Neutron ToF Spectrometer NeuLAND
NeuLAND (new Large-Area Neutron Detector) is the next-generation neutron detector designed for R3B which meets all requirements defined by the ambitious physics program proposed for the R3B facility. NeuLAND features a high detection efficiency, a high resolution, and a large multi-neutron-hit resolving power. This is achieved by a highly granular design of plastic scintillators, avoiding insensitive converter material. The detector will consist of 3000 individual submodules with a size of 5x5x250 cm3, arranged in 30 double planes with 100 submodules providing an active face size of 250x250 cm2 and a total depth of 3 m. NeuLAND can be divided into two detectors for special applications and can be placed at different distances from the target, in order to meet specific experimental demands. A momentum resolution of Δp/p of 10-3 similar to that for the charged particles is desired, resulting in resolution requirements for the time of flight of σ(t) < 150 ps and a position resolution of σ(x,y,z) ≈ 1.5 cm for given flight paths in the range from 10 to 35 m. For an experiment on a medium mass nucleus at about 500 MeV/nucleon, invariant-mass resolutions of about ΔE =20 keV at 200 keV above the neutron threshold (ΔE=30 keV at 1 MeV respectively) will be reached using the maximum flight path. Apart from the excellent energy resolution of NeuLAND, the enhanced multi-neutron recognition capability with an efficiency of up to ~50% for a reconstructed five-neutron event at 1 GeV (see tabels below) will constitute a major step forward.
The final design containing details of the technical realization including mechanics, readout electronics, submodules tests, calibrations, and the construction procedure and described in the NeuLAND Technical Report is the result of several years of R&D studies. Different design concepts have been followed, including converter-based solutions, e.g., a detector based on steel converter plus charged-particle detection with resistive-plate chambers (RPC). The RPC concept has been ruled out mainly because of its insufficient multi-neutron detection capability. A fully active detector with calorimetric properties has turned out to be the best solution. The NeuLAND Technical Design Report has been finalzed in 2011 and accepted by FAIR on January 18, 2013.
In 2012, the prototype of the NeuLAND detector consisting of 150 bars has been tested at GSI resulting in time resolutions better than the required σ(t) ≤ 150 ps, even with inexpensive photomultipliers. In accordance with simulations, improved timing properties have been obtained with optimized light guides.
The construction of the detector has started in spring 2013. During Oct. 2014 the NeuLAND demonstrator ( 1/6 of the full size detector) was successfully tested in GSI beam times. The contious mounting of NeuLAND double-planes is carried out at GSI with a team from all contributing institutes guided by the R3B project group. Necessary quality controls have been established. The construction scheme allows the production of one double-plane per month. Prior to the installation of NeuLAND at its final location in the R3B hall at the FAIR site, the detector can be commissioned and available for experiments at Cave C.
News older than January 2015 are to be found in NeuLAND News archive.
- On September 21st, the NeuLAND demonstrator, consisting of four double-planes, came back to GSI after a two-years campaign at RIKEN, see photos below.
- A campaign of three experiments has been carried out using the SAMURAI setup and the NeuLAND demonstrator, devoted to studies using 8He and 6He beams.
- During spring the NeuLAND demonstrator was used in two experiments at SAMURAI: Dipole response of neutron-rich Ca isotopes and the SEASTAR3 campaign.
- At GSI the assembly of NeuLAND double plane 11 was completed. Two more double planes will be built during 2017, which leads to more than 40% completion of NeuLAND for the phase 0 programm at GSI starting in 2018.
- On Feb. 28th the NeuLAND Working Group Meeting took place in conjunction with the NUSTAR Week at GSI. The agenda comprised reports about experiments with the NeuLAND prototype and demonstrator at GSI and RIKEN, simulation studies both on the detector performance as a function of detector depth and the possible need for a VETO detector in front of NeuLAND, the status of NeuLAND production and the upcoming experiments at RIKEN in 2017 followed by the backtransport to GSI and the preparation of the experimental campaign starting in 2018 at GSI.
- For the autumn 2016 measurement campaign at SAMURAI, the NeuLAND demonstrator has been moved back to its position at 0 degree to the beam line. Three experiments have been carried out using light ions, comprising a study of the unbound states and ground-state properties of 31Ne, an investigation of the level structure of 22C combined with the search for 21B, and an experiment exploiting a new technique to determine the neutron-decay lifetime of the 26O ground state.
- The pre-series of the new read-out electronics for NeuLAND - NeuLAND-TAMEX (200 channels) was mounted inside the electronic boxes of one double-plane and successfully taken into operation. This electronics is a GSI in-house development based on the former TacQuila electronics. It delivers a very precise time measurement from an FPGA TDC and a charge measurement using the Time-over-Threshold (ToT) method. The timing properties of the double-plane, determined using cosmic rays, exhibit results of typically 120 ps (sigma) similar to earlier extracted values using the former electronics. Based on these results, the mass production of this cost-effective solution will be launched.
- The first part of the series production of the high-voltage distribution system (HVDS) for NeuLAND was delivered to GSI/FAIR and successfully taken into operation. The delivery comprises 20 modules, each serving 50 PMTs of NeuLAND, thus 1000 channels. The HVDS is developed, produced and delivered by PNPI, Russia, and the design has been optimized for usage with NeuLAND. The second delivery comprising 2000 channels is scheduled for autumn 2017.
- The NeuLAND demonstrator was part of the Sπrit TPC experiment carried out at RIKEN. In contrast to earlier experiments, the NeuLAND demonstrator joined, here, the detector seeing both charged particles and neutrons stemming from central collisions of 108,112,124,132Sn on 112,124 Sn target.
Figure 1 shows a particle ID plot from the 1st NeuLAND plane, displaying the time of flight over the energy deposited in the hit. Protons, deuterons, tritons, 3He and 4He were identified.
Figure 2 shows the same distribution, but including a condition that no VETO hit was registered in the event.
The left-over distribution is originating from neutrons and (at small time of flights) gamma-rays.
Besides the main goal, the derivation of neutron over charged particle ratios for the Sπrit TPC experiment, the data taken are of great value for detector response studies, having charged and neutral particles hitting the detector at the same time.
The NeuLAND demonstrator, currently located at RIKEN , Japan, was moved within the SAMURAI Area to 30 degrees with respect to the target, see photo below. At this new position, NeuLAND together with a VETO wall in front will take data in an upcoming experiment, studying central collision in several combinations of Sn isotopes beams and Sn isotope targets.
- The status of the analysis of the 7Li(p,n) calibration experiment of the NeuLAND Demonstrator at RIKEN (see NeuLAND news Nov. 2015) is summarized in an RIKEN progress report. The figure below shows the preliminary experimental velocity spectrum of NeuLAND for ~ 110MeV neutrons with veto condition cut, and an energy cut E > 5MeVee. The background was evaluated with an empty-target run. The integral under the red curve indicates the neutron events, which will be used to derive the efficiency.
On March 1st the NeuLAND Working Group Meeting took place with about 30 participants at GSI. In the first session the status and the preparations needed for NeuLAND up to the experimental campaign to be started in the beginning of 2018 was summarized. The progress of detector construction was discussed as well as the HV supplying system and the readout electronics. Measures to be taken concerning the data acquisition and slow control, simulations, analysis and calibrations were specified. In the second session the status of the analysis of data from the last experiments and the ongoing progress in simulations were presented and discussed.
The first of the two NeuLAND frames has been built, see photograph. It allows to hold up to 20 double planes. Its design allows the junction with a second frame to support all foreseen 30 NeuLAND double-planes, but also allows the splitting of the detector in two independent components and placing at different distances and angles to the target, depending on the specific experimental demands. The service platform, visible in the technical drawing on the right side is currently under construction.
- Preliminary online analysis of NeuLAND data measured at RIKEN are very promising: An efficiency of (31.5±1.1)% for one-neutron events is extracted from the preliminary analysis for the 250 MeV neutron run for the NeuLAND configuration at RIKEN (4 double-planes, 40 cm of detector depth); this result is in good accordance with simulation (29%).
- The figure below shows the paddle multiplicity summed over all NeuLAND and Nebula modules for two different incoming ions at 250 AMeV. For the (p,3p) reaction of 29Ne, three neutrons are emitted in forward direction, for the (p,2p) reaction of 29F four neutrons impinge on the neutron detectors. A clear increase in paddle multiplicity was observed online, indicating the higher number of neutrons detected. The unambigious identification of the number of neutrons and their momentum reconstruction requires a more complex offline analysis.
Part of the NeuLAND detector is presently in operation as one major components in an experimental campaign performed with the SAMURAI setup at RIKEN, studying several exotic neutron-rich nuclei including the double-magic nucleus 28O. The experiments are complemented by a calibration experiment for the combination of NeuLAND and NEBULA (the neutron detector at the SAMURAI setup), determining the efficiency at neutron energies of 110 and 250 MeV.
- On June 1st the status of the NeuLAND subproject was presented during the R3B collaboration meeting. An update on the status was given for the production of double-planes at GSI, the planned in-kind contributions from PNPI and the design of the NeuLAND electronics. The planned experimental campaign at RIKEN was discussed and very first simulations on a VETO concept for NeuLAND were presented. The session closed with a presentation on the latest findings from the SiPM study for a possible use at later stages of the NeuLAND project.
- Seventh double-plane of the NeuLAND detector has been built.
- The four NeuLAND double-planes located at the SAMURAI setup at RIKEN have been successfully taken into operation and the calibration using cosmic rays has been performed. Next steps are the combined data taking with the NEBULA Veto Wall and with the NEBULA Detector itself.
- In connection with the NUSTAR week a NeuLAND working group meeting on March 3 at GSI discussed the future analysis framework for R3B, status of NeuLAND@RIKEN and future experiments there. Presentations on the status of the the analysis of S406 and S438a-c as well as on needed simulations were given. The performance of SiPMTs, which might become in the future an alternative for conventional PMTs, was presented.
- NeuLAND has been incorporated into experimental set-up in the SAMURAI cave. In the photo below, one can see four double planes of the NeuLAND detector positioned between SAMURAI exit window (left) and NEBULA detector (right).
- On February 15th the four double-planes of the NeuLAND detector have been integrated into SAMURAI setup.
- At GSI the double plane 6 has been assembled in its final configuration.
- On January 12th, the box containing the four NeuLAND double-planes has left GSI (see picture below, left) and has arrived on January 27th at RIKEN. On January 31st the box has been transported down to the SAMURAI cave, see photo below right.
Older news can be found here.
- The NeuLAND Technical Design Report, available here.
- "NeuLAND - from the demonstrator to the start version", K. Boretzky et al, Scientific Report 2016 GSI Report 2017-1, 207-210 p. (2017) [10.15120/GR-2017-1 RESEARCH-NUSTAR-KR-1]
- "NeuLAND - from double-planes to the demonstrator", K. Boretzky et al, Scientific Report 2014 GSI Report 2015-1, 200-202 p. (2015) [10.15120/GR-2015-1-MU-NUSTAR-NR-12]
- "NeuLAND test-beam data analysis with R3BRoot framework", D. Kresan et al, Scientific Report 2014 GSI Report 2015-1, 378-379 p. (2015) [10.15120/GR-2015-1-INFRASTRUCTURE-IT-10]
- "A compact readout system for the R3B High-Resolution Neutron Time-of-Flight Spectrometer (NeuLAND)", C. Ugur et al, Scientific Report 2014 GSI Report 2015-1, 204-205 p. (2015) [10.15120/GR-2015-1-MU-NUSTAR-NR-14]
- "Multi-Neutron detection in R3B at FAIR with alternative detector model", V. Wagner et al, Scientific Report 2014 GSI Report 2015-1, 203 p. (2015) [10.15120/GR-2015-1-MU-NUSTAR-NR-13]
- "NeuLAND - from prototypes to double-planes", K. Boretzky et al, Scientific Report 2013 GSI Report 2014-1, 346-350 p. (2014) [10.15120/GR-2014-1-FG-S-FRS-11]
- "Tests of timing silicon photomultipliers for NeuLAND", S. Gohl et al, Scientific Report 2013 GSI Report 2014-1, 150 p. (2014) [10.15120/GR-2014-1-NUSTAR-KR-11]
- "Construction and Test of a Large NeuLAND Prototype Array", K. Boretzky et al, GSI Scientific Report 2012, PHN-ENNA-EXP-60
- "Recent Developments in NeuLAND Simulations", D. Kresan et al, GSI Scientific Report 2012, PHN-ENNA-EXP-64
- "NeuLAND@R3B: A Fully-Active Detector for Time-of-Flight and Calorimetry of Fast Neutrons", K. Boretzky et al, GSI Sci. Rep. 2011, PHN-NUSTAR-NR-02, p. 174.
- "Recent Developments in NEULAND Simulations", D. Kresan et al, GSI Sci. Rep. 2011, PHN-NUSTAR-NR-03, p. 175.
- "Implementation and Performance of Neutron Tracking Algorithm for NEULAND", D. Kresan et al, GSI Sci. Rep. 2011, PHN-IS-IT-13, GSI Sci. Rep. 2011, p. 272.
- "NeuLAND - Concepts for the Detection of Fast Neutrons", T. Aumann et al, GSI Sci. Rep. 2010, PHN-NUSTAR-NR-18, p. 180.
- "NeuLAND: Simulations for the Scintillator Concept ", M. Heil et al, GSI Sci. Rep. 2010, PHN-NUSTAR-NR-19, p. 181.