A NEW SAMPLE CHAMBER WITH TEMPERATURE AND HUMIDITY CONTROL FOR LIPID AND FIBER S

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 为了在X射线测量过程中精确控制样品的相对湿度和温度环境，设计并建造了一种新的样品室。该设计基于反馈回路中的Peltier元件，每个控制参数都采用比例积分微分(PID)控制电子设备。这允许快速改变和可靠地控制密封室内的温度和湿度条件。初步调试和表征表明，控制机构工作正常，但优化三个独立控制回路的PID参数花费的时间比预期的要长。此外，测试表明，由于负责样品温度控制的Peltier元件的热交换效率不高，室内样品温度达到平衡的速度较慢，并显示出振荡的趋势。为此，设计并安装了一种新的水冷安装板，大大提高了样品温度的温度稳定性和稳定时间。该小室已经成功地用于光束线上的脂-蛋白质相互作用研究，并继续努力进一步优化控制的稳定性和准确性。PC可通过串口(RS232)访问控制电子设备，所有控制参数均可远程设置。我们正计划将密封室控制集成到DCS/BLU-Ice束流线软件中。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A new sample chamber has been designed and built to accurately control the relative air humidity and temperature environment of the sample during the x-ray measurement. The design is based on Peltier elements in a feed-back loop with Proportional Integral Differential (PID) control electronics for each of the control parameters. This allows for quickly changing and reliably controlling the temperature and humidity conditions inside the sealed chamber. Initial commissioning and characterization of the chamber showed that the control mechanism was working as anticipated, but it took longer than expected to optimize the PID parameters for the three independent control loops. Furthermore, the tests revealed that the sample temperature inside the chamber reached an equilibrium rather slowly and showed a tendency to oscillate due to inefficient heat exchange of the Peltier element responsible for the sample temperature control. Thus, a new water cooled mounting plate was designed and fitted to the chamber, which considerably improved the temperature stability and settling time for the sample temperature. The chamber has already successfully been used for lipid-protein interaction studies at the beamline, and efforts are continued to further optimize the stability and accuracy of the control. The control electronics is accessible by a PC through a serial port (RS232) and all the control parameters can be set remotely. We are planning to integrate the chamber control into the DCS/Blu-Ice beam line software.