NMR spectroscopy with differential pumping for liquid samples and (iii) an open station for movable experiments or those requiring UHV environment. Several proposals are being considered for these new experimental stations illustrating the broad scope of research possibilities ranging from solar cells through bio applications to solid state and physics of fundamental interactions. The anticipated scientific programme in the near future amounts to about 70 shifts to be spread over several runs in a period of two years starting from 2014. In the discussion about this proposal a technical issue was raised that the polarization of ions may be disturbed due to proximity of strong magnetic fields in the planned localisation. Nevertheless, the committee appreciates this initiative which will broaden the experimental versatility of ISOLDE and open new research topics. The general strong support was expressed. The committee has given strong endorsement to this Letter of Interest.

5. A.O.B. The next INTC meetings were discussed and the dates were fixed. The subsequent four sessions will be held in following dates: - October 23-24, 2013, - February 12-13, 2014, - June 25-26, 2014, - November 5-6, 2014.

Marek Pfützner on behalf of Magdalena Kowalska Tel. 73809 – 162844 [email protected]