The BRIKEN Neutron Detector

Detector Construction Proposal
The BRIKEN Neutron Detector
Contents
1 Introduction
2
2 Physics Cases
5
3 Experimental Configuration
3.1 General Layout . . . . . . . . . . . . . . . . . . . .
3.2 The Advanced Implantation Detector Arrray AIDA
3.2.1 AIDA support structure . . . . . . . . . . .
3.3 The BRIKEN neutron detector . . . . . . . . . . .
3.4 Hybrid BRIKEN Detector . . . . . . . . . . . . . .
3.5 Detector electronics, readout electronics and DACQ
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4 Schedule and Beam Time Request
18
5 Collaboration
18
1
Introduction
The aim of the presented proposal is to define in detail the experimental set-up to
carry out β-delayed neutron emission measurements at the RIBF of the RIKEN
Nishina Center.
Beta-delayed neutron emission probabilities of exotic nuclei are key parameters
for the understanding of the formation of the heavy elements in the universe [1,
2, 3]. They provide a unique information about the nuclear structure of most
neutron-rich nuclei. It is worth mentioning that of the nearly 3000 nuclei which
have not been discovered yet, most are expected to be β-delayed neutron emitters.
The β-delayed neutron emission probability (Pn value) is one of the fundamental gross properties of neutron-rich nuclei that reflects the beta-feeding of excited
states above neutron separation energy. The Pn values, together with half-lives,
provide first information on the underlying nuclear structure of neutron-rich nuclei,
thus providing, for example the first consistency check for mass-models and possible competition between allowed Gamow-Teller (GT) and First-Forbidden (FF)
beta transitions. This consistency check is very important because, given that
the neutron drip line is extremely far away from stability, theoretical models need
as many normalization points as possible before being reliably extended towards
the neutron drip line. The study of neutron gated gamma rays provides another
detailed spectroscopic information about the nuclear structure of daughter nuclei,
that can be used for example to test the persistence of shell gaps and to discover
changes in nuclear structure. The competition between multiple neutron emission
2
channels (P1n , P2n , P3n , . . .) provides an additional observable for testing theoretical models. Multiple neutron emitters are accessible at the RIBF and the highly
segmented and efficient BRIKEN and hybrid BRIKEN arrays can reveal and select
the decay channels by gating on measured neutron multiplicity and characteristic
γ-rays [5].
From the astrophysics point of view there is a direct interest in Pn values as they
are among the most important inputs for r-process model calculations. It has been
known from many years that Pn values are responsible for redistributing the initial
isotopic distribution of matter and thus smoothing the final abundance pattern as
observed in the solar system. Recent studies have also highlighted that freeze-out
is not instantaneous and neutron capture during this phase is responsible for some
of the main features of the r-process abundance pattern such as the rare earth peak
(REP) at A ∼ 160, which is sensitive to the later phase of the r process and to
its environment. Beta-delayed neutron emission affects significantly the neutronto-seed ratio at this stage and in the case of a cold r process, where there is no
contribution from (γ,n) reactions, β-delayed neutron emission becomes the only
source of neutrons. Reducing the uncertainty on Pn values is critical to test the
conditions of the astrophysical scenario, and to provide clues about the site of the r
process. Another example is the falling wing of the 2nd r-process abundance peak,
which is strongly affected by β-delayed neutron emission, and is also sensitive to
the details of the astrophysical environment. Examples of the r-process sensitivity
to new half-lives and Pn values measured for β-delayed neutron emitters can be
found in Refs.[6, 7, 8, 3, 9]
In addition to the urgent need of Pn predictions for astrophysical purposes,
there are large discrepancies among nuclear models and in most cases models do
not include the competition between multiple neutron emission channels. Such a
situation is shown for example in Fig. 1 where different predictions around the
shell closures at N = 50 and N = 82 are compared.
Pn values are also important for nuclear technology applications. In nuclear
reactors β-delayed neutron emission contributes to total the neutron budget. The
number of delayed neutrons per fission neutron is quite small (typically below 1%
considering the fission induced by thermal neutrons) and thus β-delayed neutron
emission does not contribute significantly to the power generation of a nuclear
reactor. It is, however, essential from the point of view of reactor operation and
safety since the delayed emission of neutrons at times ranging from a fraction of
a second up to minutes slows the dynamic time response of a nuclear reactor. A
more precise knowledge of the process will be necessary in the design of future
power reactors with new fuel compositions.
Beta-delayed neutron emission probabilities are also required in order to quantify the decay-heat in nuclear reactors. β-delayed neutron emission creates a multiisobaric β-decay chain and therefore the decay heat depends on the β-decay prop3
Figure 1: Comparison between several theoretical predictions of Pn values at closed
shell N=50 (left panel) and N=82 (right panel). Figure from Ref. [10]. The
large discrepancty between model predictions reflects the magnitude of Pn values
uncertainty.
erties and includes gamma radiation emitted after β-delayed neutron -emission as
well as further energy release in the subsequent β-decays. In this respect, accurate
data on β-delayed neutron probabilities and following β-delayed neutron -gamma
intensities are needed for the evaluation of decay heat release during a nuclear fuel
cycle.
We propose to address the large uncertainty in Pn value predictions by performing a series of β-delayed neutron experiments for a wide range of neutron-rich
nuclei. At RIKEN this program of measurements is possible within a relatively
short periods of beam time, thanks to the high intensity primary beams, large
acceptance of BigRIPS, and high efficiency of the BRIKEN detector, that we are
proposing to build and install at RIKEN (see Sec. 3.3). The research program
will serve a large nuclear physics community and will provide an unprecedented
step forward in the understanding of β-delayed neutron emission. Because the
proposed program targets the most exotic neutron-rich regions reachable at RIBF,
the measurements of new beta-decay half-lives and the discovery of new isotopes
is also foreseen. With a large potential for discoveries of unexpected anomalies in
the nuclear landscape, our proposed program will identify areas where targetted
experiments with less efficient devices (e.g., βγ coincidences and neutron timeof-flight spectroscopy) can be performed in the future to provide more selective
information.
4
2
Physics Cases
During the two BRIKEN workshops organized in 2012 and 2013, several regions
were highlighted as priorities for the BRIKEN program. The specific proposals will
be submitted to RIKEN PAC in 2014. However, some examples of experiments
already discussed within the BRIKEN collaboration are listed below with a short
summary of their physics relevance:
• Multiple neutron emission in light nuclei: The competition between
one neutron and multi-neutron emission after beta decay is poorly understood. The studies of Z=19 potassium nuclei beyond the N=28 shell closure
up to 54 K offer relatively simple shell-model cases for development and verification the modelling of the Pn and Pxn values. Other important precursors
potentially exhibiting multi-neutron emission after β-decay are 48 Cl, 51 Ar
and heavy Ca isotopes up to 56 Ca. These experiments profit from an intense
70
Zn beam developed at RIKEN for the discovery experiment on super heavy
nucleus 278 113 and available at RIBF at 50 to 100 part nA intensity.
• Multiple neutron emission in light fission fragments below Z=28:
The information on β-delayed neutron emission from nuclei located southeast of 68 Ni is non-existant or very limited. For Z=27 Co isotopes, the
conflicting data are most likely resulting from very limited statistics of previous experimental attempts. The systematic study of nuclei from 67 Cr,
70
Mn up to 76 Co can provide unique data on the competition of GamowTeller and First-Forbidden β-transitions and gross properties of β-strength
distributions.
• N = 50 r-process waiting point nuclei: The experiment on β-delayed
neutron emission from N=50 precursors, the doubly-magic nucleus 78 Ni itself
and immediate neighbors e.g. 79 Cu. Such studies offer an ultimate test of
nuclear structure modelling and important data points for an early phase of
the r process.
• N > 50 nuclei: By using the hybrid setup described in Sec. 3.4, this region
will provide data to extend the knowledge of the evolution of neutron single
particle states (e.g., search for a potential sub-shell closure ν2d5/2 -ν3s1/2 ).
Pn values in this region have already shown potential to guide theory [11],
and a first case of β-delayed two neutron emission has also been discovered
[5]. The systematic study of N > 50 isotopes of Z=29 Cu, Z=30 Zn and
Z=31 Ga, up to 82 Cu, 84 Zn and 87 Ga, will reveal the evolution of β1n and
β2n probabilities above the Z=28 proton energy gap.
5
• Very neutron rich Ge-As-Se-Br-Rb-Y-Mo: Beta delayed neutron emission probabilities in this region are sensitive to the role of first-forbidden transitions. Furthermore, because Pn values are also affected by shell-closure
effects, Pn measurements in this region will reveal potential Z = 34 and
N = 56 or N = 58 sub-shell closures. The experiments with hybrid BRIKEN
will reflect the evolution of collectivity in this region through the observation
of first 2+ states and as well as higher energy levels, compare the studies of
N=54 [4] and N=56 [5] Ge isotopes.
From the astrophysics viewpoint, β-delayed neutron measurements in this region are of relevance for understanding the r-process abundance distributions
due to the so-called Light-Element Primary Process (LEPP) [12]. In addition, β-delayed neutron emission in the A = 110 is relevant for solving the
long-lasting puzzle of the underproduction of r-process elements just below
130 peak in r-process models. Pn values also offer a chance to study nuclear
shape evolution in a region where deformation is not clearly understood.
Finally, for the design and operation of advanced nuclear reactors the accurate determination of Pn values for several specific isotopes in this region is
also required.
• Neutron-rich Cd-Te: Pn values of these nuclei determine the falling wing
of the 2nd r-process peak, a region particularly sensitive to the astrophysical
conditions of the r process. Besides, just beyond neutron shell closure, a steep
increase of Pn values and multiple neutron emission is predicted, which is an
important benchmark test for mass and nuclear structure models. In particular, the studies of 134,135,136 In and 133,134,135 Cd, both previously observed at
BigRIPS, will offer systematic data on the β1n and β2n competition below
the Z=50 shell closure.
• Neutron-rich Ba-Tb: the experimental Pn measurement of these nuclei
represents a unique opportunity to validate r-process model calculations [8],
which ascribe the origin of the Rare-Earth Peak to the late stage in the dynamical evolution of supernova explosions. Given the absence of Pn -data
beyond A∼150, at present, nucleosynthesis calculations rely purely on theoretically predicted Pn values [3, 8].
3
3.1
Experimental Configuration
General Layout
A general layout of the RIBF is shown in Fig. 2. Stable ion beams are accelerated
by the Superconducting Ring Cyclotron (SRC) up to energies of 345 MeV/u and
6
strike the production target of the BigRIPS fragment separator in order to produce
the radioactive isotopes of interest. The first stage of the BigRIPS will be employed
for selection and purification by the Bρ − ∆E − Bρ method, while in the second
stage the fragments will be identified by measuring their magnetic rigidity Bρ,
their energy loss ∆E inside an ionization chamber and their time-of-flight (TOF)
by means of plastic scintillators. All necessary detectors for particle identification
are already available and part of the BigRIPS standard setup.
Figure 2: Overview of the RIBF. The radioactive ion beams are produced and
separated with the BigRIPS fragment separator.
After transportation to the F11 focal plane the secondary beam will be slowed
down by means of an aluminum degrader and stopped into the central region
of the Advanced Implantation Detector Array AIDA (see Sec. 3.2). AIDA will be
inserted inside the central hole of the BRIKEN neutron detector, which is described
in Sec. 3.3.
3.2
The Advanced Implantation Detector Arrray AIDA
The Advanced Implantation Detector Array (AIDA) is a state of the art silicon
detector array for decay spectroscopy experiments [13], developed to cope with
the experimental conditions of the latest generation of fast radioactive ion beam
facilities, such as RIBF in RIKEN.
The detector is made of an array of several planes of double-sided silicon strip
detectors (DSSDs), and custom made electronics that include all the readout chain,
from ASICs performing the analogue signal processing up to a readout card with
an FPGA that runs the data acquisition program. The high segmentation of the
7
DSSDs provide the position information for each implanted ion, and will detect the
β particles emitted in their subsequent decay. The position and time correlation
between implantation and decay events provides the measurement of the β-decay
half-lives. The data are time-stamped to correlate decay events with β-delayed
neutrons detected by the BRIKEN neutron detector (Section 3.3).
The sensors are made of highly segmented MSL type BB18 DSSDs (Fig. 3).
In the configuration to be used with the BRIKEN neutron detector, each plane
comprises 8cm × 8cm Si wafers with a thickness of 1 mm. Each DSSD has 128
× 128 strips (of 0.560 mm pitch) on each face, providing 16384 pixels per plane.
The current instrumentation supports a stack of up to eight DSSDs.
Each channel (strip) has two readout branches, one with a low gain (20 GeV
full scale) to detect heavy ion implants and one with a high gain (20 MeV or 1 GeV
full range) for detecting decay events. A fast overload recovery of a few µs in the
high-gain branch allows the measurement of fast implantation-decay correlations to
study isotopes with very short half-lives. The low noise (< 12 keV) and threshold
of the high-gain branch allows for spectroscopic quality measurement of the decay
events. Because of the high segmentation of its DSSD sensors and the use of a
triggerless total data readout method for the data acquisition [14] that minimizes
the effect of dead time, the system is designed to be able to sustain implantation
rates exceeding ∼1 kHz.
3.2.1
AIDA support structure
The mechanical support structure is shown in Fig. 3. The support assembly consists of a movable table, which also houses the power supplies and time-stamping
hardware. A movable support structure mounted on rails on top of this table holds
the DSSD stack, front-end electronics and cooling circuits. The DSSD sensors are
located at the end of a 60 cm long snout and connected to the FEE by flexible
Kapton PCB cables, thus allowing the implantation detectors to be inserted in the
middle position of a surrounding detector array in a compact configuration.
Floor space will also be required for a Julabo recirculating chiller (≈ 1 m2 ).
8
Figure 3: The picture on the left shows the mechanical support for the Advanced
Implantation Detector Array (AIDA). A stack of double-sided silicon strip detectors (DSSDs) are located towards the end of a ≈ 60 cm long covering case.
Front-end electronic (FEE) cards, providing digitization and data acquisition, are
placed in cooled support structures in the frame behind the sensors and are connected to the DSSDs through flexible Kapton PCB cables. Rails on the support
table can be used to retract the DSSD stack from a surrounding detector array,
such as the BRIKEN neutron counter. The picture on the right shows in detail
one 8 cm × 8 cm DSSD sensor, with one of its Kapton PCB cables connected.
9
3.3
The BRIKEN neutron detector
The final design for the BRIKEN neutron detector represents the optimized configuration for most of the physics cases discussed in Sec. 2. The detector is composed
of an array of cylindrical proportional counters filled with 3 He gas, embedded in
a high-density polyethylene matrix to moderate the neutron energies. An hybrid
configuration with HPGe detectors is described in Sec. 3.4
A total of 182 3 He tubes of six different types are available for the BRIKEN
neutron detector. They are listed in Table 1.
Table 1: 3 He tubes available within the BRIKEN Collaboration.
Owner
Pressure
(atm)
GSI
JINR
ORNL
ORNL
RIKEN
UPC
10
4
10
10
5.13
8
Size
Diameter Eff. Length
(inch/cm) (inch/mm)
1 / 2.54
23.62 / 600
1.18 / 3.0
19.69/500
2 / 5.08
24/609.6
1 / 2.54
24/609.6
1 / 2.54
118.1/300
1 / 2.54
23.62/600
Total
Number of
Counters
10
20
67
17
26
42
182
The optimization of a system which combines such large number and types
of tubes represents a rather complex task, which we have tackled by means of
systematic Monte Carlo (MC) simulations. Both MCNPX [15] and Geant4 [16]
have been used to reduce possible systematic errors due to the simulation code
itself. Owing to the very large number of 3 He tubes available, it becomes possible
to achieve a flat detection efficiency over a broad initial neutron energy range.
The final chosen geometry for the BRIKEN neutron detector (Fig. 4) comprises
a total of 174 3 He tubes arranged in six rings. Its key parameters are reported
in Table 2. The number of tubes, the number and radius of the rings, the type
of tubes in each ring, and the spacing between tubes and rings has been design
via MC-simulations in order to achieve the best compromise between high and
flat efficiency, while keeping a relatively large efficiency for high neutron-energies
of 5 MeV (see Fig. 5). This aspect is important in order to reduce systematic
uncertainties related to the hardness of the emitted neutron energy spectrum,
which is in general unknown.
The HDPE-moderator matrix has a square hole of 11 cm×11 cm size and
an external size of 110×110×90 cm3 . Mechanically, the most challenging aspect
concerns the drilling of holes, which in some cases are as close as 5 mm distance
10
Figure 4: (Left) Schematic configuration of the BRIKEN neutron detector with 6
rings and 174 3 He counters. (Right) Construction design of the BRIKEN neutron
detector on its holding structure.
Table 2: Configuration of the BRIKEN neutron detector.
Ring
1
2
3
4
5
6
Ring-Radius
(cm)
9.4
13
16.8
20
27
35
Number
of 3 He tubes
14
12+12(∗)
10+26
18+18(∗)
26
38
Pressure
(atm)
10
5.13
10/8
5/8
10
10
Diameter
(inch)
1
1
1
1.18/1
2
2
Institute
ORNL
RIKEN
GSI / UPC
JINR / UPC
ORNL
ORNL
(*) Ring made from two sections along the beam axis.
11
Figure 5: (Left) Configuration of the BRIKEN neutron detector with 6 rings and
174 3 He counters. (Right) Total efficiency (red solid line) and contribution of the
6 rings to the efficiency (see labels).
12
between them. In order to achieve a configuration which is mechanically stable, a
design based on 100 mm thick polyethylene plates has been made, as it is shownn
in Fig. 6.
Figure 6: Complete BRIKEN detection setup. The square hole of 11×11 cm2
size allows the implantation detectors to be inserted in the middle position of the
neutron detector array in a compact configuration. The moderator matrix consists
of 10 cm thick 9×HD-PE plates.
The “flatness” of the efficiency curve can be quantified by means of the F
factor, which is defined as
εmax
max
=
FEEmin
,
(1)
εmin
being εmax and εmin the maximum and the minimum efficiencies in the neutron
energy interval from Emin up to a maximum neutron energy Emax .
5 M eV
This configuration shows an F100
eV = 1.12, and a maximum neutron detection
efficiency of 66%.
As discussed in Sec. 1, multiple neutron emission represents one of the main
scientific topics within the BRIKEN project. In this respect, and owing to the
very large detection efficiency and segmentation of the BRIKEN 4π setup, the
probability for two-neutron detection becomes also quite large, over 40%. This is
shown in Fig. 8 where the two-neutron detection efficiency is shown as a function
of the neutron energy. In this case, as the available decay energy is shared between
two neutrons, one can have confidence that those energies will be relatively small,
thus being the low energy part of the efficiency curve more relevant. Based on
measurements performed at the F11 area of RIBF, the neutron background is not
13
Figure 7: (Left) Efficiency as a function of the neutron energy. (Right) Efficiency
flatness as a function of the neutron energy calculated from En = 100 eV, i.e.
En
F100
eV (see text for details).
expected to cause problems for counting ion and beta correlated neutron events.
However, there are several neutron shielding elements available. There are several
plates made out of 1 inch thick HDPE and 1 mm Cd layer from ORNL and two
sheets 2×1 m of borated rubber (41% boron) from GSI. They will serve as an
efficient passive shielding of BRIKEN.
Figure 8: Two-neutron detection efficiency for the BRIKEN neutron detector.
14
3.4
Hybrid BRIKEN Detector
As discussed in Sec. 1, neutron gated γ-ray spectra represent an excellent technique
to study the nuclear structure of the daughter nuclei. Several of the proposed
experiments will benefit from an hybrid set-up, which includes two HPGe clover
detectors of the EXOGAM type. The Ge clover detectors are available at ORNL.
The proposed hybrid BRIKEN set-up is shown in Fig. 9. It is composed of 168
3
He tubes. The HDPE-moderator matrix has a transverse size of 90×90 cm2 and
a longitudinal size of 70+45 cm. The inner square hole has a size of 11×11 cm2
in order to accomodate AIDA. The efficiency at 500 keV (2.5 MeV) is of 75.6%
(66.5%). Such a high detection efficiency, however, does not extend to as large
energies as those in the setup described in Section 3.3. The efficiency flatness
2.5 M eV
in this case, between 500 keV and 2.5 MeV, is of F500
keV =0.88. The efficiency
simulated for γ-rays of 1 MeV is 3%.
Figure 9: Hybrid configuration of the BRIKEN neutron detector, which has two
lateral holes for the insertion of two EXOGAM HPGE clover detectors.
3.5
Detector electronics, readout electronics and DACQ
For AIDA, the complete analogue front-end electronics for groups of 16 strips are
contained in Application Specification Integrated Circuits (ASICs), which process
the signal with a preamplifier, through a shaping amplifier to the analogue output.
Four of these ASICs are connected to one Front End Electronics (FEE) card, in
which the analogue outputs are fed into ADCs. The FEE card also has a Field
Programmable Gate Array (Xilinx Virtex 5 FPGA) where the data acquisition program runs, taking care of the ADC/FADC readout, data buffering, event building
15
Table 3: Configuration of the Hybrid-BRIKEN neutron detector.
Number
of 3 He tubes
42
10
16
56
24
20
Pressure
(atm)
8
10
12
10
5.13
5
Diameter
(inch)
1
1
2
2
1
1.18
Institute
UPC
GSI
ORNL
ORNL
RIKEN
JINR
and control. Data are transmitted from the FEE by a Gbit ethernet interface.
A MACB system is used to distribute the time-stamp information to the FEE
modules.
For the 3 He tubes signal processing electronics are also available for all 3 He
tubes foreseen in the BRIKEN setup. They are based on the multichannel MESYTEC
MPR-16 preamplifiers, which have been used in past experiments both with BELEN and 3Hen.
Both the BRIKEN neutron counter’s digital data acquisition (BRIKEN-DDAS)
and the one for AIDA are timestamp-based acquisition systems. A clock from a
single source will be distributed to both systems along with a signal to indicate
timestamp counter reset. White Rabbit [17], an extension to Ethernet network
with accurate synchronization, will be used for AIDA and BRIKEN-DDAS. It
provides a common clock to all nodes with sub-nanosecond accuracy and precision
of synchronisation. The network is connected using fibre optics so isolation between
nodes is inherent. In AIDA the node will be a PCIe card in the Linux computer,
and for BRIKEN-DDAS it will be VME.This method will allow data items from
BRIKEN-DDAS and AIDA to be merged using their timestamps.
On the other hand,the RIBF DAQ uses an event by event data acquisition
system, in particular for the BigRIPS detectors required for particle identification. The method of integrating this kind of DAQ with timestamped DAQs was
developed for and used at GSI. It requires four fast NIM signals to be connected
between the systems: a 10 MHz Clock, a Reset Request, a Reset and a Trigger.
Both systems implement a free-running scaler using the Reset and Clock signals.
When the event by event system has an event, it reads the value of the scaler into
the event and sends a Trigger signal to the timestamped DAQ. The timestamped
DAQ reads the scaler value when the Trigger is received and puts a timestamped
item with the scalar value into its data stream. AIDA has already the infrastructure to host the timestamped end of this connection, providing the Clock and
16
Figure 10: Schematic diagram of the data acquistion and synchronization system
proposed for AIDA + BRIKEN-DDAS + RIBF.
17
Reset signals.A suitable scaler can be placed in the RIBF readout system, which
then provides the Trigger and a Reset Request. A LUPO VME module, currently
used at RIKEN, could be used for this purpose.
Thus, to merge the three systems the timestamps in BRIKEN-DDAS and AIDA
will be matched and the scaler value in both the AIDA data stream and the RIBF
events can be used. The diagram in Fig. 10 shows how the existing data acquisition
systems for AIDA, BRIKEN-DDAS and RIBF can be combined.
The solution has been designed with the aim of using techniques which have
already been used in the past or are currently being developed. A fundamental aim
is that all 3 systems can be run in a standalone mode writing data to local storage
using existing software. In line with this aim the data from the 32 AIDA FEE64
modules will be time ordered and merged, and can if required be written to data
storage at this stage. A minimal of change is required for BRIKEN-DDAS and
RIBF to provide information which will permit software to time order and merge
the 3 data streams (AIDA + BRIKEN-DDAS + RIBF). Additionally, the DAQ
subsystems will be required to format their data and transmit via an Ethernet
connection to the final Data Merge workstation. This software has previously
been used at GSI in order to send AIDA data to MBS for combination with data
from the FRS. The 3 data streams (combined AIDA, BRIKEN-DDAS and RIBF)
are combined and written to data storage.
Additionally it will be possible to distribute these final data for immediate online analysis as required. The method of access to the live data is via a nonintrusive
spy on the data in the shared memory of the workstation.
Both the software to transfer data blocks via an Ethernet connection and to
access data buffers in shared memory by online analysis programs are simple C
codes that can be provided by the BRIKEN collaboration. For more information
see [18].
4
Schedule and Beam Time Request
We are aiming for an assembly of at least partial setup including AIDA and several
3He tubes in the HDPE moderator within the calender year 2014.
5
Collaboration
References
[1] P. Möller et al., Physical Review C, 67:055802, 2003.
[2] I.N. Borzov Physical Review C, 71:065801, 2005.
18
Table 4: List of institutions (iao) officially involved in the BRIKEN project.
Institution
CIEMAT
Daresbury Laboraotry
GSI
IFIC
JINR
JYFL
Louisiana State University
Mississippi State University
MTA-Atomki
NSCL-MSU
ORNL
RIKEN Nishina Center
The University of Tokyo
TRIUMF
UPC
University of Edinburgh
University of Guelph
University of Liverpool
University of Tennessee
University of Warsaw
Country
Spain
UK
Germany
Spain
Russia
Finland
USA
USA
Hungary
USA
USA
Japan
Japan
Canada
Spain
UK
Canada
UK
USA
Poland
19
Representative(s)
D. Cano-Ott
J. Simpson
M. Marta
C. Domingo-Pardo
E. Sokol
S. Rinta-Antila
B.C. Rasco
J.A. Winger
Z. Fulop
F. Montes
K. Rykaczewski
G. Lorusso
S. Nishimura
K. Matsui
I. Dillmann
G. Cortés
A. Estrade
P. Garrett
R. Page
R. Grzywacz
A. Korgul
[3] A. Arcones and G.M. Pinedo. Dynamical r-process studies within the neutrino driven wind scenario and its sensitivity to the nuclear physics input.
Physical Review C, 83 (2011) 45809
[4] A. Korgul et al., Physical Review C, 86:024307, 2012.
[5] K. Miernik et al., Physical Review Letters 111:132502, 2013.
[6] M. Madurga et al., Physical Review Letters 109:112501, 2012.
[7] K. Miernik et al., Physical Review C, 88:014309, 2012.
[8] M. Mumpower et al. Formation of the rare-earth peak: Gaining insight into
late-time r-process dynamics Physical Review C 85 (2012) 45801
[9] C. Domingo-Pardo et al. Approaching the precursor nuclei of the third rprocess peak with RIBs. Int. Conf. on Nuclear Physics in Astrophysics VI,
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