LUCRECIA experiment

Last updated
Isotope Separator On Line Device
(ISOLDE)
List of ISOLDE experimental setups
COLLAPS, CRIS, EC-SLI, IDS, ISS, ISOLTRAP, LUCRECIA, Miniball, MIRACLS, SEC, VITO, WISArD
Other facilities
MEDICIS Medical Isotopes Collected from ISOLDE
508Solid State Physics Laboratory
LUCRECIA - the total absorption spectrometer (TAS) at ISOLDE LUCRECIA.jpg
LUCRECIA - the total absorption spectrometer (TAS) at ISOLDE

The LUCRECIA experiment is a permanent experimental setup at the ISOLDE facility at CERN. The purpose of LUCRECIA is to analyse nuclear structure and use this to confirm theoretical models and make stellar predictions. The experiment is based on a Total Absorption gamma Spectrometer (TAS) designed to measure beta ray feeding. [1] [2]

Contents

Background

When an unstable parent nucleus decays via beta decay, there may be subsequent gamma radiation emitted. The decay will depend on the parent nucleus and the available levels and gamma transitions that could take place in the daughter nucleus. [3] The technique of measuring the gamma radiation with good efficiency is known as total absorption spectroscopy.

The pandemonium effect concerns the difficulty in using high resolution detectors in beta decay experiments, to construct a complex level scheme. Low efficiency detectors will lead to some gamma ray transitions to be omitted from the data set, and the determined feeding pattern is incorrect. [4] A feeding pattern refers to the probability of the parent nucleus to directly decay to a level in the daughter nucleus.

A total absorption spectrometer is made of a scintillator crystal, covering almost all of the solid angle surrounding the radioactive sample. Ideally, the crystal would be thick enough to have close to a 100% total efficiency, and should be blind to any other type of radiation. Photomultipliers (PMTs) are attached to the crystal to collect the gamma scintillating light produced in the crystal by the gamma radiation. The technique used may counter the pandemonium effect. [5]

Experimental setup

Lucrecia measuring station with shielding in white and beam line. Lucrecia TAS detector at ISOLDE hall at CERN.png
Lucrecia measuring station with shielding in white and beam line.

LUCRECIA is installed at the end of one of the ISOLDE beam lines, and consists of the TAS with a tape station for implanting the radioactive activity. [1] Radioactive ion beams from ISOLDE are implanted onto the tape (held by a beam pipe) which is then transported to the centre of the TAS for measurement. By changing the position of the rollers, it is possible to implant the beam directly in the centre of the TAS, which allows for measurements of more exotic nuclei with shorter half-lives or outside the spectrometer and the moved into the detector.[ citation needed ]

The TAS is made of a piece of NaI(Tl) cylindrically shaped with a height of 38 cm. The 7.5 cm diameter cylindrical cavity runs perpendicularly to its axis of symmetry. [6] The cavity allows the beam pipe to enter into the detector and position the radioactive source in the centre of the detector, and allows the placement of ancillary detectors on the opposite side to measure other radiation such as the beta particles, X-rays or gamma radiation. [2] The use of the cavity decreases LUCRECIA's total efficiency (to around 90% for a range of 300 to 3000 keV). [7] Eight PMTs are used to collect light, and the total counting rate is kept below 10 kHz to avoid pilup contributions. [8] [9]

Around the TAS there is a 19 cm thick shielding box made of four layers: polythene, lead, copper and aluminium. The box absorbs most external radiation, including neutrons, cosmic rays and background from the facility. [10]

Results

The results from experiments performed at the LUCRECIA setup, have been able to confirm theoretical predictions on the prolate shape of 76Sr ground state and an admixture of prolate and oblate shape for 74Kr ground state. [11] [2] [6]

Similar studies have been carried out in the neutron deficient mercury region. [12]

Currently, several experiments are in "preparation" stages using the LUCRECIA setup at the ISOLDE facility. [13] [1]

Related Research Articles

<span class="mw-page-title-main">Beta particle</span> Ionizing radiation

A beta particle, also called beta ray or beta radiation, is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus, known as beta decay. There are two forms of beta decay, β− decay and β+ decay, which produce electrons and positrons, respectively.

A semiconductor detector in ionizing radiation detection physics is a device that uses a semiconductor to measure the effect of incident charged particles or photons.

<span class="mw-page-title-main">Gamma-ray spectrometer</span> Instrument for measuring gamma radiation

A gamma-ray spectrometer (GRS) is an instrument for measuring the distribution of the intensity of gamma radiation versus the energy of each photon. The study and analysis of gamma-ray spectra for scientific and technical use is called gamma spectroscopy, and gamma-ray spectrometers are the instruments which observe and collect such data. Because the energy of each photon of EM radiation is proportional to its frequency, gamma rays have sufficient energy that they are typically observed by counting individual photons.

<span class="mw-page-title-main">Gamma spectroscopy</span> Quantitative study of the energy spectra of gamma-ray sources

Gamma-ray spectroscopy is the qualitative study of the energy spectra of gamma-ray sources, such as in the nuclear industry, geochemical investigation, and astrophysics. Gamma-ray spectrometry, on the other hand, is the method used to acquire a quantitative spectrum measurement.

<span class="mw-page-title-main">ISOLDE</span> Physics facility at CERN

The ISOLDE Radioactive Ion Beam Facility, is an on-line isotope separator facility located at the centre of the CERN accelerator complex on the Franco-Swiss border. Created in 1964, the ISOLDE facility started delivering radioactive ion beams (RIBs) to users in 1967. Originally located at the Synchro-Cyclotron (SC) accelerator, the facility has been upgraded several times most notably in 1992 when the whole facility was moved to be connected to CERN's ProtonSynchroton Booster (PSB). ISOLDE is currently the longest-running facility in operation at CERN, with continuous developments of the facility and its experiments keeping ISOLDE at the forefront of science with RIBs. ISOLDE benefits a wide range of physics communities with applications covering nuclear, atomic, molecular and solid-state physics, but also biophysics and astrophysics, as well as high-precision experiments looking for physics beyond the Standard Model. The facility is operated by the ISOLDE Collaboration, comprising CERN and sixteen (mostly) European countries. As of 2019, close to 1,000 experimentalists around the world are coming to ISOLDE to perform typically 50 different experiments per year.

In spectroscopy, a forbidden mechanism is a spectral line associated with absorption or emission of photons by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particular selection rule but is allowed if the approximation associated with that rule is not made. For example, in a situation where, according to usual approximations, the process cannot happen, but at a higher level of approximation the process is allowed but at a low rate.

<span class="mw-page-title-main">Mössbauer spectroscopy</span> Spectroscopic technique

Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. This effect, discovered by Rudolf Mössbauer in 1958, consists of the nearly recoil-free emission and absorption of nuclear gamma rays in solids. The consequent nuclear spectroscopy method is exquisitely sensitive to small changes in the chemical environment of certain nuclei.

<span class="mw-page-title-main">COMPASS experiment</span>

The NA58 experiment, or COMPASS is a 60-metre-long fixed-target experiment at the M2 beam line of the SPS at CERN. The experimental hall is located at the CERN North Area, close to the French village of Prévessin-Moëns. The experiment is a two-staged spectrometer with numerous tracking detectors, particle identification and calorimetry. The physics results are extracted by recording and analysing the final states of the scattering processes.

<span class="mw-page-title-main">Gamma ray</span> Penetrating form of electromagnetic radiation

A gamma ray, also known as gamma radiation (symbol
γ
), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz (3×1019 Hz) and wavelengths less than 10 picometers (1×10−11 m), gamma ray photons have the highest photon energy of any form of electromagnetic radiation. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation gamma rays based on their relatively strong penetration of matter; in 1900, he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power.

<span class="mw-page-title-main">Pandemonium effect</span>

The pandemonium effect is a problem that may appear when high-resolution detectors are used in beta decay studies. It can affect the correct determination of the feeding to the different levels of the daughter nucleus. It was first introduced in 1977.

<span class="mw-page-title-main">Total absorption spectroscopy</span>

Total absorption spectroscopy is a measurement technique that allows the measurement of the gamma radiation emitted in the different nuclear gamma transitions that may take place in the daughter nucleus after its unstable parent has decayed by means of the beta decay process. This technique can be used for beta decay studies related to beta feeding measurements within the full decay energy window for nuclei far from stability.

<span class="mw-page-title-main">Neutron Time Of Flight</span> Facility at CERN with a neutron source

The Neutron Time Of Flight (n_TOF) facility is a neutron spectrometer at CERN, with the aim of studying neutron-nucleus interactions over a range of kinetic energies, using the time of flight method. The research conducted at the facility has applications in nuclear technology and nuclear astrophysics. The facility has been in operation at CERN since 2001, following a proposal from the former Director General, Carlo Rubbia, for a high-intensity neutron source.

Conversion electron Mössbauer spectroscopy (CEMS) is a Mössbauer spectroscopy technique based on conversion electron.

<span class="mw-page-title-main">Radionuclide identification device</span>

A radionuclide identification device is a small, lightweight, portable gamma-ray spectrometer used for the detection and identification of radioactive substances. As RIIDs are portable, they are suitable for medical and industrial applications, fieldwork, geological surveys, first-line responders in Homeland Security, and Environmental Monitoring and Radiological Mapping along with other industries that necessitate the identification of radioactive substances..

<span class="mw-page-title-main">Multichannel analyzer</span>

A multichannel analyzer (MCA) is an instrument used in laboratory and field applications to analyze an input signal consisting of voltage pulses. MCAs are used extensively in digitizing various spectroscopy measurements, especially those related to nuclear physics, including various types of spectroscopy.

<span class="mw-page-title-main">X-ray emission spectroscopy</span>

X-ray emission spectroscopy (XES) is a form of X-ray spectroscopy in which a core electron is excited by an incident x-ray photon and then this excited state decays by emitting an x-ray photon to fill the core hole. The energy of the emitted photon is the energy difference between the involved electronic levels. The analysis of the energy dependence of the emitted photons is the aim of the X-ray emission spectroscopy.

<span class="mw-page-title-main">ISOLDE Decay Station experiment</span>

The ISOLDE Decay Station (IDS) is a permanent experiment located in the ISOLDE facility at CERN. The purpose of the experiment is to measure decay properties of radioactive isotopes using spectroscopy techniques for a variety of applications, including nuclear engineering and astrophysics. The experimental setup has been operational since 2014.

<span class="mw-page-title-main">Miniball experiment</span>

The Miniballexperiment is a gamma-ray spectroscopy setup regularly located in the ISOLDE facility at CERN, along with other locations including GSI, Cologne, PSI and RIKEN (HiCARI). Miniball is a high-resolution germanium detector array, specifically designed to work with low-intensity radioactive ion beams post-accelerated by HIE-ISOLDE, to analyse gamma radiation emitted by short-lived nuclei. Due to six-fold detector segmentation, Miniball offers a superior Doppler-correction capability with respect to conventional gamma-ray spectrometers using unsegmented detectors. The array has been used for successful Coulomb-excitation and transfer-reaction experiments with exotic beams. Results from Miniball experiments have been used to determine and probe nuclear structure.

<span class="mw-page-title-main">VITO experiment</span>

The Versatile Ion polarisation Technique Online (VITO) experiment is a permanent experimental setup located in the ISOLDE facility at CERN, in the form of a beamline. The purpose of the beamline is to perform a wide range of studies using spin-polarised short-lived atomic nuclei. VITO uses circularly-polarised laser light to obtain polarised radioactive beams of different isotopes delivered by ISOLDE. These have already been used for weak-interaction studies, biological investigations, and more recently nuclear structure research. The beamline is located at the site of the former Ultra High Vacuum (UHV) beamline hosting ASPIC.

Laura Joanne Harkness-Brennan is a British physicist who is a professor and Associate Pro-Vice Chancellor for Research and Impact at the University of Liverpool. Her research focusses on the development of radiation detectors for gamma-ray spectroscopy and imaging. She was awarded the Institute of Physics Jocelyn Bell-Burnell Prize in 2010.

References

  1. 1 2 3 Nacher, Enrique; Algora, Alejandro; Berta, Rubio (8 Jan 2020). "Upgrade and scientific programme of LUCRECIA, the Total Absorption Spectrometer at ISOLDE". CERN. Geneva. ISOLDE and Neutron Time-of-Flight Experiments Committee.
  2. 1 2 3 Nácher, E.; Algora, A.; Rubio, B.; Taín, J. L.; Cano-Ott, D.; Courtin, S.; Dessagne, Ph.; Maréchal, F.; Miehé, Ch.; Poirier, E.; Borge, M. J. G.; Escrig, D.; Jungclaus, A.; Sarriguren, P.; Tengblad, O. (2004-06-09). "Deformation of the $N=Z$ Nucleus $^{76}\mathrm{Sr}$ using $\ensuremath{\beta}$-Decay Studies". Physical Review Letters. 92 (23): 232501. arXiv: nucl-ex/0402001 . doi:10.1103/PhysRevLett.92.232501. PMID   15245152.
  3. ↑ Rubio, B.; Gelletly, W. (2007). "Total absorption spectroscopy" (PDF). Romanian Reports in Physics. 59 (2): 635–654.
  4. ↑ Mesquita, Amir (2012-02-10). Nuclear Reactors. BoD – Books on Demand. ISBN   978-953-51-0018-8.
  5. ↑ Äystö, Juha; Eronen, Tommi; Jokinen, Ari; Kankainen, Anu; Moore, Iain; Penttilä, Heikki (2014-01-23). IGISOL: Three decades of research using IGISOL technique at the University of Jyväskylä. Springer Science & Business Media. ISBN   978-94-007-5555-0.
  6. 1 2 Rubio, B; Gelletly, W; Nácher, E; Algora, A; Taín, J L; Pérez, A; Caballero, L (2005-10-01). "Beta decay studies with the total absorption technique: past, present and future". Journal of Physics G: Nuclear and Particle Physics. 31 (10): S1477–S1483. Bibcode:2005JPhG...31S1477R. doi:10.1088/0954-3899/31/10/017. ISSN   0954-3899.
  7. ↑ Algora, A.; Ganioğlu, E.; Sarriguren, P.; Guadilla, V.; Fraile, L. M.; Nácher, E.; Rubio, B.; Tain, J. L.; Agramunt, J.; Gelletly, W.; Briz, J. A.; Cakirli, R. B.; Fallot, M.; Jordán, D.; Halász, Z. (2021-08-10). "Total absorption gamma-ray spectroscopy study of the β-decay of 186Hg". Physics Letters B. 819: 136438. doi:10.1016/j.physletb.2021.136438. hdl: 10261/261345 . ISSN   0370-2693.
  8. ↑ Briz, J. A.; Nácher, E.; Borge, M. J. G.; Algora, A.; Rubio, B.; Taín, J. L.; Cano-Ott, D.; Courtin, S.; Dessagne, Ph.; Maréchal, F.; Miehé, Ch.; Poirier, E.; Escrig, D.; Jungclaus, A.; Tengblad, O. (30 June 2015). Total Absorption Spectroscopy of the N=Z Nucleus 72 Kr. Journal of the Physical Society of Japan. doi: 10.7566/JPSCP.6.020050 . ISBN   978-4-89027-110-8.
  9. ↑ Guadilla, Victor; Pfützner, Marek; Agramunt, Jorge; Algora, Alejandro; et al. (5 Jan 2021). "Beta-decay spectroscopy of 27Na and 22O for isospin asymmetry studies in the sd shell". CERN. Geneva. ISOLDE and Neutron Time-of-Flight Experiments Committee.
  10. ↑ Nácher, E; Algora, A; Rubio, B; Taı́n, J. L; Cano-Ott, D; Borge, M. J. G; Courtin, S; Dessagne, Ph; Escrig, D; Fraile, L. M; Gelletly, W; Jungclaus, A; Le Scornet, G; Maréchal, F; Miehé, Ch (2004-04-05). "Total absorption spectroscopy of 76Sr with the Lucrecia spectrometer at ISOLDE". Nuclear Physics A. Proceedings of the Eighth International Conference on Nucleus-Nucleus Collisions (NN2003). 734: E84–E87. doi:10.1016/j.nuclphysa.2004.03.026. ISSN   0375-9474.
  11. ↑ Poirier, E.; Maréchal, F.; Dessagne, Ph.; Algora, A.; Borge, M. J. G.; Cano-Ott, D.; Caspar, J. C.; Courtin, S.; Devin, J.; Fraile, L. M.; Gelletly, W.; Heitz, G.; Jungclaus, A.; Scornet, G. Le; Miehé, Ch. (2004-03-03). "B ( GT ) strength from β -decay measurements and inferred shape mixing in Kr 74". Physical Review C. 69 (3): 034307. doi:10.1103/PhysRevC.69.034307. hdl: 10261/5958 . ISSN   0556-2813.
  12. ↑ Algora, A.; Ganioğlu, E.; Sarriguren, P.; Guadilla, V.; Fraile, L.M.; Nácher, E.; Rubio, B.; Tain, J.L.; Agramunt, J.; Gelletly, W.; Briz, J.A.; Cakirli, R.B.; Fallot, M.; Jordán, D.; Halász, Z. (August 2021). "Total absorption gamma-ray spectroscopy study of the β-decay of 186Hg". Physics Letters B. 819: 136438. doi:10.1016/j.physletb.2021.136438. hdl: 10261/261345 .
  13. ↑ "Greybook". greybook.cern.ch. Retrieved 2023-07-31.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.