Drift Chamber Beta-ray Analyzer Research Articles

Magnetic tracking detector DCBA/MTD for neutrinoless double beta decay experiments

Magnetic tracking detector is being developed at KEK for neutrinoless double beta decay experiments. Drift Chamber Beta-ray Analyzer (DCBA) is an R&D program to confirm the detection principle of the magnetic tracking detector. A prototype called DCBA-T2 has been constructed and operated to investigate its energy resolution and operation problems. Another new prototype DCBA-T3 is now under construction to improve the energy resolution and the amount of decay source. On the basis on DCBA-T2&T3, we have designed a future project temporarily called Magnetic Tracking Detector (MTD). One module of MTD will be able to accommodate a lot of decay source, so that several ten modules will give us a chance to investigate the effective neutrino mass down to 30 meV.

Neutrinoless double beta decay experiment DCBA using a magnetic momentum-analyzer

A magnetic momentum-analyzer is being developed at KEK for neutrinoless double beta decay experiment called DCBA (Drift Chamber Beta-ray Analyzer, inverted ABCD). A lot of thin plates of 150 Nd compound are installed in tracking detectors located in a uniform magnetic field. The three-dimensional position information is obtained for the helical track of a beta ray. More R&D will be studied using the second test apparatus DCBA-T2, which is now under construction.

Three-dimensional drift chambers of the DCBA experiment for neutrinoless double beta decay search

The aim of the DCBA (Drift Chamber Beta-ray Analyzer) experiment is to search for neutrinoless double beta decay ( 0 ν β β ). The half-life of 0 ν β β is expected to give us the information of Majorana nature and the absolute mass scale of neutrinos. A prototype test apparatus DCBA-T2 has the energy resolution of about 150 keV (FWHM) around 1 MeV. In order to check the detector performance, engineering runs detecting double beta decay of 100Mo started in May 2009 using natural Mo, which contains 9.6% of 100Mo. Ten candidates of the double beta decay ( β β ) have been detected so far. It has been found that the background events due to 214Bi decay are distinguishable from the double beta decays by detecting α -particles from 214Po.

Momentum analyzers DCBA for neutrinoless double beta decay experiments

Momentum analyzers called Drift Chamber Beta-ray Analyzer (DCBA) are being developed at KEK in order to search for neutrinoless double beta decays of nuclei. A test prototype, DCBA-T2, has been constructed to confirm the principle detecting electron tracks in a uniform magnetic field. Another prototype, DCBA-T3, is now under construction to improve the energy resolution. The test results and the present statuses of these prototypes are presented.

The DCBA experiment for studying neutrinoless double beta-decay

In order to search for neutrinoless double beta-decay, the DCBA (Drift Chamber Beta-ray Analyzer) experiment uses a momentum analyzer, which mainly consists of drift chamber and a uniform magnetic field. A beta ray from a source plate make helical trajectory in the drift chamber owing to the magnetic field. Momentum of each beta ray is obtained by three-dimensional track reconstruction. A test prototype called DCBA-T2 has been constructed and operated at KEK. Another prototype DCBA-T3 is also under construction to improve the energy resolution. The results of DCBA-T2 engineering run are described together with the status of DCBA-T3.

The DCBA experiment for neutrinoless double beta decay

Neutrinoless double beta decay experiment is the only realistic method to investigate the Majorana nature and the absolute mass scale of neutrinos. The DCBA (Drift Chamber Beta-ray Analyzer) experiment can separately detect electrons from other background particles in a uniform magnetic field. The kinetic energy of each electron is obtained from its momentum measurement. Therefore no energy calibration is required. The test prototype DCBA-T2 obtained the energy resolution of about 150 keV (FWHM) for 976 keV internal conversion electrons from 207Bi More improved prototype DCBA-T3 is now under construction. Its energy resolution is expected to be less than 100 keV (FWHM) according to the simulation study with Geant4. The future detector (temporarily called Magnetic Tracking Detector: MTD) enlarged from DCBA-T3 can investigate effective neutrino mass down to about 0.03 eV, if sufficient amount of 150Nd source is available.

DCBA experiment for searching for neutrinoless double beta decay (II)

R&D studies using DCBA (Drift Chamber Beta-ray Analyzer) are in progress at KEK in order to search for neutrinoless double beta decay. A test prototype DCBA-T3 has provided the information of new technologies for constructing a big size Magnetic Tracking Detector (temporarily called MTD).

DCBA experiment for searching for neutrinoless double beta decay (I)

A magnetic tracking detector called DCBA (Drift Chamber Beta-ray Analyzer) is being developed at KEK in order to search for neutrinoless double beta decay. Kinetic energy of each beta ray is obtained from its momentum, which is measured with a drift chamber installed in a uniform magnetic field. Energy resolution has been studied using a test prototype DCBA-T2. The study results are briefly described together with the structure and the principle of DCBA detector.

A FADC system based on CompactPCI for DCBA

A flash analog to digital converter (FADC) board of low cost and power saving has been developed based on Compact Peripheral Component Interface (CompactPCI) for Drift Chamber Beta-ray Analyzer (DCBA), which is an experiment to study double-beta decay. This board has been designed and constructed with 8 channels, each of which has an 8-bit 100 MHz FADC chip and a double-buffered memory. The design philosophy using recent semiconductor technology is described together with the performance of the FADC board.

Search for neutrinoless double beta decay with DCBA

A project called DCBA (Drift Chamber Beta-ray Analyzer) is in progress at KEK in order to search for the events of neutrinoless double beta decay. For investigating technical problems, a test apparatus called DCBA-T has been constructed. The preliminary results of its engineering run are described together with the simulation studies of backgrounds originating from 214Bi and 208Tl.

A separation method of 0 ν- and 2 ν-events in double beta decay experiments with DCBA

A detector called Drift Chamber Beta-ray Analyzer (DCBA) will provide momentum information of each β-ray in double beta decay. The DCBA is expected to have good capabilities for particle identification, detection efficiency, background elimination and decay-source integration. Under the assumption of mass mechanism dominance in neutrinoless double beta decay, a simulation study shows that a combination method using both sum and single-energy distributions of double beta decay events can separate 0 ν- and 2 ν-events down to 0.05 eV of the effective neutrino mass with the help of a calculated nuclear matrix element, even though the DCBA has relatively poor energy resolution.

Electrical measurement of wire tension in a multi-wire drift chamber

A new and simple technique has been developed to measure the wire tension of a multi-wire drift chamber, which is the prototype chamber of DCBA (Drift Chamber Beta-ray Analyzer) for double beta decay experiments. The present method uses two wires adjacent to each other in the chamber for applying AC and DC electric fields, and can easily detect a weak current signal at the resonance frequency corresponding to the wire tension. The wire tension has been measured with an accuracy of about 1%.

A proposed detector DCBA for double beta decay experiments

Abstract A magnetic tracking detector called DCBA (Drift Chamber Beta-ray Analyzer) is proposed for double beta decay experiments. The DCBA project is divided into two stages: DCBA-I and -II. DCBA-I will be able to measure the half life of the two-neutrino double beta decay of 150 Nd, though natural Nd is used as the decay source material. DCBA-II will make it possible to investigate the effective mass of the Majorana neutrino down to 0.5-0.1 eV, since it is expected to have the ability to measure the half-life limit up to 4 × 10 24 yr using enriched 150 Nd. A fundamental strategy of the DCBA project and some details of DCBA-I are described.