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Novel approaches in low energy threshold detectors for Dark Matter searches
Nuclear Inst. and Methods in Physics Research, A (
)
–
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
Novel approaches in low energy threshold detectors for Dark Matter searches M. Guarise a,b ,∗, C. Braggio c , R. Calabrese a,d , G. Carugno c , A. Dainelli b , A. Khanbekyan a,d , E. Luppi a,d , E. Mariotti e , L. Tomassetti a,d a
Dipartimento di Fisica e Scienze della Terra, Via G. Saragat 1, 44122 Ferrara, Italy INFN Laboratori Nazionali Legnaro, Viale dell’Università 2, 35020 Legnaro, Italy c Dipartimento di Fisica e Astronomia and INFN Padova, Via F. Marzolo 8, I-35131 Padova, Italy d INFN Ferrara, Via G. Saragat 1, 44122 Ferrara, Italy e Dipartimento di Scienze Fisiche della Terra e dell’Ambiente and INFN Siena, Via Roma 56, 53100, Siena, Italy b
ARTICLE
INFO
Keywords: Low energy threshold particle detector Matrix isolation technique Solid Neon Solidified inert gases
ABSTRACT Low energy threshold detectors are necessary in many frontier fields of the experimental physics. In particular these are extremely important for probing Dark Matter (DM) possible candidates. We present a novel detection approach that exploits the energy levels of atoms embedded into solid crystals of inert gases maintained at low temperature. We exploit laser-assisted transitions that are triggered by the absorption of the incident particle in the material and leads to a photon or an electron emission. Two possible schemes are thus possible: one is based on light signal while the other takes advantage of high efficiency-in vacuum single-electron detection using microchannel plate or channeltron sensors. Through these schemes, we could be able to detect low energy release in the range from sub eV to tens of eV in large volume crystals opening thus the possibility to investigate light DM candidates.
Contents 1. 2.
3.
Introduction ....................................................................................................................................................................................................... Detection schemes............................................................................................................................................................................................... 2.1. A: undoped matrices ................................................................................................................................................................................ 2.2. B: recycling scheme ................................................................................................................................................................................. 2.3. C: LII in doped crystals ............................................................................................................................................................................. Conclusion ......................................................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................... References..........................................................................................................................................................................................................
1. Introduction In recent years there was a significant interest in the development of low energy threshold detectors especially aimed to Dark Matter (DM) searches as well as the study of others feeble interacting phenomena characterized by low energy deposition. In fact it is well known that the Standard Model explain quite satisfactorily only the ordinary matter which is about the 5% of the Universe, while the ∼27% is the so-called DM and it is still unknown. To overcome this lack, a first generation of detectors whose main goal is the direct detection of DM candidates has been developed in the last decades and it is currently taking data. However, at present, no experimental evidence of DM has been
1 2 2 2 2 2 3 3
reported. Based on the actual observations, different theoretical models are possible and so there are many possible candidates for the solution of the DM problem. In particular, we focus our research on the Axion like particles (ALPs) that have a mass constrained in eV and sub-eV range; in addition their coupling with normal matter and radiation is very weak [1]. In the AXIOMA R&D project [2] we present a novel detection approach that exploits solid crystals of inert gases maintained at low temperature in order to obtain a low energy threshold detector for the study of Dark Matter. These kinds of crystals were initially proposed in the 50’s as unreactive environment for the study of a wide number of atoms and molecules that can be isolated within the solid crystals.
∗ Corresponding author at: Dipartimento di Fisica e Scienze della Terra, Via G. Saragat 1, 44122 Ferrara, Italy. E-mail address: [email protected] (M. Guarise).
https://doi.org/10.1016/j.nima.2018.09.148 Received 29 June 2018; Received in revised form 26 September 2018; Accepted 28 September 2018 Available online xxxx 0168-9002/© 2018 Elsevier B.V. All rights reserved.
Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.
M. Guarise et al.
Nuclear Inst. and Methods in Physics Research, A (
)
–
Fig. 2. Emission fluorescence and in the inset radiative lifetime of the band centered at ∼500 nm. The signal is fitted with an exponential curve. Fig. 1. (a) Gas purification system; (b) Cryostat chamber; (c) Recycling scheme; (d) LII in doped crystal scheme.
electrons in the crystal are more prone to be emitted through the solidvacuum interface [6]. Thus the energy release of the incident particle leads in the emission of electrons in vacuum that can be easily collected exploiting high efficiency sensors characterized also by a low dark count rate, such as microchannel plate (MCP) or channeltron. Since the energy necessary for the direct ionization process is in the eV range, each electron in vacuum bring an information of few eV and thus the energy threshold for this scheme lies in this range. We have measured electron extraction from a solid crystal of Neon (∼1 cm3 ) at 5.5 K [5].
This technique, named Matrix Isolation Spectroscopy (MIS), permits the investigation of vibrational energy levels of the dopants with a high efficiency and without the rotovibrationals degrees of freedom [3]. Based on these crystals, we propose different detection schemes that can take advantages of the energy levels of rare-earth or alkali atoms embedded into the solid matrices. A similar mechanism is the Infrared quantum counter (IRQC) that was proposed by Bloembergen in the 50’s to detect with high efficiency photons in the infrared range. In the IRQC scheme, the absorbed IR photon is up-converted into visible fluorescence light through a laser-driven process [4]. In our approach, we propose three different detection schemes with an energy threshold that ranges from tens of eV to meV in large volume crystals opening thus the possibility to investigate light DM candidates. Two of these schemes also take advantage of laser driven transitions in the energy level of the dopant embedded into the matrices.
2.2. B: recycling scheme Using doped matrices we can exploit the internal energy levels of the dopants. As we can see in Fig. 1(c), maintaining the crystal under an opportune laser pump tuned to the transition 1→3, it is possible to up-convert the energy of the incident particle into a visible photon exploiting the laser induced fluorescence (LIF). In certain conditions, the fluorescence emission ends in the level 1 and can be re-pumped again triggering a recycling mechanism. In such a way, a single excitation leads in a high number of fluorescence photons producing a gain in the light signal.
2. Detection schemes We propose three possible detection schemes all based on solid crystals of inert gases such as Neon, Nitrogen, Methane, para-Hydrogen and others. These schemes differ each other for the detectable signal and the different energy threshold that could be reached. To grow solid crystals with a large volume, both doped and undoped, according to the MIS technique, we have assembled a cryogenic facility at the INFN National Laboratories of Legnaro. As shown in Fig. 1(b) a pulse tube refrigerator provides temperatures as low as 4 K that are sufficient to condense the gas to the solid phase. To reach very pure material, we developed a gas purification system (see Fig. 1(a)) described in [5]. The purified inert gas (G) is thus sprayed by a suitable nozzle onto the growth plate linked to the cold finger of the pulse tube. In addition, in order to embed the dopants (D) into the matrix, an opportune getter can be installed near the nozzle. In this configuration, the G–D mixture solidifies in the cell and thus a crystal that incorporates the dopant species D is grown, and can be investigated with spectroscopic techniques. In the next subsections we will explain the three possible detection schemes that are under study.
2.3. C: LII in doped crystals This scheme is show in Fig. 1(d). The incident particle is absorbed in the doped crystal and promotes the transition 0→1. Then a laser pump, which is tuned to the transition 1→continuum, provides the lacking energy to ionize the atoms and to free the electron inside the matrix. In such a way, the small absorbed energy in the meV range triggers the extraction of an electron in vacuum that can be collected with MCP or channeltron that are sensitive to single electron. Exploiting Zeeman splitting one can also tune the transition 0→1 in order to probe different energies. We did initial tests with 1% Nd-doped solid Neon. Emission spectra is shown in Fig. 2 when the crystal was excited with 266 nm UV pulses. We found a long-lifetime (𝜏 = 0.602±0.004 s) emission band centered at ∼500 nm that could be used as a possible level. Further investigations are under way to characterize our crystal. 3. Conclusion
2.1. A: undoped matrices Three detection schemes based on solid crystals of inert and unreactive gases have been proposed as novel approaches aimed to the development of innovative low energy threshold particle detector. Exploiting the Matrix isolation technique combined with laser induced
When the incident particle releases its energy in the undoped crystal, it ionizes the matrix and promotes an electron in the conduction band. Due to the positive self-energy V0 typical of Neon matrices for instance, 2
Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.
M. Guarise et al.
Nuclear Inst. and Methods in Physics Research, A (
)
–
References
ionization or fluorescence, we could be able to reach an energy threshold that ranges from tens of eV to meV in a high volume active material. This could be applied in the study of feeble interacting phenomena such as Dark Matter direct searches.
[1] C. Braggio, et al., Axion dark matter detection by laser induced fluorescence in rareearth doped materials, IEEE Trans. Nucl. Sci. 54 (2007) 2646–2652. [2] AXIOMA website: https://www2pd.infn.it/gruppi/g5/axioma/. [3] E. Whittle, Matrix isolation method for the experimental study of unstable species, J. Chem. Phys. 22 (1954) 1943. [4] N. Bloembergen, Solid state infrared quantum counters, Phys. Rev. Lett. 2 (1959) 84–86. [5] M. Guarise, et al., Experimental setup for the growth of solid crystals of inert gases for particle detection, Rev. Sci. Instrum. 88 (2017) 113303. [6] A.I. Bolozdynya, Two-phase emission detectors and their applications, Nucl. Instrum. Methods A 241 (1990) 314–320.
Acknowledgments M. Guarise thanks F. Chiossi for the helpful discussions. This work was supported by the INFN Scientific Committee 5, Italy under the AXIOMA project.
3 Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.
)
–
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
Novel approaches in low energy threshold detectors for Dark Matter searches M. Guarise a,b ,∗, C. Braggio c , R. Calabrese a,d , G. Carugno c , A. Dainelli b , A. Khanbekyan a,d , E. Luppi a,d , E. Mariotti e , L. Tomassetti a,d a
Dipartimento di Fisica e Scienze della Terra, Via G. Saragat 1, 44122 Ferrara, Italy INFN Laboratori Nazionali Legnaro, Viale dell’Università 2, 35020 Legnaro, Italy c Dipartimento di Fisica e Astronomia and INFN Padova, Via F. Marzolo 8, I-35131 Padova, Italy d INFN Ferrara, Via G. Saragat 1, 44122 Ferrara, Italy e Dipartimento di Scienze Fisiche della Terra e dell’Ambiente and INFN Siena, Via Roma 56, 53100, Siena, Italy b
ARTICLE
INFO
Keywords: Low energy threshold particle detector Matrix isolation technique Solid Neon Solidified inert gases
ABSTRACT Low energy threshold detectors are necessary in many frontier fields of the experimental physics. In particular these are extremely important for probing Dark Matter (DM) possible candidates. We present a novel detection approach that exploits the energy levels of atoms embedded into solid crystals of inert gases maintained at low temperature. We exploit laser-assisted transitions that are triggered by the absorption of the incident particle in the material and leads to a photon or an electron emission. Two possible schemes are thus possible: one is based on light signal while the other takes advantage of high efficiency-in vacuum single-electron detection using microchannel plate or channeltron sensors. Through these schemes, we could be able to detect low energy release in the range from sub eV to tens of eV in large volume crystals opening thus the possibility to investigate light DM candidates.
Contents 1. 2.
3.
Introduction ....................................................................................................................................................................................................... Detection schemes............................................................................................................................................................................................... 2.1. A: undoped matrices ................................................................................................................................................................................ 2.2. B: recycling scheme ................................................................................................................................................................................. 2.3. C: LII in doped crystals ............................................................................................................................................................................. Conclusion ......................................................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................... References..........................................................................................................................................................................................................
1. Introduction In recent years there was a significant interest in the development of low energy threshold detectors especially aimed to Dark Matter (DM) searches as well as the study of others feeble interacting phenomena characterized by low energy deposition. In fact it is well known that the Standard Model explain quite satisfactorily only the ordinary matter which is about the 5% of the Universe, while the ∼27% is the so-called DM and it is still unknown. To overcome this lack, a first generation of detectors whose main goal is the direct detection of DM candidates has been developed in the last decades and it is currently taking data. However, at present, no experimental evidence of DM has been
1 2 2 2 2 2 3 3
reported. Based on the actual observations, different theoretical models are possible and so there are many possible candidates for the solution of the DM problem. In particular, we focus our research on the Axion like particles (ALPs) that have a mass constrained in eV and sub-eV range; in addition their coupling with normal matter and radiation is very weak [1]. In the AXIOMA R&D project [2] we present a novel detection approach that exploits solid crystals of inert gases maintained at low temperature in order to obtain a low energy threshold detector for the study of Dark Matter. These kinds of crystals were initially proposed in the 50’s as unreactive environment for the study of a wide number of atoms and molecules that can be isolated within the solid crystals.
∗ Corresponding author at: Dipartimento di Fisica e Scienze della Terra, Via G. Saragat 1, 44122 Ferrara, Italy. E-mail address: [email protected] (M. Guarise).
https://doi.org/10.1016/j.nima.2018.09.148 Received 29 June 2018; Received in revised form 26 September 2018; Accepted 28 September 2018 Available online xxxx 0168-9002/© 2018 Elsevier B.V. All rights reserved.
Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.
M. Guarise et al.
Nuclear Inst. and Methods in Physics Research, A (
)
–
Fig. 2. Emission fluorescence and in the inset radiative lifetime of the band centered at ∼500 nm. The signal is fitted with an exponential curve. Fig. 1. (a) Gas purification system; (b) Cryostat chamber; (c) Recycling scheme; (d) LII in doped crystal scheme.
electrons in the crystal are more prone to be emitted through the solidvacuum interface [6]. Thus the energy release of the incident particle leads in the emission of electrons in vacuum that can be easily collected exploiting high efficiency sensors characterized also by a low dark count rate, such as microchannel plate (MCP) or channeltron. Since the energy necessary for the direct ionization process is in the eV range, each electron in vacuum bring an information of few eV and thus the energy threshold for this scheme lies in this range. We have measured electron extraction from a solid crystal of Neon (∼1 cm3 ) at 5.5 K [5].
This technique, named Matrix Isolation Spectroscopy (MIS), permits the investigation of vibrational energy levels of the dopants with a high efficiency and without the rotovibrationals degrees of freedom [3]. Based on these crystals, we propose different detection schemes that can take advantages of the energy levels of rare-earth or alkali atoms embedded into the solid matrices. A similar mechanism is the Infrared quantum counter (IRQC) that was proposed by Bloembergen in the 50’s to detect with high efficiency photons in the infrared range. In the IRQC scheme, the absorbed IR photon is up-converted into visible fluorescence light through a laser-driven process [4]. In our approach, we propose three different detection schemes with an energy threshold that ranges from tens of eV to meV in large volume crystals opening thus the possibility to investigate light DM candidates. Two of these schemes also take advantage of laser driven transitions in the energy level of the dopant embedded into the matrices.
2.2. B: recycling scheme Using doped matrices we can exploit the internal energy levels of the dopants. As we can see in Fig. 1(c), maintaining the crystal under an opportune laser pump tuned to the transition 1→3, it is possible to up-convert the energy of the incident particle into a visible photon exploiting the laser induced fluorescence (LIF). In certain conditions, the fluorescence emission ends in the level 1 and can be re-pumped again triggering a recycling mechanism. In such a way, a single excitation leads in a high number of fluorescence photons producing a gain in the light signal.
2. Detection schemes We propose three possible detection schemes all based on solid crystals of inert gases such as Neon, Nitrogen, Methane, para-Hydrogen and others. These schemes differ each other for the detectable signal and the different energy threshold that could be reached. To grow solid crystals with a large volume, both doped and undoped, according to the MIS technique, we have assembled a cryogenic facility at the INFN National Laboratories of Legnaro. As shown in Fig. 1(b) a pulse tube refrigerator provides temperatures as low as 4 K that are sufficient to condense the gas to the solid phase. To reach very pure material, we developed a gas purification system (see Fig. 1(a)) described in [5]. The purified inert gas (G) is thus sprayed by a suitable nozzle onto the growth plate linked to the cold finger of the pulse tube. In addition, in order to embed the dopants (D) into the matrix, an opportune getter can be installed near the nozzle. In this configuration, the G–D mixture solidifies in the cell and thus a crystal that incorporates the dopant species D is grown, and can be investigated with spectroscopic techniques. In the next subsections we will explain the three possible detection schemes that are under study.
2.3. C: LII in doped crystals This scheme is show in Fig. 1(d). The incident particle is absorbed in the doped crystal and promotes the transition 0→1. Then a laser pump, which is tuned to the transition 1→continuum, provides the lacking energy to ionize the atoms and to free the electron inside the matrix. In such a way, the small absorbed energy in the meV range triggers the extraction of an electron in vacuum that can be collected with MCP or channeltron that are sensitive to single electron. Exploiting Zeeman splitting one can also tune the transition 0→1 in order to probe different energies. We did initial tests with 1% Nd-doped solid Neon. Emission spectra is shown in Fig. 2 when the crystal was excited with 266 nm UV pulses. We found a long-lifetime (𝜏 = 0.602±0.004 s) emission band centered at ∼500 nm that could be used as a possible level. Further investigations are under way to characterize our crystal. 3. Conclusion
2.1. A: undoped matrices Three detection schemes based on solid crystals of inert and unreactive gases have been proposed as novel approaches aimed to the development of innovative low energy threshold particle detector. Exploiting the Matrix isolation technique combined with laser induced
When the incident particle releases its energy in the undoped crystal, it ionizes the matrix and promotes an electron in the conduction band. Due to the positive self-energy V0 typical of Neon matrices for instance, 2
Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.
M. Guarise et al.
Nuclear Inst. and Methods in Physics Research, A (
)
–
References
ionization or fluorescence, we could be able to reach an energy threshold that ranges from tens of eV to meV in a high volume active material. This could be applied in the study of feeble interacting phenomena such as Dark Matter direct searches.
[1] C. Braggio, et al., Axion dark matter detection by laser induced fluorescence in rareearth doped materials, IEEE Trans. Nucl. Sci. 54 (2007) 2646–2652. [2] AXIOMA website: https://www2pd.infn.it/gruppi/g5/axioma/. [3] E. Whittle, Matrix isolation method for the experimental study of unstable species, J. Chem. Phys. 22 (1954) 1943. [4] N. Bloembergen, Solid state infrared quantum counters, Phys. Rev. Lett. 2 (1959) 84–86. [5] M. Guarise, et al., Experimental setup for the growth of solid crystals of inert gases for particle detection, Rev. Sci. Instrum. 88 (2017) 113303. [6] A.I. Bolozdynya, Two-phase emission detectors and their applications, Nucl. Instrum. Methods A 241 (1990) 314–320.
Acknowledgments M. Guarise thanks F. Chiossi for the helpful discussions. This work was supported by the INFN Scientific Committee 5, Italy under the AXIOMA project.
3 Please cite this article in press as: M. Guarise, et al., Novel approaches in low energy threshold detectors for Dark Matter searches, Nuclear Inst. and Methods in Physics Research, A (2018), https://doi.org/10.1016/j.nima.2018.09.148.