Slow components in the photoluminescence and scintillation decays of PbWO₄ single crystals

Abstract

The decay kinetics of PhWOd luminescence and scintillation is investigated in a broad time scale lo-' to lo-" s rnairily at room temperatiire using a selected set of PbW04 crystals. The light suin released in different time gates is estimated showing rather high content of slow rcconibinatioii proes related rnaiiily to the green PbWOl emission component. Correlations are found olute green emission intensity, crystal light yield, arid the amplitude of very slow p the PbWOA scintillation decay.Das Ahkliiigeri tler Liirnineszeriz urid der Sciritillat,iori vori PbWO 1 wirtl iri eiriem breiten Zeit,t)ereich von lo-' his s vor allem bei Zirnmertemperatur untersucht. Die in vcrschicdcnen Zeitsparineii entstchende Lichtsumme wird abgeschiitzt, wit1 cs wird gezeigt. daB sie einen holien Gehalt VOII laiigsameii Rekornbinationsprozessen urnfafit, dic vor allern auf die griiiie LumineszenzkompoIicnte bezogen ist. Es wird eirie Korrelation zwischen der wirklichen Intensitat der griinen Emission. dem Kristallichtertrag iind der Amplitude der larigsarrien Prozesse des Sciritillationsahklingeris von PbWOd gefundcn.

The Model for Luminescence Center Excitation in PbWO4

“…This change of spectrum occurs since the decay or formation time of gręen luminescence is slower than that of blue luminescence. One can point out the similar differences of luminescence decay times at 80 K are known from experiments under selective photoexcitation [9], however in our experiments under pulsed electron beam irradiation only the blue luminescence was observed. These facts lead to conclusion that energy transfer to the green luminescence centers is.…”

Tunneling recombination processes in PbWO4 crystals

“…The same slope was obtained under 5.0 eV excitation. The data obtained in [10] under N 2 -laser excitation at t > 50 µs indicate that the dose dependence is superlinear and at large irradiation dose α >> 1. The superlinear dose dependence was observed also for the TSL intensity measured after irradiation in the Mo-related band (Fig.…”

“…The shortening of the decay time at T > 150 K, accompanied with the decrease of the emission intensity, was explained by the decay of the corresponding excited state [6,9]. Besides the fast decay, much slower processes were observed in the luminescence decay kinetics at RT (see, e.g., [10,11]), which influence also scintillation characteristics of PbWO 4 . The contribution of these processes is especially high in the green spectral region.…”

“…Luminescence characteristics of this crystal under steady-state excitation were studied in [4,5,10]. The Mo-doped PbWO 4 crystals were prepared in Prague and in Japan and studied in [11,13,14].…”

Contribution of structural order-disorder to the green photoluminescence ofPbWO4

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] In particular, the undoped PWO crystal has attracted much interest because of plans to use it as a scintillation detector at the Large Hadron Collider in CERN. 4,6,10,[16][17][18][19] Nevertheless, the understanding of PWO spectral behavior is still debated and some problems are left unsolved. [20][21][22][23] For example, numerous experimental works directed at identifying several types of defects and their spectral roles in PWO have recently been published.…”