The Time Projection Chamber (TPC) has been recognized as a potentially highly effective detector for the search of WIMPs by measuring the directions of nuclear recoils, by which probably the most convincing signature of WIMPs, brought on by the Earth’s motion across the Galaxy, appears. We report on the primary results of a performance examine of the neutron publicity of our prototype micro TPC with Ar-C2H6 (90:10) and CF4 gasoline at 150 Torr. These particles might be detected immediately by measuring the nuclear recoils produced by their elastic scattering off nuclei in detectors. Essentially the most convincing signature of WIMPs appears within the instructions of nuclear recoils. Since the power deposits of WIMPs to nuclei are only some tens of keV and the range of nuclei is limited, the micro-TPC needs to be operated at low pressures. In the current work, as a way to look at the response of the micro-TPC to nuclear recoils at low pressures as a primary step, we irradiated a 150 Torr Ar-C2H6 (90:10 mixture) gasoline (one among the usual gases for TPCs) and CF4 with neutrons from 252Cf. The track lengths and deposited energies of Ar, C, and F recoils have been investigated.
The prototype micro-TPC used on this measurements is proven in Fig.1. PIC and GEM. The details of this GEM are described in Refs. The pre-amplified alerts are summed and digitized by a hundred MHz 8bit flash ADCs in order to find out the deposited power and the observe route as the waveforms hold the Bragg curve shapes. Ar-C2H6 (90:10) or CF4 fuel to a stress of one hundred fifty Torr and sealed for the duration of the measurement. For measuring the fuel achieve and the power calibration, the fuel was irradiated with 109Cd 22 keV and 133Ba 31.Zero keV X-rays via a 1mm thick aluminum window near the sensitive volume. We irradiated the micro-TPC with neutrons from a 1 MBq 252Cf supply on the highest of the vessel. 2 cm3 plastic scintillator were used because the occasion set off. PIC and GEM with a slightly low fuel achieve (under 1000) as a way to observe the nuclear recoils.
PIC and adjusted the voltage between the GEM electrodes. Below a fuel gain of about 2000, our system was not in a position to measure the 109Cd 22 keV x-ray accurately resulting from a mismatch of the dynamic vary of the ASD chips and the flash ADC