| ホーム > CERN Experiments > Fixed Target Experiments > COMPASS > COMPASS Conference Proceedings > Performance of the COMPASS polarized target dilution refrigerator |
| Article | |
| Title | Performance of the COMPASS polarized target dilution refrigerator |
| Author(s) | Doshita, N ; Ball, J ; Baum, G ; Berglund, P ; Gautheron, F ; Görtz, S ; Gustafsson, K K ; Hasegawa, T ; Horikawa, N ; Ishimoto, S ; Iwata, T ; Kisselev, Yu V ; Koivuniemi, J H ; Kondo, K ; Matsuda, T ; Meyer, W ; Reicherz, G ; Takabayashi, N |
| Affiliation | (CERN) |
| Publication | 2004 |
| In: | Nucl. Instrum. Methods Phys. Res., A 526 (2004) 138-143 |
| DOI | 10.1016/j.nima.2004.03.164 |
| Subject category | Detectors and Experimental Techniques |
| Accelerator/Facility, Experiment | CERN SPS ; COMPASS NA58 |
| Abstract | The dynamic nuclear polarization (DNP) of **6LiD requires 1 mW/g or more microwave power in the beginning of the process. With the material of 350 g, this gives more than 350 mW in total for the COMPASS polarized target. A temperature around 300 mK or below is needed for an efficient polarization. These low temperatures can only be achieved with a dilution refrigerator designed to operate with a **3He flow of 100 mmol/s. In order to keep the polarization in the frozen mode, temperatures of about 65 mK are used with typical magnetic relaxation times of more than 1400 h at 0.42 T and of more than 15000 h at 2.5 T. Low lattice temperature is important in achieving high nuclear polarization. The base temperature is limited by the heat brought to the mixing chamber by the inlet **3He and by radiation and conduction of heat. |