else if (pos.x < 0.7) mask.b = 1.0.;
The extra dot after 1.0 looks suspicious. 
Dr. Venom made a very nice job producing and documenting these:
"CRT Colors" for CRT-Guest-Dr-Venom -- Additional information.
3 x spec
2 x calibration
Specifications for three standards
1. EBU Standard Phosphors
// Amongst others used in Sony BVMs and Higher-end PVMs
// Tolerances are described in the E.B.U. standard reference document "E.B.U. standard for chromaticity tolerances for studio monitors" tech-3213-E.
// PVM-1440QM service manual quotes 0.01 as tolerance on the RGB CIE coordinates.
xb0 = "150.000000"
xg0 = "290.000000"
xr0 = "640.000000"
yb0 = "60.000000"
yg0 = "600.000000"
yr0 = "330.000000"
Whitepoint is D65
X 95,04 --> Xw0 950.4
Y 100 --> Yw0 1000
Z 108,88 --> Zw0 1088.8
2. P22 Phosphors
// These phosphors are often quoted as the "default" phosphors used in CRTs
// Also used in lower-end PVMs, see Sony PVM-20M4E 20M2E Colour Video Monitor.pdf
// These can still be bought :-) https://www.phosphor-technology.com/crt-phosphors/ -- includes CIE coordinates.
xb0 = "148.000000"
xg0 = "310.000000"
xr0 = "647.000000"
yb0 = "62.000000"
yg0 = "594.000000"
yr0 = "343.000000"
3. SMPTE-C
// Spec for most of America.
// I have forgone on the 1953 NTSC standard, as apart from very few early color TV's the 1953 NTSC standard was never actually used. Instead less saturated primaries were used to achieve brighter screens.
// Taken from the WIKI on NTSC (https://en.wikipedia.org/wiki/NTSC) In 1968-69 the Conrac Corp., working with RCA, defined a set of controlled phosphors for use in broadcast color picture video monitors. This specification survives today as the SMPTE "C" phosphor specification:
xb0 = "155.000000"
xg0 = "310.000000"
xr0 = "630.000000"
yb0 = "70.000000"
yg0 = "595.000000"
yr0 = "340.000000"
Whitepoint is D65
X 95,04 --> Xw0 950.4
Y 100 --> Yw0 1000
Z 108,88 --> Zw0 1088.8
4. Calibrated profile for Philips CRT monitors. Of course an approximation, but I'm pleased with the "quite accurate" results.
// Manually calibrated and compared to real Philips based CRT monitors, running side by side with the shader on a 10-bit DCI-P3 gamut panel. This calibrated CRT profile covers amongst others Philips CM8533, Philips VS-0080, and Commodore 1084.
// Note the whitepoint is significantly different from D65. It's closer to 6100K, but clearly not on the blackbody curve. Possibly an ISO-line target, given the slight hue on the whitepoint. Other than that it could be aging / whitepoint drift. I compared four CRT monitors, one of them in very mint condition, and they all have this slight hue on the whitepoint, so I would guess this is how they came out of the factory. But then again since these things are now getting close to 30 years old, who knows? Either way the profile should be good: factory out or true to life aged CRTs... :D.
// It's important this specific whitepoint is used in the shader or the colors will not be accurate.
// Also it's important to note that this profile should be used with "Gamma Out" at 2.25 or the colors will be less accurate.
xb0 = "154.000000"
xg0 = "300.000000"
xr0 = "635.000000"
yb0 = "60.000000"
yg0 = "620.000000"
yr0 = "339.000000"
Whitepoint:
Xw0 = "910.000000"
Yw0 = "1000.000000"
Zw0 = "960.000000"
5. Calibrated profile for Sony Trinitron Monitor.
// In a similar fashion as the Philips CRT based profile, this is a manually calibrated profile for a Sony Trinitron monitor, model KX-14CP1.
// This monitor uses a Whitepoint that is close to 9300K. The Z value in the calibration process has been raised to the point where the "blue-ishness" of the white matches. To achieve further 9300K white, I guess one has to raise the hardware whitepoint of the host PC monitor...
// It's important this specific whitepoint is used in the shader or the colors will not be accurate.
// Also it's important to note that this profile should be used with "Gamma Out" at 2.25 or the colors will be less accurate.
xb0 = "152.000000"
xg0 = "279.000000"
xr0 = "647.000000"
yb0 = "60.000000"
yg0 = "635.000000"
yr0 = "335.000000"
Whitepoint:
Xw0 = "903.000000"
Yw0 = "1000.000000"
Zw0 = "1185.000000"
Reference is the readme file in the /guest folder, also included with newer versions.
