Design of Grid Ionization Chambers

Bunemann, O.; Cranshaw, T. E.; Harvey, J. A.

doi:10.1139/cjr49a-019

Cited by 333 publications

(101 citation statements)

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“…It has to be noted that Eq. 3.1 and 3.3 are valid only for a grid of equally spaced parallel wires [14,15]. The TPC can be positioned inside the vessel in two different orientations: with the electrodes parallel to the ground for a vertical drift (figure 7), and with the electrodes orthogonal to the ground for a horizontal drift (figure 9).…”

Section: Tpc Hv System and Read-out Electrodesmentioning

confidence: 99%

“…The purity of the liquid Argon before passing through the OXYSORB cartridge has a nominal concentration of water and Oxygen of the order of the ppm. Filling of the TPC takes 5 hours and it is monitored by a capacitance 14 level metre made of a cylindrical capacitor about 1 m long. The increase of the liquid level in the vessel produces a directly proportional increase of the capacitance of the device.…”

Section: Detector Operationmentioning

confidence: 99%

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A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

et al. 2009

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This paper describes the design, realization and operation of a prototype liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the development of a novel online monitoring and calibration system exploiting UV laser beams. In particular, the system is intended to measure the lifetime of the primary ionization in LAr, in turn related to the LAr purity level. This technique could be exploited by present and next generation large mass LAr TPCs for which monitoring of the performance and calibration plays an important role. Results from the first measurements are presented together with some considerations and outlook.

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Section: Tpc Hv System and Read-out Electrodesmentioning

confidence: 99%

Section: Detector Operationmentioning

confidence: 99%

A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

et al. 2009

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“…Choosing for this region a field of 300 V/cm, double of the one in the drift to ensure good electron transmission [26], a 6 mm gap is sufficient to delay the ions by about 1 ms, as required by the ILC operation; their injection in the drift volume can then be inhibited pulse-closing the gate, after the delay, for a time equal to the spill length.…”

Section: Gem Charge Transmission Propertiesmentioning

confidence: 99%

Ion feedback suppression in time projection chambers

Sauli

Ropelewski

Everaerts

2006

Nuclear Instruments and Methods in Physics Research Section A:

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A controlled-voltage Gas Electron Multiplier (GEM) can be used to block the re-injection of positive ions in large volume Time Projection Chambers. With proper choice of geometry, gas filling and external fields, good electron transmission can be obtained at very low GEM voltages; pulsed ion gating is then much easier than with conventional wire grids, requiring hundreds of volts. Gating schemes suited for the TPC detector planned for the International Linear Collider detector are described. The possibility of GEM-based DC-operated ion filters, exploiting the difference in diffusion properties of ions and electrons, is also discussed.

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“…Drifted electrons are collected on a low-capacitance anode surrounded by a field defining ring held at the same ground potential. An electron transparency of 100% is obtained by maintaining the anode-to-grid field, (E AG ), double in value with respect to the drift field, (E KG ) 10 , for all the measurements reported here. All data was collected at a LXe temperature of 169.2 ± 0.5 K and pressure of 990 +30 −50 Torr.…”

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confidence: 99%

Correlated Fluctuations between Luminescence and Ionization in Liquid Xenon

Bower¹

2003

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(EXO Collaboration)The ionization of liquefied noble gases by radiation is known to be accompanied by fluctuations much larger than predicted by Poisson statistics. We have studied the fluctuations of both scintillation and ionization in liquid xenon and have measured, for the first time, a strong anti-correlation between the two at a microscopic level, with coefficient −0.80 < ρep < −0.60. This provides direct experimental evidence that electron-ion recombination is partially responsible for the anomalously large fluctuations and at the same time allows substantial improvement of calorimetric energy resolution.The measurement of ionizing radiation in a liquiefied noble gas 1 such as Ar, Kr, or Xe can be characterized by two parameters: W e , the mean energy required to create a free electron-ion pair and the Fano factor, F e , which parameterizes the fluctuations in the number of ion pairs.2 The Fano factor is defined bywhere σ 2 e is the variance of the charge expressed in units of the electron charge, e, and N e is the number of ion pairs. F e = 1 corresponds to Poisson statistics. Fano originally predicted that the charge fluctuations would be sub-Poissonian, F e < 1, because the individual ion-pair creation processes are not independent once the additional constraint E = N e W e is included, where E is the energy deposited by the incident particle. The Fano factor for gaseous noble elements is relatively well understood, where for example the theory for argon predicts F e = 0.16 while experiment yields F e = 0.20. 3The Fano factor for the liquid phase has been far more difficult to understand, even though the values of W e are similar to those of the gas. The pioneering theoretical work of Doke 4 in 1976 predicted F e ≈ 0.05 for liquid Xe (LXe). Experiments, however, showed F e > 20, that is, a variance 20 times worse than Poissonian and 400 times worse than predicted by Fano's original argument. This discrepancy has not only raised important issues for the understanding of the phenomena of energy loss and conversion, but it is also of interest for experimental physics since this large Fano factor limits the resolution of calorimeters used in nuclear and particle physics.Luminescence light provides a second process, complementary to ionization, with which to study energy loss and conversion phenomena. The properties of luminescence light emitted by ionizing radiation (scintillation) in liquid Ar, Kr, and Xe detectors have been extensively studied and have been exploited in calorimetry 1,5 . As described elsewhere 6 , scintillation photons are produced by the relaxation of a xenon excimer, Xe * 2 → 2Xe + γ. The excimer is formed in two ways; 1) direct excitation by an energetic particle, 2) recombination of an electron with a xenon molecular ion, Xe7 . The electron-ion recombination rate depends upon the ionization density and the applied electric field. The quantities W p and F p can be defined in analogy with the ionization case, where W p is the mean energy absorbed per emitted photon and F p parameterize...

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Design of Grid Ionization Chambers

Cited by 333 publications

References 0 publications

A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization

Ion feedback suppression in time projection chambers

Correlated Fluctuations between Luminescence and Ionization in Liquid Xenon

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