Development of the windowless solid para hydrogen target

IRIS实验是在加拿大的TRIUMF进行的，它使用的是无窗口的固体氢(氚)靶。固体氢靶的厚度为50-100微米。在真空GM制冷机冷却温度低于4K的条件下，在纯银箔(t=5微米)表面喷洒室温氢气，生成固体氢薄膜。在本实验中，测量了靶内的束流能量损失，并对靶厚进行了监测。由于靶厚度在8-24小时内减半，因此重新创建了氢靶。在固体氘的情况下，用能量损失法不能观察到靶厚度的减少。

The IRIS-experiment using the windowless solid hydrogen (deuteron) target was conducted at TRIUMF in Canada. The thickness of the solid hydrogen target was 50-100 micron. Hydrogen gas at room temperature was sprayed on the surface of pure silver foil (t=5 micron) at lower than 4 K cooled by the GM-Cryocooler in the vacuum, and the solid hydrogen thin film was created. During this experiment, the beam energy loss in the target was measured and the target thickness was always monitored. Since the target thickness was halved in 8-24 hours, the hydrogen target was re-created. In the case of solid deuterium, the reduction of target thickness could not be observed by the energy loss method.