Note to Reader

Refer to https://www.appropedia.org/Open_Source_Automated_Scanning_Monochromator for previous work done on this system

Background

Searches

Google Scholar for Open source hardware monochromator
Google for Monochromator for sale
Google for Monochromatization
Google for Monochromator collider

Journals

Monochromator and Monochromatization

From Wikipedia: [1]

"Monochromatization in the context of accelerator physics is a theoretical principle used to increase center-of-mass energy resolution in high-luminosity particle collisions."

From Source 5: [B. M et al., “A novel monochromator for experiments with ultrashort X-ray pulses,” Journal of Synchrotron Radiation, vol. 20, no. 4, pp. 522–530, 2013, doi: 10.1107/S0909049513008613.]

Monochromator is optical device
Can be used to focus signals from x-ray
Variable gratings depend on application (experimental conditions, target observation, etc)
First photons are separated based on wavelength, then filtered to only allow photons travelling at a specific wavelength reach the receiver

Current Market

From Source 2: [Delta Optical https://www.deltaopticalthinfilm.com/product-category/lvf/]

Delta offers 23 different monochromator filters, ranging from 100 EU to 2950 EU
Quote from representative:

From Source 3: [ HP Spectroscopy https://www.hp-spectroscopy.com/monolight]

monoLIGHT is used with lab VUV sources with 2 grating actuators
Quote from representative:

From Source 4: [MTS Newport https://www.newport.com/c/monochromators]

Available in variety of arrangments with fixed/adjustable slit holders, number of ports, and wavelength ranges
Anywhere from around $7000 to $16000

Design

From Source 1: [J. Cerino, J. Stöhr, N. Hower, and R. Z. Bachrach, “An ultra-high-vacuum double crystal monochromator beam line for studies in the spectral range 500–4000 eV,” Nuclear Instruments and Methods, vol. 172, no. 1, pp. 227–236, May 1980, doi: 10.1016/0029-554X(80)90639-4.]

From Source 4: [MTS Newport https://www.newport.com/c/monochromators]

Can vary number/adjustability of slits, wavelength range, grating type, and blaze wavelength

From Source 6: [D. J. Meier, “MONOCHROMATOR-TESTING SYSTEM,” p. 14.]

Designed an apparatus to shoot monochromatic light through a solution

From Source 7: [W. Freund et al., “First measurements with the K-monochromator at the European XFEL,” J Synchrotron Rad, vol. 26, no. 4, Art. no. 4, Jul. 2019, doi: 10.1107/S1600577519005307.]

Study used 3 devices in one apparatus (filter chamber, monochromator, and spontaneous radiation imager)
Schematic of monochromator in FIGURE 2
Contains a number of elements including shielding plate, chassis, Huber goniometer, Si(111) crystal, x-ray beam undulator, cooling/water cooling, 2nd stage, and 2-bounce/4-bounce beams

From Source 8: [R. Cimino, I. R. Collins, and V. Baglin, “VUV photoemission studies of candidate Large Hadron Collider vacuum chamber materials,” Phys. Rev. ST Accel. Beams, vol. 2, no. 6, p. 063201, Jun. 1999, doi: 10.1103/PhysRevSTAB.2.063201]

Monochromator used in this study simply had entry/exit slits and toroidal gratings
Schematic of monochromator in FIGURE 1

From Source 9: [2]

Entry and exit slits
Collimating mirror - forms a "parallel beam after the entry slit"
Camera mirror - directs light toward exit slit
Dispersive element (prism or grating)
- Prism is known for high light utilization efficiency, no higher order light, low stray light, and low polarization
- Gratings are known for high and consistent dependence on wavelength for dispersion and low temperature dependence of dispersion
Aligning Element (mounting)
- Typical mounts are - Littrow, Czerny-Turner, or Seya-Namioka (concave)
- Concave mounts require curved diffraction grating and eliminates need for collimating and camera mirrors (sacrifices resolution)
- Off-axis parabolic or spherical mirror does both collimate entering light and focus exiting light (Littrow)
- Two symmetrically placed spherical mirrors (Czerny-Turner)

From Source 10: [K. Ito, E. Haraguchi, K. Kaneshima, and T. Sekikawa, “Polarimetry of a single-order circularly polarized high harmonic separated by a time-delay compensated monochromator,” Opt. Express, vol. 27, no. 26, p. 38735, Dec. 2019, doi: 10.1364/OE.382423.]

Used 2 toroidal gratings and one slit, I think?
Schematic of apparatus in FIGURE 1

From Source 11: [E. Rubies and J. Palacín, “Design and FDM/FFF Implementation of a Compact Omnidirectional Wheel for a Mobile Robot and Assessment of ABS and PLA Printing Materials,” Robotics, vol. 9, no. 2, Art. no. 2, Jun. 2020, doi: 10.3390/robotics9020043.]

Found that using metallic bearings and U-grooved pieces proved cost effective (Design 1 in Table 1)
Possibly redesign lens mounts to fit into bearings

From Source 12: [C. J. Bruckner-Lea, M. S. Stottlemyre, D. A. Holman, J. W. Grate, F. J. Brockman, and D. P. Chandler, “Rotating Rod Renewable Microcolumns for Automated, Solid-Phase DNA Hybridization Studies,” Anal. Chem., vol. 72, no. 17, pp. 4135–4141, Sep. 2000, doi: 10.1021/ac000246m.]

Rotational movement may be better than axial
But how to relate rotation to angle that the "mirror" shifts and therefore the incident angle(?)

From Source 13: [“Friction performance of 3D printed ball bearing_ Feasibility study | Elsevier Enhanced Reader.” https://reader.elsevier.com/reader/sd/pii/S2211379717325196?token=A86958E20A5F1EB3ECDB689477204E23992EA68AC510D29E85D57751930C862DE3A369602D86126FBE984A3398296505 (accessed Sep. 23, 2020).]

Could we print bearings to help rotation

From Source 14: [T. C. Wilkes, A. J. S. McGonigle, J. R. Willmott, T. D. Pering, and J. M. Cook, “Low-cost 3D printed 1 nm resolution smartphone sensor-based spectrometer: instrument design and application in ultraviolet spectroscopy,” Opt. Lett., vol. 42, no. 21, p. 4323, Nov. 2017, doi: 10.1364/OL.42.004323.]

Maybe try a more simple box shape - forego the "L" shape
Crossed Czerny-Turner employed
Used UV-enhanced aluminum coated mirrors for focusing/collimating
Used UV-reflective holographic diffraction grating (1200 lines/mm)
Non adjustable slit dimensions
They got good sensitivity of detector by using R-Pi camera with removed Bayer filter
Using CD/DVD for grating provides less dispersion
0.2 MM TOLERANCE FOR SYSTEM HOUSING, but housing was made out of "laser sintering in graphite reinforced nylon" (quoted precision is +/-0.2 mm)
"Non-UV specific sensor design" (talking about spectrometer)
Bandwidth is resctricted by its compact form but could employ "multiple detectors"

From Source 15: [“Open-Source 3D-Printable Optics Equipment - ProQuest.” https://services.lib.mtu.edu:5003/docview/1330908576/fulltextPDF/3B84FB35CFB642E1PQ/1?accountid=28041 (accessed Sep. 23, 2020).]

Consider an indicator of current position of gratings(or incident angle)
Try to cut down on print/assembly time
Table 1 contains examples of cost savings

From Source 16: [X. Wang, S. Lu, and S. Zhang, “Rotating Angle Estimation for Hybrid Stepper Motors With Application to Bearing Fault Diagnosis,” IEEE Trans. Instrum. Meas., vol. 69, no. 8, pp. 5556–5568, Aug. 2020, doi: 10.1109/TIM.2019.2963582.]

Discusses hybrid stepper motor and rotating angle estimation

From Source 17: [3]

Discusses how to calculate rotation angle and speed in a stepper motor

From Source 18: [“Comparison of Low Cost Miniature Spectrometers for Volcanic SO2 Emission Measurements - ProQuest.” https://services.lib.mtu.edu:5003/docview/1537510944?accountid=28041 (accessed Sep. 23, 2020).]

Both traditional and crossed Czerny-Turner configurations shown in FIGURE 1
Their "non-folded" or traditional configuration yielded better performance
Used cylindrical lense for focusing mirror "to enhance signal to noise ratio"
Simplified explanation of spectrometer in section 2

Opportunity

Prism: I'd like to add "cutouts" to box for prism to sit into and be secure when box is closed; pay attention to tolerances(?)
Grating
Remote adjustments for
- Slits
- Mounting: Look to improve rotation of diffraction grating via mechanical structure; verify how much to turn stepper per nm wavelength...(do some math?); figure out if their code/motor/gears actually shift the grating

Application

From Source 1: [J. Cerino, J. Stöhr, N. Hower, and R. Z. Bachrach, “An ultra-high-vacuum double crystal monochromator beam line for studies in the spectral range 500–4000 eV,” Nuclear Instruments and Methods, vol. 172, no. 1, pp. 227–236, May 1980, doi: 10.1016/0029-554X(80)90639-4.]

From Source 2: [Delta Optical https://www.deltaopticalthinfilm.com/applications/lvf-monochromators/]

"Flourescence microplate readers" and "Supercontinuum lasers"